Your FREE USMLE Step 3 Practice Test 2026 – 950+ Q&A

USMLE Step 3 Practice Questions

1. A 24-year-old woman with anorexia nervosa is admitted weighing 38 kg. Nutrition is being planned. According to current refeeding guidance, what initial caloric strategy minimizes her risk of life-threatening electrolyte shifts?
   • Start at full estimated energy needs on day one
   • Give a single high-calorie meal then fast
   • Start at roughly 10 to 20 kcal/kg/day and advance over several days
   • Withhold all feeding for 72 hours

   Correct answer: Start at roughly 10 to 20 kcal/kg/day and advance over several days

   The answer is to start at roughly 10 to 20 kcal/kg/day and advance over several days. Conservative initial calories with slow advancement limits the insulin-driven intracellular electrolyte shifts that cause refeeding syndrome.

2. A malnourished man develops a phosphate of 0.9 mg/dL on the second day of feeds. Which cardiac consequence of severe hypophosphatemia in refeeding syndrome is most concerning?
   • Impaired myocardial contractility and arrhythmia
   • Aortic dissection
   • Pericardial calcification
   • Accelerated coronary atherosclerosis

   Correct answer: Impaired myocardial contractility and arrhythmia

   The answer is impaired myocardial contractility and arrhythmia. Phosphate is needed for ATP, so severe hypophosphatemia weakens the myocardium and predisposes to dangerous arrhythmias during refeeding.

3. In refeeding syndrome, the reintroduction of carbohydrate triggers a surge of which hormone that drives electrolytes into cells?
   • Insulin
   • Aldosterone
   • Glucagon
   • Cortisol

   Correct answer: Insulin

   The answer is insulin. Carbohydrate refeeding stimulates insulin, which shifts phosphate, potassium, and magnesium intracellularly, producing the hallmark deficiencies of refeeding syndrome.

4. A patient at high refeeding risk is identified. Which combination is the strongest indication to give thiamine before starting carbohydrate calories?
   • Isolated mild hypertension
   • Prolonged poor intake plus chronic alcohol use
   • A single missed meal
   • Recent normal diet with mild dehydration

   Correct answer: Prolonged poor intake plus chronic alcohol use

   The answer is prolonged poor intake plus chronic alcohol use. Both deplete thiamine, so a carbohydrate load could precipitate Wernicke encephalopathy unless thiamine is given first.

5. A chronically starved patient is being refed. Which laboratory value should be checked and corrected before initiating calories to reduce refeeding risk?
   • Serum phosphate, potassium, and magnesium
   • Serum amylase only
   • Serum bilirubin only
   • Serum uric acid only

   Correct answer: Serum phosphate, potassium, and magnesium

   The answer is serum phosphate, potassium, and magnesium. Baseline correction of these electrolytes before feeding reduces the danger of refeeding syndrome.

6. A patient recovering from prolonged fasting develops sudden peripheral edema and fluid overload during refeeding. Which mechanism best explains the fluid retention seen in refeeding syndrome?
   • Insulin-mediated sodium and water retention
   • Loss of renal sodium reabsorption
   • Aldosterone deficiency
   • Excess free-water loss

   Correct answer: Insulin-mediated sodium and water retention

   The answer is insulin-mediated sodium and water retention. The insulin surge of refeeding promotes renal sodium and water retention, which can cause edema and even heart failure.

7. A 49-year-old man with alcohol use disorder has confusion and gait instability. MRI would most likely show abnormal signal in which structures affected by thiamine deficiency?
   • Cerebellar tonsils
   • Mammillary bodies and periaqueductal gray
   • Caudate nucleus
   • Frontal white matter only

   Correct answer: Mammillary bodies and periaqueductal gray

   The answer is the mammillary bodies and periaqueductal gray. Thiamine deficiency in Wernicke encephalopathy characteristically damages these periventricular diencephalic structures.

8. A patient with chronic alcohol use is started on intravenous fluids in the emergency department. To prevent precipitating Wernicke encephalopathy, which fluid choice is most appropriate?
   • Pure dextrose bolus before labs
   • Dextrose 5% alone given rapidly
   • Half-normal saline with extra dextrose
   • Thiamine added before or with any dextrose-containing fluid

   Correct answer: Thiamine added before or with any dextrose-containing fluid

   The answer is thiamine added before or with any dextrose-containing fluid. Giving dextrose to a thiamine-deficient patient can trigger Wernicke encephalopathy, so thiamine must precede or accompany glucose.

9. A patient with confirmed Wernicke encephalopathy is treated. Which route and dosing of thiamine is recommended for acute treatment?
   • Topical thiamine
   • High-dose intravenous thiamine
   • A single low oral dose
   • Thiamine only after symptoms resolve

   Correct answer: High-dose intravenous thiamine

   The answer is high-dose intravenous thiamine. Acute Wernicke encephalopathy requires prompt high-dose parenteral thiamine because oral absorption is unreliable and delay risks permanent injury.

10. A patient after bariatric surgery with persistent vomiting develops nystagmus, confusion, and ataxia. Which deficiency should be treated immediately even before laboratory confirmation?
    • Vitamin K deficiency
    • Selenium deficiency
    • Thiamine deficiency
    • Vitamin C deficiency

    Correct answer: Thiamine deficiency

    The answer is thiamine deficiency. Post-bariatric vomiting can rapidly deplete thiamine and cause Wernicke encephalopathy, so empiric thiamine is given without waiting for levels.

11. Which dietary or clinical setting, besides alcohol use, is a recognized cause of thiamine deficiency leading to Wernicke encephalopathy?
    • Routine multivitamin use
    • Hyperemesis gravidarum with prolonged vomiting
    • A high-protein bodybuilding diet
    • Excess citrus intake

    Correct answer: Hyperemesis gravidarum with prolonged vomiting

    The answer is hyperemesis gravidarum with prolonged vomiting. Severe pregnancy-related vomiting depletes thiamine and can cause Wernicke encephalopathy, requiring thiamine repletion.

12. A patient with pernicious anemia is treated. Which route of vitamin B12 is most reliable when intrinsic factor is absent?
    • Topical B12 cream
    • Intramuscular cyanocobalamin injection
    • Inhaled B12
    • Standard low-dose oral B12 once weekly

    Correct answer: Intramuscular cyanocobalamin injection

    The answer is intramuscular cyanocobalamin injection. Without intrinsic factor, normal oral absorption fails, so parenteral B12 reliably corrects pernicious anemia.

13. A patient with vitamin B12 deficiency begins replacement therapy. Which electrolyte should be monitored closely as new red cells are produced rapidly?
    • Chloride
    • Sodium
    • Potassium
    • Bicarbonate

    Correct answer: Potassium

    The answer is potassium. Brisk erythropoiesis after B12 replacement can drive hypokalemia as cells take up potassium, so it should be monitored during recovery.

14. A vegan patient with B12 deficiency asks how the body normally stores this vitamin. Which statement about vitamin B12 stores is correct?
    • The body holds no B12 reserve
    • Stores are depleted within days of poor intake
    • B12 is stored mainly in adipose tissue
    • Hepatic stores are large and deficiency takes years to develop

    Correct answer: Hepatic stores are large and deficiency takes years to develop

    The answer is that hepatic stores are large and deficiency takes years to develop. Because the liver holds several years of B12, dietary deficiency manifests slowly.

15. A patient with a fish tapeworm infection (Diphyllobothrium latum) develops macrocytic anemia. Which mechanism explains the resulting B12 deficiency?
    • The parasite competes for dietary vitamin B12
    • The parasite increases renal B12 loss
    • The parasite destroys intrinsic factor
    • The parasite blocks folate absorption

    Correct answer: The parasite competes for dietary vitamin B12

    The answer is that the parasite competes for dietary vitamin B12. The fish tapeworm consumes ingested B12 in the gut, leading to deficiency and megaloblastic anemia.

16. A patient with suspected B12 deficiency has a normal serum B12 but clear clinical features. Which finding would best confirm true intracellular B12 deficiency?
    • Low alkaline phosphatase
    • Elevated serum calcium
    • Elevated serum methylmalonic acid
    • Low serum ferritin

    Correct answer: Elevated serum methylmalonic acid

    The answer is elevated serum methylmalonic acid. Methylmalonic acid accumulates specifically in B12 deficiency and confirms it when the serum B12 is equivocal.

17. A general-population woman capable of becoming pregnant asks about folic acid. What daily folic acid amount is recommended for routine neural tube defect prevention?
    • About 10 milligrams daily
    • Zero, dietary folate is always sufficient
    • About 400 micrograms daily
    • Only after the first trimester

    Correct answer: About 400 micrograms daily

    The answer is about 400 micrograms daily. Routine periconceptional folic acid at this dose lowers neural tube defect risk for average-risk women.

18. A patient with sickle cell disease has high red cell turnover. Why is routine folic acid supplementation often recommended in this condition?
    • Increased erythropoiesis raises folate demand
    • Folate replaces hydroxyurea
    • Folate lowers bilirubin
    • Folate prevents sickling directly

    Correct answer: Increased erythropoiesis raises folate demand

    The answer is that increased erythropoiesis raises folate demand. Chronic hemolysis and rapid red cell production deplete folate, so supplementation prevents megaloblastic crisis.

19. A pregnant patient is taking trimethoprim, which interferes with folate. Why is this a concern during pregnancy?
    • It has no effect on folate
    • It increases folate absorption excessively
    • It converts folate to B12
    • It inhibits dihydrofolate reductase and can promote folate deficiency

    Correct answer: It inhibits dihydrofolate reductase and can promote folate deficiency

    The answer is that it inhibits dihydrofolate reductase and can promote folate deficiency. Antifolate drugs in pregnancy raise the risk of folate-related fetal harm, so they are generally avoided early.

20. A folate-deficient patient has macrocytic anemia. Which finding distinguishes pure folate deficiency from B12 deficiency?
    • Presence of dorsal column signs
    • Absence of neurologic deficits
    • Elevated methylmalonic acid
    • Hypersegmented neutrophils are absent

    Correct answer: Absence of neurologic deficits

    The answer is the absence of neurologic deficits. Folate deficiency causes megaloblastic anemia without the neurologic damage characteristic of B12 deficiency.

21. Which biochemical reaction explains why folate deficiency raises homocysteine?
    • Increased renal homocysteine reabsorption
    • Excess conversion of methionine to cysteine
    • Impaired remethylation of homocysteine to methionine
    • Blocked methylmalonyl-CoA mutase

    Correct answer: Impaired remethylation of homocysteine to methionine

    The answer is impaired remethylation of homocysteine to methionine. Folate provides the methyl group for this conversion, so its deficiency raises homocysteine.

22. A patient on long-term parenteral nutrition develops a microcytic anemia despite iron in the formula plus a depigmented skin and neurologic changes. Deficiency of which trace element is most likely?
    • Copper
    • Iodine
    • Selenium
    • Chromium

    Correct answer: Copper

    The answer is copper. Copper deficiency in parenteral nutrition causes anemia, neutropenia, depigmentation, and myeloneuropathy, distinct from iron deficiency.

23. A patient receiving parenteral nutrition develops impaired glucose tolerance and a peripheral neuropathy attributed to a missing trace element involved in insulin action. Which element is most likely deficient?
    • Zinc
    • Copper
    • Fluoride
    • Chromium

    Correct answer: Chromium

    The answer is chromium. Chromium deficiency in long-term parenteral nutrition can impair glucose tolerance because chromium contributes to insulin action.

24. A patient on parenteral nutrition is found to have metabolic bone disease after years of therapy. Which complication of long-term parenteral nutrition does this represent?
    • Vitamin A toxicity
    • Hemochromatosis
    • Acute gout
    • Parenteral nutrition-associated metabolic bone disease

    Correct answer: Parenteral nutrition-associated metabolic bone disease

    The answer is parenteral nutrition-associated metabolic bone disease. Prolonged parenteral nutrition can cause osteopenia and osteomalacia from altered mineral and vitamin D handling.

25. When transitioning a patient from parenteral nutrition back to enteral feeding, which approach is most appropriate?
    • Stop parenteral nutrition abruptly once any oral intake begins
    • Withhold enteral feeds until parenteral nutrition is fully stopped
    • Overlap and taper parenteral nutrition as enteral intake increases
    • Double the dextrose before stopping

    Correct answer: Overlap and taper parenteral nutrition as enteral intake increases

    The answer is to overlap and taper parenteral nutrition as enteral intake increases. Gradual transition maintains nutrition and avoids rebound hypoglycemia from abrupt discontinuation.

26. A patient on parenteral nutrition with excessive carbohydrate calories develops a rising carbon dioxide and difficulty weaning from the ventilator. Which metabolic effect of carbohydrate overfeeding explains this?
    • Decreased metabolic rate
    • Increased carbon dioxide production from lipogenesis
    • Reduced oxygen consumption to zero
    • Loss of all carbohydrate metabolism

    Correct answer: Increased carbon dioxide production from lipogenesis

    The answer is increased carbon dioxide production from lipogenesis. Overfeeding carbohydrate raises carbon dioxide output, which can hinder ventilator weaning, so calories should be balanced.

27. A dark-skinned patient living at high latitude with little sun exposure is at risk for vitamin D deficiency. Which mechanism explains the increased risk with darker skin?
    • Dark skin blocks intestinal vitamin D absorption
    • Melanin raises renal vitamin D excretion
    • Melanin increases vitamin D destruction in the liver
    • Melanin reduces cutaneous vitamin D synthesis from sunlight

    Correct answer: Melanin reduces cutaneous vitamin D synthesis from sunlight

    The answer is that melanin reduces cutaneous vitamin D synthesis from sunlight. Greater skin pigmentation requires more sun for the same vitamin D production, raising deficiency risk at high latitudes.

28. A patient with osteomalacia from vitamin D deficiency has a characteristic radiographic finding. Which finding is most specific for osteomalacia?
    • Looser zones (pseudofractures)
    • Periosteal new bone over joints
    • Bamboo spine
    • Punched-out lytic lesions

    Correct answer: Looser zones (pseudofractures)

    The answer is Looser zones, or pseudofractures. These ribbon-like lucencies of unmineralized osteoid are characteristic of osteomalacia from vitamin D deficiency.

29. A patient with malabsorption is repleted with vitamin D. Which laboratory change confirms an appropriate response over the following weeks?
    • Worsening hypophosphatemia
    • Rising 25-hydroxyvitamin D with normalizing parathyroid hormone
    • Rising alkaline phosphatase indefinitely
    • Falling serum calcium toward zero

    Correct answer: Rising 25-hydroxyvitamin D with normalizing parathyroid hormone

    The answer is rising 25-hydroxyvitamin D with normalizing parathyroid hormone. Successful repletion raises stores and corrects the secondary hyperparathyroidism of deficiency.

30. A breastfed infant who is dark-skinned and rarely outdoors develops widened wrists and a rachitic rosary. Which intervention best prevents and treats this nutritional bone disease?
    • High-dose vitamin A
    • Vitamin D supplementation
    • Iron supplementation
    • Phosphate restriction

    Correct answer: Vitamin D supplementation

    The answer is vitamin D supplementation. Nutritional rickets in this infant reflects vitamin D deficiency, prevented and treated with vitamin D and adequate calcium.

31. Which dietary sources are the most reliable natural contributors of vitamin D for a patient with limited sun exposure?
    • Citrus fruits
    • Leafy green vegetables
    • Whole grains
    • Fatty fish and fortified milk

    Correct answer: Fatty fish and fortified milk

    The answer is fatty fish and fortified milk. These provide meaningful dietary vitamin D, which matters when cutaneous synthesis from sunlight is inadequate.

32. A patient with scurvy is treated. Beyond bleeding gums, which hematologic finding can accompany vitamin C deficiency?
    • Polycythemia
    • Thrombocytosis
    • Anemia, partly from impaired iron absorption
    • Leukemoid reaction

    Correct answer: Anemia, partly from impaired iron absorption

    The answer is anemia, partly from impaired iron absorption. Vitamin C deficiency causes anemia through bleeding and reduced nonheme iron absorption.

33. A young child fed an extremely restricted diet develops painful pseudoparalysis from subperiosteal hemorrhage and bleeding gums. Which deficiency is most likely?
    • Iron deficiency
    • Vitamin C deficiency
    • Vitamin D deficiency
    • Vitamin B12 deficiency

    Correct answer: Vitamin C deficiency

    The answer is vitamin C deficiency. Infantile scurvy causes painful subperiosteal bleeding and gum changes from defective collagen.

34. A child with measles in a low-resource setting is at risk of severe complications. Supplementation with which vitamin reduces measles morbidity and mortality?
    • Vitamin A
    • Vitamin E
    • Vitamin C
    • Vitamin K

    Correct answer: Vitamin A

    The answer is vitamin A. Vitamin A supplementation reduces complications and mortality in childhood measles, especially where deficiency is common.

35. A patient with chronic fat malabsorption develops difficulty seeing in dim light as the earliest symptom. Which deficiency explains this presentation?
    • Zinc deficiency causing isolated night blindness
    • Vitamin A deficiency
    • Vitamin K deficiency
    • Folate deficiency

    Correct answer: Vitamin A deficiency

    The answer is vitamin A deficiency. Night blindness is the earliest manifestation because vitamin A is required for rod photopigment regeneration.

36. A pregnant patient asks which form of vitamin A in foods does NOT carry the teratogenic risk of high-dose preformed retinol. Which is correct?
    • Beta-carotene from plant foods
    • Liver consumed in large amounts
    • High-dose retinol supplements
    • Prescription isotretinoin

    Correct answer: Beta-carotene from plant foods

    The answer is beta-carotene from plant foods. Provitamin A carotenoids are converted as needed and lack the teratogenic risk of high-dose preformed retinoids.

37. A patient on high-dose vitamin A develops headaches and papilledema with normal imaging. Which condition does excess vitamin A characteristically mimic?
    • Acute glaucoma
    • Idiopathic intracranial hypertension
    • Subdural hematoma
    • Bacterial meningitis

    Correct answer: Idiopathic intracranial hypertension

    The answer is idiopathic intracranial hypertension. Vitamin A toxicity can raise intracranial pressure, producing headache and papilledema resembling pseudotumor cerebri.

38. A patient with prolonged antibiotic use and poor intake develops a prolonged prothrombin time that corrects after vitamin administration. Which mechanism links antibiotics to this deficiency?
    • Suppression of gut bacteria that synthesize vitamin K
    • Increased renal vitamin K loss
    • Direct destruction of clotting factors
    • Blocked dietary vitamin C

    Correct answer: Suppression of gut bacteria that synthesize vitamin K

    The answer is suppression of gut bacteria that synthesize vitamin K. Broad-spectrum antibiotics reduce intestinal vitamin K production, and with poor intake this can cause deficiency.

39. A newborn whose parents declined the vitamin K injection presents at five weeks with intracranial hemorrhage. This late hemorrhagic disease of the newborn is best prevented by which intervention?
    • Vitamin C drops weekly
    • Intramuscular vitamin K at birth
    • Folate supplementation
    • Iron drops at birth

    Correct answer: Intramuscular vitamin K at birth

    The answer is intramuscular vitamin K at birth. The routine injection prevents both early and late vitamin K deficiency bleeding in the newborn.

40. A patient with Hartnup disease develops a pellagra-like rash and ataxia. Which mechanism links this disorder to niacin deficiency?
    • Excess niacin destruction in the gut
    • Defective tryptophan absorption reduces niacin synthesis
    • Impaired vitamin K absorption
    • Increased renal niacin loss only

    Correct answer: Defective tryptophan absorption reduces niacin synthesis

    The answer is defective tryptophan absorption reduces niacin synthesis. Hartnup disease impairs neutral amino acid transport, lowering tryptophan available for niacin production.

41. A patient treated for tuberculosis develops a pellagra-like dermatitis. Which drug can precipitate niacin deficiency by interfering with its synthesis from tryptophan?
    • Rifampin
    • Pyrazinamide
    • Isoniazid
    • Ethambutol

    Correct answer: Isoniazid

    The answer is isoniazid. Isoniazid interferes with vitamin B6, a cofactor for niacin synthesis from tryptophan, and can contribute to pellagra-like symptoms.

42. A patient on isoniazid is also at risk for which hematologic problem from vitamin B6 deficiency, in addition to neuropathy?
    • Sideroblastic anemia
    • Macrocytic megaloblastic anemia
    • Hemolytic anemia
    • Polycythemia

    Correct answer: Sideroblastic anemia

    The answer is sideroblastic anemia. Vitamin B6 is needed for heme synthesis, so its deficiency, as with isoniazid, can cause sideroblastic anemia along with neuropathy.

43. A patient taking high-dose pyridoxine supplements over a long period develops a sensory neuropathy. What does this illustrate about vitamin B6?
    • Pyridoxine only affects clotting
    • Excess pyridoxine can itself cause a sensory neuropathy
    • Pyridoxine has no toxicity
    • Pyridoxine deficiency cannot cause neuropathy

    Correct answer: Excess pyridoxine can itself cause a sensory neuropathy

    The answer is that excess pyridoxine can itself cause a sensory neuropathy. Both deficiency and high-dose excess of vitamin B6 can produce peripheral neuropathy.

44. A premenopausal woman with iron deficiency anemia is repleted with oral iron. Which finding best confirms an early treatment response within two weeks?
    • An immediate normalization of hemoglobin
    • A rise in ferritin to normal within days
    • A fall in mean corpuscular volume to microcytic immediately
    • A reticulocytosis

    Correct answer: A reticulocytosis

    The answer is a reticulocytosis. An early reticulocyte rise signals the marrow is responding to iron repletion before hemoglobin fully normalizes.

45. A patient cannot tolerate oral iron due to gastrointestinal side effects and has ongoing losses. Which alternative is most appropriate for repletion?
    • Vitamin B12 injections
    • Intravenous iron
    • Folic acid alone
    • Erythropoietin without iron

    Correct answer: Intravenous iron

    The answer is intravenous iron. When oral iron is not tolerated or absorbed, intravenous iron reliably replenishes stores.

46. A patient with iron deficiency and concurrent achlorhydria from acid suppression absorbs oral iron poorly. Which mechanism explains the impaired absorption?
    • Acid suppression increases hepcidin only
    • Iron binds intrinsic factor
    • Iron is destroyed by low acid
    • Reduced gastric acid limits reduction of iron to the absorbable ferrous form

    Correct answer: Reduced gastric acid limits reduction of iron to the absorbable ferrous form

    The answer is that reduced gastric acid limits reduction of iron to the absorbable ferrous form. Acid aids conversion of ferric to ferrous iron, so achlorhydria impairs nonheme iron absorption.

47. A pregnant patient screened in the second trimester has a low hemoglobin and low ferritin. Which is the most appropriate management of this iron deficiency?
    • Folate alone
    • Vitamin B12 injections
    • Oral iron supplementation
    • No treatment until postpartum

    Correct answer: Oral iron supplementation

    The answer is oral iron supplementation. Iron deficiency anemia in pregnancy is treated with iron to meet the increased demands of pregnancy.

48. A public health program adds iodine to table salt in a deficient region. Which condition is this intervention most designed to prevent?
    • Rickets
    • Endemic goiter and congenital hypothyroidism
    • Scurvy
    • Dental fluorosis

    Correct answer: Endemic goiter and congenital hypothyroidism

    The answer is endemic goiter and congenital hypothyroidism. Salt iodization corrects iodine deficiency, preventing goiter and the neurodevelopmental harm of fetal hypothyroidism.

49. Which laboratory pattern would you expect in a patient with simple iodine-deficiency goiter and resulting mild hypothyroidism?
    • Elevated TSH with low or low-normal thyroid hormone
    • Elevated calcitonin
    • Normal TSH with high calcium
    • Suppressed TSH with high thyroid hormone

    Correct answer: Elevated TSH with low or low-normal thyroid hormone

    The answer is elevated TSH with low or low-normal thyroid hormone. Iodine deficiency limits hormone synthesis, raising TSH and driving goiter.

50. An infant with the inherited disorder acrodermatitis enteropathica develops a perioral and acral rash, diarrhea, and alopecia. Deficiency of which mineral underlies this condition?
    • Magnesium
    • Copper
    • Zinc
    • Selenium

    Correct answer: Zinc

    The answer is zinc. Acrodermatitis enteropathica is a defect in zinc absorption, producing the classic perioral and acral dermatitis, diarrhea, and alopecia, treated with zinc.

51. A patient with poor wound healing and an impaired sense of taste and smell is found to have a nutritional cause. Deficiency of which mineral classically causes impaired taste and delayed healing?
    • Fluoride
    • Zinc
    • Iodine
    • Chromium

    Correct answer: Zinc

    The answer is zinc. Zinc deficiency impairs taste and smell and delays wound healing, reflecting zinc's role in many enzymes.

52. A patient with hypocalcemia from poor intake has a positive Chvostek sign. What does eliciting this sign demonstrate?
    • Decreased neuromuscular excitability
    • Magnesium excess
    • High serum calcium
    • Increased neuromuscular excitability from low calcium

    Correct answer: Increased neuromuscular excitability from low calcium

    The answer is increased neuromuscular excitability from low calcium. Tapping the facial nerve produces twitching because hypocalcemia heightens nerve and muscle excitability.

53. A patient with chronic low calcium intake develops secondary hyperparathyroidism. Which compensatory change drives this response?
    • Vitamin D falls to lower calcium
    • Parathyroid hormone falls to retain bone
    • Parathyroid hormone rises to mobilize calcium from bone
    • Calcitonin rises to raise calcium

    Correct answer: Parathyroid hormone rises to mobilize calcium from bone

    The answer is that parathyroid hormone rises to mobilize calcium from bone. Low dietary calcium stimulates parathyroid hormone, which raises serum calcium at the expense of bone.

54. A patient on a potassium-restricted diet for kidney disease accidentally uses a salt substitute and becomes hyperkalemic. Why did this occur?
    • Salt substitutes contain extra sodium
    • Salt substitutes are pure water
    • Salt substitutes often replace sodium with potassium chloride
    • Salt substitutes add calcium

    Correct answer: Salt substitutes often replace sodium with potassium chloride

    The answer is that salt substitutes often replace sodium with potassium chloride. In a patient who cannot excrete potassium, these products can cause dangerous hyperkalemia.

55. A patient with hypokalemia from poor intake and vomiting is repleted. Which coexisting deficiency must also be corrected for potassium to normalize?
    • Vitamin C deficiency
    • Folate deficiency
    • Iron deficiency
    • Magnesium deficiency

    Correct answer: Magnesium deficiency

    The answer is magnesium deficiency. Hypomagnesemia promotes renal potassium wasting, so potassium often will not correct until magnesium is also repleted.

56. A patient with stage 1 hypertension wants to lower blood pressure with diet. Which dietary change has the strongest evidence for reducing blood pressure?
    • Adopting the DASH eating pattern with reduced sodium
    • Adding more table salt
    • Increasing processed meat intake
    • Eliminating all dietary potassium

    Correct answer: Adopting the DASH eating pattern with reduced sodium

    The answer is adopting the DASH eating pattern with reduced sodium. The combination of the DASH diet and sodium reduction produces meaningful blood pressure lowering.

57. A patient asks how much daily sodium is generally recommended as an upper limit for blood pressure control. Which figure is most appropriate to counsel?
    • About 6,000 mg per day
    • Less than about 2,300 mg per day, with greater benefit nearer 1,500 mg
    • Sodium has no limit
    • At least 5,000 mg per day

    Correct answer: Less than about 2,300 mg per day, with greater benefit nearer 1,500 mg

    The answer is less than about 2,300 mg per day, with greater benefit nearer 1,500 mg. Reducing sodium within these ranges helps lower blood pressure.

58. A clinician documents malnutrition in a hospitalized patient. Which pair of findings is part of the consensus diagnostic criteria for malnutrition?
    • High white count and fever
    • Reduced energy intake and loss of muscle mass
    • Elevated blood pressure and tachycardia
    • Elevated glucose and lipids

    Correct answer: Reduced energy intake and loss of muscle mass

    The answer is reduced energy intake and loss of muscle mass. Diagnostic criteria for malnutrition include inadequate intake, weight loss, and loss of muscle and fat.

59. A patient is being assessed for sarcopenia. Which finding best characterizes this nutrition-related condition of aging?
    • Excess fluid retention
    • Increased bone density
    • Gain of fat mass only
    • Loss of skeletal muscle mass and strength

    Correct answer: Loss of skeletal muscle mass and strength

    The answer is loss of skeletal muscle mass and strength. Sarcopenia is the age- and nutrition-related decline in muscle mass and function.

60. A clinician wants a bedside measure that reflects loss of subcutaneous fat and muscle in malnutrition. Which assessment is most appropriate?
    • A single random glucose
    • A chest radiograph
    • A focused nutrition-oriented physical exam of muscle and fat stores
    • An electrocardiogram

    Correct answer: A focused nutrition-oriented physical exam of muscle and fat stores

    The answer is a focused nutrition-oriented physical exam of muscle and fat stores. Examining temporal, clavicular, and other regions for wasting is central to diagnosing malnutrition.

61. A child with marasmus is contrasted with one who has kwashiorkor. Which feature best characterizes marasmus?
    • Severe wasting of muscle and fat without edema
    • Macrocytic anemia as the defining sign
    • Excess weight gain
    • Generalized edema with fatty liver

    Correct answer: Severe wasting of muscle and fat without edema

    The answer is severe wasting of muscle and fat without edema. Marasmus reflects total energy deprivation with profound wasting, distinguishing it from edematous kwashiorkor.

62. A severely malnourished child with kwashiorkor is refed. Which complication must be anticipated during early nutritional rehabilitation?
    • Hypertensive emergency
    • Rapid healthy weight gain without risk
    • Iron overload
    • Refeeding syndrome with electrolyte shifts

    Correct answer: Refeeding syndrome with electrolyte shifts

    The answer is refeeding syndrome with electrolyte shifts. Severely malnourished children are at high risk of refeeding syndrome, so calories are advanced cautiously with electrolyte monitoring.

63. A patient with a BMI of 32 and type 2 diabetes is started on a weight-management plan. Which medication class both improves glucose and produces meaningful weight loss?
    • Beta-blockers
    • Thiazide diuretics
    • GLP-1 receptor agonists
    • Sulfonylureas

    Correct answer: GLP-1 receptor agonists

    The answer is GLP-1 receptor agonists. These agents lower glucose and produce substantial weight loss, making them useful in obesity with type 2 diabetes.

64. A patient asks what magnitude of energy deficit generally produces about half a kilogram of fat loss per week. Which approximate daily deficit is correct?
    • No deficit is needed
    • About a 3,000 kcal/day deficit
    • About a 50 kcal/day deficit
    • About a 500 kcal/day deficit

    Correct answer: About a 500 kcal/day deficit

    The answer is about a 500 kcal/day deficit. A daily deficit near 500 kcal corresponds to roughly half a kilogram of fat loss per week.

65. A clinician counsels a patient on sustainable weight management. Which behavioral element most predicts long-term maintenance of weight loss?
    • Avoiding all follow-up
    • Ongoing self-monitoring of intake and activity
    • Brief crash dieting only
    • Eliminating an entire macronutrient permanently

    Correct answer: Ongoing self-monitoring of intake and activity

    The answer is ongoing self-monitoring of intake and activity. Continued self-monitoring and support are strongly associated with maintaining weight loss.

66. A patient years after sleeve gastrectomy develops fatigue and a low ferritin. Which mechanism best explains iron deficiency after this procedure?
    • Iron destruction in the stomach pouch
    • Excess dietary iron
    • Increased iron excretion in urine
    • Reduced acid and intake impair iron absorption

    Correct answer: Reduced acid and intake impair iron absorption

    The answer is that reduced acid and intake impair iron absorption. Bariatric surgery lowers acid and food volume, reducing iron absorption and risking deficiency.

67. A patient after Roux-en-Y gastric bypass develops neurologic symptoms and macrocytosis. Which supplement deficiency is the most likely culprit and should be replaced?
    • Chloride
    • Vitamin C
    • Sodium
    • Vitamin B12

    Correct answer: Vitamin B12

    The answer is vitamin B12. Bypass reduces acid and intrinsic factor function, impairing B12 absorption and causing deficiency that requires supplementation.

68. A patient after gastric bypass who skips supplements develops dumping syndrome after sugary meals. Which dietary advice best reduces these symptoms?
    • Eat fewer but very large meals
    • Drink large volumes with meals
    • Increase simple sugar intake
    • Eat small meals low in simple sugars and separate fluids from solids

    Correct answer: Eat small meals low in simple sugars and separate fluids from solids

    The answer is to eat small meals low in simple sugars and separate fluids from solids. This dietary modification reduces rapid carbohydrate delivery and dumping symptoms after bypass.

69. A patient needs short-term enteral feeding for under four weeks with a functioning gut. Which access is most appropriate?
    • A surgical gastrostomy
    • A nasogastric tube
    • A peripherally inserted central catheter
    • A tunneled central catheter

    Correct answer: A nasogastric tube

    The answer is a nasogastric tube. Short-term enteral feeding under about four weeks is typically delivered by a nasoenteric tube rather than a surgical stoma.

70. A patient at high aspiration risk needs enteral feeding because of severe gastroparesis. Which tube placement reduces aspiration risk compared with gastric feeding?
    • Post-pyloric (jejunal) feeding
    • Rectal feeding
    • Oral bolus feeding
    • Gastric bolus feeding

    Correct answer: Post-pyloric (jejunal) feeding

    The answer is post-pyloric, or jejunal, feeding. Delivering feeds beyond the pylorus can reduce aspiration risk in patients with delayed gastric emptying.

71. A tube-fed patient develops sudden high gastric residuals and abdominal distension. Which initial step is most appropriate before continuing feeds?
    • Switch immediately to parenteral nutrition permanently
    • Hold feeds and assess for intolerance or obstruction
    • Double the feeding rate
    • Give a large dextrose bolus

    Correct answer: Hold feeds and assess for intolerance or obstruction

    The answer is to hold feeds and assess for intolerance or obstruction. New distension and high residuals warrant evaluation before resuming enteral nutrition.

72. A premature infant deficient in vitamin E may develop which condition reflecting the vitamin's antioxidant role?
    • Hemolytic anemia
    • Microcytic anemia from iron loss
    • Megaloblastic anemia
    • Polycythemia

    Correct answer: Hemolytic anemia

    The answer is hemolytic anemia. Vitamin E protects red cell membranes from oxidative damage, so deficiency in premature infants can cause hemolysis.

73. A patient with abetalipoproteinemia cannot absorb fat-soluble vitamins and develops a progressive ataxia. Deficiency of which vitamin is the principal driver of the neurologic syndrome?
    • Vitamin E
    • Folate
    • Vitamin C
    • Vitamin K

    Correct answer: Vitamin E

    The answer is vitamin E. Severe vitamin E deficiency from fat malabsorption causes a spinocerebellar and peripheral neurologic syndrome with ataxia.

74. A patient with irritable bowel syndrome and constipation is advised about fiber. Which type of fiber is generally better tolerated and helpful for stool regularity?
    • Only insoluble bran in large amounts
    • Complete fiber elimination
    • A purely liquid diet
    • Soluble fiber such as psyllium

    Correct answer: Soluble fiber such as psyllium

    The answer is soluble fiber such as psyllium. Soluble fiber improves stool form and is often better tolerated than coarse insoluble fiber in irritable bowel syndrome.

75. A patient is counseled that adequate dietary fiber may lower the risk of which condition over the long term?
    • Vitamin A toxicity
    • Iron overload
    • Diverticular disease and constipation
    • Hypernatremia

    Correct answer: Diverticular disease and constipation

    The answer is diverticular disease and constipation. Adequate fiber adds stool bulk and is associated with reduced diverticular disease and improved bowel regularity.

76. An infant at high risk for peanut allergy is being counseled. According to current guidance, what is the recommended approach to peanut introduction?
    • Avoid peanuts entirely until age five
    • Give large amounts of whole peanuts at birth
    • Avoid all solid foods for two years
    • Introduce peanut-containing foods early, around four to six months, often after evaluation

    Correct answer: Introduce peanut-containing foods early, around four to six months, often after evaluation

    The answer is to introduce peanut-containing foods early, around four to six months, often after evaluation in high-risk infants. Early introduction reduces the risk of developing peanut allergy.

77. A patient with a confirmed shellfish allergy asks how to prevent reactions. Which is the cornerstone of management?
    • Avoidance of all carbohydrates
    • Daily small exposures without supervision
    • Strict avoidance of the offending food and carrying epinephrine
    • Antihistamines instead of avoidance

    Correct answer: Strict avoidance of the offending food and carrying epinephrine

    The answer is strict avoidance of the offending food and carrying epinephrine. IgE-mediated food allergy is managed by eliminating the trigger and being prepared to treat anaphylaxis.

78. A patient with celiac disease on a strict gluten-free diet still has persistent symptoms. Which is the most appropriate first consideration?
    • Need for a high-gluten challenge
    • Vitamin A toxicity
    • Excess dietary fiber as the cause
    • Inadvertent ongoing gluten exposure

    Correct answer: Inadvertent ongoing gluten exposure

    The answer is inadvertent ongoing gluten exposure. Hidden gluten is the most common reason for persistent symptoms in celiac disease before considering other diagnoses.

79. A patient newly diagnosed with celiac disease should be evaluated for deficiencies of which nutrients due to proximal small-bowel damage?
    • Vitamin C only
    • Iron, folate, and fat-soluble vitamins
    • Sodium and chloride
    • Excess vitamin K

    Correct answer: Iron, folate, and fat-soluble vitamins

    The answer is iron, folate, and fat-soluble vitamins. Duodenal and proximal jejunal damage in celiac disease impairs absorption of these nutrients.

80. An adult with well-controlled phenylketonuria asks about a common artificial sweetener. Which sweetener must they avoid because it is a source of phenylalanine?
    • Stevia
    • Sucralose
    • Saccharin
    • Aspartame

    Correct answer: Aspartame

    The answer is aspartame. Aspartame contains phenylalanine, so patients with phenylketonuria must avoid it.

81. A child with phenylketonuria is prescribed a special medical formula. What is the purpose of this formula in the diet?
    • To provide only carbohydrate
    • To eliminate all protein
    • To provide protein and amino acids while limiting phenylalanine
    • To add extra phenylalanine

    Correct answer: To provide protein and amino acids while limiting phenylalanine

    The answer is to provide protein and amino acids while limiting phenylalanine. The medical formula supplies needed amino acids without the phenylalanine the child cannot metabolize.

82. A patient with Menkes disease has impaired copper transport. Which clinical feature reflects copper's role in connective tissue and pigment?
    • Kinky, sparse hair and connective tissue abnormalities
    • Bleeding gums and corkscrew hairs
    • Night blindness
    • Megaloblastic anemia

    Correct answer: Kinky, sparse hair and connective tissue abnormalities

    The answer is kinky, sparse hair and connective tissue abnormalities. Menkes disease impairs copper-dependent enzymes, producing the characteristic hair and vascular changes.

83. A patient using large amounts of denture cream containing zinc develops a myeloneuropathy and anemia. Which deficiency does excess zinc cause to explain these findings?
    • Vitamin K deficiency
    • Copper deficiency
    • Magnesium excess
    • Iron overload

    Correct answer: Copper deficiency

    The answer is copper deficiency. Chronic high zinc, even from denture creams, induces copper malabsorption and a copper-deficiency myeloneuropathy with anemia.

84. A child in a selenium-deficient area develops an osteoarthropathy affecting joints and growth plates. Deficiency of selenium is associated with which named condition besides cardiomyopathy?
    • Keshan cardiomyopathy alone
    • Kashin-Beck disease
    • Hartnup disease
    • Wilson disease

    Correct answer: Kashin-Beck disease

    The answer is Kashin-Beck disease. Selenium deficiency is linked to this osteoarthropathy in addition to the cardiomyopathy of Keshan disease.

85. A patient on long-term proton pump inhibitor therapy develops refractory hypocalcemia and arrhythmia from a related deficiency. Which mineral deficiency is associated with chronic proton pump inhibitor use?
    • Phosphate excess
    • Sodium deficiency
    • Chloride deficiency
    • Magnesium deficiency

    Correct answer: Magnesium deficiency

    The answer is magnesium deficiency. Chronic proton pump inhibitor use can cause hypomagnesemia, which in turn impairs calcium and potassium handling.

86. A patient with severe hypomagnesemia has ECG changes and tetany. Which other electrolyte abnormality commonly coexists and worsens the arrhythmia risk?
    • Hypokalemia
    • Hyperchloremia
    • Hypernatremia
    • Hyperphosphatemia

    Correct answer: Hypokalemia

    The answer is hypokalemia. Magnesium deficiency promotes potassium wasting, so coexisting hypokalemia compounds the arrhythmia risk of hypomagnesemia.

87. A patient on long-term anticonvulsant therapy may have low biotin. Which clinical features would suggest biotin deficiency?
    • Dermatitis, alopecia, and neurologic symptoms
    • Bleeding gums and scurvy
    • Night blindness
    • Megaloblastic anemia with neuropathy

    Correct answer: Dermatitis, alopecia, and neurologic symptoms

    The answer is dermatitis, alopecia, and neurologic symptoms. Biotin deficiency presents with these findings, and certain anticonvulsants can lower biotin.

88. A child living where drinking water contains excessive fluoride develops mottled, discolored tooth enamel. Which condition does this represent?
    • Scurvy
    • Dental fluorosis
    • Dental caries from low fluoride
    • Rickets

    Correct answer: Dental fluorosis

    The answer is dental fluorosis. Excess fluoride during tooth development causes enamel mottling, the counterpart to caries protection at optimal levels.

89. A critically ill patient on the ICU has high protein needs. Which approximate protein target is generally recommended for critically ill catabolic patients?
    • About 1.2 to 2.0 g/kg/day
    • About 5 g/kg/day
    • Zero protein to rest the gut
    • About 0.2 g/kg/day

    Correct answer: About 1.2 to 2.0 g/kg/day

    The answer is about 1.2 to 2.0 g/kg/day. Critically ill catabolic patients need elevated protein to offset breakdown and support healing.

90. A patient with extensive burns is in a hypermetabolic state. Why does providing adequate protein and calories matter most in this setting?
    • To prevent fat absorption
    • To limit lean body mass loss and support wound healing
    • To promote ketosis
    • To reduce caloric needs

    Correct answer: To limit lean body mass loss and support wound healing

    The answer is to limit lean body mass loss and support wound healing. The hypermetabolic burn state drives catabolism, so adequate protein and calories preserve muscle and promote repair.

91. A patient with cirrhosis and hepatic encephalopathy is malnourished. Which feeding strategy supports both nutrition and reduced overnight catabolism?
    • Prolonged daytime fasting
    • Complete protein restriction
    • A late-evening snack to shorten the overnight fast
    • A single large breakfast only

    Correct answer: A late-evening snack to shorten the overnight fast

    The answer is a late-evening snack to shorten the overnight fast. In cirrhosis, a bedtime snack reduces catabolism from the prolonged overnight fast and supports nutrition.

92. A cirrhotic patient with encephalopathy may benefit from which protein source consideration when standard protein is poorly tolerated?
    • Eliminating all amino acids
    • Switching to pure glucose only
    • Branched-chain amino acid supplementation
    • Maximizing aromatic amino acids

    Correct answer: Branched-chain amino acid supplementation

    The answer is branched-chain amino acid supplementation. Branched-chain amino acids may be better tolerated and help maintain nutrition in cirrhotic encephalopathy when standard protein is limited.

93. A patient with type 2 diabetes asks how the glycemic index of foods affects glucose. Which choice best reflects sound dietary counseling?
    • Add refined sugar to each meal
    • Eliminate all carbohydrate permanently
    • Favor lower glycemic index foods like whole grains and legumes
    • Favor high glycemic index sugary drinks

    Correct answer: Favor lower glycemic index foods like whole grains and legumes

    The answer is to favor lower glycemic index foods like whole grains and legumes. Lower glycemic index choices blunt postprandial glucose spikes in diabetes.

94. A patient with prediabetes is counseled on diet to prevent progression to diabetes. Which intervention has the strongest evidence?
    • High-sugar diet
    • Reduced-calorie diet with weight loss and increased activity
    • No dietary change
    • Total fasting indefinitely

    Correct answer: Reduced-calorie diet with weight loss and increased activity

    The answer is a reduced-calorie diet with weight loss and increased activity. Lifestyle change with modest weight loss strongly reduces progression from prediabetes to diabetes.

95. A patient on dialysis is advised to limit fluid between sessions. Which symptom of fluid overload does this restriction help prevent?
    • Night blindness
    • Scurvy
    • Pulmonary edema and shortness of breath
    • Megaloblastic anemia

    Correct answer: Pulmonary edema and shortness of breath

    The answer is pulmonary edema and shortness of breath. Limiting fluid between dialysis sessions prevents volume overload and pulmonary congestion.

96. A patient with advanced kidney disease and hyperphosphatemia takes a calcium-based phosphate binder with meals. Why is timing with meals essential?
    • Binders only work on an empty stomach
    • Binders raise serum phosphate when taken with meals
    • Binders work by trapping dietary phosphate in the gut during meals
    • Binders increase phosphate absorption

    Correct answer: Binders work by trapping dietary phosphate in the gut during meals

    The answer is that binders work by trapping dietary phosphate in the gut during meals. Taking them with food allows them to bind meal phosphate and lower absorption.

97. A patient with chronic alcohol use is admitted. Beyond thiamine, deficiency of which other water-soluble vitamin commonly contributes to macrocytic anemia in this population?
    • Vitamin A
    • Folate
    • Vitamin K
    • Vitamin D

    Correct answer: Folate

    The answer is folate. Alcohol impairs folate intake, absorption, and metabolism, making folate deficiency a common cause of macrocytosis in heavy drinkers.

98. A patient with alcoholic liver disease and poor intake is being repleted. Which mineral deficiency commonly coexists and should be checked because it impairs correction of other electrolytes?
    • Magnesium
    • Chromium
    • Fluoride
    • Iodine

    Correct answer: Magnesium

    The answer is magnesium. Heavy alcohol use frequently causes hypomagnesemia, which must be corrected for potassium and calcium to normalize.

99. Parents ask whether honey is safe for their six-month-old. What is the correct counseling regarding honey in infancy?
    • Honey prevents botulism
    • Honey is safe at any age
    • Avoid honey under 12 months due to infant botulism risk
    • Honey is encouraged from birth

    Correct answer: Avoid honey under 12 months due to infant botulism risk

    The answer is to avoid honey under 12 months due to infant botulism risk. Honey can contain Clostridium botulinum spores dangerous to infants, so it is withheld in the first year.

100. Parents introducing solids ask about choking-hazard foods. Which food should be avoided or modified for a young infant?
     • Pureed vegetables
     • Whole nuts and grapes
     • Iron-fortified cereal
     • Mashed banana

     Correct answer: Whole nuts and grapes

     The answer is whole nuts and grapes. These are choking hazards for infants and toddlers and should be avoided or cut into safe shapes.

101. A clinician is counseling parents of an exclusively breastfed infant about supplementation. Which supplement is routinely recommended from the first days of life?
     • Vitamin D
     • Vitamin C
     • Folate
     • Niacin

     Correct answer: Vitamin D

     The answer is vitamin D. Because breast milk is low in vitamin D, exclusively breastfed infants receive routine vitamin D supplementation to prevent deficiency.

102. At what approximate age do full-term infants typically need additional dietary iron as their birth iron stores become inadequate?
     • Not until age five
     • Only after age ten
     • At birth
     • Around four to six months

     Correct answer: Around four to six months

     The answer is around four to six months. Birth iron stores decline by this age, so iron-rich complementary foods or supplementation becomes important.

103. Why are newborns specifically at risk for vitamin K deficiency bleeding without prophylaxis?
     • Low placental transfer, sterile gut, and low vitamin K in breast milk
     • High gut bacterial vitamin K production at birth
     • High vitamin K stores at birth
     • Excess vitamin K from the placenta

     Correct answer: Low placental transfer, sterile gut, and low vitamin K in breast milk

     The answer is low placental transfer, sterile gut, and low vitamin K in breast milk. These factors leave newborns with minimal vitamin K, justifying routine prophylaxis.

104. A homebound elder is losing weight. Which reversible factor should be screened first as a treatable cause of undernutrition?
     • Overeating
     • High blood pressure alone
     • Poor dentition, depression, and medication side effects
     • Excess physical activity

     Correct answer: Poor dentition, depression, and medication side effects

     The answer is poor dentition, depression, and medication side effects. These common reversible contributors to geriatric undernutrition should be sought before invasive feeding.

105. A patient is found to have hypercalcemia from vitamin D toxicity. Which initial management step is most appropriate?
     • Increase vitamin D dosing
     • Restrict all fluids
     • Give additional calcium
     • Stop vitamin D and calcium supplements and provide hydration

     Correct answer: Stop vitamin D and calcium supplements and provide hydration

     The answer is to stop vitamin D and calcium supplements and provide hydration. Discontinuing the source and hydrating are first steps in managing vitamin D toxicity hypercalcemia.

106. A patient achieves positive nitrogen balance during recovery from illness. What does this indicate about protein metabolism?
     • Protein losses exceed intake
     • No protein turnover
     • Net muscle breakdown
     • Protein intake exceeds losses, indicating net anabolism

     Correct answer: Protein intake exceeds losses, indicating net anabolism

     The answer is that protein intake exceeds losses, indicating net anabolism. Positive nitrogen balance reflects net protein synthesis during recovery and growth.

107. A patient with bulimia nervosa who abuses diuretics develops a contraction alkalosis. Which nutritional and acid-base disturbance is most expected?
     • Respiratory acidosis
     • Hypernatremia with acidosis
     • Hyperkalemic metabolic acidosis
     • Hypokalemic, hypochloremic metabolic alkalosis

     Correct answer: Hypokalemic, hypochloremic metabolic alkalosis

     The answer is hypokalemic, hypochloremic metabolic alkalosis. Diuretic and purging behaviors waste potassium and chloride, producing this characteristic disturbance in bulimia.

108. A pregnant vegan patient asks how to ensure adequate intake of a nutrient absent from plant foods. Which supplement is essential to prevent fetal and maternal deficiency?
     • Vitamin B12
     • Vitamin C
     • Sodium
     • Vitamin K

     Correct answer: Vitamin B12

     The answer is vitamin B12. Because plant foods lack reliable B12, a pregnant vegan must supplement to protect both maternal and fetal status.

109. A child of a mother who drank heavily in pregnancy has a smooth philtrum, thin upper lip, and growth and developmental problems. Which condition does this represent?
     • Neonatal vitamin K deficiency
     • Congenital hypothyroidism
     • Fetal scurvy
     • Fetal alcohol spectrum disorder

     Correct answer: Fetal alcohol spectrum disorder

     The answer is fetal alcohol spectrum disorder. Prenatal alcohol exposure causes characteristic facial features and neurodevelopmental impairment, which is why abstinence is advised.

110. A patient with chronic secretory diarrhea develops weakness and a low potassium and bicarbonate. Which acid-base and electrolyte pattern is typical of large-volume lower gastrointestinal losses?
     • Hypokalemia with metabolic alkalosis
     • Hypernatremia with acidosis
     • Hypokalemia with metabolic acidosis from bicarbonate loss
     • Hyperkalemia with alkalosis

     Correct answer: Hypokalemia with metabolic acidosis from bicarbonate loss

     The answer is hypokalemia with metabolic acidosis from bicarbonate loss. Lower gastrointestinal fluid is rich in potassium and bicarbonate, so large losses cause this pattern.

111. A severely underweight patient with anorexia nervosa has profound bradycardia and hypotension. Which nutritional mechanism best explains these cardiovascular findings?
     • Reduced cardiac muscle mass and metabolic adaptation to starvation
     • Hypertensive remodeling
     • Excess thyroid hormone
     • Volume overload from overfeeding

     Correct answer: Reduced cardiac muscle mass and metabolic adaptation to starvation

     The answer is reduced cardiac muscle mass and metabolic adaptation to starvation. Chronic malnutrition shrinks the myocardium and lowers metabolic rate, producing bradycardia and hypotension.

112. A patient eating a mixed meal wants to maximize iron absorption from plant foods. Which combination best enhances nonheme iron uptake?
     • Taking iron with dairy
     • Eating iron with antacids
     • Pairing plant iron with tea
     • Pairing plant iron with vitamin C-rich foods

     Correct answer: Pairing plant iron with vitamin C-rich foods

     The answer is pairing plant iron with vitamin C-rich foods. Vitamin C enhances nonheme iron absorption, while tea, calcium, and antacids inhibit it.

113. A patient with marginal iron status is advised about beverages with meals. Which beverage most reduces nonheme iron absorption and should be separated from iron-rich meals?
     • Tea, due to its tannin content
     • Orange juice
     • Water
     • Vitamin C-fortified juice

     Correct answer: Tea, due to its tannin content

     The answer is tea, due to its tannin content. Tannins in tea bind nonheme iron and reduce its absorption, so tea should be separated from iron-rich meals.

114. A patient taking many supplements develops milk-alkali syndrome with hypercalcemia and metabolic alkalosis. Which intake combination most likely caused this?
     • Excess potassium and chloride
     • Excess iron and folate
     • Excessive calcium with absorbable alkali
     • Excess vitamin C

     Correct answer: Excessive calcium with absorbable alkali

     The answer is excessive calcium with absorbable alkali. High calcium and absorbable alkali intake causes milk-alkali syndrome with hypercalcemia and alkalosis.

115. A clinician estimates resting energy needs for a stable hospitalized patient. Which factor most increases a patient's estimated caloric requirement?
     • Complete bed rest alone
     • Hypothermia
     • Deep sedation lowering metabolism
     • Fever and a hypermetabolic stress state

     Correct answer: Fever and a hypermetabolic stress state

     The answer is fever and a hypermetabolic stress state. Stress, fever, and injury raise metabolic rate and thus caloric needs, which must be factored into estimates.

116. A patient with short bowel syndrome is transitioned toward enteral autonomy. Which strategy supports intestinal adaptation over time?
     • Providing enteral nutrition to stimulate the remaining bowel
     • Eliminating all oral intake
     • Permanent bowel rest with no enteral feeds
     • Maximizing simple sugars only

     Correct answer: Providing enteral nutrition to stimulate the remaining bowel

     The answer is providing enteral nutrition to stimulate the remaining bowel. Enteral feeding promotes intestinal adaptation and can reduce dependence on parenteral nutrition.

117. A patient with a chronic pressure ulcer has poor healing. Optimizing intake of which nutrient most directly supports collagen synthesis in wound repair?
     • Vitamin K
     • Chloride
     • Sodium
     • Vitamin C

     Correct answer: Vitamin C

     The answer is vitamin C. Vitamin C is essential for collagen hydroxylation, so adequate intake supports wound and pressure-ulcer healing.

118. A patient with primary biliary cholangitis and chronic cholestasis is at risk for which group of nutrient deficiencies due to impaired fat absorption?
     • Water-soluble B vitamins only
     • Vitamin C alone
     • Fat-soluble vitamins A, D, E, and K
     • Sodium and chloride

     Correct answer: Fat-soluble vitamins A, D, E, and K

     The answer is fat-soluble vitamins A, D, E, and K. Cholestasis reduces bile-dependent fat absorption, predisposing to deficiency of the fat-soluble vitamins.

119. A cirrhotic patient with ascites continues to gain fluid weight despite diuretics. Which dietary measure should be reinforced first?
     • Protein elimination
     • Fluid loading
     • Strict dietary sodium restriction
     • Increasing sodium to stimulate appetite

     Correct answer: Strict dietary sodium restriction

     The answer is strict dietary sodium restriction. Sodium restriction is fundamental to controlling ascites, and nonadherence often undermines diuretic therapy.

120. A woman with phenylketonuria planning pregnancy is counseled. When should strict phenylalanine control be established to protect the fetus?
     • After delivery
     • Only in the third trimester
     • Only during labor
     • Before conception and maintained throughout pregnancy

     Correct answer: Before conception and maintained throughout pregnancy

     The answer is before conception and maintained throughout pregnancy. Tight maternal phenylalanine control from before conception prevents fetal harm in maternal phenylketonuria.

121. A toddler drinking nearly two liters of cow's milk daily is pale and tired with microcytic anemia. Besides limiting milk, which counseling helps correct the deficiency?
     • Restrict all solids
     • Add vitamin A supplements
     • Offer iron-rich foods and consider iron supplementation
     • Increase milk further

     Correct answer: Offer iron-rich foods and consider iron supplementation

     The answer is to offer iron-rich foods and consider iron supplementation. Excess milk causes iron deficiency by displacing iron-rich foods, corrected by reducing milk and adding iron.

122. A patient on stable warfarin suddenly starts a green-vegetable juice cleanse and the INR drops. Which dietary principle should be reinforced?
     • Keep vitamin K intake consistent rather than abruptly changing it
     • Maximize vitamin K to help warfarin
     • Vitamin K does not affect warfarin
     • Eliminate all vitamin K permanently

     Correct answer: Keep vitamin K intake consistent rather than abruptly changing it

     The answer is to keep vitamin K intake consistent rather than abruptly changing it. Sudden increases in vitamin K antagonize warfarin and lower the INR, so consistency is key.

123. A patient with non-dialysis chronic kidney disease is counseled on protein. Which goal balances slowing progression against malnutrition risk?
     • Moderate protein intake rather than severe restriction
     • Complete protein elimination
     • Replacing protein with sugar
     • Maximal high-protein intake

     Correct answer: Moderate protein intake rather than severe restriction

     The answer is moderate protein intake rather than severe restriction. Moderation reduces nitrogenous load while avoiding the malnutrition of severe protein restriction.

124. A patient with riboflavin (vitamin B2) deficiency presents with angular cheilitis and a magenta tongue. Which dietary or clinical setting predisposes to this deficiency?
     • Excess sun exposure
     • Poor dietary intake, especially of dairy and fortified grains
     • High dairy intake
     • Excess citrus intake

     Correct answer: Poor dietary intake, especially of dairy and fortified grains

     The answer is poor dietary intake, especially of dairy and fortified grains. Riboflavin deficiency from inadequate intake causes angular cheilitis and glossitis.

125. A patient with chronic cholestasis and a prolonged prothrombin time receives parenteral vitamin K, and the prothrombin time corrects within a day. What does this rapid correction indicate?
     • The coagulopathy was due to vitamin K deficiency, not liver synthetic failure
     • Severe irreversible liver failure
     • A platelet disorder
     • Disseminated intravascular coagulation

     Correct answer: The coagulopathy was due to vitamin K deficiency, not liver synthetic failure

     The answer is that the coagulopathy was due to vitamin K deficiency, not liver synthetic failure. Rapid correction after vitamin K confirms a reversible nutritional cause.

126. A pregnant patient asks why iron needs rise most in the later trimesters. Which physiologic change best explains the increased demand later in pregnancy?
     • Rapid fetal growth and accelerated maternal red cell mass expansion
     • Declining fetal needs
     • Reduced placental transfer of iron
     • Loss of maternal blood volume

     Correct answer: Rapid fetal growth and accelerated maternal red cell mass expansion

     The answer is rapid fetal growth and accelerated maternal red cell mass expansion. Iron demand peaks later in pregnancy to support these increases.

127. A patient on parenteral nutrition develops worsening diarrhea, which further increases losses of a specific mineral and worsens a perioral rash. Replacing which mineral is indicated?
     • Sodium
     • Phosphate
     • Zinc
     • Calcium

     Correct answer: Zinc

     The answer is zinc. Diarrhea increases zinc losses, and in a parenteral nutrition patient this can cause or worsen zinc deficiency with a perioral rash, requiring zinc repletion.

128. A postmenopausal woman is counseled on diet to support bone density. Adequate intake of which combination most directly supports bone mineralization?
     • Iron and vitamin C
     • Sodium and potassium
     • Calcium and vitamin D
     • Folate and B12

     Correct answer: Calcium and vitamin D

     The answer is calcium and vitamin D. These nutrients underpin bone mineralization and are central to osteoporosis prevention in postmenopausal women.

129. A patient with type 1 diabetes uses an insulin-to-carbohydrate ratio. What does this ratio allow the patient to do?
     • Eliminate insulin entirely
     • Count grams of fat for dosing
     • Calculate mealtime insulin based on grams of carbohydrate
     • Dose insulin by protein only

     Correct answer: Calculate mealtime insulin based on grams of carbohydrate

     The answer is to calculate mealtime insulin based on grams of carbohydrate. The insulin-to-carbohydrate ratio matches bolus insulin to carbohydrate intake.

130. A preterm infant is monitored for nutritional deficiencies. Why is the preterm infant at greater risk for iron deficiency than a term infant?
     • Preterm infants lose iron in stool only
     • Preterm infants have excess iron stores
     • Iron is accrued mostly in the third trimester, which is shortened
     • Preterm infants absorb too much iron

     Correct answer: Iron is accrued mostly in the third trimester, which is shortened

     The answer is that iron is accrued mostly in the third trimester, which is shortened. Preterm birth interrupts iron accumulation, leaving low stores.

131. A child with recurrent infections and dry eyes in a deficient region improves with a specific supplement. Which vitamin supports both epithelial barriers and immunity to explain this benefit?
     • Vitamin K
     • Vitamin A
     • Folate
     • Vitamin D

     Correct answer: Vitamin A

     The answer is vitamin A. Vitamin A maintains epithelial integrity and immune function, so deficiency increases infections and supplementation helps.

132. A patient with refractory iron deficiency anemia despite oral iron is found to have celiac disease. Which mechanism best explains the poor response to oral iron?
     • Increased iron storage
     • Duodenal villous damage impairs iron absorption
     • Excess renal iron loss
     • Iron destruction by gluten

     Correct answer: Duodenal villous damage impairs iron absorption

     The answer is duodenal villous damage impairs iron absorption. Celiac disease damages the iron-absorbing duodenum, so oral iron fails until the diet is corrected.

133. A patient planning rapid weight loss asks how to lower gallstone risk. Which measure can reduce the risk of gallstones during rapid weight loss?
     • Maximizing weight loss rate
     • Eliminating all dietary fat
     • Fasting completely for weeks
     • Avoiding extreme caloric restriction and ensuring some dietary fat

     Correct answer: Avoiding extreme caloric restriction and ensuring some dietary fat

     The answer is avoiding extreme caloric restriction and ensuring some dietary fat. Including some fat stimulates gallbladder emptying and slowing weight loss reduces gallstone formation.

134. A patient with hypertension and normal kidney function is advised to increase dietary potassium. Which food group best provides this potassium?
     • Refined white bread
     • Sugary sodas
     • Processed lunch meats
     • Fruits and vegetables

     Correct answer: Fruits and vegetables

     The answer is fruits and vegetables. Produce is potassium-rich, and higher potassium intake supports lower blood pressure in those with normal renal function.

135. A patient with chronic steatorrhea reports difficulty driving at night. Which fat-soluble vitamin should be measured and repleted to address this symptom?
     • Vitamin E
     • Vitamin K
     • Vitamin D
     • Vitamin A

     Correct answer: Vitamin A

     The answer is vitamin A. Night blindness from fat malabsorption reflects vitamin A deficiency, which should be measured and repleted.

136. A child with acute gastroenteritis and mild dehydration is best managed with oral rehydration solution. Why is glucose included in the solution?
     • Glucose drives sodium and water absorption via cotransport
     • Glucose provides most of the caloric needs
     • Glucose blocks sodium absorption
     • Glucose replaces potassium losses directly

     Correct answer: Glucose drives sodium and water absorption via cotransport

     The answer is that glucose drives sodium and water absorption via cotransport. The intestinal sodium-glucose cotransporter pulls water along, making oral rehydration solution effective.

137. A patient with elevated cardiovascular risk asks which fat to emphasize in a heart-healthy diet. Which choice aligns with a Mediterranean-style pattern?
     • Saturated fats from butter
     • Monounsaturated fats such as olive oil
     • Trans fats from processed foods
     • Hydrogenated oils

     Correct answer: Monounsaturated fats such as olive oil

     The answer is monounsaturated fats such as olive oil. The Mediterranean pattern emphasizes such fats and is associated with lower cardiovascular risk.

138. A patient with diabetic gastroparesis cannot tolerate solid meals. Which dietary texture modification best supports nutrition during flares?
     • A single large solid meal daily
     • High-fat fried foods
     • Large solid high-fiber meals
     • Liquid or pureed nutrient-dense meals

     Correct answer: Liquid or pureed nutrient-dense meals

     The answer is liquid or pureed nutrient-dense meals. Liquids empty more readily than solids, improving tolerance and nutrition during gastroparesis flares.

139. A patient with nonalcoholic fatty liver disease asks how much weight loss can improve liver inflammation. Which approximate target is associated with histologic improvement?
     • A loss of at least 50 percent
     • No weight loss is helpful
     • A sustained loss of about 7 to 10 percent of body weight
     • A loss of under 1 percent

     Correct answer: A sustained loss of about 7 to 10 percent of body weight

     The answer is a sustained loss of about 7 to 10 percent of body weight. This degree of weight loss can improve steatohepatitis and inflammation in fatty liver disease.

140. A heavy drinker has macrocytosis with normal B12 and folate and no anemia. Which finding supports a direct alcohol effect rather than a vitamin deficiency?
     • Elevated methylmalonic acid
     • Macrocytosis that resolves with abstinence and normal vitamin levels
     • Markedly low B12
     • Low folate stores

     Correct answer: Macrocytosis that resolves with abstinence and normal vitamin levels

     The answer is macrocytosis that resolves with abstinence and normal vitamin levels. Alcohol can directly enlarge red cells, and the macrocytosis improves when drinking stops.

141. A child on a ketogenic diet for epilepsy is monitored for nutritional complications. Which complication is recognized with this restrictive diet?
     • Hypernatremia from salt loading
     • Vitamin A overload
     • Kidney stones and micronutrient deficiencies
     • Excess folate

     Correct answer: Kidney stones and micronutrient deficiencies

     The answer is kidney stones and micronutrient deficiencies. The ketogenic diet increases the risk of nephrolithiasis and several micronutrient deficiencies, requiring monitoring.

142. A patient has a BMI of 31 kg/m2. Which weight classification does this represent?
     • Overweight
     • Obesity class III
     • Normal weight
     • Obesity class I

     Correct answer: Obesity class I

     The answer is obesity class I. A BMI between 30 and 34.9 kg/m2 is classified as class I obesity.

143. A patient with heart failure is counseled to read food labels for sodium. Which category of foods contributes the most dietary sodium for most people?
     • Processed and restaurant foods
     • Fresh fruit
     • Plain rice
     • Unsalted nuts

     Correct answer: Processed and restaurant foods

     The answer is processed and restaurant foods. Most dietary sodium comes from processed and prepared foods rather than the salt shaker, so label reading helps.

144. A 19-year-old woman with type 1 diabetes presents with vomiting, abdominal pain, and Kussmaul breathing after stopping insulin during an illness. Her glucose is 480 mg/dL, arterial pH is 7.18, bicarbonate is 10 mEq/L, and serum ketones are elevated. After beginning isotonic saline, her initial serum potassium returns at 5.4 mEq/L. Which sequence of management is most appropriate?
     • Start an insulin infusion only after potassium drops below 3.3 mEq/L
     • Give intravenous bicarbonate first to correct the acidosis before any insulin
     • Give an insulin bolus and start an infusion immediately while continuing fluids, then add potassium once potassium falls below 5.3 mEq/L with adequate urine output
     • Withhold insulin entirely until the glucose normalizes with fluids alone

     Correct answer: Give an insulin bolus and start an infusion immediately while continuing fluids, then add potassium once potassium falls below 5.3 mEq/L with adequate urine output

     Starting insulin while continuing fluids and adding potassium once it falls into the upper-normal range (about 5.0 to 5.3 mEq/L) is correct. In diabetic ketoacidosis, isotonic fluids plus an insulin infusion close the anion gap, and potassium replacement begins once the level falls below roughly 5.0 to 5.3 mEq/L with urine output, because insulin drives potassium intracellularly. Insulin is held only if potassium is low at presentation (below about 3.3 to 3.5 mEq/L), not at 5.4 mEq/L. Bicarbonate is reserved for severe acidemia (pH below about 6.9 to 7.0) and is not routine first-line therapy, and withholding insulin altogether fails to suppress ketogenesis.

145. A 24-year-old man with type 1 diabetes is being treated for diabetic ketoacidosis with an insulin infusion and normal saline. His glucose has fallen from 520 mg/dL to 210 mg/dL, but his anion gap remains elevated and serum ketones are still positive. What is the most appropriate next step?
     • Stop the insulin infusion now that glucose is near normal
     • Add dextrose-containing fluids and continue the insulin infusion until the anion gap closes
     • Switch immediately to subcutaneous basal insulin and discharge planning
     • Double the insulin infusion rate to accelerate glucose lowering

     Correct answer: Add dextrose-containing fluids and continue the insulin infusion until the anion gap closes

     Adding dextrose while continuing the insulin infusion until the anion gap closes is correct. In diabetic ketoacidosis, insulin must continue to suppress ketogenesis until the gap normalizes and ketosis resolves, even after glucose falls; dextrose is added once glucose reaches roughly 200 to 250 mg/dL to permit ongoing insulin without hypoglycemia. Stopping insulin prematurely allows recurrent ketoacidosis, transitioning to subcutaneous insulin requires anion-gap closure and an overlap period, and simply increasing the insulin rate risks hypoglycemia without addressing the need for dextrose.

146. A 16-year-old girl with type 1 diabetes is admitted in diabetic ketoacidosis. Her initial potassium is 3.0 mEq/L, glucose is 410 mg/dL, and pH is 7.20. Intravenous fluids have been started. Which action is most appropriate before beginning the insulin infusion?
     • Begin insulin immediately because acidosis is the priority
     • Hold insulin and replace potassium until it exceeds 3.3 mEq/L
     • Give intravenous bicarbonate to raise the pH first
     • Restrict all intravenous fluids until potassium normalizes

     Correct answer: Hold insulin and replace potassium until it exceeds 3.3 mEq/L

     Holding insulin and replacing potassium until it rises into a safe range (above about 3.3 to 3.5 mEq/L) is correct. When the initial potassium in diabetic ketoacidosis is low (below roughly 3.3 to 3.5 mEq/L), giving insulin would shift more potassium intracellularly and could precipitate dangerous hypokalemia, arrhythmia, or respiratory muscle weakness, so potassium is repleted first. With a presenting potassium of 3.0 mEq/L, starting insulin immediately is unsafe, bicarbonate is not indicated at this pH, and continued isotonic fluid resuscitation is appropriate, not restricted.

147. A 62-year-old man with type 2 diabetes is brought in confused with a glucose of 1,050 mg/dL, serum osmolality of 350 mOsm/kg, minimal ketones, and a near-normal pH. He is profoundly dehydrated. Compared with diabetic ketoacidosis, which feature most distinguishes this hyperosmolar hyperglycemic state and guides initial therapy?
     • Profound free-water and volume deficit with minimal ketoacidosis, requiring aggressive fluid resuscitation
     • Marked acidosis requiring early bicarbonate
     • Severe hyperkalemia requiring urgent dialysis
     • Rapid onset over hours rather than days

     Correct answer: Profound free-water and volume deficit with minimal ketoacidosis, requiring aggressive fluid resuscitation

     A profound fluid deficit with minimal ketoacidosis requiring aggressive fluid resuscitation is correct. Hyperosmolar hyperglycemic state features extreme hyperglycemia and hyperosmolality with little ketosis because residual insulin suppresses ketogenesis, and the total body water deficit is larger than in diabetic ketoacidosis, so fluids are the cornerstone of therapy. There is no significant acidosis to treat with bicarbonate, hyperkalemia and dialysis are not defining features, and this state typically develops insidiously over days, not hours.

148. A 54-year-old woman with type 2 diabetes has an A1c of 8.6% despite metformin at maximum dose and good adherence. She has established atherosclerotic cardiovascular disease and is overweight. Which add-on agent best addresses both glycemic control and her cardiovascular risk?
     • A GLP-1 receptor agonist or SGLT2 inhibitor with proven cardiovascular benefit
     • A sulfonylurea such as glipizide
     • A thiazolidinedione such as pioglitazone
     • Basal insulin titrated to fasting glucose

     Correct answer: A GLP-1 receptor agonist or SGLT2 inhibitor with proven cardiovascular benefit

     Adding a GLP-1 receptor agonist or SGLT2 inhibitor with proven cardiovascular benefit is correct. For a patient with type 2 diabetes and established atherosclerotic cardiovascular disease, guidelines preferentially recommend these agents because they lower glucose and reduce cardiovascular events, with the added benefit of weight loss. Sulfonylureas and thiazolidinediones cause weight gain and lack this cardiovascular benefit, and basal insulin, while effective, is not the preferred next step when a cardioprotective oral or injectable agent is available.

149. A 48-year-old man with type 2 diabetes and no other major comorbidities asks what hemoglobin A1c goal he should aim for. He has a long life expectancy, no history of severe hypoglycemia, and tolerates therapy well. Which A1c target is most appropriate for this patient?
     • Less than 8.5%
     • Less than 6.0% regardless of hypoglycemia
     • No specific target is needed
     • Less than 7%

     Correct answer: Less than 7%

     A target of less than 7% is correct. For most nonpregnant adults with type 2 diabetes who have a long life expectancy and no significant risk of hypoglycemia, an A1c below 7% balances microvascular benefit against treatment burden and hypoglycemia risk. A looser goal near 8% is reserved for older patients with limited life expectancy or hypoglycemia risk, an extremely tight goal below 6% increases hypoglycemia without clear benefit, and abandoning a target altogether is not appropriate.

150. A 60-year-old man with type 2 diabetes and an A1c of 7.9% has albuminuria and an estimated GFR of 55 mL/min. He is already on metformin and an ACE inhibitor. Which additional agent provides both glycemic and kidney-protective benefit?
     • A sulfonylurea
     • A dipeptidyl peptidase-4 inhibitor
     • An SGLT2 inhibitor
     • Prandial insulin only

     Correct answer: An SGLT2 inhibitor

     Adding an SGLT2 inhibitor is correct. In type 2 diabetes with albuminuric chronic kidney disease, SGLT2 inhibitors slow progression of kidney disease and reduce cardiovascular and heart-failure events in addition to lowering glucose, making them the preferred add-on. Sulfonylureas and DPP-4 inhibitors lower glucose without this renal protection, and prandial insulin does not provide the kidney benefit that defines the best choice here.

151. A 45-year-old woman is found to have a fasting plasma glucose of 118 mg/dL on two occasions and an A1c of 6.0%. She is overweight and sedentary but asymptomatic. How should this result be classified and managed?
     • Prediabetes warranting intensive lifestyle modification and consideration of metformin
     • Normal glucose tolerance requiring no intervention
     • Type 1 diabetes requiring insulin
     • Overt type 2 diabetes requiring immediate combination drug therapy

     Correct answer: Prediabetes warranting intensive lifestyle modification and consideration of metformin

     Prediabetes warranting intensive lifestyle modification and consideration of metformin is correct. A fasting glucose of 100 to 125 mg/dL or an A1c of 5.7 to 6.4% defines prediabetes, for which structured lifestyle change is first-line and metformin is considered in higher-risk individuals such as those who are obese. This range is not normal, does not meet criteria for overt diabetes (which would require a fasting glucose of 126 mg/dL or higher or A1c of 6.5% or higher), and is not type 1 diabetes.

152. A 70-year-old woman with longstanding type 2 diabetes on a sulfonylurea is brought in diaphoretic and confused. Her fingerstick glucose is 38 mg/dL. She is able to protect her airway and swallow. What is the most appropriate immediate treatment?
     • Intramuscular glucagon only
     • Intravenous insulin to stabilize glucose
     • Oral fast-acting carbohydrate such as glucose tablets or juice
     • Oral metformin to improve control

     Correct answer: Oral fast-acting carbohydrate such as glucose tablets or juice

     Oral fast-acting carbohydrate such as glucose tablets or juice is correct. In a conscious patient with hypoglycemia who can swallow safely, rapidly absorbed oral carbohydrate is the fastest, simplest treatment and should be followed by recheck and a longer-acting snack. Glucagon is reserved for patients who cannot take oral intake, insulin would worsen the hypoglycemia, and metformin is irrelevant to acute hypoglycemia and is contraindicated in this acute setting.

153. A 38-year-old woman reports fatigue, cold intolerance, constipation, weight gain, and dry skin over several months. Her TSH is 14 mU/L and free T4 is low. There are no compressive symptoms. What is the most appropriate management?
     • Start methimazole to suppress the thyroid
     • Start levothyroxine and titrate to a normal TSH
     • Order radioactive iodine ablation
     • Begin liothyronine (T3) monotherapy

     Correct answer: Start levothyroxine and titrate to a normal TSH

     Starting levothyroxine and titrating to a normal TSH is correct. Primary hypothyroidism, shown by an elevated TSH with low free T4 and classic symptoms, is treated with levothyroxine (T4), with the dose adjusted to bring TSH into the normal range. Methimazole and radioactive iodine treat hyperthyroidism, not hypothyroidism, and T3 monotherapy is not standard because T4 provides stable conversion to T3 and steadier levels.

154. A 35-year-old woman who started levothyroxine for primary hypothyroidism returns 6 weeks later. She feels somewhat better, and her repeat TSH is 8 mU/L (still above the reference range). She takes the medication consistently on an empty stomach. What is the most appropriate next step?
     • Keep the dose unchanged and recheck in 1 year
     • Stop levothyroxine because symptoms improved
     • Increase the levothyroxine dose and recheck TSH in about 6 weeks
     • Add methimazole to balance the thyroid

     Correct answer: Increase the levothyroxine dose and recheck TSH in about 6 weeks

     Increasing the levothyroxine dose and rechecking TSH in about 6 weeks is correct. When the TSH remains elevated on therapy, the levothyroxine dose is increased and TSH is rechecked after roughly 6 weeks, the time needed for a new steady state. Leaving an above-range TSH unchanged undertreats the patient, stopping therapy would worsen hypothyroidism, and methimazole is for hyperthyroidism and would be harmful here.

155. A 68-year-old woman with known hypothyroidism is found obtunded, hypothermic, bradycardic, and hyponatremic after several days of skipped medication and pneumonia. She is hypoventilating. Which intervention is most critical in managing this myxedema coma?
     • Oral levothyroxine once she is more awake
     • Intravenous levothyroxine (often with intravenous corticosteroids) plus supportive care
     • Methimazole and beta-blockade
     • Fluid restriction alone for the hyponatremia

     Correct answer: Intravenous levothyroxine (often with intravenous corticosteroids) plus supportive care

     Intravenous levothyroxine, often with corticosteroids, plus supportive care is correct. Myxedema coma is a life-threatening decompensation of severe hypothyroidism requiring intravenous thyroid hormone, empiric stress-dose steroids until coexisting adrenal insufficiency is excluded, and aggressive support of temperature, ventilation, and sodium. Oral therapy is unreliable in an obtunded, hypothermic patient, methimazole would worsen the hypothyroid state, and fluid management alone does not address the hormone deficiency driving the crisis.

156. A 30-year-old woman who is 9 weeks pregnant is found to have an elevated TSH consistent with overt hypothyroidism. She was not previously diagnosed. Which approach to treatment is most appropriate during pregnancy?
     • Start levothyroxine promptly and monitor TSH against trimester-specific goals
     • Defer all treatment until after delivery
     • Treat with methimazole to protect the fetus
     • Use iodine supplementation alone in place of thyroid hormone

     Correct answer: Start levothyroxine promptly and monitor TSH against trimester-specific goals

     Starting levothyroxine promptly with trimester-specific TSH goals is correct. Overt hypothyroidism in pregnancy increases risks to mother and fetus, so levothyroxine is begun without delay and titrated to lower, pregnancy-specific TSH targets, with frequent monitoring because requirements rise. Delaying treatment endangers the pregnancy, methimazole treats hyperthyroidism, and iodine alone cannot replace needed thyroid hormone in established hypothyroidism.

157. A 42-year-old man with autoimmune hypothyroidism on a stable levothyroxine dose develops new heartburn and is prescribed calcium carbonate and an iron supplement, which he takes with his morning levothyroxine. Six weeks later his TSH has risen. What is the best explanation and corrective action?
     • Calcium and iron impair levothyroxine absorption; separate their administration by several hours
     • He needs a higher levothyroxine dose permanently regardless of timing
     • The levothyroxine has become ineffective and should be switched to T3
     • He has developed hyperthyroidism and needs methimazole

     Correct answer: Calcium and iron impair levothyroxine absorption; separate their administration by several hours

     Calcium and iron impairing absorption, requiring separation by several hours, is correct. Calcium and iron bind levothyroxine in the gut and reduce its absorption, raising TSH when taken simultaneously; spacing the supplements from levothyroxine by about 4 hours restores absorption. A permanent dose increase is unnecessary once timing is fixed, switching to T3 is not indicated, and a rising TSH reflects undertreatment rather than hyperthyroidism.

158. A 28-year-old woman reports palpitations, heat intolerance, weight loss, and tremor. Examination shows a diffuse goiter and mild proptosis. Her TSH is suppressed and free T4 is elevated, and thyrotropin receptor antibodies are positive. Which diagnosis best fits?
     • Hashimoto thyroiditis
     • Subacute (de Quervain) thyroiditis
     • Graves disease
     • Toxic adenoma

     Correct answer: Graves disease

     Graves disease is correct. The combination of hyperthyroidism, a diffuse goiter, ophthalmopathy (proptosis), and positive thyrotropin receptor (stimulating) antibodies is characteristic of Graves disease, the most common cause of hyperthyroidism. Hashimoto thyroiditis typically causes hypothyroidism, subacute thyroiditis presents with a painful tender gland and a transient hyperthyroid phase without these antibodies, and a toxic adenoma causes a solitary nodule rather than a diffuse goiter with eye disease.

159. A 26-year-old pregnant woman in her first trimester has newly diagnosed Graves hyperthyroidism with palpitations and weight loss. Which antithyroid medication is preferred during the first trimester to minimize fetal risk?
     • Methimazole
     • Radioactive iodine
     • Levothyroxine
     • Propylthiouracil

     Correct answer: Propylthiouracil

     Propylthiouracil is correct. In the first trimester, propylthiouracil is preferred over methimazole because methimazole carries a higher risk of specific congenital malformations (such as aplasia cutis and choanal atresia) during early organogenesis; therapy is often switched to methimazole later in pregnancy due to propylthiouracil hepatotoxicity. Radioactive iodine is contraindicated in pregnancy because it ablates the fetal thyroid, and levothyroxine would worsen hyperthyroidism.

160. A 55-year-old woman with Graves disease is admitted with fever to 40 degrees Celsius, atrial fibrillation with rapid ventricular response, agitation, and vomiting after a recent infection. She appears to be in thyroid storm. Which combination of therapies is most appropriate?
     • A beta-blocker, a thionamide (such as propylthiouracil), iodine given after the thionamide, and corticosteroids
     • Levothyroxine plus intravenous fluids
     • Radioactive iodine ablation immediately
     • Methimazole alone without supportive care

     Correct answer: A beta-blocker, a thionamide (such as propylthiouracil), iodine given after the thionamide, and corticosteroids

     A beta-blocker, a thionamide, iodine after the thionamide, and corticosteroids is correct. Thyroid storm is treated with a multi-pronged approach: beta-blockade to control adrenergic symptoms, a thionamide to block new hormone synthesis, iodine given at least an hour after the thionamide to block hormone release, and corticosteroids to reduce peripheral T4-to-T3 conversion. Levothyroxine would worsen the crisis, immediate radioactive iodine is not the acute treatment, and a thionamide alone omits essential supportive and synergistic therapies.

161. A 33-year-old woman develops a tender, painful thyroid gland, low-grade fever, and transient hyperthyroid symptoms two weeks after a viral upper respiratory illness. Her ESR is elevated and radioactive iodine uptake is low. What is the most appropriate management of this subacute thyroiditis?
     • Methimazole to block hormone synthesis
     • NSAIDs or corticosteroids for pain plus a beta-blocker for symptoms, with monitoring
     • Radioactive iodine ablation
     • Lifelong levothyroxine started immediately

     Correct answer: NSAIDs or corticosteroids for pain plus a beta-blocker for symptoms, with monitoring

     NSAIDs or corticosteroids for pain plus a beta-blocker, with monitoring, is correct. Subacute (de Quervain) thyroiditis is a self-limited inflammatory condition with hormone leakage and low radioiodine uptake, so treatment is supportive: anti-inflammatory drugs for pain and beta-blockers for thyrotoxic symptoms. Thionamides are ineffective because the gland is not overproducing hormone, radioactive iodine has no role given low uptake, and any hypothyroid phase is usually transient so lifelong levothyroxine is not started reflexively.

162. A 50-year-old man undergoing evaluation has a TSH of 9 mU/L with a normal free T4 and no symptoms. Thyroid peroxidase antibodies are positive. Which term best describes this thyroid status?
     • Overt hypothyroidism
     • Subclinical hyperthyroidism
     • Euthyroid sick syndrome
     • Subclinical hypothyroidism

     Correct answer: Subclinical hypothyroidism

     Subclinical hypothyroidism is correct. A mildly elevated TSH with a normal free T4 defines subclinical hypothyroidism; positive thyroid peroxidase antibodies indicate autoimmune thyroiditis and a higher likelihood of progression to overt disease. Overt hypothyroidism requires a low free T4, subclinical hyperthyroidism would show a low TSH with normal free T4, and euthyroid sick syndrome occurs in acute illness with characteristically low T3 and variable TSH rather than this pattern.

163. A 47-year-old woman is found to have a 1.5 cm solitary thyroid nodule on examination. Her TSH is normal. What is the most appropriate next step in evaluation?
     • Thyroid ultrasound and, based on features and size, fine-needle aspiration biopsy
     • Immediate total thyroidectomy
     • Radioactive iodine ablation
     • Start levothyroxine to suppress the nodule

     Correct answer: Thyroid ultrasound and, based on features and size, fine-needle aspiration biopsy

     Thyroid ultrasound followed by fine-needle aspiration based on features and size is correct. A palpable nodule with normal TSH is evaluated with ultrasound to characterize sonographic risk, and fine-needle aspiration is performed when size and features warrant it to exclude malignancy. Upfront surgery is premature without cytology, radioactive iodine ablation treats hyperfunctioning glands rather than evaluating a euthyroid nodule, and TSH-suppressive levothyroxine is not recommended for routine nodule management.

164. A 58-year-old woman has a suppressed TSH and an elevated free T4. A radioactive iodine uptake scan shows a single hot nodule with suppression of the surrounding gland. Which diagnosis does this finding best support?
     • Graves disease
     • Subacute thyroiditis
     • Hashimoto thyroiditis
     • Toxic adenoma

     Correct answer: Toxic adenoma

     Toxic adenoma is correct. A solitary hot nodule on radioiodine scan with suppression of the remaining gland indicates an autonomously functioning toxic adenoma producing excess hormone. Graves disease shows diffuse increased uptake, subacute thyroiditis shows low uptake because hormone is leaking rather than being synthesized, and Hashimoto thyroiditis usually causes hypothyroidism rather than a hyperfunctioning hot nodule.

165. A 40-year-old man presents with progressive fatigue, weight loss, salt craving, hyperpigmentation, and lightheadedness on standing. Labs show hyponatremia and hyperkalemia. Which test best confirms primary adrenal insufficiency?
     • A dexamethasone suppression test
     • A cosyntropin (ACTH) stimulation test showing inadequate cortisol response
     • A glucose tolerance test
     • A TSH level

     Correct answer: A cosyntropin (ACTH) stimulation test showing inadequate cortisol response

     A cosyntropin (ACTH) stimulation test showing an inadequate cortisol response is correct. Primary adrenal insufficiency (Addison disease) is confirmed when cortisol fails to rise appropriately after synthetic ACTH; hyperpigmentation, salt craving, hyponatremia, and hyperkalemia reflect cortisol and aldosterone deficiency with elevated ACTH. The dexamethasone suppression test evaluates cortisol excess, the glucose tolerance test assesses diabetes, and TSH evaluates thyroid function, none of which confirm adrenal insufficiency.

166. A 52-year-old woman with known primary adrenal insufficiency on hydrocortisone and fludrocortisone develops vomiting, hypotension, and severe weakness during an acute gastroenteritis. She appears to be in adrenal crisis. What is the most appropriate immediate management?
     • Continue her usual oral hydrocortisone dose only
     • Start an insulin infusion
     • Give intravenous fluids and high-dose intravenous hydrocortisone (stress dosing) immediately
     • Administer methimazole

     Correct answer: Give intravenous fluids and high-dose intravenous hydrocortisone (stress dosing) immediately

     Intravenous fluids and high-dose stress-dose hydrocortisone is correct. Adrenal crisis is life-threatening and requires immediate aggressive intravenous fluid resuscitation and stress-dose intravenous glucocorticoids, without waiting for confirmatory testing, because the patient cannot mount a cortisol response to the stress of illness. Her usual oral dose is inadequate during crisis (and she is vomiting), insulin is not indicated, and methimazole is irrelevant to adrenal disease.

167. A 30-year-old woman taking 30 mg of prednisone daily for several months for an inflammatory condition is about to undergo major surgery. Which perioperative consideration is most important regarding her adrenal function?
     • She needs no special steroid management because the prednisone is oral
     • She should stop prednisone abruptly the day before surgery
     • She should receive fludrocortisone instead of glucocorticoids
     • Chronic exogenous glucocorticoids suppress the HPA axis, so she requires stress-dose steroids to prevent secondary adrenal insufficiency

     Correct answer: Chronic exogenous glucocorticoids suppress the HPA axis, so she requires stress-dose steroids to prevent secondary adrenal insufficiency

     Chronic glucocorticoids suppressing the HPA axis and requiring stress-dose steroids is correct. Prolonged exogenous steroid use suppresses ACTH and the adrenal axis, so during major surgical stress the patient cannot increase endogenous cortisol and needs supplemental glucocorticoids to prevent secondary adrenal insufficiency and crisis. Assuming no risk because the drug is oral is wrong, abrupt cessation can precipitate crisis, and fludrocortisone (a mineralocorticoid) does not replace the needed glucocorticoid stress coverage.

168. A 44-year-old woman presents with central obesity, a dorsocervical fat pad, purple abdominal striae, proximal muscle weakness, hypertension, and hyperglycemia. Cushing syndrome is suspected. Which test is most appropriate as an initial screen for cortisol excess?
     • A morning ACTH level alone
     • A cosyntropin stimulation test
     • A late-night salivary cortisol, 24-hour urinary free cortisol, or low-dose dexamethasone suppression test
     • A random daytime cortisol level

     Correct answer: A late-night salivary cortisol, 24-hour urinary free cortisol, or low-dose dexamethasone suppression test

     Late-night salivary cortisol, 24-hour urinary free cortisol, or low-dose dexamethasone suppression is correct. These three tests are the validated first-line screens for cortisol excess because they capture loss of the normal circadian nadir or failure to suppress with dexamethasone. A morning ACTH helps localize the cause only after excess is confirmed, the cosyntropin test screens for deficiency rather than excess, and a single random cortisol is unreliable because of normal diurnal variation.

169. A 50-year-old man with poorly controlled hypertension on three agents is found to have hypokalemia and an elevated aldosterone-to-renin ratio. Which diagnosis should be evaluated further with confirmatory testing and imaging?
     • Pheochromocytoma
     • Cushing disease
     • Primary hyperaldosteronism (Conn syndrome)
     • Hypothyroidism

     Correct answer: Primary hyperaldosteronism (Conn syndrome)

     Primary hyperaldosteronism (Conn syndrome) is correct. Resistant hypertension with spontaneous or easily provoked hypokalemia and a high aldosterone-to-renin ratio points to primary hyperaldosteronism, which is confirmed with aldosterone suppression testing and localized with adrenal imaging and sometimes venous sampling. Pheochromocytoma causes episodic catecholamine symptoms, Cushing disease causes cortisol excess features, and hypothyroidism does not produce this aldosterone-renin pattern.

170. A 38-year-old woman has episodic headaches, palpitations, diaphoresis, and severe paroxysmal hypertension. Plasma and urinary metanephrines are markedly elevated, and imaging shows an adrenal mass consistent with pheochromocytoma. Which preoperative preparation is essential before surgical resection?
     • Beta-blockade started first, then alpha-blockade
     • Immediate surgery without medical preparation
     • Alpha-blockade (such as phenoxybenzamine) first, with adequate volume repletion, before any beta-blockade
     • Levothyroxine to control symptoms

     Correct answer: Alpha-blockade (such as phenoxybenzamine) first, with adequate volume repletion, before any beta-blockade

     Alpha-blockade first, with volume repletion, before beta-blockade is correct. In pheochromocytoma, alpha-adrenergic blockade is initiated first to control catecholamine-driven vasoconstriction and hypertension and to allow volume expansion; beta-blockade is added only afterward, because giving a beta-blocker first leaves unopposed alpha stimulation and can precipitate hypertensive crisis. Operating without blockade risks catastrophic intraoperative surges, and levothyroxine does not address catecholamine excess.

171. A 29-year-old woman reports amenorrhea and milky nipple discharge. She is not pregnant, takes no dopamine-blocking medications, and her TSH is normal. Her serum prolactin is markedly elevated, and MRI shows a pituitary adenoma. What is the most appropriate first-line treatment for this prolactinoma?
     • Transsphenoidal surgery as the initial therapy
     • A dopamine agonist such as cabergoline or bromocriptine
     • Radiation therapy
     • Levothyroxine

     Correct answer: A dopamine agonist such as cabergoline or bromocriptine

     A dopamine agonist such as cabergoline or bromocriptine is correct. Prolactinomas respond well to dopamine agonists, which lower prolactin, shrink the tumor, and restore gonadal function, making them first-line even for many large tumors. Surgery is reserved for patients who fail or cannot tolerate medical therapy or who have certain complications, radiation is a later option, and levothyroxine is irrelevant because the TSH is normal and the problem is prolactin excess.

172. A 48-year-old man notes enlarging hands and feet, coarsening facial features, a prominent jaw, and new diabetes and hypertension. Acromegaly is suspected. Which test best screens for growth hormone excess?
     • A random growth hormone level
     • An insulin-like growth factor 1 (IGF-1) level, confirmed by an oral glucose growth hormone suppression test
     • A dexamethasone suppression test
     • A cosyntropin stimulation test

     Correct answer: An insulin-like growth factor 1 (IGF-1) level, confirmed by an oral glucose growth hormone suppression test

     An IGF-1 level confirmed by an oral glucose growth hormone suppression test is correct. Because growth hormone is secreted in pulses, IGF-1 (which is stable and reflects integrated GH activity) is the best screening test for acromegaly, and the diagnosis is confirmed when oral glucose fails to suppress growth hormone. A single random GH level is unreliable, the dexamethasone test evaluates cortisol, and cosyntropin testing assesses adrenal reserve.

173. A 25-year-old man develops polyuria, intense thirst, and dilute urine after a traumatic brain injury. His serum sodium is high, urine osmolality is low, and administration of desmopressin concentrates the urine. Which diagnosis does this best support?
     • Nephrogenic diabetes insipidus
     • Syndrome of inappropriate antidiuretic hormone secretion
     • Primary polydipsia
     • Central diabetes insipidus

     Correct answer: Central diabetes insipidus

     Central diabetes insipidus is correct. The combination of dilute polyuria, hypernatremia, and a robust response to desmopressin indicates deficient antidiuretic hormone production, classic after pituitary or hypothalamic injury, and treatment is desmopressin replacement. Nephrogenic diabetes insipidus would not respond to desmopressin because the kidney is resistant to the hormone, SIADH causes water retention with hyponatremia, and primary polydipsia is driven by excess water intake rather than hormone deficiency.

174. A 60-year-old woman is found to have a serum calcium of 11.6 mg/dL with an inappropriately elevated parathyroid hormone level. She is asymptomatic and has normal renal function. Which diagnosis is most consistent with these findings?
     • Hypoparathyroidism
     • Vitamin D toxicity
     • Secondary hyperparathyroidism from kidney disease
     • Primary hyperparathyroidism

     Correct answer: Primary hyperparathyroidism

     Primary hyperparathyroidism is correct. Hypercalcemia with an inappropriately high (non-suppressed) parathyroid hormone level is the hallmark of primary hyperparathyroidism, most often from a parathyroid adenoma. Hypoparathyroidism produces low calcium with low PTH, vitamin D toxicity raises calcium but suppresses PTH, and secondary hyperparathyroidism from kidney disease typically features low or normal calcium with high PTH driven by renal failure.

175. A 55-year-old woman is found to have primary hyperparathyroidism with a serum calcium of 11.9 mg/dL, a fragility fracture history, and reduced bone density. She is otherwise healthy. What is the most appropriate definitive treatment?
     • Observation with annual calcium checks
     • Thiazide diuretic therapy
     • Parathyroidectomy
     • High-dose vitamin D supplementation

     Correct answer: Parathyroidectomy

     Parathyroidectomy is correct. In primary hyperparathyroidism, surgery is indicated when there is significant hypercalcemia, osteoporosis or fragility fracture, kidney involvement, or younger age, all of which this patient meets, and parathyroidectomy is curative. Observation is reserved for asymptomatic patients without surgical criteria, thiazides can worsen hypercalcemia, and high-dose vitamin D could further raise calcium.

176. A 45-year-old woman develops perioral numbness, tingling fingers, and carpopedal spasm two days after a total thyroidectomy. Tapping over the facial nerve produces a twitch, and her serum calcium is low with a low parathyroid hormone level. What is the most appropriate management?
     • Bisphosphonate therapy
     • Parathyroidectomy
     • Fluid restriction
     • Calcium and vitamin D (calcitriol) supplementation

     Correct answer: Calcium and vitamin D (calcitriol) supplementation

     Calcium and calcitriol supplementation is correct. Postsurgical hypoparathyroidism after thyroidectomy causes hypocalcemia with low PTH and neuromuscular irritability such as the Chvostek sign and carpopedal spasm, treated with calcium and active vitamin D (calcitriol). Bisphosphonates lower calcium and would worsen the problem, further parathyroid surgery is illogical when the issue is too little PTH, and fluid restriction does not correct hypocalcemia.

177. A 30-year-old woman with poorly controlled type 2 diabetes is started on an SGLT2 inhibitor. She later presents with nausea, malaise, and an elevated anion gap acidosis with ketones, but her glucose is only 180 mg/dL. Which complication should be recognized?
     • Hyperosmolar hyperglycemic state
     • Euglycemic diabetic ketoacidosis related to SGLT2 inhibitor therapy
     • Lactic acidosis from metformin alone
     • Hypoglycemia

     Correct answer: Euglycemic diabetic ketoacidosis related to SGLT2 inhibitor therapy

     Euglycemic diabetic ketoacidosis related to SGLT2 inhibitor therapy is correct. SGLT2 inhibitors can precipitate ketoacidosis with only modestly elevated glucose because urinary glucose loss lowers the measured glucose while ketogenesis proceeds; recognition requires checking ketones and the anion gap despite near-normal glucose. This presentation is not hyperosmolar state (which features very high glucose), and the ketones and acidosis distinguish it from simple hypoglycemia or isolated lactic acidosis.

178. A 19-year-old woman of normal weight develops type 1 diabetes confirmed by positive islet autoantibodies and low C-peptide. Which therapy is essential and lifelong for her glycemic management?
     • Metformin monotherapy
     • A sulfonylurea
     • Lifestyle modification alone
     • Basal-bolus insulin (or insulin pump) replacement

     Correct answer: Basal-bolus insulin (or insulin pump) replacement

     Basal-bolus insulin replacement is correct. Type 1 diabetes results from autoimmune destruction of beta cells and absolute insulin deficiency, so patients require exogenous insulin in a basal-bolus regimen or via pump for survival and glycemic control. Metformin and sulfonylureas act on residual endogenous insulin or insulin resistance and cannot replace the missing hormone, and lifestyle change alone cannot manage absolute insulin deficiency.

179. A 47-year-old woman has hypercalcemia, a low parathyroid hormone level, and a known diagnosis of sarcoidosis. Which mechanism best explains her elevated calcium?
     • Excess parathyroid hormone from an adenoma
     • Renal failure causing phosphate retention
     • Thyroid hormone excess driving bone turnover
     • Increased 1-alpha-hydroxylase activity in granulomas producing excess active vitamin D

     Correct answer: Increased 1-alpha-hydroxylase activity in granulomas producing excess active vitamin D

     Increased 1-alpha-hydroxylase activity in granulomas producing excess active vitamin D is correct. Granulomatous diseases such as sarcoidosis cause hypercalcemia because macrophages in granulomas convert vitamin D to its active form (calcitriol) independent of normal regulation, which suppresses PTH. A parathyroid adenoma would raise PTH rather than suppress it, renal failure causes a different pattern with secondary hyperparathyroidism, and thyroid hormone excess is not the mechanism here.

180. A 65-year-old man with metastatic squamous cell lung cancer presents with a serum calcium of 14 mg/dL, confusion, and dehydration. His parathyroid hormone is suppressed. What is the most appropriate initial treatment for this hypercalcemia of malignancy?
     • Aggressive intravenous isotonic saline, followed by a bisphosphonate or calcitonin
     • Oral calcium and vitamin D
     • Thiazide diuretic
     • Parathyroidectomy

     Correct answer: Aggressive intravenous isotonic saline, followed by a bisphosphonate or calcitonin

     Aggressive intravenous saline followed by a bisphosphonate or calcitonin is correct. Severe symptomatic hypercalcemia of malignancy is treated first with volume expansion using isotonic saline to restore perfusion and promote calcium excretion, then with a bisphosphonate (for durable control) and calcitonin (for rapid but transient lowering). Calcium and vitamin D would worsen it, thiazides raise calcium, and parathyroidectomy is irrelevant because PTH is suppressed.

181. A 23-year-old man is incidentally found to have a 2 cm adrenal mass on abdominal CT done for trauma. He has no symptoms of hormone excess. Which is the most appropriate initial approach to this adrenal incidentaloma?
     • Immediate surgical removal regardless of features
     • Start lifelong glucocorticoid replacement
     • Hormonal evaluation for cortisol, catecholamine, and (if hypertensive) aldosterone excess, plus assessment of imaging features for malignancy
     • Ignore it because all adrenal masses are benign

     Correct answer: Hormonal evaluation for cortisol, catecholamine, and (if hypertensive) aldosterone excess, plus assessment of imaging features for malignancy

     Hormonal evaluation plus imaging assessment for malignancy is correct. An adrenal incidentaloma is worked up by screening for functional hormone excess (cortisol, catecholamines, and aldosterone if hypertensive or hypokalemic) and by evaluating size and imaging characteristics for malignant potential. Routine immediate surgery is not warranted for small nonfunctioning benign-appearing masses, glucocorticoid replacement is unnecessary without insufficiency, and dismissing the mass ignores the need to exclude hormone excess and malignancy.

182. A 16-year-old boy has not begun puberty by age 15 and has a small testicular volume, low testosterone, and low LH and FSH levels. He also reports an impaired sense of smell. Which diagnosis best explains this combination?
     • Klinefelter syndrome
     • Primary testicular failure
     • Constitutional delay of growth and puberty
     • Kallmann syndrome (hypogonadotropic hypogonadism with anosmia)

     Correct answer: Kallmann syndrome (hypogonadotropic hypogonadism with anosmia)

     Kallmann syndrome is correct. The association of delayed puberty, low sex hormones with inappropriately low gonadotropins (hypogonadotropic hypogonadism), and impaired smell is characteristic of Kallmann syndrome, caused by defective migration of GnRH neurons. Klinefelter syndrome and other primary testicular failure show high gonadotropins from loss of feedback, and constitutional delay does not include anosmia and eventually proceeds spontaneously.

183. A 35-year-old woman with hyperthyroidism due to Graves disease is treated with radioactive iodine ablation. Several months later she reports fatigue, weight gain, and cold intolerance. Which outcome should be anticipated and managed?
     • Post-ablative hypothyroidism requiring levothyroxine replacement
     • Recurrent hyperthyroidism requiring more antithyroid drugs
     • Adrenal insufficiency
     • Hyperparathyroidism

     Correct answer: Post-ablative hypothyroidism requiring levothyroxine replacement

     Post-ablative hypothyroidism requiring levothyroxine is correct. Radioactive iodine for Graves disease commonly destroys enough thyroid tissue to cause permanent hypothyroidism, so the expected later course is hypothyroid symptoms treated with lifelong levothyroxine. The symptoms described are hypothyroid, not hyperthyroid, and ablation does not characteristically cause adrenal insufficiency or hyperparathyroidism.

184. A 52-year-old man with type 2 diabetes has retinopathy on dilated eye examination and persistent albuminuria. Beyond glucose control, which intervention most directly slows progression of his diabetic kidney disease?
     • A calcium channel blocker alone
     • A loop diuretic alone
     • An ACE inhibitor or angiotensin receptor blocker
     • High-protein diet

     Correct answer: An ACE inhibitor or angiotensin receptor blocker

     An ACE inhibitor or angiotensin receptor blocker is correct. In diabetic kidney disease with albuminuria, renin-angiotensin system blockade reduces intraglomerular pressure and proteinuria, slowing progression, and is a cornerstone alongside glycemic and blood-pressure control. A calcium channel blocker or loop diuretic alone does not provide this specific renoprotective antiproteinuric effect, and a high-protein diet can increase glomerular workload rather than protect the kidney.

185. A 60-year-old woman with type 2 diabetes is found to have an LDL cholesterol of 130 mg/dL and is 60 years old with diabetes but no known atherosclerotic disease. Which lipid-lowering approach aligns with guideline-based diabetes care?
     • A moderate-intensity (or high-intensity if higher risk) statin for primary prevention
     • No statin because she has no cardiovascular disease
     • Niacin monotherapy
     • A fibrate as first-line for LDL lowering

     Correct answer: A moderate-intensity (or high-intensity if higher risk) statin for primary prevention

     A moderate-intensity statin (high-intensity if higher risk) for primary prevention is correct. Most adults aged 40 to 75 with diabetes warrant statin therapy for cardiovascular risk reduction even without established disease, with intensity guided by additional risk factors. Withholding a statin ignores diabetes as a major risk enhancer, niacin is not a preferred first-line agent, and fibrates primarily target triglycerides rather than serving as first-line LDL therapy.

186. A 70-year-old hospitalized patient with type 2 diabetes is on a sliding-scale-only insulin regimen and has persistently elevated glucose readings throughout the day. Which inpatient insulin strategy is preferred for better glycemic control?
     • Use a scheduled basal-bolus (basal plus nutritional plus correction) insulin regimen
     • Continue sliding-scale insulin alone
     • Switch to oral metformin during acute illness
     • Stop all insulin and monitor only

     Correct answer: Use a scheduled basal-bolus (basal plus nutritional plus correction) insulin regimen

     A scheduled basal-bolus regimen is correct. For hospitalized patients with hyperglycemia, a proactive basal-bolus insulin approach combining basal, nutritional, and correction components controls glucose better than reactive sliding-scale insulin alone, which only chases highs after they occur. Metformin is generally held in acutely ill inpatients because of risks with changing renal function and procedures, and stopping insulin would worsen hyperglycemia.

187. A 58-year-old man with type 2 diabetes reports burning, tingling, and numbness in a stocking distribution of both feet, worse at night, with reduced monofilament sensation. Glucose control is suboptimal. Which approach best addresses his diabetic peripheral neuropathy?
     • Start a broad-spectrum antibiotic
     • Optimize glycemic control and use an agent such as duloxetine, pregabalin, or gabapentin for neuropathic pain
     • Order urgent vascular bypass surgery
     • Begin corticosteroids

     Correct answer: Optimize glycemic control and use an agent such as duloxetine, pregabalin, or gabapentin for neuropathic pain

     Optimizing glycemic control plus a neuropathic pain agent such as duloxetine, pregabalin, or gabapentin is correct. Diabetic distal symmetric polyneuropathy is managed by improving glucose control to slow progression and by treating painful symptoms with agents proven for neuropathic pain. Antibiotics treat infection, not neuropathy; vascular surgery addresses ischemia rather than this sensory neuropathy; and corticosteroids have no role in routine diabetic peripheral neuropathy.

188. A 33-year-old woman presents with weight gain, fatigue, and a TSH that is low-normal along with a low free T4 while she is critically ill in the intensive care unit with sepsis. A reverse T3 is elevated. Which is the most appropriate interpretation and action?
     • Start levothyroxine immediately for central hypothyroidism
     • Recognize euthyroid sick (nonthyroidal illness) syndrome and recheck thyroid function after recovery rather than treating
     • Start methimazole for hyperthyroidism
     • Order radioactive iodine ablation

     Correct answer: Recognize euthyroid sick (nonthyroidal illness) syndrome and recheck thyroid function after recovery rather than treating

     Recognizing euthyroid sick syndrome and rechecking after recovery is correct. Acute severe illness alters thyroid testing, classically lowering T3 and sometimes T4 and TSH with elevated reverse T3, without true thyroid disease, so the appropriate action is supportive care of the underlying illness and repeat testing after recovery rather than starting thyroid medication. Treating with levothyroxine or methimazole based on these transient changes is inappropriate, and ablation has no role.

189. A 50-year-old man with type 2 diabetes is found to have an A1c of 6.8% on metformin alone with no hypoglycemia. He feels well and has no complications. What is the most appropriate management of his pharmacotherapy?
     • Add basal insulin to push the A1c lower
     • Continue metformin and reassess, since he is at goal without hypoglycemia
     • Stop metformin because the A1c is acceptable
     • Add a sulfonylurea to intensify therapy

     Correct answer: Continue metformin and reassess, since he is at goal without hypoglycemia

     Continuing metformin and reassessing is correct. An A1c of 6.8% on metformin without hypoglycemia meets a typical target of below 7%, so the appropriate step is to maintain effective therapy and continue routine monitoring rather than intensify or deintensify. Adding insulin or a sulfonylurea would increase hypoglycemia risk without benefit at goal, and stopping metformin would worsen control of a chronic disease that is currently well managed.

190. A 41-year-old woman with type 1 diabetes wishes to conceive. Her current A1c is 9%. Which preconception recommendation most reduces the risk of congenital malformations?
     • Optimize glycemic control to a near-normal A1c before conception
     • Conceive now and improve control during pregnancy
     • Switch to oral agents during pregnancy
     • Stop insulin to avoid fetal exposure

     Correct answer: Optimize glycemic control to a near-normal A1c before conception

     Optimizing glycemic control to a near-normal A1c before conception is correct. Maternal hyperglycemia during organogenesis raises the risk of congenital malformations, so achieving tight control before pregnancy in type 1 diabetes is the most effective way to reduce that risk, along with folic acid and complication screening. Delaying control until pregnancy misses the critical early window, oral agents do not replace insulin in type 1 diabetes, and stopping insulin would cause dangerous hyperglycemia and ketoacidosis.

191. A 26-year-old man develops persistent hyponatremia with low serum osmolality, concentrated urine, and clinical euvolemia after a head injury, with normal thyroid and adrenal function. He has SIADH. Beyond treating the cause, which initial management is most appropriate for asymptomatic hyponatremia of this type?
     • Free-water (fluid) restriction
     • Rapid infusion of large-volume hypotonic fluids
     • Desmopressin administration
     • High-dose glucocorticoids

     Correct answer: Free-water (fluid) restriction

     Free-water restriction is correct. In the syndrome of inappropriate antidiuretic hormone secretion, excess water retention causes euvolemic hyponatremia, so the cornerstone of management for mild or asymptomatic cases is fluid restriction to allow free water to be excreted. Hypotonic fluids and desmopressin would worsen water retention and hyponatremia, and glucocorticoids treat adrenal insufficiency, which has been excluded here.

192. A 30-year-old woman has hirsutism, irregular menses, and acne, with mildly elevated androgens and a normal cortisol and prolactin. Pelvic ultrasound shows multiple small ovarian follicles, and she has insulin resistance. Which endocrine diagnosis best fits, and what first-line therapy addresses both menstrual and metabolic concerns?
     • Cushing syndrome treated with surgery
     • Congenital adrenal hyperplasia treated with high-dose iodine
     • Prolactinoma treated with levothyroxine
     • Polycystic ovary syndrome managed with lifestyle change and, depending on goals, combined oral contraceptives or metformin

     Correct answer: Polycystic ovary syndrome managed with lifestyle change and, depending on goals, combined oral contraceptives or metformin

     Polycystic ovary syndrome managed with lifestyle change plus combined oral contraceptives or metformin is correct. The combination of hyperandrogenism, ovulatory dysfunction, and polycystic ovaries with insulin resistance defines PCOS, for which weight management is foundational and combined oral contraceptives regulate menses and androgens while metformin helps the metabolic component. Cushing syndrome and prolactinoma were excluded by normal cortisol and prolactin, and iodine does not treat congenital adrenal hyperplasia.

193. A 64-year-old man with gout treated with allopurinol is hospitalized for pneumonia and develops an acute flare of his great toe during the admission. He is already on a stable allopurinol dose with a serum urate of 5.6 mg/dL. Which of the following is the most appropriate approach to his allopurinol during this acute flare?
     • Continue the allopurinol at the same dose and treat the flare with an anti-inflammatory agent
     • Stop the allopurinol until the flare resolves, then restart it
     • Double the allopurinol dose to drive urate lower during the flare
     • Replace the allopurinol with probenecid for the duration of the flare

     Correct answer: Continue the allopurinol at the same dose and treat the flare with an anti-inflammatory agent

     Continuing allopurinol unchanged while treating the flare is correct. Once a patient is established on urate-lowering therapy, it should not be interrupted during an acute attack because abrupt changes in serum urate can prolong or worsen the flare; the attack itself is managed with an NSAID, colchicine, or a corticosteroid. Stopping the drug, doubling the dose, or switching agents during the acute attack all destabilize urate levels and are not recommended.

194. A 58-year-old man with tophaceous gout cannot reach his serum urate target despite maximized allopurinol, and probenecid is contraindicated by recurrent kidney stones. He has severe disease with frequent flares and visible tophi. Which of the following intravenous agents enzymatically degrades uric acid and is an option for refractory tophaceous gout?
     • Rasburicase given daily for life
     • Pegloticase
     • Febuxostat
     • Colchicine

     Correct answer: Pegloticase

     Pegloticase is correct. Pegloticase is a recombinant uricase that converts uric acid to soluble allantoin and is used for severe refractory tophaceous gout when oral urate-lowering therapy fails. Febuxostat is another xanthine oxidase inhibitor (oral) rather than a uricase, colchicine is an anti-inflammatory that does not lower urate, and rasburicase is used short-term for tumor lysis syndrome, not chronic gout management.

195. A 52-year-old man started on febuxostat for gout has well-controlled urate but has established coronary artery disease. Counseling about this drug should emphasize awareness of which of the following safety considerations associated with febuxostat?
     • It causes irreversible retinal toxicity requiring eye exams
     • It mandates routine bone marrow biopsy
     • Cardiovascular risk warrants caution in patients with established cardiovascular disease
     • It commonly causes thyroid storm

     Correct answer: Cardiovascular risk warrants caution in patients with established cardiovascular disease

     Caution because of cardiovascular risk in patients with established cardiovascular disease is correct. Febuxostat carries a boxed warning regarding cardiovascular death, so allopurinol is generally preferred and febuxostat is used with care in those with significant cardiovascular disease. Retinal toxicity is associated with hydroxychloroquine, bone marrow biopsy is not a febuxostat requirement, and thyroid storm is unrelated to this urate-lowering drug.

196. A 49-year-old man presents with an acute gout flare confined to a single ankle and has hypertension, heart failure, and chronic kidney disease that make systemic NSAIDs and oral colchicine poor choices, and he prefers to avoid systemic steroids. Which of the following is the most appropriate localized treatment for his single-joint flare?
     • Initiate allopurinol at high dose immediately
     • Begin probenecid to abort the flare
     • Apply a topical anesthetic patch only
     • Intra-articular corticosteroid injection after excluding infection

     Correct answer: Intra-articular corticosteroid injection after excluding infection

     Intra-articular corticosteroid injection after excluding infection is correct. When a gout flare involves only one or two accessible joints and systemic anti-inflammatory options are limited by comorbidities, an intra-articular corticosteroid injection effectively treats the flare once septic arthritis has been ruled out by aspiration. Urate-lowering drugs such as allopurinol and probenecid do not treat the acute attack, and a topical anesthetic does not address the inflammation.

197. A 55-year-old woman with rheumatoid arthritis on methotrexate develops a new dry cough and progressive dyspnea, and imaging shows diffuse interstitial infiltrates. Distinguishing the cause is important because which of the following is a recognized pulmonary complication that can be directly attributable to this drug?
     • Methotrexate-induced pneumonitis
     • Methotrexate-induced asthma
     • Methotrexate-induced pulmonary embolism
     • Methotrexate-induced pleural calcification

     Correct answer: Methotrexate-induced pneumonitis

     Methotrexate-induced pneumonitis is correct. Methotrexate can cause a hypersensitivity pneumonitis presenting with cough, dyspnea, and diffuse infiltrates, which requires stopping the drug and is an important consideration alongside infection and rheumatoid lung disease. Methotrexate is not a recognized cause of asthma, pulmonary embolism, or pleural calcification, so those would not explain a drug-attributable interstitial process.

198. A 60-year-old woman with seropositive rheumatoid arthritis has achieved sustained remission for over a year on methotrexate plus a biologic. She asks whether her medications can be reduced. Which of the following best reflects the current treat-to-target approach to tapering therapy in sustained remission?
     • All medications should be stopped abruptly once remission is reached
     • Cautious tapering of therapy may be considered while monitoring closely for flare
     • Therapy must always be escalated regardless of remission
     • Tapering is never appropriate and the regimen must be fixed for life

     Correct answer: Cautious tapering of therapy may be considered while monitoring closely for flare

     Cautious tapering with close monitoring is correct. In patients with rheumatoid arthritis who maintain sustained remission, careful dose reduction or spacing of therapy can be considered while watching for recurrence, although complete withdrawal often leads to flare. Abruptly stopping everything risks loss of disease control, mandatory escalation ignores remission, and an absolute prohibition on tapering does not match a treat-to-target strategy.

199. A 50-year-old woman with rheumatoid arthritis is being evaluated before starting therapy. Beyond joint symptoms, recognition of which of the following is important because rheumatoid arthritis independently increases the risk of this common cause of mortality?
     • Pancreatic cancer
     • Chronic kidney stones
     • Accelerated cardiovascular (atherosclerotic) disease
     • Peptic ulcer disease as the leading cause of death

     Correct answer: Accelerated cardiovascular (atherosclerotic) disease

     Accelerated cardiovascular disease is correct. Chronic systemic inflammation in rheumatoid arthritis accelerates atherosclerosis, making cardiovascular disease a leading cause of excess mortality and a reason to aggressively manage traditional risk factors and control disease activity. Pancreatic cancer and kidney stones are not characteristic risks of rheumatoid arthritis, and peptic ulcer disease relates to therapy rather than being the leading cause of death.

200. A 45-year-old man newly diagnosed with rheumatoid arthritis is to start a tumor necrosis factor inhibitor. In addition to screening for latent tuberculosis, screening for which of the following chronic infections is most important before this biologic because of the risk of reactivation?
     • Cytomegalovirus retinitis
     • Helicobacter pylori
     • Lyme disease
     • Hepatitis B virus

     Correct answer: Hepatitis B virus

     Hepatitis B virus is correct. Tumor necrosis factor inhibitors and other biologics can reactivate hepatitis B, so screening for hepatitis B (and hepatitis C) is recommended before starting therapy, alongside tuberculosis screening. Routine screening for Helicobacter pylori, cytomegalovirus retinitis, and Lyme disease is not a prerequisite for initiating a tumor necrosis factor inhibitor.

201. A 70-year-old woman is intolerant of oral bisphosphonates because of severe reflux and difficulty remaining upright, but she has osteoporosis requiring treatment. Which of the following antiresorptive options is administered as a once-yearly intravenous infusion and avoids the gastrointestinal issues of oral therapy?
     • Zoledronic acid
     • Daily oral risedronate
     • Calcitonin nasal spray
     • Oral raloxifene

     Correct answer: Zoledronic acid

     Zoledronic acid is correct. Zoledronic acid is an intravenous bisphosphonate given once yearly, making it a good option when oral bisphosphonates cannot be tolerated because of esophageal or upright-posture limitations. Risedronate is another oral bisphosphonate with the same gastrointestinal constraints, calcitonin is weakly effective, and raloxifene is an oral agent that does not solve the problem of avoiding oral dosing.

202. A 68-year-old woman is started on denosumab for osteoporosis. Counseling should emphasize which of the following because abrupt discontinuation of this drug is associated with a characteristic rebound effect?
     • Stopping it causes permanent hypercalcemia
     • Stopping it without transitioning to another agent can cause rapid bone loss and rebound vertebral fractures
     • Stopping it triggers acute gout flares
     • Stopping it has no consequences and it can be discontinued freely

     Correct answer: Stopping it without transitioning to another agent can cause rapid bone loss and rebound vertebral fractures

     Rapid bone loss and rebound vertebral fractures after stopping without a transition agent is correct. Discontinuing denosumab leads to a rapid rise in bone turnover and a risk of multiple rebound vertebral fractures, so therapy should not be stopped without transitioning to a bisphosphonate. It does not cause permanent hypercalcemia or gout, and the notion that it can be stopped without consequence is incorrect.

203. A 72-year-old woman with osteoporosis is about to begin a bisphosphonate and is scheduled for a tooth extraction. To reduce the risk of a known oral complication of antiresorptive therapy, which of the following is the most appropriate recommendation?
     • Begin the bisphosphonate the same day as the extraction for convenience
     • Avoid all dental care permanently while on the drug
     • Complete needed invasive dental procedures and ensure good oral health before or early in therapy
     • Switch to teriparatide solely to allow the extraction

     Correct answer: Complete needed invasive dental procedures and ensure good oral health before or early in therapy

     Completing needed invasive dental work and optimizing oral health before or early in therapy is correct. Antiresorptive agents are associated with osteonecrosis of the jaw, particularly after invasive dental procedures, so addressing dental needs beforehand and maintaining good oral hygiene reduces this risk. Starting the drug the same day as an extraction is ill-timed, avoiding all dental care is impractical, and switching agents solely for one extraction is unnecessary.

204. A 30-year-old man presents with a hot, swollen knee and fever, and synovial fluid analysis reveals an inflammatory effusion. The Gram stain is negative but cultures are pending. Which of the following synovial fluid findings, if present, would most specifically confirm a bacterial septic arthritis?
     • A synovial glucose at the upper end of normal
     • Mildly turbid appearance alone
     • A white cell count of 5,000/microL
     • A positive synovial fluid culture growing a bacterial pathogen

     Correct answer: A positive synovial fluid culture growing a bacterial pathogen

     A positive synovial fluid culture is correct. Although a high white cell count and a positive Gram stain raise suspicion, growth of a bacterial organism on synovial fluid culture is the most specific confirmation of septic arthritis and guides targeted antibiotics. A normal or high glucose, mild turbidity, and a white cell count of 5,000/microL are nonspecific and do not confirm bacterial infection.

205. A 24-year-old man is found to have a Staphylococcus aureus septic knee, and after joint drainage and intravenous antibiotics the synovial reaccumulates with persistent purulence over several days despite appropriate antimicrobial therapy. Which of the following is the most appropriate next step?
     • Repeat drainage of the joint (serial aspiration or surgical washout)
     • Stop antibiotics because the joint is sterile by now
     • Inject intra-articular corticosteroids to reduce inflammation
     • Switch to oral antibiotics and discharge

     Correct answer: Repeat drainage of the joint (serial aspiration or surgical washout)

     Repeat drainage of the joint is correct. Septic arthritis requires ongoing removal of purulent material, so persistent or reaccumulating pus despite appropriate antibiotics warrants repeat aspiration or surgical washout to control the infection and protect cartilage. Stopping antibiotics prematurely, injecting steroids into an infected joint, or switching to oral therapy and discharging would all jeopardize source control.

206. A 30-year-old man with diabetes steps on a nail that punctures through his rubber-soled shoe into the plantar foot and several days later develops a deep foot infection with bone involvement. Which of the following organisms is classically associated with osteomyelitis following a puncture wound through a sneaker?
     • Group A Streptococcus
     • Pseudomonas aeruginosa
     • Bartonella henselae
     • Clostridium tetani

     Correct answer: Pseudomonas aeruginosa

     Pseudomonas aeruginosa is correct. Osteomyelitis following a nail puncture through a rubber-soled shoe is classically caused by Pseudomonas aeruginosa, which colonizes the moist foam of footwear. Group A Streptococcus and Clostridium tetani cause other wound infections, and Bartonella henselae causes cat-scratch disease, none of which carry this specific footwear-puncture association.

207. A 35-year-old woman from a region with high tuberculosis prevalence presents with months of chronic back pain, low-grade fevers, and night sweats. Imaging shows destruction of two adjacent vertebral bodies with a paraspinal abscess and relative disc preservation. Which of the following is the most likely diagnosis?
     • Acute pyogenic vertebral osteomyelitis
     • Osteoporotic compression fracture
     • Tuberculous spondylitis (Pott disease)
     • Metastatic carcinoma of the spine

     Correct answer: Tuberculous spondylitis (Pott disease)

     Tuberculous spondylitis (Pott disease) is correct. Chronic indolent back pain with constitutional symptoms, contiguous vertebral body destruction, a paraspinal (cold) abscess, and relative preservation of the disc space in a patient from an endemic area is characteristic of spinal tuberculosis. Pyogenic osteomyelitis tends to be more acute with early disc involvement, osteoporotic fractures lack infection signs, and metastases usually spare the disc but lack the granulomatous abscess pattern.

208. A 28-year-old woman with systemic lupus erythematosus develops new hip pain while on high-dose corticosteroids. To detect the most likely musculoskeletal complication at an early, radiographically occult stage, which of the following imaging studies is most sensitive?
     • Plain anteroposterior pelvic radiograph
     • Bone densitometry (DEXA)
     • Joint aspiration
     • Magnetic resonance imaging of the hip

     Correct answer: Magnetic resonance imaging of the hip

     Magnetic resonance imaging of the hip is correct. Corticosteroid use predisposes to osteonecrosis of the femoral head, which MRI can detect before plain radiographs show changes, making MRI the most sensitive early test. Plain radiographs miss early disease, DEXA measures bone density rather than necrosis, and joint aspiration evaluates effusions rather than bone perfusion.

209. A 60-year-old man presents with an acutely red, hot, swollen knee. Polarized microscopy shows weakly positively birefringent rhomboid crystals. Beyond treating the flare, identification of which of the following endocrine disorders is most appropriate to consider as an underlying contributor?
     • Primary hyperparathyroidism
     • Cushing syndrome
     • Pheochromocytoma
     • Addison disease

     Correct answer: Primary hyperparathyroidism

     Primary hyperparathyroidism is correct. Calcium pyrophosphate deposition disease (pseudogout) is associated with several metabolic conditions, including hyperparathyroidism, hemochromatosis, hypomagnesemia, and hypophosphatasia, so screening for hyperparathyroidism is appropriate, particularly in younger patients or those with recurrent attacks. Cushing syndrome, pheochromocytoma, and Addison disease are not recognized metabolic associations of calcium pyrophosphate deposition.

210. A 55-year-old man with hereditary hemochromatosis develops chronic arthritis predominantly affecting which of the following joint locations, a distribution that is a clinical clue to the underlying iron overload?
     • The first metatarsophalangeal joint only
     • The second and third metacarpophalangeal joints
     • The sacroiliac joints exclusively
     • The temporomandibular joints

     Correct answer: The second and third metacarpophalangeal joints

     The second and third metacarpophalangeal joints are correct. Hemochromatosis arthropathy characteristically involves the second and third metacarpophalangeal joints with hook-like osteophytes and is often accompanied by calcium pyrophosphate deposition, providing a clue to the underlying iron overload. Isolated first metatarsophalangeal disease suggests gout, exclusive sacroiliac involvement suggests spondyloarthritis, and temporomandibular involvement is not characteristic of hemochromatosis.

211. A 35-year-old man returns from a camping trip and develops a few days of fever and an acutely swollen knee weeks after an untreated tick bite, with no crystals and sterile routine cultures. Lyme serology with confirmatory immunoblot is positive. He has no neurologic or cardiac involvement. Which of the following is the most appropriate first-line therapy for this Lyme arthritis?
     • A single dose of intramuscular benzathine penicillin
     • Lifelong methotrexate
     • A 28-day course of oral doxycycline
     • Intra-articular corticosteroids without antibiotics

     Correct answer: A 28-day course of oral doxycycline

     A 28-day course of oral doxycycline is correct. Lyme arthritis without neurologic or cardiac involvement is treated with a 28-day course of oral antibiotics such as doxycycline, with intravenous therapy or a repeat course reserved for persistent disease. A single penicillin dose is inadequate, methotrexate targets autoimmune arthritis rather than infection, and intra-articular steroids without antibiotics fail to treat the underlying spirochetal infection.

212. A 48-year-old man with severe difficult-to-control psoriasis and psoriatic arthritis has prominent enthesitis and dactylitis with an inadequate response to a tumor necrosis factor inhibitor. Which of the following targeted biologic classes specifically inhibits interleukin-17 and is effective for both the skin and joint manifestations of this disease?
     • Rituximab (anti-CD20)
     • Allopurinol
     • An interleukin-6 inhibitor used only for giant cell arteritis
     • Interleukin-17 inhibitor (such as secukinumab)

     Correct answer: Interleukin-17 inhibitor (such as secukinumab)

     An interleukin-17 inhibitor is correct. Interleukin-17 inhibitors such as secukinumab effectively treat both the cutaneous psoriasis and the joint, enthesitis, and dactylitis of psoriatic arthritis and are appropriate when a tumor necrosis factor inhibitor is inadequate. Rituximab targets B cells in conditions like rheumatoid arthritis, allopurinol treats gout, and interleukin-6 inhibition is not the targeted pathway highlighted here for psoriatic disease.

213. A 25-year-old woman with limited cutaneous systemic sclerosis develops recurrent painful digital ulcers and color changes of the fingers triggered by cold. Which of the following is the most appropriate first-line pharmacologic therapy to reduce the frequency and severity of these vasospastic attacks?
     • A dihydropyridine calcium channel blocker such as nifedipine
     • A nonselective beta-blocker
     • Oral allopurinol
     • Systemic corticosteroids

     Correct answer: A dihydropyridine calcium channel blocker such as nifedipine

     A dihydropyridine calcium channel blocker such as nifedipine is correct. Raynaud phenomenon in systemic sclerosis is first treated with cold avoidance and a dihydropyridine calcium channel blocker, which reduces vasospasm and the frequency of attacks. Nonselective beta-blockers can worsen vasospasm, allopurinol treats gout, and systemic corticosteroids do not relieve the vasospastic attacks and can precipitate scleroderma renal crisis.

214. A 40-year-old woman with limited cutaneous systemic sclerosis presents with progressive exertional dyspnea, a loud P2, and signs of right heart strain, with normal lung parenchyma on imaging. Which of the following complications, for which she should be periodically screened, best explains her findings?
     • Septic arthritis
     • Pulmonary arterial hypertension
     • Acute gout
     • Carpal tunnel syndrome

     Correct answer: Pulmonary arterial hypertension

     Pulmonary arterial hypertension is correct. Limited cutaneous systemic sclerosis (the CREST pattern) carries a risk of pulmonary arterial hypertension, presenting with exertional dyspnea, a loud pulmonic component, and right heart strain without parenchymal lung disease, so periodic echocardiographic screening is recommended. Septic arthritis, gout, and carpal tunnel syndrome are musculoskeletal problems that do not explain isolated pulmonary hypertension.

215. A 50-year-old woman with newly diagnosed inflammatory myositis and proximal weakness is started on therapy. Which of the following is the appropriate first-line pharmacologic treatment to control the muscle inflammation?
     • Allopurinol
     • Colchicine
     • High-dose corticosteroids, often with a steroid-sparing immunosuppressant
     • A bisphosphonate as monotherapy

     Correct answer: High-dose corticosteroids, often with a steroid-sparing immunosuppressant

     High-dose corticosteroids with a steroid-sparing agent is correct. Idiopathic inflammatory myopathies such as polymyositis and dermatomyositis are treated initially with high-dose corticosteroids, frequently combined with a steroid-sparing immunosuppressant such as azathioprine or methotrexate to control inflammation and limit steroid exposure. Allopurinol and colchicine treat crystal disease, and a bisphosphonate addresses steroid-induced bone loss rather than the myositis itself.

216. A 65-year-old man has progressive proximal and distal muscle weakness that is asymmetric, with notable weakness of the finger flexors and quadriceps, only a mildly elevated creatine kinase, and a poor response to corticosteroids. Muscle biopsy shows rimmed vacuoles. Which of the following is the most likely diagnosis?
     • Polymyositis
     • Polymyalgia rheumatica
     • Dermatomyositis
     • Inclusion body myositis

     Correct answer: Inclusion body myositis

     Inclusion body myositis is correct. An older patient with slowly progressive asymmetric weakness involving the finger flexors and quadriceps, only mild creatine kinase elevation, rimmed vacuoles on biopsy, and poor steroid responsiveness is typical of inclusion body myositis. Polymyositis and dermatomyositis usually have symmetric proximal weakness and respond better to steroids, and polymyalgia rheumatica causes stiffness without true weakness or biopsy vacuoles.

217. A 30-year-old man presents with several weeks of low back and buttock pain that is worst in the early morning, awakens him in the second half of the night, and improves after he gets up and moves around. Which of the following features best classifies this as inflammatory rather than mechanical back pain?
     • Improvement with exercise and worsening with rest, with insidious onset before age 40
     • Sudden onset after heavy lifting that improves with rest
     • Pain that is sharply localized and worsens with activity
     • Pain that resolves completely within 48 hours

     Correct answer: Improvement with exercise and worsening with rest, with insidious onset before age 40

     Improvement with exercise and worsening with rest, with insidious onset before age 40, is correct. Inflammatory back pain is defined by features such as onset before age 40, insidious development, morning stiffness, nocturnal awakening, and improvement with activity rather than rest, which should prompt evaluation for axial spondyloarthritis. Acute pain after lifting that eases with rest and resolves quickly is the mechanical pattern.

218. A 70-year-old woman has chronic stable knee osteoarthritis and asks about the role of arthroscopic surgery for her degenerative knee. Which of the following best reflects current evidence regarding arthroscopic debridement and lavage for knee osteoarthritis?
     • Arthroscopy reliably regenerates lost cartilage
     • Arthroscopic debridement and lavage are not recommended for osteoarthritis without a true mechanical lock
     • Arthroscopy is the first-line treatment before any conservative measures
     • Arthroscopy is mandatory before considering joint replacement

     Correct answer: Arthroscopic debridement and lavage are not recommended for osteoarthritis without a true mechanical lock

     Arthroscopic debridement and lavage not being recommended for osteoarthritis is correct. Trials show no meaningful benefit of arthroscopic debridement or lavage for degenerative knee osteoarthritis over conservative care, so it is not recommended in the absence of true mechanical symptoms such as locking from a displaced meniscal fragment. It does not regenerate cartilage, is not first-line, and is not a required step before arthroplasty.

219. A 75-year-old man with severe symptomatic knee osteoarthritis is being counseled about total knee arthroplasty. Which of the following best describes the most appropriate timing for proceeding with joint replacement?
     • As soon as radiographs show any joint-space narrowing regardless of symptoms
     • Only after complete loss of all knee motion
     • When pain and functional limitation persist despite an adequate trial of nonsurgical management
     • Only when the patient develops a septic joint

     Correct answer: When pain and functional limitation persist despite an adequate trial of nonsurgical management

     Proceeding when pain and functional limitation persist despite adequate nonsurgical management is correct. Total knee arthroplasty is indicated for advanced symptomatic osteoarthritis that significantly impairs function and quality of life after appropriate conservative treatment has failed, not on the basis of radiographic findings alone. Surgery is not triggered by incidental imaging, complete ankylosis, or a joint infection.

220. A 32-year-old man with ankylosing spondylitis has a markedly reduced chest expansion on examination. Which of the following best explains this finding in his disease?
     • Diaphragmatic paralysis from phrenic nerve involvement
     • A large pleural effusion
     • Bilateral rib fractures
     • Inflammation and ankylosis of the costovertebral and costosternal joints restricting the rib cage

     Correct answer: Inflammation and ankylosis of the costovertebral and costosternal joints restricting the rib cage

     Inflammation and ankylosis of the costovertebral and costosternal joints is correct. Ankylosing spondylitis can involve the thoracic cage joints, fusing the costovertebral and costosternal articulations and limiting chest wall expansion, which is why chest expansion is measured during examination. Diaphragmatic paralysis, pleural effusion, and rib fractures are not the mechanism of reduced chest expansion in this axial inflammatory disease.

221. A 14-year-old girl with adolescent idiopathic scoliosis has a progressive curve measured at 35 degrees and remains skeletally immature with significant growth remaining. Which of the following is the most appropriate management to prevent further progression?
     • Bracing
     • Observation alone
     • Immediate spinal fusion
     • Systemic corticosteroids

     Correct answer: Bracing

     Bracing is correct. For a skeletally immature adolescent with a moderate curve in the roughly 25 to 45 degree range and remaining growth, bracing is used to halt or slow progression. Observation alone is reserved for smaller curves, surgery is generally reserved for larger curves (often greater than 45 to 50 degrees) or progression despite bracing, and corticosteroids have no role in idiopathic scoliosis.

222. A 78-year-old woman with an osteoporotic vertebral compression fracture has severe, persistent focal back pain that has not responded to several weeks of analgesics, activity, and bracing, with no neurologic deficit. Which of the following procedures may be considered for refractory pain from the fracture?
     • Emergency spinal cord decompression
     • Vertebral augmentation (vertebroplasty or kyphoplasty)
     • Total disc replacement
     • Sacroiliac joint fusion

     Correct answer: Vertebral augmentation (vertebroplasty or kyphoplasty)

     Vertebral augmentation is correct. For an osteoporotic vertebral compression fracture with severe pain refractory to conservative care and no neurologic compromise, percutaneous vertebroplasty or kyphoplasty may be considered to relieve pain and stabilize the vertebra. Emergency cord decompression is reserved for neurologic compression, and disc replacement and sacroiliac fusion address entirely different problems.

223. A 26-year-old woman with several months of inflammatory low back pain is suspected of having nonradiographic axial spondyloarthritis, but her HLA-B27 test is negative. Which of the following statements best guides interpretation of this result?
     • A negative HLA-B27 definitively rules out axial spondyloarthritis
     • HLA-B27 must be positive to obtain spinal imaging
     • A negative HLA-B27 does not exclude axial spondyloarthritis, which remains a clinical and imaging-based diagnosis
     • A negative HLA-B27 means the pain is purely mechanical

     Correct answer: A negative HLA-B27 does not exclude axial spondyloarthritis, which remains a clinical and imaging-based diagnosis

     A negative HLA-B27 not excluding axial spondyloarthritis is correct. Although HLA-B27 is strongly associated with axial spondyloarthritis, a substantial minority of patients are negative, so the diagnosis rests on the overall clinical picture plus imaging such as sacroiliac MRI. A negative test neither rules out the disease, prohibits imaging, nor proves the pain is mechanical.

224. A 16-year-old basketball player reports knee pain and a sensation of the knee 'locking' intermittently, and on one occasion the joint became transiently fixed and then released. Synovial fluid and ligament testing are unremarkable. Which of the following structures is most likely responsible for these mechanical symptoms?
     • The anterior cruciate ligament
     • The patellar tendon
     • The iliotibial band
     • A torn meniscus

     Correct answer: A torn meniscus

     A torn meniscus is correct. True mechanical locking, where a displaced fragment blocks full extension and then releases, is characteristic of a meniscal tear, often with joint-line tenderness. The anterior cruciate ligament causes instability rather than locking, the patellar tendon affects active extension, and the iliotibial band causes lateral friction pain without intra-articular locking.

225. A 19-year-old college athlete sustains a noncontact knee injury and has a large hemarthrosis, a positive Lachman test, and is found to have a combined injury. Which of the following structures, when injured together with the anterior cruciate and medial collateral ligaments, completes the classic 'unhappy triad' of the knee?
     • The medial meniscus
     • The patellar tendon
     • The posterior cruciate ligament
     • The quadriceps tendon

     Correct answer: The medial meniscus

     The medial meniscus is correct. The classic unhappy triad describes simultaneous injury to the anterior cruciate ligament, the medial collateral ligament, and the medial meniscus, typically from a lateral blow to a planted knee. The posterior cruciate ligament, patellar tendon, and quadriceps tendon are not part of this described triad.

226. A 22-year-old soccer player has recurrent ankle instability and 'giving way' months after multiple lateral ankle sprains, with persistent looseness on examination. After failing rehabilitation, which of the following is the most appropriate next step?
     • Permanent bed rest
     • Referral for evaluation of chronic lateral ankle instability, potentially including ligament reconstruction
     • Lifelong systemic corticosteroids
     • Initiation of allopurinol

     Correct answer: Referral for evaluation of chronic lateral ankle instability, potentially including ligament reconstruction

     Referral for evaluation of chronic lateral ankle instability is correct. Recurrent sprains with persistent mechanical instability that fails a structured rehabilitation program warrant orthopedic evaluation and may require surgical ligament reconstruction. Bed rest worsens function, systemic corticosteroids are not a treatment for ligamentous laxity, and allopurinol treats gout rather than ankle instability.

227. A 25-year-old man sustains an inversion ankle injury, and radiographs reveal a fracture of both the medial and lateral malleoli with talar shift, rendering the ankle mortise unstable. Which of the following is the most appropriate management of this unstable bimalleolar fracture?
     • A removable brace with immediate full weight-bearing
     • Reassurance and an elastic wrap
     • Open reduction and internal fixation
     • Aspiration of the ankle joint

     Correct answer: Open reduction and internal fixation

     Open reduction and internal fixation is correct. A bimalleolar fracture with talar shift is an unstable ankle injury that disrupts the mortise and generally requires surgical fixation to restore alignment and stability and to prevent post-traumatic arthritis. A removable brace with full weight-bearing, an elastic wrap, or joint aspiration would fail to stabilize this unstable fracture.

228. A 16-year-old gymnast lands on a hyperextended finger and the distal interphalangeal joint dislocates dorsally; after reduction it is stable through a functional range of motion and neurovascularly intact, with no fracture. Which of the following is the most appropriate management?
     • Open surgical fusion of the joint
     • Prolonged rigid casting of the entire hand for 3 months
     • No treatment and immediate return to competition
     • Brief splinting followed by early protected motion

     Correct answer: Brief splinting followed by early protected motion

     Brief splinting followed by early protected motion is correct. A simple finger interphalangeal dislocation that is stable after closed reduction and has no fracture is managed with a short period of splinting and then early motion to preserve function and avoid stiffness. Surgical fusion and prolonged casting are excessive for a stable reduced dislocation, and returning to play with no protection risks reinjury.

229. A 45-year-old construction worker develops a small, deep abscess and tracking redness of the finger pulp with throbbing pain and tense swelling of the fingertip pad after a puncture injury. Which of the following best describes this infection of the closed fingertip pulp space?
     • Felon
     • Paronychia
     • Flexor tenosynovitis
     • Ganglion cyst

     Correct answer: Felon

     Felon is correct. A felon is an infection of the closed pulp space of the fingertip, producing a tense, throbbing, swollen pad that often requires incision and drainage along with antibiotics. A paronychia involves the soft tissue alongside the nail fold, flexor tenosynovitis is an infection along the tendon sheath, and a ganglion cyst is a noninfectious soft-tissue swelling.

230. A 40-year-old man presents with a finger held in slight flexion that is uniformly swollen (fusiform), exquisitely tender along the flexor tendon sheath, and intensely painful with passive extension, two days after a penetrating palm injury. Which of the following is the most appropriate management of this surgical hand emergency?
     • Oral antibiotics and outpatient follow-up in a week
     • Urgent surgical evaluation with antibiotics for suppurative flexor tenosynovitis
     • Cold compresses and reassurance
     • Aspiration of the distal interphalangeal joint only

     Correct answer: Urgent surgical evaluation with antibiotics for suppurative flexor tenosynovitis

     Urgent surgical evaluation with antibiotics is correct. The Kanavel signs (fusiform swelling, flexed posture, tenderness along the sheath, and pain on passive extension) indicate suppurative flexor tenosynovitis, a surgical emergency requiring prompt drainage and antibiotics to prevent tendon necrosis and loss of function. Outpatient oral antibiotics, reassurance, or isolated joint aspiration would dangerously underestimate this infection.

231. A 70-year-old man with severe knee osteoarthritis is concerned about progression. Which of the following modifiable factors has the strongest evidence as a target for slowing the progression and reducing the symptoms of knee osteoarthritis?
     • Daily high-dose vitamin C
     • Avoiding all walking
     • Weight loss in overweight or obese patients
     • Routine antibiotic prophylaxis

     Correct answer: Weight loss in overweight or obese patients

     Weight loss in overweight or obese patients is correct. Excess weight increases mechanical load and inflammatory burden on the knee, and weight reduction improves pain and function and is a cornerstone of osteoarthritis management. High-dose vitamin C, avoiding all walking (which causes deconditioning), and antibiotic prophylaxis are not evidence-based strategies for osteoarthritis.

232. A 16-year-old long-distance runner with low body weight, irregular menstrual periods, and a recent stress fracture is evaluated. Recognition of which of the following clinical clusters is most important to guide her overall management?
     • Polymyalgia rheumatica
     • Reactive arthritis
     • Paget disease of bone
     • The female athlete triad (low energy availability, menstrual dysfunction, and low bone density)

     Correct answer: The female athlete triad (low energy availability, menstrual dysfunction, and low bone density)

     The female athlete triad is correct. Low energy availability, menstrual dysfunction, and impaired bone health in a young athlete with a stress fracture define the female athlete triad, which requires addressing nutrition and energy balance to restore menses and protect bone. Polymyalgia rheumatica and Paget disease are diseases of older adults, and reactive arthritis is a postinfectious joint condition unrelated to this triad.

233. A 35-year-old previously healthy man presents with an acutely red, hot, swollen knee and fever after no clear injury. Before initiating empiric therapy, which of the following is the single most important diagnostic step to differentiate among septic arthritis, crystal arthritis, and other inflammatory causes?
     • Arthrocentesis with synovial fluid cell count, Gram stain, culture, and crystal analysis
     • An immediate MRI of the knee
     • Serum rheumatoid factor
     • A trial of oral antibiotics with reassessment in 3 days

     Correct answer: Arthrocentesis with synovial fluid cell count, Gram stain, culture, and crystal analysis

     Arthrocentesis with full synovial fluid analysis is correct. Acute monoarthritis requires joint aspiration with cell count, Gram stain, culture, and crystal examination, because this single test distinguishes septic arthritis from crystal-induced and other inflammatory arthritides and directs treatment. MRI, serum rheumatoid factor, and an empiric antibiotic trial neither establish the diagnosis nor exclude a joint infection.

234. A 30-year-old man is being counseled on gout prevention and asks whether vitamin C supplementation will help. Which of the following lifestyle or dietary measures has the best support for helping lower serum uric acid in patients with gout?
     • Increasing daily beer intake for hydration
     • Weight loss and limiting alcohol, especially beer, and sugary fructose drinks
     • Eating more organ meats for nutrition
     • Adding a high-fructose sports drink with every meal

     Correct answer: Weight loss and limiting alcohol, especially beer, and sugary fructose drinks

     Weight loss and limiting alcohol and sugary fructose drinks is correct. Obesity, beer, spirits, and fructose-sweetened beverages raise serum uric acid, so weight reduction and limiting these substances are effective lifestyle measures in gout. Increasing beer, eating more organ meats, and adding high-fructose drinks all raise urate and would worsen the disease.

235. A 68-year-old woman started on a bisphosphonate for osteoporosis is reassessed regarding whether she should also be taking supplemental vitamin D. Which of the following best describes why correcting vitamin D status is important before and during antiresorptive therapy?
     • Vitamin D causes the bisphosphonate to become toxic
     • Vitamin D is only relevant in children
     • Untreated vitamin D deficiency reduces drug efficacy and can precipitate hypocalcemia
     • Vitamin D status has no relationship to bone therapy

     Correct answer: Untreated vitamin D deficiency reduces drug efficacy and can precipitate hypocalcemia

     Untreated vitamin D deficiency reducing efficacy and risking hypocalcemia is correct. Adequate vitamin D and calcium are needed for antiresorptive drugs to work properly and to prevent treatment-induced hypocalcemia, so deficiency should be corrected before and maintained during therapy. Vitamin D does not make the drug toxic, is relevant across the lifespan, and is clearly linked to effective bone treatment.

236. A 55-year-old woman with rheumatoid arthritis develops dry, gritty eyes and a dry mouth in addition to her joint disease, and testing reveals positive anti-Ro (SSA) antibodies. Which of the following best describes this development?
     • A new diagnosis of gout
     • An adverse effect of calcium supplementation
     • Septic arthritis spreading to the eyes
     • A secondary Sjogren syndrome occurring in the setting of rheumatoid arthritis

     Correct answer: A secondary Sjogren syndrome occurring in the setting of rheumatoid arthritis

     Secondary Sjogren syndrome in the setting of rheumatoid arthritis is correct. Sicca symptoms with positive anti-Ro antibodies in a patient who already has a defined connective tissue disease such as rheumatoid arthritis represent secondary Sjogren syndrome, an overlapping autoimmune exocrinopathy. This is not gout, an effect of calcium supplementation, or a spreading joint infection.

237. A 24-year-old man with HLA-B27-associated peripheral spondyloarthritis has an acutely swollen knee and an inflamed Achilles insertion. Beyond NSAIDs, an intra-articular corticosteroid injection is being considered for the knee. Which of the following must be excluded before injecting the joint?
     • Septic arthritis, by aspirating and analyzing the synovial fluid
     • Pregnancy
     • Vitamin D deficiency
     • Carpal tunnel syndrome

     Correct answer: Septic arthritis, by aspirating and analyzing the synovial fluid

     Excluding septic arthritis by synovial fluid analysis is correct. Before injecting any acutely inflamed joint with corticosteroids, infection must be excluded by aspiration and fluid analysis, because injecting steroids into a septic joint is harmful. Pregnancy, vitamin D status, and carpal tunnel syndrome are not the prerequisite exclusions for an intra-articular steroid injection of an acutely inflamed joint.

238. A 62-year-old woman with longstanding rheumatoid arthritis on chronic prednisone is admitted for sepsis. To reduce her risk of a fracture from her cumulative steroid exposure, which of the following preventive measures is most appropriate for ongoing glucocorticoid therapy?
     • Increase the prednisone dose to strengthen bone
     • Ensure calcium and vitamin D and consider a bisphosphonate for fracture prevention
     • Begin allopurinol for bone protection
     • Restrict all weight-bearing activity to protect the skeleton

     Correct answer: Ensure calcium and vitamin D and consider a bisphosphonate for fracture prevention

     Ensuring calcium and vitamin D and considering a bisphosphonate is correct. Patients on chronic glucocorticoids are at risk for steroid-induced osteoporosis, so adequate calcium and vitamin D plus bisphosphonate therapy in those at sufficient fracture risk are recommended. Increasing the steroid worsens bone loss, allopurinol treats gout, and restricting weight-bearing promotes further bone loss and deconditioning.

239. A 55-year-old man with chronic tophaceous gout is started on allopurinol and is counseled that flares may initially increase. Which of the following best explains why acute flares can occur when urate-lowering therapy is first begun?
     • Allopurinol directly forms new urate crystals
     • Allopurinol causes flares by raising serum urate
     • Mobilization of urate from tissue deposits as serum urate falls can precipitate flares
     • The flares represent an allergic reaction in every patient

     Correct answer: Mobilization of urate from tissue deposits as serum urate falls can precipitate flares

     Mobilization of urate from tissue deposits as serum urate falls is correct. When urate-lowering therapy is started, the drop in serum urate causes deposited crystals to dissolve and shed, which can trigger flares, which is why anti-inflammatory prophylaxis is co-prescribed during initiation. Allopurinol lowers rather than raises urate, does not create crystals, and these mobilization flares are not allergic reactions.

240. A 70-year-old woman with osteoporosis has been adherent to oral alendronate but sustains a new fragility fracture and her bone density has continued to decline. Which of the following is the most appropriate next step before assuming the drug has failed?
     • Immediately stop all osteoporosis treatment permanently
     • Double the calcium dose alone and make no other change
     • Conclude that osteoporosis cannot be treated
     • Assess adherence, absorption, and secondary causes, and consider switching therapy

     Correct answer: Assess adherence, absorption, and secondary causes, and consider switching therapy

     Assessing adherence, absorption, and secondary causes and considering a change in therapy is correct. Apparent treatment failure on a bisphosphonate should prompt evaluation of medication adherence and proper administration, vitamin D status, and unrecognized secondary causes, with a switch to a more potent or anabolic agent if appropriate. Stopping treatment, adjusting only calcium, or declaring the disease untreatable are not appropriate responses.

241. A 35-year-old man presents with an acutely painful, swollen first toe joint and is found to have monosodium urate crystals on aspiration during his first-ever gout flare. He has no tophi, normal renal function, and only this single episode. Which of the following is the most appropriate decision regarding urate-lowering therapy at this time?
     • Treat the acute flare now and defer routine urate-lowering therapy after a single uncomplicated attack
     • Start lifelong allopurinol immediately during this first flare
     • Begin probenecid during the acute attack
     • Start febuxostat at maximum dose today

     Correct answer: Treat the acute flare now and defer routine urate-lowering therapy after a single uncomplicated attack

     Treating the flare and deferring routine urate-lowering therapy after a single uncomplicated attack is correct. Urate-lowering therapy is generally reserved for patients with recurrent flares, tophi, urate stones, or chronic kidney disease, so after a first uncomplicated attack it is reasonable to treat the flare and counsel on lifestyle rather than commit to lifelong therapy. Starting allopurinol or febuxostat during the acute flare, or using probenecid as flare treatment, are not appropriate here.

242. A 42-year-old woman with major depressive disorder has been stable on paroxetine for a year and now wishes to stop. She abruptly discontinues it, and two days later develops dizziness, flu-like malaise, nausea, irritability, and brief electric-shock sensations in her head. Which is the most likely explanation for her symptoms?
     • Antidepressant discontinuation syndrome
     • A relapse of her major depressive episode
     • Serotonin syndrome
     • A new generalized anxiety disorder

     Correct answer: Antidepressant discontinuation syndrome

     Antidepressant discontinuation syndrome is correct. Abruptly stopping a short half-life SSRI such as paroxetine commonly produces flu-like symptoms, dizziness, nausea, irritability, and sensory disturbances like brain zaps within days, which is why these drugs are tapered. A depressive relapse develops over weeks rather than two days, serotonin syndrome arises from excess serotonergic activity rather than withdrawal, and a new anxiety disorder would not produce electric-shock sensations and flu-like malaise.

243. A 55-year-old man with major depressive disorder has not responded adequately to two sequential SSRI trials at full dose and duration. His clinician wants to switch to a different antidepressant class that inhibits reuptake of both serotonin and norepinephrine. Which agent fits this plan?
     • Sertraline
     • Duloxetine
     • Mirtazapine
     • Bupropion

     Correct answer: Duloxetine

     Duloxetine is correct. It is a serotonin-norepinephrine reuptake inhibitor, a reasonable next-class switch after failed SSRI trials in major depressive disorder. Sertraline is itself an SSRI, mirtazapine works through alpha-2 antagonism and serotonin receptor blockade rather than dual reuptake inhibition, and bupropion acts on norepinephrine and dopamine, not serotonin.

244. A 36-year-old man with major depressive disorder is being started on bupropion because he also wants help cutting down on smoking and is concerned about weight gain. Which element of his history would most strongly contraindicate bupropion?
     • A history of well-controlled hypertension
     • A family history of depression
     • A history of a seizure disorder
     • A history of seasonal allergies

     Correct answer: A history of a seizure disorder

     A history of a seizure disorder is correct. Bupropion lowers the seizure threshold and is contraindicated in patients with a seizure disorder or conditions predisposing to seizures such as active eating disorders. Well-controlled hypertension, a family history of depression, and seasonal allergies do not contraindicate bupropion.

245. A 28-year-old woman with major depressive disorder scores 18 on a depression severity questionnaire at her initial visit. After 10 weeks of treatment her repeat score is 3. Which best describes her current status using standard depression outcome terminology?
     • Relapse
     • Recurrence
     • Treatment resistance
     • Remission

     Correct answer: Remission

     Remission is correct. Remission refers to a return to a nearly symptom-free state during treatment of the current episode, reflected here by a drop to a minimal severity score. Relapse is a return of symptoms before full recovery, recurrence is a new episode after recovery, and treatment resistance describes failure to respond to adequate trials, none of which describe this marked improvement.

246. A 40-year-old man with major depressive disorder and significant fatigue and low motivation is concerned about sexual side effects he experienced on a prior SSRI. His clinician selects an antidepressant that acts on dopamine and norepinephrine and is least likely to cause sexual dysfunction. Which agent is being chosen?
     • Bupropion
     • Paroxetine
     • Citalopram
     • Venlafaxine

     Correct answer: Bupropion

     Bupropion is correct. As a norepinephrine-dopamine reuptake inhibitor it has a low rate of sexual side effects and can be activating, which suits a patient troubled by fatigue and prior SSRI-related sexual dysfunction. Paroxetine and citalopram are SSRIs commonly associated with sexual side effects, and venlafaxine, an SNRI, also frequently causes them.

247. A 33-year-old woman with generalized anxiety disorder is started on an SSRI. She asks which single class of medications, although fast-acting, is generally avoided as ongoing monotherapy for her condition because of tolerance and dependence. Which class is she being cautioned about?
     • Selective serotonin reuptake inhibitors
     • Benzodiazepines
     • Serotonin-norepinephrine reuptake inhibitors
     • Azapirones such as buspirone

     Correct answer: Benzodiazepines

     Benzodiazepines are correct. Although they relieve anxiety quickly, their potential for tolerance, dependence, and withdrawal makes them unsuitable for long-term monotherapy in generalized anxiety disorder, where they are reserved for short-term or bridging use. SSRIs and SNRIs are first-line maintenance treatments, and buspirone is a non-dependence-forming anxiolytic.

248. A 47-year-old woman with generalized anxiety disorder also has comorbid neuropathic pain. Her clinician wants a single first-line agent that can address both the anxiety and the neuropathic pain. Which medication best accomplishes both goals?
     • Alprazolam
     • Hydroxyzine
     • Duloxetine
     • Propranolol

     Correct answer: Duloxetine

     Duloxetine is correct. This SNRI is first-line for generalized anxiety disorder and also carries an indication for neuropathic pain, allowing one drug to treat both problems. Alprazolam is a benzodiazepine without neuropathic pain benefit, hydroxyzine treats anxiety acutely but not neuropathic pain, and propranolol addresses some physical anxiety symptoms but not neuropathic pain or the core disorder.

249. A 38-year-old man with generalized anxiety disorder reports that worry about finances, his children, his health, and his job consumes most of his day and he cannot control it, accompanied by muscle tension and irritability. Which feature most distinguishes generalized anxiety disorder from panic disorder in this patient?
     • Sudden discrete surges of fear peaking within minutes
     • Fear of a single specific object or situation
     • A fixed false belief held with full conviction
     • Persistent uncontrollable worry across multiple life domains

     Correct answer: Persistent uncontrollable worry across multiple life domains

     Persistent uncontrollable worry across multiple life domains is correct. Generalized anxiety disorder is characterized by chronic, hard-to-control worry spanning many areas of life with physical symptoms such as muscle tension, in contrast to the discrete attacks of panic disorder. Sudden surges of fear peaking within minutes describe panic attacks, fear of a single object describes specific phobia, and a fixed false belief describes a delusion.

250. A 60-year-old man hospitalized for alcohol withdrawal is being treated with a benzodiazepine. The team uses a validated 10-item scale that rates symptoms such as tremor, sweating, agitation, and hallucinations to guide dosing. Which scale is being used?
     • CIWA-Ar
     • PHQ-9
     • GAD-7
     • MMSE

     Correct answer: CIWA-Ar

     CIWA-Ar is correct. The Clinical Institute Withdrawal Assessment for Alcohol, revised, scores the severity of withdrawal symptoms and is widely used to guide symptom-triggered benzodiazepine dosing. The PHQ-9 measures depression, the GAD-7 measures anxiety, and the MMSE assesses cognition, none of which quantify alcohol withdrawal severity.

251. A 52-year-old man stopped drinking 10 hours ago and now has tremulousness, anxiety, sweating, and tachycardia, but his sensorium is clear and he has no hallucinations or seizures. Which stage of alcohol withdrawal does this presentation most likely represent?
     • Withdrawal seizures
     • Minor (early) withdrawal
     • Delirium tremens
     • Alcoholic hallucinosis

     Correct answer: Minor (early) withdrawal

     Minor or early withdrawal is correct. In the first 6 to 24 hours after the last drink, patients typically develop tremor, anxiety, sweating, and mild autonomic hyperactivity with an intact sensorium, which is the earliest withdrawal stage. Withdrawal seizures peak somewhat later, alcoholic hallucinosis adds hallucinations with a clear sensorium, and delirium tremens involves clouded consciousness and severe autonomic instability days later.

252. A 58-year-old man with severe alcohol withdrawal continues to have escalating agitation and dangerously high benzodiazepine requirements despite repeated, large benzodiazepine doses. Which adjunctive agent is most appropriate for this benzodiazepine-refractory withdrawal?
     • Haloperidol as monotherapy
     • Methylphenidate
     • Phenobarbital
     • Naloxone

     Correct answer: Phenobarbital

     Phenobarbital is correct. In benzodiazepine-refractory alcohol withdrawal, a barbiturate such as phenobarbital potentiates GABAergic tone and helps control symptoms when escalating benzodiazepine doses are insufficient. Haloperidol lowers the seizure threshold and does not treat the underlying GABA deficit, methylphenidate would worsen agitation, and naloxone reverses opioids and has no role.

253. A clinician is using a structured framework during a suicide risk assessment that separates current suicidal thoughts, the presence of a specific plan, the intent to act, and access to lethal means. Which combination of these elements indicates the highest acute risk?
     • Passive thoughts of death with no plan, intent, or access to means
     • A past attempt years ago with no current ideation
     • A vague wish that life were over without intent
     • Active ideation with a specific plan, strong intent, and ready access to lethal means

     Correct answer: Active ideation with a specific plan, strong intent, and ready access to lethal means

     Active ideation with a specific plan, strong intent, and ready access to lethal means is correct. Acute suicide risk rises sharply when a patient has not only thoughts but also a formulated plan, the intent to carry it out, and the means available. Passive thoughts without plan or intent, a remote past attempt without current ideation, and a vague wish that life were over reflect lower acute risk than this convergence of plan, intent, and access.

254. A 16-year-old girl is brought to the emergency department after telling a friend she wanted to die. During the suicide risk assessment, which factor is considered protective and would tend to lower her acute risk?
     • Strong, supportive connection to family and future plans she values
     • Recent breakup and social isolation
     • Access to a firearm at home
     • Prior suicide attempt last month

     Correct answer: Strong, supportive connection to family and future plans she values

     A strong, supportive connection to family and future plans she values is correct. Protective factors such as social support, a sense of responsibility to others, and reasons for living reduce suicide risk and should be assessed alongside risk factors. Recent loss with isolation, firearm access, and a recent prior attempt are all risk factors that raise, rather than lower, acute risk.

255. A psychiatrist evaluating a depressed patient documents that he completed a suicide risk assessment, the patient denied current ideation, and they created a plan for follow-up and crisis access. Which statement about so-called no-suicide contracts is correct?
     • A signed no-suicide contract reliably prevents suicide and substitutes for ongoing assessment
     • No-suicide contracts have not been shown to prevent suicide and should not replace a thorough risk assessment and safety planning
     • A no-suicide contract is legally binding on the patient
     • Asking the patient to promise not to attempt eliminates the need for follow-up

     Correct answer: No-suicide contracts have not been shown to prevent suicide and should not replace a thorough risk assessment and safety planning

     The correct statement is that no-suicide contracts have not been shown to prevent suicide and should not replace ongoing risk assessment and structured safety planning. They can create false reassurance, so collaborative safety planning and means restriction are preferred. A contract does not reliably prevent suicide, is not legally binding, and does not remove the need for continued follow-up.

256. A 24-year-old man is brought to the emergency department after smoking a substance, with marked anxiety, a feeling of slowed time, conjunctival injection, dry mouth, increased appetite, and tachycardia. He is not aggressive and has no nystagmus. Which substance most likely accounts for his presentation?
     • Cocaine
     • Phencyclidine
     • Cannabis
     • Heroin

     Correct answer: Cannabis

     Cannabis is correct. Acute cannabis intoxication produces conjunctival injection, dry mouth, increased appetite, tachycardia, and altered time perception, sometimes with anxiety or paranoia. Cocaine causes sympathetic excess with dilated pupils and agitation, phencyclidine causes violent agitation and nystagmus, and heroin causes sedation and pinpoint pupils.

257. A 19-year-old man who uses heroin daily presents 12 hours after his last use with dilated pupils, yawning, lacrimation, rhinorrhea, piloerection, myalgias, abdominal cramps, and diarrhea. He is uncomfortable but his vital signs are not life-threatening. Which is the most likely diagnosis?
     • Opioid intoxication
     • Alcohol withdrawal
     • Stimulant intoxication
     • Opioid withdrawal

     Correct answer: Opioid withdrawal

     Opioid withdrawal is correct. It produces dilated pupils, yawning, lacrimation, rhinorrhea, piloerection, myalgias, and gastrointestinal symptoms, and although intensely uncomfortable it is generally not life-threatening in otherwise healthy adults. Opioid intoxication causes pinpoint pupils and sedation, alcohol withdrawal causes hyperadrenergic symptoms with seizure and delirium risk, and stimulant intoxication causes agitation and sympathetic excess.

258. A 30-year-old man with severe opioid use disorder wants to begin buprenorphine-naloxone maintenance. To avoid precipitating acute withdrawal, when should the first dose be given?
     • Only once he is showing objective signs of early to moderate opioid withdrawal
     • Immediately after his last opioid dose while he still feels well
     • After a week of complete abstinence with no symptoms
     • Only while he is acutely intoxicated

     Correct answer: Only once he is showing objective signs of early to moderate opioid withdrawal

     Initiating buprenorphine only once the patient shows objective signs of early to moderate withdrawal is correct. Because buprenorphine is a partial agonist with high receptor affinity, giving it while full agonists still occupy receptors can displace them and precipitate withdrawal, so it is started after withdrawal has begun. Dosing immediately after last use or during intoxication risks precipitated withdrawal, and waiting a fully asymptomatic week is unnecessary and impractical.

259. A 21-year-old man is brought in agitated and euphoric with dilated pupils, hypertension, tachycardia, hyperthermia, and a perforated nasal septum. He admits to snorting a stimulant repeatedly. Which complication is he at greatest acute risk for during this intoxication?
     • Respiratory depression and apnea
     • Myocardial ischemia and seizures
     • Profound bradycardia
     • Hypoglycemic coma

     Correct answer: Myocardial ischemia and seizures

     Myocardial ischemia and seizures are correct. Cocaine intoxication causes intense sympathetic stimulation and coronary vasoconstriction, raising the risk of myocardial ischemia, arrhythmia, seizures, and hyperthermia. Respiratory depression and bradycardia are features of opioid rather than stimulant toxicity, and hypoglycemic coma is unrelated to cocaine intoxication.

260. A 14-year-old boy is brought in after inhaling fumes from a can of spray paint to get high, presenting with euphoria, slurred speech, ataxia, and a faint chemical odor with a perioral rash. Which substance category does this represent?
     • Opioids
     • Cannabinoids
     • Inhalants
     • Benzodiazepines

     Correct answer: Inhalants

     Inhalants are correct. Volatile substances such as those in spray paint, glue, and solvents produce rapid, brief intoxication with euphoria, slurred speech, and ataxia, sometimes with a perioral rash and chemical odor, and are more common among adolescents. Opioids cause sedation and pinpoint pupils, cannabinoids cause conjunctival injection and increased appetite, and benzodiazepines cause sedation without the chemical odor and perioral findings.

261. A 27-year-old woman with a history of childhood trauma reports periods where she suddenly finds herself in places with no memory of how she got there, and family describe times she seems to be a different person with a distinct name and behaviors. Which is the most likely diagnosis?
     • Borderline personality disorder
     • Bipolar I disorder
     • Schizophrenia
     • Dissociative identity disorder

     Correct answer: Dissociative identity disorder

     Dissociative identity disorder is correct. It involves two or more distinct personality states and recurrent gaps in memory for everyday events, often associated with severe early trauma. Borderline personality disorder features instability of mood and relationships without distinct alternating identities, bipolar I disorder involves mood episodes rather than identity disruption, and schizophrenia involves psychosis rather than separate identity states.

262. A 34-year-old man is brought in after disappearing for three weeks; he was found living in another city under a new name with no memory of his prior identity, having left abruptly after a major financial crisis. He is otherwise alert and oriented to the present. Which is the most likely diagnosis?
     • Dissociative amnesia with dissociative fugue
     • Delirium
     • Malingering
     • Transient global amnesia

     Correct answer: Dissociative amnesia with dissociative fugue

     Dissociative amnesia with dissociative fugue is correct. Dissociative fugue involves sudden, unexpected travel away from home with inability to recall one's past and sometimes assumption of a new identity, typically precipitated by severe stress. Delirium causes fluctuating attention and a clouded sensorium, transient global amnesia is a brief self-limited memory episode without travel or new identity, and malingering involves conscious feigning for external gain.

263. A 26-year-old woman has a pervasive pattern of unstable relationships, recurrent self-harm, intense fear of abandonment, identity disturbance, and rapidly shifting moods lasting hours. Which psychotherapy has the strongest evidence as a first-line treatment for this personality disorder?
     • Aversion therapy
     • Dialectical behavior therapy
     • Long-term benzodiazepine therapy
     • Standard exposure therapy

     Correct answer: Dialectical behavior therapy

     Dialectical behavior therapy is correct. It is the best-supported first-line treatment for borderline personality disorder, targeting emotion regulation, distress tolerance, and self-harm. Aversion therapy and standard exposure therapy do not address this disorder, and benzodiazepines are not a treatment and may worsen impulsivity.

264. A 40-year-old woman has a longstanding pattern of excessive emotionality and attention-seeking, dressing provocatively, speaking dramatically with little detail, and feeling uncomfortable when she is not the center of attention. Which personality disorder best fits this pattern?
     • Narcissistic personality disorder
     • Dependent personality disorder
     • Histrionic personality disorder
     • Obsessive-compulsive personality disorder

     Correct answer: Histrionic personality disorder

     Histrionic personality disorder is correct. It is a Cluster B disorder marked by pervasive attention-seeking, excessive and shallow emotionality, theatrical behavior, and discomfort when not the center of attention. Narcissistic personality disorder centers on grandiosity and entitlement, dependent personality disorder on submissive clinging behavior, and obsessive-compulsive personality disorder on rigidity and perfectionism.

265. A 45-year-old man is described by colleagues as a perfectionist who is preoccupied with rules, lists, and order to the point that tasks are never finished, is rigidly inflexible about morality, and cannot delegate work. He does not have true obsessions or compulsions. Which personality disorder best fits?
     • Obsessive-compulsive disorder
     • Paranoid personality disorder
     • Schizotypal personality disorder
     • Obsessive-compulsive personality disorder

     Correct answer: Obsessive-compulsive personality disorder

     Obsessive-compulsive personality disorder is correct. It is a pervasive pattern of preoccupation with orderliness, perfectionism, and control at the expense of flexibility and efficiency, without the true obsessions and compulsions seen in obsessive-compulsive disorder. Obsessive-compulsive disorder is an anxiety-related disorder with intrusive thoughts and rituals, paranoid personality disorder centers on distrust, and schizotypal personality disorder on odd beliefs and perceptual distortions.

266. A 32-year-old woman has a longstanding pattern of pervasive distrust, reading hidden demeaning meanings into benign remarks, bearing grudges, and questioning the loyalty of friends, without hallucinations or a fixed delusion. Which personality disorder best fits?
     • Paranoid personality disorder
     • Schizoid personality disorder
     • Delusional disorder
     • Avoidant personality disorder

     Correct answer: Paranoid personality disorder

     Paranoid personality disorder is correct. It is a Cluster A disorder defined by pervasive distrust and suspiciousness, interpreting others' motives as malevolent, without psychotic symptoms or a sustained fixed delusion. Schizoid personality disorder involves detachment and indifference rather than suspicion, delusional disorder involves a fixed false belief, and avoidant personality disorder is driven by fear of rejection rather than distrust.

267. A 23-year-old man develops acute onset of delusions, hallucinations, and disorganized speech lasting three weeks following the sudden death of his mother, then returns fully to his prior level of functioning. Which is the most likely diagnosis?
     • Schizophrenia
     • Brief psychotic disorder
     • Schizophreniform disorder
     • Delusional disorder

     Correct answer: Brief psychotic disorder

     Brief psychotic disorder is correct. It involves at least one psychotic symptom lasting more than one day but less than one month with full return to baseline, often precipitated by a marked stressor. Schizophreniform disorder lasts one to six months, schizophrenia requires at least six months of symptoms, and delusional disorder involves a persistent delusion without the other prominent psychotic features.

268. A 25-year-old man has had hallucinations, disorganized speech, and social withdrawal for three months that are not explained by a mood disorder or substance use. The symptoms have persisted beyond one month but for less than six months. Which is the most likely diagnosis?
     • Brief psychotic disorder
     • Schizophrenia
     • Schizophreniform disorder
     • Schizoaffective disorder

     Correct answer: Schizophreniform disorder

     Schizophreniform disorder is correct. It is diagnosed when characteristic schizophrenia symptoms last at least one month but less than six months. Brief psychotic disorder resolves within one month, schizophrenia requires symptoms for at least six months, and schizoaffective disorder requires a concurrent major mood episode along with periods of psychosis without mood symptoms.

269. A 30-year-old man with schizophrenia has been stable on an oral antipsychotic but repeatedly stops taking it, leading to relapses and rehospitalizations. He agrees that adherence is his main barrier. Which intervention most directly addresses this problem?
     • Doubling the oral dose
     • Adding a daily benzodiazepine
     • Discontinuing antipsychotics and using therapy alone
     • Switching to a long-acting injectable antipsychotic

     Correct answer: Switching to a long-acting injectable antipsychotic

     Switching to a long-acting injectable antipsychotic is correct. Long-acting injectables are given every few weeks to months and improve adherence in patients who struggle to take daily oral medication, reducing relapse. Doubling the oral dose does not solve nonadherence, a benzodiazepine does not treat the psychosis, and stopping antipsychotics would worsen the illness.

270. A 22-year-old woman started on a high-potency antipsychotic two days ago suddenly develops a sustained, painful contraction of her neck muscles twisting her head to one side, along with an upward deviation of her eyes. She is afebrile with normal mentation. Which is the most appropriate immediate treatment?
     • Intramuscular benztropine or diphenhydramine
     • Dantrolene
     • Increasing the antipsychotic dose
     • Lithium

     Correct answer: Intramuscular benztropine or diphenhydramine

     Intramuscular benztropine or diphenhydramine is correct. The acute dystonic reaction described, with torticollis and oculogyric crisis shortly after starting a high-potency antipsychotic, is treated rapidly with an anticholinergic or antihistamine. Dantrolene is used for malignant hyperthermia and severe neuroleptic malignant syndrome, increasing the antipsychotic would worsen the reaction, and lithium has no role here.

271. A 60-year-old woman who has taken a first-generation antipsychotic for years develops involuntary repetitive lip-smacking, tongue protrusion, and chewing movements that persist even when the drug is reduced. Which adverse effect does this represent?
     • Acute dystonia
     • Tardive dyskinesia
     • Akathisia
     • Parkinsonism

     Correct answer: Tardive dyskinesia

     Tardive dyskinesia is correct. It is a late-onset movement disorder from chronic dopamine-receptor blockade, classically producing involuntary orofacial movements such as lip-smacking and tongue protrusion that can be irreversible. Acute dystonia occurs early with sustained muscle contractions, akathisia is a subjective restlessness, and drug-induced parkinsonism causes tremor, rigidity, and bradykinesia rather than choreiform orofacial movements.

272. A 35-year-old man started on an antipsychotic two weeks ago complains of an intense inner sense of restlessness and an inability to sit still, constantly pacing and shifting in his chair, which he finds distressing. There is no rigidity or fever. Which adverse effect is most likely?
     • Tardive dyskinesia
     • Neuroleptic malignant syndrome
     • Akathisia
     • Acute dystonia

     Correct answer: Akathisia

     Akathisia is correct. It is an antipsychotic-induced syndrome of subjective inner restlessness and an irresistible urge to move, often relieved by reducing the dose or adding a beta-blocker. Tardive dyskinesia is a late involuntary movement disorder, neuroleptic malignant syndrome involves fever and rigidity, and acute dystonia produces sustained abnormal muscle contractions rather than restlessness.

273. A 48-year-old woman taking a second-generation antipsychotic for two years is found to have new weight gain, a fasting glucose of 138 mg/dL, and elevated triglycerides. Which adverse effect category does this represent, and what monitoring is indicated?
     • Extrapyramidal symptoms, warranting movement assessment only
     • Agranulocytosis, warranting weekly neutrophil counts
     • QT prolongation, warranting only ECG monitoring
     • Metabolic syndrome, warranting regular weight, glucose, and lipid monitoring

     Correct answer: Metabolic syndrome, warranting regular weight, glucose, and lipid monitoring

     Metabolic syndrome warranting regular weight, glucose, and lipid monitoring is correct. Second-generation antipsychotics frequently cause weight gain, hyperglycemia, and dyslipidemia, so periodic monitoring of weight, fasting glucose, and lipids is recommended. Extrapyramidal monitoring addresses movement effects, neutrophil counts are specific to clozapine-related agranulocytosis, and ECG monitoring addresses QT effects rather than these metabolic abnormalities.

274. A 31-year-old woman is brought in by her partner who reports that for the past week she has slept only two hours a night yet is full of energy, talking rapidly, spending impulsively, and convinced she will start three new businesses. She has been hospitalized once before for similar behavior. Which is the most likely diagnosis?
     • Bipolar I disorder
     • Bipolar II disorder
     • Cyclothymic disorder
     • Major depressive disorder

     Correct answer: Bipolar I disorder

     Bipolar I disorder is correct. A full manic episode with decreased need for sleep, grandiosity, pressured speech, impulsivity, and marked impairment, especially with a prior similar hospitalization, defines bipolar I disorder. Bipolar II disorder requires hypomania without full mania, cyclothymic disorder involves chronic subthreshold symptoms, and major depressive disorder lacks manic symptoms.

275. A 29-year-old woman with bipolar disorder is severely depressed and her physician wants to add an antidepressant. Which precaution is most important when treating bipolar depression with an antidepressant?
     • Antidepressants are always preferred as monotherapy for bipolar depression
     • Antidepressants should be combined with a mood stabilizer to reduce the risk of inducing a manic switch
     • Stimulants should replace mood stabilizers in this setting
     • Mood stabilizers must be stopped before starting any antidepressant

     Correct answer: Antidepressants should be combined with a mood stabilizer to reduce the risk of inducing a manic switch

     Combining an antidepressant with a mood stabilizer to reduce the risk of a manic switch is correct. Antidepressant monotherapy in bipolar disorder can precipitate mania or rapid cycling, so a mood stabilizer or appropriate antipsychotic should be in place. Antidepressant monotherapy is not preferred, stimulants do not replace mood stabilizers, and stopping the mood stabilizer would remove the very protection against a switch.

276. A 26-year-old man newly started on lithium asks how the medication will be monitored. Which monitoring is most important given lithium's narrow therapeutic index and route of elimination?
     • Liver enzymes and complete blood counts only
     • Daily electrocardiograms indefinitely
     • Serum lithium levels along with renal and thyroid function
     • No laboratory monitoring is required

     Correct answer: Serum lithium levels along with renal and thyroid function

     Monitoring serum lithium levels along with renal and thyroid function is correct. Lithium has a narrow therapeutic window, is cleared by the kidneys, and can cause thyroid and renal effects, so periodic levels with renal and thyroid testing are essential. Liver enzymes are not the primary concern, daily indefinite ECGs are unnecessary, and skipping monitoring would be dangerous.

277. A 35-year-old woman started on lamotrigine for bipolar maintenance develops a spreading rash with mucosal involvement and skin sloughing. Which is the most appropriate immediate action?
     • Reassure her it is a benign drug rash and continue the medication
     • Double the lamotrigine dose to push through tolerance
     • Add a second mood stabilizer and continue lamotrigine
     • Stop lamotrigine immediately and evaluate for a serious cutaneous reaction

     Correct answer: Stop lamotrigine immediately and evaluate for a serious cutaneous reaction

     Stopping lamotrigine immediately and evaluating for a serious cutaneous reaction is correct. Lamotrigine can cause life-threatening rashes such as Stevens-Johnson syndrome, especially with rapid titration, so any rash with mucosal involvement or systemic features mandates prompt discontinuation. Continuing or increasing the drug or adding another agent while exposure continues would be dangerous.

278. A 30-year-old woman is preoccupied for hours each day with the belief that her nose is grotesquely deformed, though others see it as normal. She repeatedly checks mirrors, seeks cosmetic consultations, and avoids social situations because of it. Which is the most likely diagnosis?
     • Body dysmorphic disorder
     • Anorexia nervosa
     • Illness anxiety disorder
     • Social anxiety disorder

     Correct answer: Body dysmorphic disorder

     Body dysmorphic disorder is correct. It involves preoccupation with one or more perceived defects in physical appearance that are not observable or appear slight to others, with repetitive behaviors such as mirror-checking and significant distress or impairment. Anorexia nervosa centers on body weight and shape with food restriction, illness anxiety disorder centers on fear of having a disease, and social anxiety disorder centers on fear of scrutiny in social situations generally.

279. A 68-year-old man whose home is filled to the ceiling with accumulated items he cannot discard, creating fire and fall hazards, becomes extremely distressed at any suggestion to throw things away. Which is the most likely diagnosis?
     • Obsessive-compulsive disorder
     • Hoarding disorder
     • Major depressive disorder
     • Generalized anxiety disorder

     Correct answer: Hoarding disorder

     Hoarding disorder is correct. It is characterized by persistent difficulty discarding possessions due to a perceived need to save them, resulting in accumulation that congests living spaces and causes distress or impairment. Obsessive-compulsive disorder involves intrusive obsessions and rituals, major depressive disorder centers on mood, and generalized anxiety disorder on pervasive worry rather than acquisition and saving of objects.

280. A 7-year-old boy who is fully toilet-trained begins repeatedly wetting the bed at night after the birth of a sibling. A medical workup, including urinalysis, is normal, and the episodes occur more than twice a week for several months. Which is the most appropriate first-line behavioral intervention?
     • Long-term oral antibiotics
     • Fluid loading before bedtime
     • An enuresis alarm
     • Indefinite diaper use without other measures

     Correct answer: An enuresis alarm

     An enuresis alarm is correct. For nocturnal enuresis without an organic cause, behavioral measures such as an enuresis alarm are first-line and have the most durable benefit, with desmopressin as a pharmacologic option for select situations. Antibiotics treat infection, which is excluded here, fluid loading before bed would worsen wetting, and indefinite diapers alone do not address the problem.

281. A 5-year-old girl speaks normally and freely at home with family but has consistently failed to speak at all in preschool and other social settings for the past eight months, interfering with her schooling. Her hearing and language development are otherwise normal. Which is the most likely diagnosis?
     • Autism spectrum disorder
     • Intellectual disability
     • Social anxiety disorder of adulthood
     • Selective mutism

     Correct answer: Selective mutism

     Selective mutism is correct. It is an anxiety-related childhood disorder in which a child who can speak normally consistently fails to speak in specific social situations, such as school, despite speaking in others, for at least one month and interfering with functioning. Autism spectrum disorder involves pervasive social-communication deficits across settings, intellectual disability involves global cognitive impairment, and adult social anxiety disorder is not the appropriate label for this young child's situational mutism.

282. A 38-year-old man with no medical illness reports that for several months he has felt persistently sad, but during a clinical interview he denies any thoughts of harming himself and has no plan, while still meeting criteria for a major depressive episode. Which action remains essential at this visit despite his denial of suicidal thoughts?
     • Documenting a focused suicide risk assessment including risk and protective factors
     • Skipping any further suicide inquiry because he denied ideation
     • Discharging without a follow-up plan
     • Avoiding any mention of self-harm to prevent distress

     Correct answer: Documenting a focused suicide risk assessment including risk and protective factors

     Documenting a focused suicide risk assessment including risk and protective factors is correct. Every patient with major depression warrants a suicide risk assessment that weighs risk and protective factors and informs the safety and follow-up plan, even when current ideation is denied. Skipping further inquiry, discharging without follow-up, and avoiding the topic all neglect the standard of care for a depressed patient.

283. A 17-year-old girl is brought in by her parents because she insists she is overweight despite a body mass index of 16, restricts her eating severely, and exercises compulsively. She has not had a menstrual period in four months. Which physiologic finding is most directly explained by her starvation state?
     • Hypertension and tachycardia
     • Bradycardia and amenorrhea
     • Hyperthermia
     • Leukocytosis with fever

     Correct answer: Bradycardia and amenorrhea

     Bradycardia and amenorrhea are correct. The starvation physiology of anorexia nervosa lowers metabolic rate and produces bradycardia, hypotension, hypothermia, and hypothalamic suppression causing amenorrhea. Hypertension with tachycardia and hyperthermia are the opposite of the expected starvation findings, and leukocytosis with fever is not characteristic of uncomplicated anorexia nervosa.

284. A 64-year-old man with stage G4 chronic kidney disease is admitted with worsening shortness of breath and bilateral leg edema. His blood pressure is 172/96 mm Hg, jugular venous pressure is elevated, and he has crackles at both lung bases. His urine output remains adequate. Which is the most appropriate initial therapy to relieve his volume overload?
     • An intravenous loop diuretic, often at higher doses than usual
     • A liberal intravenous saline bolus
     • An oral thiazide diuretic as monotherapy
     • Withholding all diuretics and observing

     Correct answer: An intravenous loop diuretic, often at higher doses than usual

     An intravenous loop diuretic, often at higher doses than usual, is the most appropriate initial therapy. Volume overload in chronic kidney disease is treated with loop diuretics, and reduced filtration means higher doses are needed for an adequate amount of drug to reach its tubular site of action. A saline bolus would worsen overload, a thiazide alone is weak in advanced kidney disease, and withholding diuretics leaves the congestion untreated.

285. A 71-year-old man with chronic kidney disease (estimated GFR 26 mL/min/1.73 m2) and hypertension with an albumin-to-creatinine ratio of 800 mg/g is reviewed for blood pressure management. He is not currently on a renin-angiotensin system agent and his potassium is 4.3 mEq/L. Which antihypertensive class provides the greatest kidney protection in proteinuric chronic kidney disease?
     • A peripheral alpha-1 blocker
     • An angiotensin-converting enzyme inhibitor or angiotensin receptor blocker
     • A short-acting dihydropyridine calcium channel blocker
     • A centrally acting alpha-2 agonist

     Correct answer: An angiotensin-converting enzyme inhibitor or angiotensin receptor blocker

     An angiotensin-converting enzyme inhibitor or angiotensin receptor blocker provides the greatest kidney protection in proteinuric chronic kidney disease. By reducing intraglomerular pressure and proteinuria, these agents slow progression beyond their blood-pressure effect, making them first-line when albuminuria is present and potassium permits. Alpha-blockers, central agonists, and short-acting calcium channel blockers lower blood pressure but lack this specific antiproteinuric, kidney-protective benefit.

286. A 58-year-old man with chronic kidney disease is started on an angiotensin-converting enzyme inhibitor for proteinuria. At a follow-up visit two weeks later, his serum creatinine has risen from 1.6 mg/dL to 1.9 mg/dL and his potassium is 4.8 mEq/L. He is asymptomatic and euvolemic. Which is the most appropriate next step?
     • Stop the medication permanently because any rise signals harm
     • Double the dose to overcome the resistance
     • Continue the medication because this degree of creatinine rise is acceptable
     • Add a potassium-sparing diuretic to the regimen

     Correct answer: Continue the medication because this degree of creatinine rise is acceptable

     Continuing the medication is most appropriate because a rise in creatinine of up to roughly 30% that then stabilizes is expected and acceptable after starting renin-angiotensin blockade, reflecting reduced intraglomerular pressure rather than injury. A larger or progressive rise or hyperkalemia would prompt re-evaluation. Stopping for a small expected rise forgoes kidney protection, doubling the dose is not indicated, and adding a potassium-sparing diuretic raises hyperkalemia risk.

287. A 49-year-old man with biopsy-proven membranous nephropathy has nephrotic-range proteinuria and a serum albumin of 2.1 g/dL. His clinician notes he is at increased risk of a particular type of complication that warrants consideration of prophylaxis. Which complication is the heavy urinary protein loss most likely to predispose him to?
     • Hemorrhagic stroke
     • Aplastic anemia
     • Acute pancreatitis
     • Venous thromboembolism

     Correct answer: Venous thromboembolism

     Venous thromboembolism is the complication he is most likely to develop. The nephrotic syndrome, especially membranous nephropathy with marked hypoalbuminemia, creates a hypercoagulable state through urinary loss of anticoagulant proteins such as antithrombin, increasing the risk of deep vein and renal vein thrombosis. Hemorrhagic stroke, aplastic anemia, and acute pancreatitis are not characteristic consequences of heavy proteinuria.

288. A 6-year-old boy with steroid-sensitive minimal change disease is in the nephrotic phase with marked edema and a serum albumin of 1.8 g/dL. His parents ask why he is more prone to infections during a flare. Which mechanism best explains the increased infection risk in the nephrotic syndrome?
     • Urinary loss of immunoglobulins and complement factors
     • Bone marrow failure caused by the proteinuria
     • Excess production of neutralizing antibodies
     • Direct toxic effect of edema on lymphocytes

     Correct answer: Urinary loss of immunoglobulins and complement factors

     Urinary loss of immunoglobulins and complement factors best explains the increased infection risk. In the nephrotic syndrome the damaged glomerular barrier allows loss of protective proteins, lowering opsonizing antibody and complement and predisposing to infections such as pneumococcal peritonitis. Proteinuria does not cause marrow failure or boost neutralizing antibody, and edema is not directly toxic to lymphocytes.

289. A 52-year-old man with longstanding type 2 diabetes is found to have nephrotic-range proteinuria and a slowly declining estimated GFR over several years, with retinopathy on examination and no hematuria. His urine sediment is bland. Which is the most likely diagnosis without need for biopsy?
     • Rapidly progressive glomerulonephritis
     • Diabetic nephropathy
     • Acute interstitial nephritis
     • Renal artery thrombosis

     Correct answer: Diabetic nephropathy

     Diabetic nephropathy is the most likely diagnosis. In a patient with longstanding diabetes, gradually worsening proteinuria and kidney function with concurrent retinopathy and a bland sediment is the classic clinical picture, and biopsy is usually unnecessary when this typical pattern is present. Rapidly progressive glomerulonephritis has an active sediment with crescents, interstitial nephritis follows a drug exposure, and arterial thrombosis presents acutely.

290. A 32-year-old African American man with poorly controlled hypertension and a family history of kidney failure is found to have an estimated GFR of 40 mL/min/1.73 m2 with modest proteinuria and a bland sediment. Biopsy shows global and focal segmental glomerulosclerosis with hypertensive arteriolar changes. Which is the most important long-term intervention to slow his kidney disease?
     • Chronic high-dose corticosteroids
     • A permanent low-protein, low-calorie diet
     • Aggressive blood pressure control, preferably with renin-angiotensin blockade
     • Empiric long-term antibiotics

     Correct answer: Aggressive blood pressure control, preferably with renin-angiotensin blockade

     Aggressive blood pressure control, preferably with renin-angiotensin blockade, is the most important long-term intervention. Hypertensive nephrosclerosis is driven by elevated pressure transmitted to the glomeruli, so reaching target blood pressure with agents that also reduce proteinuria slows progression. Corticosteroids treat inflammatory glomerulonephritis rather than nephrosclerosis, severe caloric restriction is not the answer, and antibiotics are unrelated.

291. A 70-year-old man on hemodialysis is brought to the emergency department after missing two dialysis sessions, with weakness and palpitations. His potassium is 7.4 mEq/L, and the electrocardiogram shows widened QRS complexes. After intravenous calcium is administered, which combination of measures will most rapidly shift potassium into cells while definitive removal is arranged?
     • Oral potassium binder alone
     • Intravenous normal saline bolus alone
     • A potassium-sparing diuretic
     • Insulin with dextrose plus a nebulized beta-2 agonist

     Correct answer: Insulin with dextrose plus a nebulized beta-2 agonist

     Insulin with dextrose plus a nebulized beta-2 agonist will most rapidly shift potassium into cells. Both drive potassium intracellularly within minutes, lowering the serum level temporarily while dialysis is mobilized to remove the excess from the body. An oral potassium binder works too slowly for an emergency, saline does not shift potassium intracellularly, and a potassium-sparing diuretic would worsen the hyperkalemia.

292. A 68-year-old woman with chronic kidney disease and recurrent hyperkalemia is maintained on an angiotensin receptor blocker that her clinician wishes to continue for kidney and heart protection. Her potassium runs persistently around 5.6 mEq/L on a low-potassium diet. Which therapy best allows continuation of the renin-angiotensin blocker by chronically lowering potassium?
     • A potassium-binding resin such as patiromer or sodium zirconium cyclosilicate
     • Daily intravenous calcium gluconate
     • Routine prophylactic hemodialysis
     • A potassium supplement to test tolerance

     Correct answer: A potassium-binding resin such as patiromer or sodium zirconium cyclosilicate

     A potassium-binding resin such as patiromer or sodium zirconium cyclosilicate best allows continuation of the renin-angiotensin blocker. These oral binders chronically increase fecal potassium excretion, controlling hyperkalemia so a guideline-recommended blocker can be maintained. Daily intravenous calcium only stabilizes the membrane acutely, prophylactic dialysis is not indicated for mild chronic hyperkalemia, and potassium supplementation would be harmful.

293. A 55-year-old man on chronic dialysis is found to have a serum potassium of 6.2 mEq/L on routine pre-dialysis labs. He is asymptomatic, and his electrocardiogram is reviewed for changes that would prompt urgent treatment. Which electrocardiographic finding is the earliest characteristic change of hyperkalemia?
     • A prolonged QT interval
     • Peaked T waves
     • Delta waves
     • Deep symmetric T-wave inversions

     Correct answer: Peaked T waves

     Peaked T waves are the earliest characteristic electrocardiographic change of hyperkalemia. As potassium rises, repolarization is altered and the T waves become tall and peaked, later progressing to PR prolongation, QRS widening, and a sine-wave pattern. A prolonged QT interval is typical of hypokalemia or hypocalcemia, delta waves indicate pre-excitation, and deep T-wave inversions reflect ischemia rather than hyperkalemia.

294. A 24-year-old man is brought in after being trapped under heavy debris for several hours, then suddenly released. Shortly after extrication he becomes hypotensive with a potassium of 7.0 mEq/L, dark urine, and a markedly elevated creatine kinase. Which mechanism is most directly responsible for the dangerous hyperkalemia in this crush injury?
     • Excess dietary potassium intake during entrapment
     • Reduced aldosterone secretion
     • Release of intracellular potassium from damaged muscle cells
     • A respiratory alkalosis shifting potassium out of cells

     Correct answer: Release of intracellular potassium from damaged muscle cells

     Release of intracellular potassium from damaged muscle cells is most directly responsible. Crush injury with rhabdomyolysis liberates large amounts of potassium and myoglobin from necrotic muscle, and reperfusion floods the circulation, causing life-threatening hyperkalemia that can precipitate arrest. Dietary intake, reduced aldosterone, and alkalosis do not account for the acute potassium surge from muscle breakdown.

295. A 60-year-old man with type 2 diabetes is found on routine labs to have a potassium of 5.9 mEq/L with a mild normal-anion-gap metabolic acidosis and a relatively normal estimated GFR. His renin and aldosterone are both low. Which condition best explains this combination of hyperkalemia and acidosis?
     • Distal type 1 renal tubular acidosis
     • Diabetic ketoacidosis
     • Primary hyperaldosteronism
     • Type 4 renal tubular acidosis (hyporeninemic hypoaldosteronism)

     Correct answer: Type 4 renal tubular acidosis (hyporeninemic hypoaldosteronism)

     Type 4 renal tubular acidosis from hyporeninemic hypoaldosteronism best explains this combination. In diabetic kidney disease, reduced renin and aldosterone impair potassium and acid excretion, producing a hyperkalemic, normal-anion-gap acidosis with relatively preserved filtration. Distal type 1 acidosis causes hypokalemia, diabetic ketoacidosis is a high-gap state, and primary hyperaldosteronism causes hypokalemia with hypertension.

296. A 78-year-old man with severe benign prostatic hyperplasia and chronic incomplete bladder emptying is found to have an estimated GFR of 30 mL/min/1.73 m2 and bilateral hydronephrosis on ultrasound. He has no flank pain. Which mechanism best explains his chronic kidney injury?
     • Chronic bladder outlet obstruction transmitting back-pressure to both kidneys
     • Immune-complex glomerulonephritis
     • Bilateral renal artery atherosclerosis
     • Crystal-induced tubular obstruction

     Correct answer: Chronic bladder outlet obstruction transmitting back-pressure to both kidneys

     Chronic bladder outlet obstruction transmitting back-pressure to both kidneys best explains the injury. Long-standing prostatic obstruction with high residual volumes raises pressure throughout the urinary tract, producing bilateral hydronephrosis and obstructive nephropathy that can be partly reversed by relieving the obstruction. Glomerulonephritis, renal artery disease, and crystal nephropathy do not produce this bilateral hydronephrotic, obstructive picture.

297. A 72-year-old man with severe benign prostatic hyperplasia in acute urinary retention has 1,400 mL drained after catheter placement. Over the next several hours he produces more than 250 mL of urine per hour. Which complication should be anticipated and monitored after relief of the obstruction?
     • Immediate anuria from tubular shutdown
     • Postobstructive diuresis with volume depletion and electrolyte loss
     • Rapidly rising serum potassium
     • Acute hypertensive crisis from fluid overload

     Correct answer: Postobstructive diuresis with volume depletion and electrolyte loss

     Postobstructive diuresis with volume depletion and electrolyte loss should be anticipated. After relief of a chronic obstruction, the previously stressed tubules transiently cannot concentrate urine or conserve sodium and water, leading to brisk diuresis that requires monitoring of volume status and electrolytes with judicious replacement. Anuria, rising potassium, and a hypertensive crisis are not the expected sequelae of relieving obstruction.

298. A 65-year-old man with benign prostatic hyperplasia who also has poorly controlled symptomatic orthostatic hypotension needs medical therapy for his urinary symptoms. His clinician wants an alpha-blocker less likely to lower his blood pressure. Which agent is the most appropriate uroselective choice?
     • Doxazosin
     • Terazosin
     • Tamsulosin or silodosin
     • Prazosin

     Correct answer: Tamsulosin or silodosin

     Tamsulosin or silodosin is the most appropriate choice. These uroselective alpha-1A blockers act preferentially on prostatic and bladder neck smooth muscle with less effect on vascular alpha-1 receptors, so they cause less orthostatic hypotension than the nonselective agents. Doxazosin, terazosin, and prazosin have greater blood-pressure-lowering effects and are more likely to worsen orthostasis.

299. A 67-year-old man is found on screening to have a prostate-specific antigen of 9 ng/mL, and a subsequent biopsy confirms localized prostate adenocarcinoma. The pathologist reports a Gleason score. What does the Gleason score primarily describe about the tumor?
     • The serum prostate-specific antigen level
     • The number of positive lymph nodes
     • The presence of distant metastases
     • The histologic grade based on the architectural differentiation of the cancer

     Correct answer: The histologic grade based on the architectural differentiation of the cancer

     The Gleason score primarily describes the histologic grade based on the architectural differentiation of the cancer. Pathologists sum the two most prevalent glandular patterns to grade how aggressive the tumor appears, which helps guide prognosis and treatment. It does not report the prostate-specific antigen level, nodal count, or distant spread, which are captured separately by staging.

300. A 58-year-old man with metastatic prostate adenocarcinoma is started on systemic therapy. His oncologist explains that the mainstay of treatment for advanced prostate cancer targets the hormone that drives tumor growth. Which therapeutic strategy is the foundation of treatment for metastatic prostate cancer?
     • Androgen deprivation therapy
     • High-dose estrogen replacement
     • Thyroid hormone suppression
     • Insulin sensitization

     Correct answer: Androgen deprivation therapy

     Androgen deprivation therapy is the foundation of treatment for metastatic prostate cancer. Because prostate adenocarcinoma growth is androgen-dependent, lowering testosterone with gonadotropin-releasing hormone agonists or antagonists, or with antiandrogens, slows progression. Estrogen replacement, thyroid suppression, and insulin sensitization do not target the androgen pathway that drives this cancer.

301. A 70-year-old man presents with fever, perineal pain, dysuria, and an exquisitely tender prostate on gentle rectal examination, with pyuria and bacteriuria. His clinician is asked about an aspect of the examination. Which action should be avoided in suspected acute bacterial prostatitis?
     • Obtaining a urine culture
     • Vigorous prostatic massage
     • Starting empiric antibiotics
     • Assessing for urinary retention

     Correct answer: Vigorous prostatic massage

     Vigorous prostatic massage should be avoided in suspected acute bacterial prostatitis. Aggressive manipulation of an acutely inflamed, infected prostate can precipitate bacteremia, so only a gentle examination is performed. Obtaining a urine culture, starting empiric antibiotics, and assessing for retention are all appropriate parts of management of acute prostatitis.

302. A 38-year-old man reports several months of recurrent perineal and pelvic discomfort, dysuria, and post-ejaculatory pain. He is afebrile, urine cultures are repeatedly negative, and there is no evidence of infection. Which is the most likely diagnosis?
     • Acute bacterial prostatitis
     • Bladder cancer
     • Chronic prostatitis/chronic pelvic pain syndrome
     • Acute epididymitis

     Correct answer: Chronic prostatitis/chronic pelvic pain syndrome

     Chronic prostatitis/chronic pelvic pain syndrome is the most likely diagnosis. Persistent pelvic and perineal pain with voiding and ejaculatory symptoms, no fever, and repeatedly negative cultures characterize this common noninfectious syndrome managed symptomatically. Acute bacterial prostatitis is febrile with positive cultures, bladder cancer causes painless hematuria, and epididymitis presents with localized scrotal pain and swelling.

303. A 60-year-old man undergoing evaluation for microscopic hematuria found on a routine urinalysis has no infection, no recent vigorous exercise, and no menstrual contamination, with three or more red blood cells per high-power field confirmed on repeat testing. Given his age and smoking history, which evaluation is most appropriate to exclude urinary tract malignancy?
     • Reassurance with no further testing
     • A single repeat urinalysis only
     • Serum prostate-specific antigen alone
     • CT urography and cystoscopy

     Correct answer: CT urography and cystoscopy

     CT urography and cystoscopy are most appropriate to exclude urinary tract malignancy. Persistent microscopic hematuria in an older patient with smoking history warrants upper tract imaging plus direct bladder inspection to detect urothelial and renal cancers. Reassurance, a single repeat urinalysis, and prostate-specific antigen alone do not adequately evaluate the bladder and upper tracts for tumor.

304. A 45-year-old man notes brief, painless reddish discoloration only at the very beginning of his urinary stream that clears as he continues to void. Which anatomic location does this initial (terminal-sparing) hematuria pattern most strongly suggest as the source of bleeding?
     • The urethra
     • The kidney
     • The bladder dome
     • The ureter

     Correct answer: The urethra

     Initial hematuria appearing only at the start of voiding most strongly suggests a urethral source. Blood seen at the beginning of the stream that then clears reflects bleeding from the distal urethra washed out early, whereas total hematuria throughout voiding points to the bladder or upper tracts and terminal hematuria suggests the bladder neck or prostate. The kidney and ureter typically produce total hematuria.

305. A 30-year-old man is referred for evaluation of red-colored urine, but his urinalysis dipstick is positive for blood while microscopy shows no red blood cells. He recently completed a strenuous endurance run and has muscle soreness. Which is the most likely explanation for the discrepancy?
     • Active glomerular bleeding
     • Myoglobinuria producing a positive dipstick without red cells
     • Bladder cancer
     • A urinary tract infection

     Correct answer: Myoglobinuria producing a positive dipstick without red cells

     Myoglobinuria producing a positive dipstick without red cells is the most likely explanation. The urine heme dipstick detects both hemoglobin and myoglobin, so after exertional muscle injury, released myoglobin turns the dipstick positive even though microscopy shows no red blood cells. Glomerular bleeding and bladder cancer would show red cells on microscopy, and a urinary infection produces other characteristic findings.

306. A 35-year-old man returns from a freshwater swimming trip to sub-Saharan Africa and presents with painless terminal hematuria. Urine microscopy reveals eggs with a terminal spine. Which infection is the most likely cause of his hematuria?
     • Escherichia coli cystitis
     • Genital herpes
     • Schistosoma haematobium infection
     • Gonococcal urethritis

     Correct answer: Schistosoma haematobium infection

     Schistosoma haematobium infection is the most likely cause. Freshwater exposure in endemic regions allows this fluke to infect the urinary tract, and its terminal-spined eggs in the bladder wall cause painless hematuria and chronic inflammation that can later predispose to bladder cancer. Bacterial cystitis, herpes, and gonococcal urethritis do not produce terminal-spined eggs in the urine.

307. A 60-year-old man with metastatic small cell lung cancer is found to have a sodium of 122 mEq/L. He is clinically euvolemic, his urine osmolality is inappropriately concentrated, his urine sodium is elevated, and thyroid and adrenal function are normal. He is asymptomatic. Beyond water restriction, which oral agent specifically antagonizes the action of antidiuretic hormone to raise the sodium?
     • Desmopressin
     • A loop diuretic alone
     • Oral hypertonic saline tablets only
     • A vasopressin receptor antagonist (vaptan)

     Correct answer: A vasopressin receptor antagonist (vaptan)

     A vasopressin receptor antagonist specifically antagonizes antidiuretic hormone in the syndrome of inappropriate antidiuretic hormone secretion, promoting free-water excretion and raising the sodium when water restriction is insufficient. Desmopressin would worsen water retention, a loop diuretic alone is adjunctive, and salt tablets address only sodium intake rather than the underlying excess hormone effect.

308. A 70-year-old man with severe heart failure has a serum sodium of 126 mEq/L. On examination he has jugular venous distension, an S3 gallop, and pitting edema, with low serum osmolality and a low urine sodium. Which volume category best classifies his hyponatremia?
     • Hypervolemic hyponatremia
     • Euvolemic hyponatremia
     • Hypovolemic hyponatremia
     • Pseudohyponatremia

     Correct answer: Hypervolemic hyponatremia

     His hyponatremia is best classified as hypervolemic. In heart failure, reduced effective circulating volume triggers antidiuretic hormone and water retention despite total-body fluid excess, producing edema, elevated jugular venous pressure, a low urine sodium, and dilutional hyponatremia. This differs from euvolemic SIADH, hypovolemic depletion, and pseudohyponatremia, which lack the signs of volume overload.

309. A 19-year-old man has had lifelong episodes of weakness, polyuria, and salt craving, with persistent hypokalemia, metabolic alkalosis, and a low-to-normal blood pressure. Renin and aldosterone are elevated, and there is no diuretic use or vomiting. Which inherited tubular disorder best fits this presentation?
     • Liddle syndrome
     • Bartter or Gitelman syndrome
     • Primary hyperaldosteronism
     • Type 4 renal tubular acidosis

     Correct answer: Bartter or Gitelman syndrome

     Bartter or Gitelman syndrome best fits this presentation. These inherited tubular transport defects cause renal salt wasting with hypokalemia, metabolic alkalosis, and high renin and aldosterone, yet normal or low blood pressure, mimicking chronic diuretic use. Liddle syndrome and primary hyperaldosteronism cause hypertension with low renin, and type 4 renal tubular acidosis causes hyperkalemic acidosis.

310. A 50-year-old man hospitalized for alcohol withdrawal and poor nutrition develops generalized weakness and a serum phosphorus of 1.0 mg/dL after several days of refeeding. His kidney function is normal. Which is the most appropriate management of this severe hypophosphatemia?
     • A phosphate binder with meals
     • Restriction of dietary phosphorus
     • Intravenous phosphate repletion
     • Intravenous calcium gluconate

     Correct answer: Intravenous phosphate repletion

     Intravenous phosphate repletion is the most appropriate management of severe symptomatic hypophosphatemia. Refeeding drives phosphate into cells, and very low levels impair muscle and cellular energy function, requiring intravenous replacement with monitoring. A phosphate binder and dietary restriction would lower phosphate further, and calcium does not correct hypophosphatemia.

311. A 62-year-old man on a proton pump inhibitor and a loop diuretic presents with tetany, carpopedal spasm, and a prolonged QT interval, with a low serum calcium that does not correct after calcium replacement. His magnesium is very low. Which step is essential to successfully correct his hypocalcemia?
     • Administer a phosphate load
     • Give a thiazide diuretic
     • Start calcitonin
     • Replete the magnesium

     Correct answer: Replete the magnesium

     Repleting the magnesium is essential to correct this hypocalcemia. Severe hypomagnesemia impairs parathyroid hormone secretion and its action, causing a hypocalcemia that is refractory to calcium until the magnesium is restored. A phosphate load would worsen calcium levels, a thiazide is not the treatment, and calcitonin lowers rather than raises calcium.

312. A 55-year-old man with metastatic cancer has a serum calcium of 14.5 mg/dL, lethargy, and acute kidney injury. After diagnosis, which is the most appropriate immediate first step in management of his severe hypercalcemia?
     • Aggressive intravenous isotonic saline hydration
     • A loop diuretic before any fluids
     • Oral calcium carbonate
     • A thiazide diuretic

     Correct answer: Aggressive intravenous isotonic saline hydration

     Aggressive intravenous isotonic saline hydration is the most appropriate immediate first step. Patients with severe hypercalcemia are volume depleted, and restoring volume with saline improves perfusion and promotes urinary calcium excretion before longer-acting agents such as bisphosphonates take effect. Loop diuretics before adequate hydration worsen depletion, oral calcium raises calcium, and thiazides reduce calcium excretion.

313. A 45-year-old man with a 9 mm proximal ureteral stone causing persistent obstruction and pain undergoes a planned procedure that uses focused external acoustic energy to fragment the stone without an incision. Which intervention does this describe?
     • Percutaneous nephrolithotomy
     • Extracorporeal shock wave lithotripsy
     • Open ureterolithotomy
     • Ureteral stent placement only

     Correct answer: Extracorporeal shock wave lithotripsy

     This describes extracorporeal shock wave lithotripsy. Focused acoustic shock waves delivered from outside the body fragment a stone into passable pieces without an incision, making it suitable for certain upper-tract stones of appropriate size and location. Percutaneous nephrolithotomy and open surgery require an access tract or incision, and a stent alone relieves obstruction without fragmenting the stone.

314. A 35-year-old man passes a kidney stone and brings it for analysis, which returns as calcium oxalate, the most common stone type. His metabolic evaluation is otherwise normal aside from low fluid intake. Beyond increasing fluids, which dietary change most appropriately reduces his risk of calcium oxalate stone recurrence?
     • Severely restrict all dietary calcium
     • Increase intake of high-oxalate foods
     • Reduce sodium and animal-protein intake while maintaining normal dietary calcium
     • Add a daily oral calcium oxalate supplement

     Correct answer: Reduce sodium and animal-protein intake while maintaining normal dietary calcium

     Reducing sodium and animal-protein intake while maintaining normal dietary calcium most appropriately reduces recurrence. Lower sodium decreases urinary calcium, moderating animal protein reduces acid and urate load, and adequate dietary calcium binds oxalate in the gut to limit its absorption. Severely restricting calcium paradoxically raises oxalate absorption, and increasing oxalate intake or oxalate supplements would worsen risk.

315. A 45-year-old man with chronic kidney disease (estimated GFR 28 mL/min/1.73 m2) is scheduled for a contrast-enhanced MRI. His clinician notes a specific risk associated with one type of contrast agent in advanced kidney disease. Which serious complication is associated with gadolinium-based contrast in patients with severely reduced kidney function?
     • Acute hemolytic anemia
     • Malignant hyperthermia
     • Serotonin syndrome
     • Nephrogenic systemic fibrosis

     Correct answer: Nephrogenic systemic fibrosis

     Nephrogenic systemic fibrosis is the complication associated with gadolinium-based contrast in patients with severely reduced kidney function. Impaired clearance allows prolonged gadolinium exposure, which can trigger this fibrosing disorder of skin and other tissues, so the lowest-risk agents and careful risk assessment are used in advanced kidney disease. Hemolytic anemia, malignant hyperthermia, and serotonin syndrome are unrelated to gadolinium in this setting.

316. A 62-year-old man with metastatic cancer beginning chemotherapy with a high tumor burden develops acute kidney injury with hyperuricemia, hyperkalemia, hyperphosphatemia, and hypocalcemia shortly after treatment. Which is the most appropriate measure to prevent and treat the kidney injury from this syndrome?
     • Aggressive intravenous hydration with a urate-lowering agent such as rasburicase or allopurinol
     • Strict fluid restriction
     • Empiric broad-spectrum antibiotics
     • Oral calcium carbonate supplementation

     Correct answer: Aggressive intravenous hydration with a urate-lowering agent such as rasburicase or allopurinol

     Aggressive intravenous hydration with a urate-lowering agent such as rasburicase or allopurinol is most appropriate for tumor lysis syndrome. Rapid tumor cell breakdown releases uric acid, potassium, and phosphate that injure the kidneys, so vigorous fluids to maintain urine flow plus agents that reduce uric acid prevent and treat the acute kidney injury. Fluid restriction worsens it, antibiotics are not the issue, and calcium is given only for symptomatic hypocalcemia.

317. A 40-year-old man is admitted with severe acute pancreatitis and develops oliguric acute kidney injury with hyperkalemia, a serum bicarbonate of 10 mEq/L refractory to therapy, and pulmonary edema unresponsive to diuretics. Which intervention is most clearly indicated?
     • Continued high-dose loop diuretics only
     • Initiation of renal replacement therapy (dialysis)
     • A large isotonic fluid bolus
     • Oral sodium bicarbonate alone

     Correct answer: Initiation of renal replacement therapy (dialysis)

     Initiation of renal replacement therapy is most clearly indicated. Acute kidney injury with refractory hyperkalemia, severe acidosis, and volume overload unresponsive to medical measures meets accepted indications for urgent dialysis to correct the life-threatening derangements. Continued diuretics, a fluid bolus, and oral bicarbonate cannot adequately address these refractory, dangerous metabolic and volume problems.

318. A 67-year-old man is admitted with acute kidney injury, and microscopy of his urine sediment shows numerous muddy brown granular casts. He had several days of profound hypotension during a recent surgery. Which type of acute kidney injury do these casts most strongly indicate?
     • Prerenal azotemia
     • Acute interstitial nephritis
     • Acute tubular necrosis
     • Postrenal obstruction

     Correct answer: Acute tubular necrosis

     Muddy brown granular casts most strongly indicate acute tubular necrosis. Ischemic injury from prolonged hypotension sloughs tubular epithelial cells, which form characteristic pigmented granular casts in the urine, distinguishing intrinsic tubular injury from other causes. Prerenal azotemia has a bland sediment, interstitial nephritis shows white cells and white cell casts, and obstruction lacks these casts.

319. A 5-year-old boy develops acute kidney injury with oliguria, microangiopathic hemolytic anemia, and thrombocytopenia about a week after an episode of bloody diarrhea. Which is the most likely diagnosis?
     • Minimal change disease
     • Post-streptococcal glomerulonephritis
     • Acute interstitial nephritis
     • Hemolytic uremic syndrome

     Correct answer: Hemolytic uremic syndrome

     Hemolytic uremic syndrome is the most likely diagnosis. The triad of acute kidney injury, microangiopathic hemolytic anemia, and thrombocytopenia following a Shiga toxin-producing bacterial diarrheal illness in a young child is characteristic and managed largely with supportive care. Minimal change disease is nephrotic without hemolysis, post-streptococcal disease follows infection by one to two weeks without microangiopathy, and interstitial nephritis is drug-related.

320. A 28-year-old man with deeply pigmented skin reports that for years his urine turns dark, almost black, on standing, though he feels well and has normal kidney function. He recalls a sibling with the same finding. Urine testing reveals homogentisic acid. Which inherited metabolic disorder best explains the dark urine?
     • Alkaptonuria
     • Cystinuria
     • Primary hyperoxaluria
     • Acute intermittent porphyria

     Correct answer: Alkaptonuria

     Alkaptonuria best explains the dark urine. A deficiency of homogentisate oxidase leads to accumulation and urinary excretion of homogentisic acid, which oxidizes and darkens the urine on standing, a benign familial finding apart from later joint and connective tissue changes. Cystinuria causes stones, primary hyperoxaluria causes oxalate stones, and acute intermittent porphyria causes neurovisceral attacks rather than this benign darkening.

321. A 24-year-old man presents with severe right flank pain and gross hematuria, and a noncontrast CT scan is obtained. Which imaging study is the preferred initial test to diagnose a suspected acute ureteral stone?
     • Voiding cystourethrogram
     • Noncontrast helical CT of the abdomen and pelvis
     • Renal nuclear medicine scan
     • Contrast-enhanced MRI of the brain

     Correct answer: Noncontrast helical CT of the abdomen and pelvis

     A noncontrast helical CT of the abdomen and pelvis is the preferred initial test for a suspected acute ureteral stone. It rapidly and sensitively detects stones of nearly any composition and shows their size, location, and any obstruction, guiding management. A voiding cystourethrogram evaluates reflux, a nuclear scan assesses function rather than stones, and brain MRI is unrelated to ureteral colic.

322. A 55-year-old man with poorly controlled diabetes is admitted with severe pyelonephritis, and CT imaging shows gas within the renal parenchyma. Which is the most likely diagnosis and a key consideration in management?
     • Simple uncomplicated cystitis treated with oral antibiotics
     • A benign renal cyst
     • Emphysematous pyelonephritis, a urologic emergency often requiring drainage or nephrectomy
     • Renal artery stenosis

     Correct answer: Emphysematous pyelonephritis, a urologic emergency often requiring drainage or nephrectomy

     Emphysematous pyelonephritis is the most likely diagnosis and a urologic emergency. Gas-forming infection of the kidney, most often in poorly controlled diabetics, is life-threatening and requires prompt antibiotics, control of glucose, and frequently drainage or nephrectomy in addition to supportive care. Simple cystitis, a benign cyst, and renal artery stenosis do not produce gas within the renal parenchyma.

323. A 60-year-old man with chronic kidney disease (estimated GFR 25 mL/min/1.73 m2) needs imaging for new abdominal pain. His clinician weighs the risk of a renally cleared contrast agent against the diagnostic benefit and elects to proceed with intravenous iodinated contrast after counseling. Which periprocedural measure best reduces his risk of contrast-associated acute kidney injury?
     • A single dose of an oral nonsteroidal anti-inflammatory drug
     • Withholding all fluids before and after the scan
     • A high-protein meal before the procedure
     • Intravenous isotonic saline volume expansion around the time of contrast

     Correct answer: Intravenous isotonic saline volume expansion around the time of contrast

     Intravenous isotonic saline volume expansion around the time of contrast best reduces the risk of contrast-associated acute kidney injury. Maintaining renal perfusion and diluting the contrast load with isotonic fluid is the best-supported preventive strategy in patients with reduced kidney function. A nonsteroidal anti-inflammatory drug further reduces renal blood flow, withholding fluids promotes depletion, and a high-protein meal offers no protection.

324. A 30-year-old man develops acute scrotal pain, and color Doppler ultrasound is ordered urgently. In a patient with suspected testicular torsion, which Doppler finding most strongly supports the diagnosis and the need for emergent surgery?
     • Absent or markedly reduced blood flow to the affected testis
     • Increased blood flow to the affected testis
     • A fluid collection that transilluminates
     • Dilated veins that decompress when supine

     Correct answer: Absent or markedly reduced blood flow to the affected testis

     Absent or markedly reduced blood flow to the affected testis most strongly supports torsion and the need for emergent surgery. Twisting of the spermatic cord cuts off the testicular blood supply, so the loss of Doppler flow confirms ischemia that requires immediate detorsion to salvage the testis. Increased flow suggests inflammation such as epididymitis, a transilluminating collection indicates a hydrocele, and decompressing veins indicate a varicocele.

325. A 55-year-old man with hypertension is found to have a 3 cm solid, enhancing renal mass confined to the kidney on imaging, with normal kidney function and no metastases. He is otherwise healthy. Which is the most appropriate treatment for this localized renal cell carcinoma?
     • Systemic chemotherapy as the primary treatment
     • Surgical resection, preferably a partial (nephron-sparing) nephrectomy when feasible
     • Whole-kidney external beam radiation alone
     • Long-term observation with no intervention

     Correct answer: Surgical resection, preferably a partial (nephron-sparing) nephrectomy when feasible

     Surgical resection, preferably a partial (nephron-sparing) nephrectomy when feasible, is the most appropriate treatment for a small localized renal cell carcinoma. Removing the tumor while preserving functioning kidney tissue offers the best chance of cure and protects long-term kidney function. Renal cell carcinoma is relatively resistant to conventional chemotherapy and radiation, and simple observation is not appropriate for an enhancing solid mass in a healthy patient.

326. A 68-year-old man with cellulitis of the lower leg has not improved after 72 hours of appropriately dosed oral cephalexin; the erythema, warmth, and tenderness are unchanged and he now has a low-grade fever, though there is no fluctuance, crepitus, or skin necrosis. Which of the following is the most appropriate next step?
     • Broaden coverage to include methicillin-resistant Staphylococcus aureus and consider intravenous therapy
     • Continue the same oral regimen for three more days before reassessing
     • Switch to a topical antibiotic to reduce systemic exposure
     • Stop antibiotics and treat with compression alone

     Correct answer: Broaden coverage to include methicillin-resistant Staphylococcus aureus and consider intravenous therapy

     Broadening coverage to include resistant organisms is the most appropriate step. When cellulitis fails to respond to first-line therapy targeting streptococci and methicillin-susceptible staphylococci after an adequate trial, the next move is to reconsider the diagnosis for mimics and to broaden coverage to include methicillin-resistant Staphylococcus aureus, often with a transition to intravenous therapy. Simply continuing an ineffective oral regimen delays control, a topical antibiotic cannot reach dermal infection, and stopping antibiotics undertreats an active bacterial process.

327. A 45-year-old man develops fever and a tender, erythematous leg, and his clinician is trying to distinguish simple cellulitis from a deeper necrotizing infection at the bedside. Which of the following features, if present, would most strongly favor a necrotizing soft-tissue infection over uncomplicated cellulitis?
     • Erythema with sharply demarcated borders that blanch on pressure
     • Pain markedly out of proportion to the visible skin findings
     • Pruritus and fine scaling at the margins of the redness
     • Gradual improvement of warmth over the first day of antibiotics

     Correct answer: Pain markedly out of proportion to the visible skin findings

     Pain out of proportion to the exam most strongly favors a necrotizing infection. Severe pain disproportionate to the modest cutaneous appearance, along with rapid progression, systemic toxicity, crepitus, bullae, and skin anesthesia, signals a deep necrotizing soft-tissue infection requiring urgent surgical evaluation. Blanching sharply demarcated erythema, pruritus with scaling, and steady improvement on antibiotics are reassuring features more consistent with uncomplicated cellulitis or a non-infectious mimic.

328. A 35-year-old man develops a severe blistering drug reaction with widespread epidermal detachment, and the dermatology team estimates body surface area involvement to gauge severity. Which of the following methods is the standard bedside approach for quantifying the extent of skin involvement in this condition?
     • The Breslow depth measured in millimeters
     • The Wells score for venous thromboembolism
     • The patient's palm including fingers approximating about 1 percent of body surface area
     • The ankle-brachial index

     Correct answer: The patient's palm including fingers approximating about 1 percent of body surface area

     Using the patient's palm as roughly 1 percent of body surface area is the standard bedside estimation. In Stevens-Johnson syndrome and toxic epidermal necrolysis, the percentage of detached skin determines classification and prognosis, and the patient's own palm with the fingers approximates about 1 percent, allowing rapid estimation comparable to burn assessment. Breslow depth applies to melanoma, the Wells score estimates thromboembolism risk, and the ankle-brachial index assesses peripheral arterial disease.

329. A 28-year-old woman of Han Chinese ancestry is to begin carbamazepine for a new seizure disorder. The neurologist orders genetic testing before starting the drug to reduce the risk of a life-threatening cutaneous reaction. Which of the following best explains the rationale for this pretreatment testing?
     • The testing predicts how quickly the drug will be metabolized to a safe dose
     • The testing identifies an immunity that prevents any drug rash
     • The testing determines the patient's blood type for transfusion readiness
     • A specific HLA allele is associated with a markedly increased risk of severe carbamazepine-induced skin reactions

     Correct answer: A specific HLA allele is associated with a markedly increased risk of severe carbamazepine-induced skin reactions

     A specific HLA allele markedly raises the risk of severe carbamazepine reactions. Carriage of the HLA-B*15:02 allele, more common in some Asian populations, strongly predisposes to carbamazepine-induced Stevens-Johnson syndrome and toxic epidermal necrolysis, so screening before initiation allows avoidance of the drug in carriers. The testing does not gauge metabolic clearance for dosing, does not confer protective immunity against rashes, and is unrelated to blood typing.

330. A 60-year-old man with a 0.6 mm thick melanoma on the shoulder undergoes definitive treatment. Pathology confirms negative deep and peripheral margins. Which of the following is the most appropriate surgical margin principle for the wide local excision of a thin invasive melanoma of this thickness?
     • A wide local excision with a margin of about 1 centimeter of clinically normal skin
     • No excision is needed once the diagnostic biopsy is done
     • A 5-centimeter radical margin in all directions
     • Mohs surgery with no defined margin because melanoma has no measurable spread

     Correct answer: A wide local excision with a margin of about 1 centimeter of clinically normal skin

     A roughly 1-centimeter margin is appropriate for a thin invasive melanoma. Wide local excision margins for melanoma scale with Breslow thickness, and a thin melanoma up to about 1 mm is excised with approximately a 1-centimeter margin of normal skin, whereas thicker lesions warrant 2-centimeter margins. The diagnostic biopsy alone is insufficient, a uniform 5-centimeter radical margin is excessive and outdated, and depth-based margins remain essential rather than ignored.

331. A 50-year-old fair-skinned woman with many atypical nevi and a family history of melanoma asks how she can lower her personal risk and detect new melanomas early. Which of the following is the most appropriate evidence-based recommendation?
     • Use indoor tanning beds in moderation to build a protective base tan
     • Practice regular sun protection and undergo routine total-body skin surveillance
     • Take oral antibiotics indefinitely to prevent melanoma
     • Avoid all skin examinations to reduce unnecessary biopsies

     Correct answer: Practice regular sun protection and undergo routine total-body skin surveillance

     Sun protection plus routine skin surveillance is the appropriate recommendation. Patients at elevated melanoma risk from numerous atypical nevi and family history benefit from consistent photoprotection, avoidance of tanning beds, periodic clinician total-body skin examinations, and self-examination to catch evolving lesions early when they are most curable. Tanning beds increase rather than reduce risk, antibiotics have no preventive role, and avoiding skin examinations would delay diagnosis of dangerous lesions.

332. A 40-year-old woman presents with a painful, deep, fluctuant abscess on the buttock. After incision and drainage, the wound culture grows methicillin-resistant Staphylococcus aureus. She is afebrile and has minimal surrounding cellulitis. Which of the following oral agents is an appropriate choice if antibiotics are added to cover this organism?
     • Amoxicillin
     • Penicillin V
     • Trimethoprim-sulfamethoxazole
     • Cephalexin

     Correct answer: Trimethoprim-sulfamethoxazole

     Trimethoprim-sulfamethoxazole is an appropriate oral choice for community-acquired methicillin-resistant Staphylococcus aureus. When antibiotics supplement drainage of a purulent skin infection caused by this organism, oral agents with reliable activity such as trimethoprim-sulfamethoxazole, doxycycline, or clindamycin are used, since drainage remains the primary therapy. Amoxicillin, penicillin V, and cephalexin lack reliable activity against methicillin-resistant strains and would be inadequate coverage for this culture result.

333. A 70-year-old man develops a sudden, intensely painful, unilateral vesicular eruption in a band on the left chest that does not cross the midline. He presented within 48 hours of the rash appearing. Beyond analgesia, which of the following is the most appropriate management to reduce the severity and duration of this infection?
     • Topical corticosteroid cream alone
     • Oral fluconazole
     • Topical mupirocin
     • Oral antiviral therapy such as valacyclovir

     Correct answer: Oral antiviral therapy such as valacyclovir

     Oral antiviral therapy is the most appropriate management. Herpes zoster, the dermatomal reactivation of varicella-zoster virus, is treated with systemic antivirals such as valacyclovir, acyclovir, or famciclovir, which are most effective when started within about 72 hours of rash onset to shorten the course and may reduce postherpetic neuralgia. A topical steroid, an antifungal, and a topical antibacterial do not treat the underlying viral reactivation.

334. A 65-year-old immunocompetent adult asks about preventing shingles after a friend developed a painful rash. He has never received the relevant vaccine. Which of the following is the most appropriate recommendation for reducing his risk of herpes zoster and its complications?
     • The recombinant zoster vaccine, given as a two-dose series
     • No vaccine exists to prevent shingles
     • Lifelong daily oral antivirals for all adults over 60
     • A single dose of antibiotics each winter

     Correct answer: The recombinant zoster vaccine, given as a two-dose series

     The recombinant zoster vaccine is the appropriate recommendation. Immunocompetent adults aged 50 and older are advised to receive the two-dose recombinant zoster vaccine, which substantially reduces the incidence of herpes zoster and postherpetic neuralgia. There is, therefore, an effective vaccine, so the claim that none exists is incorrect, while routine lifelong prophylactic antivirals and seasonal antibiotics are neither standard nor effective preventive strategies.

335. A 30-year-old man develops painful, grouped vesicles on the lip preceded by tingling and is diagnosed with recurrent orolabial herpes simplex. He has only a few outbreaks per year and wants treatment for individual episodes rather than daily medication. Which of the following best describes the appropriate approach to episodic therapy?
     • Begin oral antibiotics at the first sign of crusting
     • Start an oral antiviral at the earliest prodromal symptom of an outbreak
     • Apply a topical corticosteroid to suppress the lesions
     • Wait until the vesicles fully crust before any treatment

     Correct answer: Start an oral antiviral at the earliest prodromal symptom of an outbreak

     Starting an antiviral at the earliest prodrome is the appropriate episodic approach. For infrequent recurrent herpes simplex, episodic therapy with an oral antiviral such as valacyclovir is most effective when initiated at the first prodromal tingling or burning, before or as lesions appear, shortening the episode. Antibiotics treat bacterial infection rather than the virus, topical steroids can worsen herpetic lesions, and waiting until crusting forfeits the window for antiviral benefit.

336. A 30-year-old woman with chronic spontaneous urticaria continues to have daily hives despite a standard once-daily dose of a second-generation oral antihistamine. The wheals are pruritic and individually transient, and she has no angioedema or systemic symptoms. Which of the following is the most appropriate next step in management?
     • Switch to a first-generation sedating antihistamine at bedtime only
     • Start chronic systemic corticosteroids as maintenance therapy
     • Increase the second-generation antihistamine up to fourfold the standard dose
     • Begin empiric antifungal therapy

     Correct answer: Increase the second-generation antihistamine up to fourfold the standard dose

     Up-titrating the second-generation antihistamine is the appropriate next step. When chronic spontaneous urticaria is not controlled by a standard dose, guidelines recommend increasing the non-sedating second-generation antihistamine up to fourfold before adding agents such as omalizumab, since this improves control with a favorable safety profile. Relying solely on a sedating antihistamine is less ideal, chronic systemic steroids are avoided for maintenance, and antifungals have no role in this condition.

337. A 25-year-old man develops generalized hives within 30 minutes of eating shellfish, accompanied by lip swelling, wheezing, and lightheadedness with a fall in blood pressure. Which of the following is the most appropriate immediate treatment?
     • Oral diphenhydramine and observation at home
     • Topical corticosteroid cream
     • Oral prednisone as the sole therapy
     • Intramuscular epinephrine

     Correct answer: Intramuscular epinephrine

     Intramuscular epinephrine is the immediate treatment. When urticaria accompanies signs of anaphylaxis such as airway swelling, bronchospasm, and hypotension after an allergen exposure, prompt intramuscular epinephrine into the lateral thigh is the first-line, life-saving intervention, with antihistamines and corticosteroids as adjuncts. Oral antihistamines alone, a topical steroid, or oral prednisone as sole therapy would dangerously undertreat a systemic, potentially fatal allergic reaction.

338. A 16-year-old boy presents with comedones, numerous inflammatory papules and pustules, and several painful nodules with early scarring on the face, chest, and back that have not responded to topical therapy or oral antibiotics. Which of the following is the most appropriate treatment for this severe nodular disease?
     • Oral isotretinoin
     • Topical benzoyl peroxide alone
     • A longer course of the same oral antibiotic
     • Oral antihistamines

     Correct answer: Oral isotretinoin

     Oral isotretinoin is the most appropriate treatment for severe nodular acne. Severe nodulocystic or scarring acne that has failed topical agents and oral antibiotics is an indication for oral isotretinoin, which addresses all four pathogenic factors and can produce durable remission, with mandatory pregnancy prevention and laboratory monitoring. Benzoyl peroxide alone is insufficient for severe disease, repeating an ineffective antibiotic promotes resistance, and antihistamines do not treat acne.

339. A 32-year-old woman has predominantly inflammatory papules and pustules of acne along the jawline that flare before menses, and she does not desire pregnancy. She prefers an oral systemic option targeting the hormonal component. Which of the following oral agents reduces androgen-driven sebum production and is useful for this pattern of acne?
     • Acyclovir
     • Spironolactone
     • Metronidazole
     • Griseofulvin

     Correct answer: Spironolactone

     Spironolactone targets the hormonal component of acne. This aldosterone antagonist has antiandrogenic activity that decreases sebum production and benefits women with hormonally influenced inflammatory acne, particularly a perimenstrual jawline pattern, and is often combined with reliable contraception given teratogenic potential. Acyclovir is an antiviral, metronidazole is used for rosacea rather than this hormonal acne, and griseofulvin is an antifungal for dermatophyte infections.

340. A 45-year-old man with stable plaque psoriasis on the elbows and knees has limited disease covering less than 5 percent of his body surface area. He has well-defined, salmon-pink plaques with silvery scale. Which of the following is the most appropriate first-line treatment for this limited plaque psoriasis?
     • Oral methotrexate
     • A systemic biologic agent
     • Topical corticosteroids with or without a topical vitamin D analog
     • Oral systemic corticosteroids

     Correct answer: Topical corticosteroids with or without a topical vitamin D analog

     Topical therapy is first-line for limited plaque psoriasis. Localized disease affecting a small body surface area is managed with topical corticosteroids, often combined with a topical vitamin D analog such as calcipotriene, reserving phototherapy and systemic agents for extensive or refractory disease. Methotrexate and biologics are escalation options for widespread disease, and systemic corticosteroids are avoided because their withdrawal can precipitate a severe pustular or erythrodermic flare.

341. A 35-year-old man with psoriasis notices that new plaques consistently appear along a recent surgical scar and at a site where his watchband repeatedly rubs. Which of the following phenomena best explains the development of psoriatic lesions at sites of skin trauma?
     • Auspitz sign
     • Nikolsky sign
     • Darier sign
     • Koebner phenomenon

     Correct answer: Koebner phenomenon

     The Koebner phenomenon best explains lesions arising at sites of trauma. In psoriasis and several other dermatoses, new lesions can develop at areas of cutaneous injury such as scratches, scars, or friction, a process termed the Koebner or isomorphic response. The Auspitz sign is pinpoint bleeding after scale removal, the Nikolsky sign is epidermal shearing in blistering disease, and the Darier sign is wheal formation on stroking a mastocytosis lesion.

342. A 4-year-old child with moderate atopic dermatitis has thickened, lichenified, itchy plaques in the antecubital and popliteal folds that flare despite daily emollients. Which of the following is the most appropriate next step to control active inflammation during a flare?
     • Apply a topical corticosteroid of appropriate potency to the affected areas
     • Begin long-term oral antibiotics
     • Start systemic isotretinoin
     • Discontinue all moisturizers

     Correct answer: Apply a topical corticosteroid of appropriate potency to the affected areas

     A topical corticosteroid is the appropriate next step for an atopic dermatitis flare. When emollients alone fail to control active eczematous inflammation, a topical corticosteroid of suitable potency for the site and severity is first-line anti-inflammatory therapy, with topical calcineurin inhibitors as steroid-sparing alternatives for sensitive areas. Antibiotics are reserved for secondary infection, isotretinoin treats acne, and stopping moisturizers would worsen the barrier defect.

343. A 38-year-old landscaper develops a sharply marginated, linear, intensely pruritic eruption with vesicles and bullae in streaks on the forearms two days after clearing brush that included a vine with three-leaflet clusters. Which of the following best explains the streaky, linear pattern of this allergic contact dermatitis?
     • Spread of the rash along dermatomes
     • Brushing of the plant resin across the skin in lines during contact
     • Hematogenous dissemination of the allergen
     • Migration of a parasite under the skin

     Correct answer: Brushing of the plant resin across the skin in lines during contact

     The linear streaks reflect where the plant resin brushed across the skin. Allergic contact dermatitis from urushiol in poison ivy, oak, or sumac produces a delayed hypersensitivity reaction whose distribution mirrors contact, so dragging the resin across the skin yields characteristic linear streaks of vesicles. The pattern is not dermatomal, the allergen is not spread through the bloodstream, and no parasite migration is involved.

344. A 70-year-old woman has tense, pruritic bullae on an urticarial base over the trunk and flexures, with sparing of the mucosa, and direct immunofluorescence shows linear IgG and C3 along the basement membrane. Which of the following is the most appropriate first-line treatment for localized to moderate disease of this type?
     • Lifelong systemic antibiotics
     • Oral antifungal therapy
     • High-potency topical corticosteroids
     • Permethrin applied to the whole body

     Correct answer: High-potency topical corticosteroids

     High-potency topical corticosteroids are appropriate first-line therapy for bullous pemphigoid. For localized or moderate bullous pemphigoid, potent topical corticosteroids such as clobetasol are effective and have a better safety profile than systemic steroids, which are reserved with steroid-sparing immunosuppressants for extensive disease. Systemic antibiotics are not primary therapy, antifungals do not treat this autoimmune subepidermal blistering disease, and permethrin treats scabies.

345. A 55-year-old woman is diagnosed with pemphigus vulgaris with painful oral erosions and flaccid skin blisters. Which of the following best describes the immunologic mechanism underlying the loss of keratinocyte adhesion in this disease?
     • IgA deposition in the dermal papillae from gluten sensitivity
     • T-cell-mediated destruction of melanocytes
     • Deposition of immune complexes in small dermal vessels
     • Autoantibodies against desmoglein adhesion proteins between keratinocytes

     Correct answer: Autoantibodies against desmoglein adhesion proteins between keratinocytes

     Autoantibodies against desmoglein cause the acantholysis in pemphigus vulgaris. Pathogenic IgG targets desmoglein desmosomal proteins, disrupting cell-to-cell adhesion between keratinocytes and producing intraepidermal flaccid blisters and mucosal erosions with a positive Nikolsky sign. IgA in the dermal papillae characterizes dermatitis herpetiformis, melanocyte destruction underlies vitiligo, and immune-complex deposition in dermal vessels underlies leukocytoclastic vasculitis.

346. A 35-year-old woman returns from camping with a hot, swollen, tender, sharply demarcated bright-red plaque on the face with a raised border, accompanied by abrupt high fever and chills. The lesion is well-circumscribed and elevated above surrounding skin. Which of the following organisms is the most common cause of this superficial dermal infection?
     • Group A Streptococcus
     • Pseudomonas aeruginosa
     • Candida albicans
     • Bartonella henselae

     Correct answer: Group A Streptococcus

     Group A Streptococcus is the most common cause of erysipelas. This superficial cellulitis of the upper dermis and lymphatics produces a sharply demarcated, raised, fiery-red plaque, frequently on the face or lower legs, with an abrupt onset of fever and chills, and beta-hemolytic streptococci are the predominant pathogen. Pseudomonas causes hot-tub folliculitis, Candida causes intertriginous infection, and Bartonella henselae causes cat-scratch disease.

347. A 50-year-old man with diabetes presents with rapidly spreading erythema, swelling, and exquisite pain of the perineum and scrotum, with crepitus and patches of dusky skin, and he is febrile and hypotensive. Which of the following is the most appropriate immediate management?
     • Outpatient oral antibiotics with next-day urology follow-up
     • Emergent surgical debridement with broad-spectrum antibiotics and resuscitation
     • Warm sitz baths and observation
     • Topical antifungal cream to the affected skin

     Correct answer: Emergent surgical debridement with broad-spectrum antibiotics and resuscitation

     Emergent surgical debridement with broad-spectrum antibiotics is the appropriate management. Fournier gangrene is a necrotizing soft-tissue infection of the perineum and genitalia, often polymicrobial and seen in diabetics, and survival depends on rapid aggressive surgical debridement combined with broad-spectrum antibiotics and hemodynamic resuscitation. Outpatient oral therapy, conservative sitz baths, and topical antifungals would all fatally delay control of this fulminant infection.

348. A 22-year-old man presents with a recurrent, well-defined, dusky red, slightly itchy oval patch that reappears at the exact same spot on the glans each time he takes an over-the-counter cold medication, healing with brown hyperpigmentation between episodes. Which of the following classes of agents is a classic trigger of this reaction?
     • Topical emollients
     • Inhaled corticosteroids
     • Sulfonamides, tetracyclines, and NSAIDs
     • Oral rehydration salts

     Correct answer: Sulfonamides, tetracyclines, and NSAIDs

     Sulfonamides, tetracyclines, and NSAIDs are classic triggers of fixed drug eruption. This reaction recurs at the same site with each exposure to the culprit and commonly involves the lips, hands, or genitalia, with frequent offenders including sulfonamides, tetracyclines, NSAIDs, and certain laxatives, leaving residual hyperpigmentation. Emollients, inhaled corticosteroids, and oral rehydration salts are not recognized causes of this drug-specific recurring eruption.

349. A 78-year-old bedbound man is found to have a sacral pressure injury with full-thickness skin loss in which the wound bed is completely obscured by thick yellow slough and adherent brown eschar, so the true depth cannot be determined. Which of the following best describes the stage of this pressure injury?
     • Stage 2 pressure injury
     • Stage 1 pressure injury
     • Deep tissue pressure injury
     • Unstageable pressure injury

     Correct answer: Unstageable pressure injury

     This is an unstageable pressure injury. When full-thickness tissue loss is present but the base is obscured by slough or eschar so that the depth and true stage cannot be assessed, the injury is classified as unstageable until enough nonviable tissue is removed to visualize the wound bed. Stage 2 is a shallow partial-thickness ulcer, stage 1 is non-blanchable erythema of intact skin, and deep tissue injury presents as intact discolored or blistered skin.

350. An 82-year-old woman with limited mobility is at high risk for pressure injuries during a prolonged hospitalization. Which of the following interventions is the most effective primary strategy to prevent pressure ulcers in an immobile patient?
     • Scheduled repositioning, pressure-redistributing support surfaces, and skin care
     • Massaging reddened bony prominences vigorously
     • Applying topical antibiotics to intact skin
     • Restricting fluids to reduce skin moisture

     Correct answer: Scheduled repositioning, pressure-redistributing support surfaces, and skin care

     Scheduled repositioning with support surfaces and skin care is the most effective prevention. Pressure ulcer prevention in immobile patients centers on regular turning and repositioning, pressure-redistributing mattresses or cushions, keeping skin clean and dry, managing moisture and incontinence, and optimizing nutrition. Vigorous massage of reddened areas can worsen tissue injury, topical antibiotics are not preventive on intact skin, and fluid restriction risks dehydration that impairs skin integrity.

351. A 45-year-old man notices that the skin in both armpits and the back of his neck has gradually become darker, thickened, and velvety over the past year. He is obese with a recent diagnosis of type 2 diabetes. Beyond skin-directed care, which of the following is the most appropriate management of this finding?
     • Surgical excision of the affected skin
     • Address the underlying insulin resistance with weight loss and glycemic control
     • Cryotherapy to each plaque
     • Long-term oral antibiotics

     Correct answer: Address the underlying insulin resistance with weight loss and glycemic control

     Treating the underlying insulin resistance is the most appropriate management. Acanthosis nigricans most often reflects insulin resistance associated with obesity and type 2 diabetes, so weight loss, improved glycemic control, and management of the metabolic cause are central, which can lighten the plaques over time. Surgical excision and cryotherapy do not address the systemic driver, and antibiotics have no role in this noninfectious pigmentary and hyperkeratotic change.

352. A 28-year-old man presents with several itchy, annular, scaly plaques with central clearing and active raised borders on the trunk that he has been treating for two weeks with an over-the-counter combination cream containing a potent corticosteroid. The lesions have become larger, less scaly, and harder to recognize. Which of the following best explains this change?
     • The corticosteroid cured the dermatophyte infection
     • The lesions transformed into psoriasis
     • The corticosteroid suppressed inflammation while allowing the fungal infection to spread, producing tinea incognito
     • The change indicates the lesions were never fungal

     Correct answer: The corticosteroid suppressed inflammation while allowing the fungal infection to spread, producing tinea incognito

     Topical steroid use produced tinea incognito. Applying a corticosteroid to a dermatophyte infection blunts the inflammatory signs such as scale and a sharp border while permitting the fungus to spread, creating an atypical, less recognizable, often larger eruption termed tinea incognito; KOH testing and an antifungal are needed. The steroid does not cure the fungus, the lesions did not become psoriasis, and the original annular scaly clearing pattern was consistent with tinea.

353. A 30-year-old man presents with a single, oval, scaly plaque with a thin collarette of scale at the trailing edge of the border on the trunk. He recalls it appeared about a week before a more generalized eruption. Which of the following best describes this initial lesion?
     • Erythema migrans of Lyme disease
     • Plaque of guttate psoriasis
     • Patch of vitiligo
     • Herald patch of pityriasis rosea

     Correct answer: Herald patch of pityriasis rosea

     This is the herald patch of pityriasis rosea. The condition often begins with a single larger oval, salmon-colored plaque bearing a fine inner collarette of scale, the herald patch, which precedes the generalized eruption of smaller oval plaques along skin cleavage lines by days to a week or two. Erythema migrans is an expanding ring after a tick bite, guttate psoriasis lacks a herald lesion, and vitiligo produces depigmented macules without scale.

354. A 6-year-old boy has an itchy, annular, scaly patch of hair loss on the scalp with broken hairs. Under a Wood lamp the affected hairs are not fluorescent, and the clinician explains that confirming the diagnosis and identifying the organism guides therapy. Which of the following is the most appropriate diagnostic test before starting systemic therapy?
     • Fungal culture or KOH microscopy of plucked hairs and scale
     • Skin biopsy with immunofluorescence
     • Patch testing
     • Serum antinuclear antibody

     Correct answer: Fungal culture or KOH microscopy of plucked hairs and scale

     Fungal culture or KOH microscopy is the appropriate confirmatory test. Tinea capitis is confirmed by KOH examination and fungal culture of plucked hairs and scale, which identify the dermatophyte and support the need for systemic antifungal therapy, since many causative species do not fluoresce under a Wood lamp. Immunofluorescence biopsy targets autoimmune blistering disease, patch testing evaluates contact allergy, and antinuclear antibody testing assesses autoimmune connective-tissue disease.

355. A 26-year-old woman has tinea versicolor of the upper trunk that has responded to topical antifungal therapy, but she notes that some affected areas remain lighter than the surrounding skin even after treatment. She asks whether this means the infection persists. Which of the following is the most accurate explanation?
     • The lighter areas confirm the infection is still active
     • The residual color change can persist for weeks to months after successful treatment and does not indicate ongoing infection
     • The pigment change indicates the lesions have become cancerous
     • Permanent scarring has occurred

     Correct answer: The residual color change can persist for weeks to months after successful treatment and does not indicate ongoing infection

     Residual pigment change after treatment is expected and does not mean persistent infection. Tinea versicolor caused by Malassezia alters melanin production, so the hypopigmented or hyperpigmented patches commonly take weeks to months to normalize even after the yeast is eradicated, as repigmentation lags behind cure. The lingering color does not signify active infection, malignant change, or permanent scarring, and sun exposure can make the contrast more noticeable temporarily.

356. A 9-year-old child has multiple small, dome-shaped, umbilicated, pink papules on the trunk, and one lesion has become red, swollen, and crusted with surrounding inflammation before resolving. The parents worry it is infected. Which of the following best explains this inflammatory change in molluscum contagiosum?
     • Bacterial superinfection requiring intravenous antibiotics
     • The beginning of melanoma transformation
     • The BOTE (beginning of the end) inflammatory response heralding spontaneous resolution
     • A drug reaction

     Correct answer: The BOTE (beginning of the end) inflammatory response heralding spontaneous resolution

     This inflammatory reaction often signals imminent resolution. In molluscum contagiosum, individual lesions can become red, swollen, and tender as the immune system mounts a response, the so-called beginning-of-the-end reaction, which frequently precedes spontaneous clearance and can be mistaken for bacterial infection. It is not melanoma transformation or a drug reaction, and true secondary bacterial infection is less common and usually does not require intravenous therapy.

357. A 60-year-old man presents with a long-standing, slow-growing, pearly papule with rolled borders and central ulceration on the nasal ala. A shave biopsy confirms basal cell carcinoma in a cosmetically sensitive area with poorly defined margins. Which of the following treatments offers the highest cure rate with maximal tissue conservation for this location?
     • Cryotherapy alone
     • Topical antibiotic ointment
     • Observation without treatment
     • Mohs micrographic surgery

     Correct answer: Mohs micrographic surgery

     Mohs micrographic surgery offers the highest cure rate with tissue conservation here. For basal cell carcinoma in high-risk or cosmetically sensitive sites such as the central face, with ill-defined borders or recurrence risk, Mohs surgery allows complete margin assessment while sparing the maximum normal tissue, optimizing both cure and reconstruction. Cryotherapy is less precise for such locations, a topical antibiotic does not treat the cancer, and observation allows continued local invasion.

358. A 72-year-old man has a biopsy-proven cutaneous squamous cell carcinoma on the lower lip with a depth and size that place it at higher risk. The clinician explains why this lesion warrants closer surveillance than most basal cell carcinomas. Which of the following best describes the key difference?
     • Squamous cell carcinoma has a meaningfully higher risk of regional and distant metastasis, especially on the lip and ear
     • Squamous cell carcinoma never invades beyond the epidermis
     • Basal cell carcinoma metastasizes more readily than squamous cell carcinoma
     • Squamous cell carcinoma is a benign growth

     Correct answer: Squamous cell carcinoma has a meaningfully higher risk of regional and distant metastasis, especially on the lip and ear

     Squamous cell carcinoma carries a higher metastatic risk than basal cell carcinoma. While both are sun-related keratinocyte cancers, cutaneous squamous cell carcinoma has a greater propensity for regional lymph node and distant metastasis, particularly at high-risk sites such as the lip and ear, and with larger, deeper, or poorly differentiated tumors, warranting closer follow-up. It can invade beyond the epidermis, basal cell carcinoma rarely metastasizes, and squamous cell carcinoma is malignant rather than benign.

359. A 70-year-old man with extensive sun damage has numerous rough, scaly, erythematous actinic keratoses spread diffusely across the bald scalp and forehead, too many to treat individually with cryotherapy. Which of the following is the most appropriate approach for this extensive field of damage?
     • Surgical excision of the entire scalp
     • Field-directed therapy such as topical 5-fluorouracil or photodynamic therapy
     • Oral antibiotics
     • No treatment because actinic keratoses are always harmless

     Correct answer: Field-directed therapy such as topical 5-fluorouracil or photodynamic therapy

     Field-directed therapy is most appropriate for diffuse actinic damage. When actinic keratoses are too numerous for lesion-directed cryotherapy, field treatments such as topical 5-fluorouracil, imiquimod, or photodynamic therapy treat both visible lesions and subclinical damage across the affected area, reducing progression to squamous cell carcinoma. Excising the entire scalp is impractical and disfiguring, antibiotics have no role, and leaving extensive actinic keratoses untreated ignores their malignant potential.

360. A 7-year-old child has several discrete, thick, golden-yellow crusted lesions on the leg that began as small pustules and have a stuck-on appearance, with no surrounding cellulitis or systemic symptoms, and only a few lesions present. Which of the following is the most appropriate first-line treatment for this limited impetigo?
     • Intravenous vancomycin
     • Oral acyclovir
     • Topical mupirocin
     • Topical corticosteroid

     Correct answer: Topical mupirocin

     Topical mupirocin is the appropriate first-line treatment for limited impetigo. A few localized lesions of nonbullous impetigo with the characteristic honey-colored crust can be treated effectively with a topical antibiotic such as mupirocin, reserving oral antibiotics for numerous lesions, widespread involvement, or systemic features. Intravenous vancomycin is excessive for this localized superficial infection, acyclovir treats herpes rather than this bacterial infection, and a corticosteroid does not address the pathogen.

361. A 28-year-old woman develops painful, tender, red, raised nodules on both shins along with fever and joint aches. She was started on a new medication and has no other findings. In addition to medications, which of the following is a classic underlying cause that should be considered for erythema nodosum?
     • Iron deficiency anemia
     • Essential hypertension
     • Osteoarthritis
     • Recent streptococcal infection

     Correct answer: Recent streptococcal infection

     Recent streptococcal infection is a classic cause of erythema nodosum. This septal panniculitis presenting as tender shin nodules has well-recognized associations including streptococcal infection, sarcoidosis, inflammatory bowel disease, tuberculosis, certain fungal infections, pregnancy, and drugs such as oral contraceptives and sulfonamides, prompting an evaluation for an underlying trigger. Iron deficiency, essential hypertension, and osteoarthritis are not recognized causes of erythema nodosum.

362. A 25-year-old man presents with multiple discrete, target-shaped lesions with a dusky center, a pale ring, and an outer red rim on the palms and forearms, appearing about a week after an outbreak of herpes labialis. He has only mild oral involvement and is otherwise well. Which of the following is the most likely diagnosis?
     • Erythema multiforme
     • Urticaria
     • Granuloma annulare
     • Tinea corporis

     Correct answer: Erythema multiforme

     Erythema multiforme is the most likely diagnosis. Classic targetoid lesions with three concentric zones, favoring the palms, soles, and extensor extremities and often triggered by herpes simplex virus, characterize erythema multiforme, which is usually self-limited and distinct from the more severe Stevens-Johnson spectrum. Urticarial wheals are transient and migratory, granuloma annulare forms non-scaly rings of papules, and tinea corporis is a scaly annular plaque with KOH-positive hyphae.

363. A 45-year-old woman develops recurrent crops of targetoid erythema multiforme lesions several times a year, and each episode is preceded by a cold sore on the lip. Which of the following is the most appropriate strategy to prevent these recurrent episodes?
     • Long-term systemic corticosteroids
     • Daily suppressive antiviral therapy for herpes simplex virus
     • Chronic oral antibiotics
     • Topical antifungal therapy

     Correct answer: Daily suppressive antiviral therapy for herpes simplex virus

     Daily suppressive antiviral therapy is the appropriate prevention. When recurrent erythema multiforme is triggered by reactivation of herpes simplex virus, continuous suppressive antiviral therapy such as acyclovir or valacyclovir reduces the frequency of both the herpes outbreaks and the subsequent erythema multiforme episodes. Long-term systemic steroids carry significant risks for prophylaxis, chronic antibiotics do not address the viral trigger, and antifungal therapy is irrelevant to this herpes-associated condition.

364. A 30-year-old woman of African ancestry develops a firm, raised, shiny, pink-purple scar on the chest that grew beyond the margins of a small acne lesion and is itchy and tender. She wants treatment that minimizes the chance of worsening the growth. Which of the following is a commonly used first-line treatment for a symptomatic keloid?
     • Wide surgical excision alone
     • Cryotherapy of the entire chest
     • Intralesional corticosteroid injection
     • Oral antibiotics

     Correct answer: Intralesional corticosteroid injection

     Intralesional corticosteroid injection is a common first-line keloid treatment. Injecting a corticosteroid such as triamcinolone directly into a keloid flattens and softens it and relieves symptoms, and it is often combined with other modalities because keloids recur readily. Surgical excision alone has a high recurrence rate and can stimulate a larger keloid unless combined with adjuncts, broad cryotherapy of normal skin is inappropriate, and antibiotics do not treat this fibroproliferative scar.

365. A 40-year-old woman with vitiligo has several enlarging depigmented patches on the hands and face and asks about treatment to restore pigment. Which of the following is an appropriate first-line treatment for limited, active vitiligo?
     • Oral antifungal therapy
     • Systemic chemotherapy
     • Long-term oral antibiotics
     • Topical corticosteroids or topical calcineurin inhibitors

     Correct answer: Topical corticosteroids or topical calcineurin inhibitors

     Topical corticosteroids or calcineurin inhibitors are appropriate first-line therapy for limited vitiligo. These topical anti-inflammatory agents can halt progression and promote repigmentation in localized disease, with calcineurin inhibitors particularly favored for the face and intertriginous areas, while phototherapy is used for more widespread involvement. Antifungals do not treat this autoimmune depigmentation, systemic chemotherapy is inappropriate, and antibiotics have no role.

366. A 65-year-old woman with chronic venous insufficiency has a shallow ulcer over the medial malleolus surrounded by hemosiderin staining and edema, with palpable pedal pulses and a normal ankle-brachial index. Which of the following is the cornerstone of management for this venous leg ulcer?
     • Compression therapy
     • Strict limb elevation avoidance and dependency
     • Long-term systemic antibiotics
     • Arterial bypass surgery

     Correct answer: Compression therapy

     Compression therapy is the cornerstone of venous ulcer management. Because venous ulcers result from venous hypertension and edema, graduated compression bandaging or stockings to reduce edema and improve venous return, combined with leg elevation and local wound care, is the central treatment once adequate arterial perfusion is confirmed. Promoting dependency would worsen edema, antibiotics are reserved for true infection, and arterial bypass addresses arterial rather than venous disease.

367. A 50-year-old woman with longstanding diabetes has a callus-rimmed, painless ulcer beneath the first metatarsal head with intact pulses and absent monofilament sensation. Which of the following is the single most important intervention to promote healing of this neuropathic foot ulcer?
     • Strict bed rest with the foot dependent
     • Pressure offloading of the affected area
     • Daily soaking of the foot in hot water
     • Tight occlusive wrapping to compress the ulcer

     Correct answer: Pressure offloading of the affected area

     Pressure offloading is the single most important intervention for a neuropathic diabetic foot ulcer. Because repetitive pressure on an insensate foot drives ulceration over weight-bearing points, redistributing or removing that pressure with total-contact casting, special footwear, or offloading devices, along with debridement, glucose control, and infection surveillance, is essential for healing. A dependent foot worsens edema, hot soaks risk burns in neuropathy, and tight compressive wraps can impair perfusion.

368. A healthy 3-year-old is seen for a routine visit and her parents have no concerns. Which gross motor skill is most consistent with normal development at this age?
     • Hopping on one foot several times in a row
     • Skipping smoothly while alternating feet
     • Cruising along furniture while holding on
     • Pedaling a tricycle and walking up stairs alternating feet

     Correct answer: Pedaling a tricycle and walking up stairs alternating feet

     Pedaling a tricycle and ascending stairs using alternating feet are typical gross motor accomplishments for a 3-year-old. Hopping repeatedly on one foot generally appears around 4 years, smooth skipping with alternating feet is closer to 5 to 6 years, and cruising along furniture is a late-infancy skill seen near 9 to 11 months. Recognizing these age norms supports accurate developmental surveillance.

369. Parents of a healthy 4-month-old ask which behaviors are normal for their baby. Which combination of milestones best fits a typical 4-month-old?
     • Pulling to stand, pincer grasp, and waving bye-bye
     • Holding head steady, laughing, and reaching for objects
     • Sitting unsupported, raking objects, and babbling consonants
     • Walking with one hand held and saying first words

     Correct answer: Holding head steady, laughing, and reaching for objects

     A 4-month-old typically holds the head steady when upright, laughs aloud, and reaches for objects, making that grouping correct. Pulling to stand with a pincer grasp and waving belongs near 9 to 12 months, independent sitting with babbling consonants fits about 6 to 9 months, and walking with one hand held with first words occurs around 11 to 12 months. Grouping skills across motor, social, and fine motor streams helps confirm normal progress.

370. A 2-year-old is brought for a routine visit. The parents report no concerns. Which language milestone is most consistent with normal development at 24 months?
     • Speech that is fully understood by strangers
     • Using only single words with no word combinations
     • Combining two words and having about a 50-word vocabulary
     • Telling a short story with several connected sentences

     Correct answer: Combining two words and having about a 50-word vocabulary

     By about 24 months a typically developing child combines two words into short phrases and has a vocabulary of roughly 50 words or more. Speech that is fully intelligible to strangers is closer to 4 years, using only single words at 2 years suggests possible delay, and telling connected multi-sentence stories develops later in the preschool years. These norms help separate typical development from a true language concern.

371. A normally developing 5-year-old is seen before kindergarten entry. Which fine motor or cognitive skill would you expect a typical 5-year-old to demonstrate?
     • Copying a square and drawing a person with several body parts
     • Copying a circle for the first time
     • Scribbling spontaneously but not imitating shapes
     • Building a tower of only three to four blocks

     Correct answer: Copying a square and drawing a person with several body parts

     Copying a square and drawing a person with several body parts are expected fine motor and cognitive skills for a typical 5-year-old, who can also often print some letters. First copying a circle occurs near age 3, spontaneous scribbling without imitating shapes is a toddler-level skill, and a tower of only three to four blocks fits roughly 18 months. These benchmarks guide school-readiness assessment.

372. A 4-month-old is brought in because the parents report he still does not hold his head up when pulled to sit and has lost the ability to grasp objects he previously reached for. Which single feature most strongly indicates the need for prompt developmental evaluation rather than reassurance?
     • Loss of a previously attained motor skill
     • Preference for being held by the mother
     • Crying when a stranger approaches
     • Sleeping for long stretches at night

     Correct answer: Loss of a previously attained motor skill

     Loss of a previously attained skill, known as developmental regression, is the most concerning feature and mandates prompt evaluation for a neurologic or metabolic cause. A preference for the mother, crying with strangers, and long nighttime sleep stretches are all within normal infant behavior. Regression is a recognized developmental red flag that distinguishes pathology from normal variation.

373. During a well-child visit, the parents of a healthy 9-month-old ask which social and communication behaviors are normal. Which finding is most age-appropriate?
     • Using two-word phrases to make requests
     • Following a one-step command with a gesture and responding to his name
     • Engaging in imaginative pretend play with dolls
     • Pointing to several named body parts on request

     Correct answer: Following a one-step command with a gesture and responding to his name

     A 9-month-old typically responds to his own name and can follow a simple one-step command when paired with a gesture, such as waving bye-bye, making that finding age-appropriate. Two-word phrases appear near 24 months, imaginative pretend play emerges around 18 to 24 months, and pointing to named body parts is closer to 18 months. These social-communication norms anchor anticipatory guidance.

374. A 30-month-old is seen for a routine visit. The parents note he plays alongside other children at daycare but rarely plays cooperatively with them, and he engages in pretend play with toy figures. How should this play behavior be interpreted?
     • It indicates a likely social-emotional disorder requiring referral
     • It reflects regression from earlier cooperative play
     • It is normal, as parallel play with emerging pretend play is typical for this age
     • It signals that cooperative play milestones are delayed by two years

     Correct answer: It is normal, as parallel play with emerging pretend play is typical for this age

     Parallel play, in which a toddler plays beside but not yet cooperatively with peers, alongside emerging pretend play, is normal social development around 2 to 3 years. Cooperative and associative play develops later, typically around 3 to 4 years, so its absence here is not delayed. There is no evidence of regression or disorder, and this pattern reflects expected social-emotional milestones for the age.

375. A 30-month-old is brought for a routine health-supervision visit. Under current guidance, which structured screening is specifically recommended at the 18- and 24-month visits and may be repeated here if not yet done?
     • Autism spectrum disorder screening with a validated tool
     • Fasting lipid screening
     • Audiometric pure-tone hearing testing
     • Spirometry for asthma risk

     Correct answer: Autism spectrum disorder screening with a validated tool

     Structured autism spectrum disorder screening with a validated instrument is recommended at the 18- and 24-month visits and may be completed at a 30-month visit if not already performed. Fasting lipid screening, pure-tone audiometry, and spirometry are not part of routine toddler preventive screening. Targeted autism screening at these ages is a defining feature of the well-child schedule.

376. A 1-year-old is seen for a routine visit. Which screening test is recommended as a standard component of preventive care at about this age in the United States?
     • Resting electrocardiogram
     • Screening for elevated blood lead level
     • Routine abdominal ultrasound
     • Pulmonary function testing

     Correct answer: Screening for elevated blood lead level

     Blood lead level screening is recommended around 12 months, often repeated at 24 months, as a standard part of preventive care because young children are vulnerable to lead-related neurodevelopmental harm. A resting electrocardiogram, routine abdominal ultrasound, and pulmonary function testing are not part of routine care for a healthy 1-year-old. Lead screening reflects how the well-child visit targets age-specific developmental risks.

377. A previously healthy 16-year-old comes for a routine health-maintenance visit. Beyond growth and immunizations, which screening is an age-appropriate standard component of preventive care for an adolescent?
     • Routine bone density (DEXA) scanning
     • Routine coronary calcium scoring
     • Confidential screening for depression and risk behaviors
     • Newborn metabolic panel

     Correct answer: Confidential screening for depression and risk behaviors

     Confidential screening for depression and risk behaviors, often using a psychosocial framework, is a standard part of the adolescent well visit because mood disorders and risk-taking emerge during this developmental stage. Routine DEXA scanning, coronary calcium scoring, and the newborn metabolic panel are not appropriate routine screens for a healthy 16-year-old. Adolescent preventive care is tailored to the psychosocial tasks of this period.

378. A father asks why his healthy 18-month-old is being weighed, measured, and plotted on a chart at every visit. Which statement best explains the role of routine growth monitoring at the well-child visit?
     • It is performed only when a child appears underweight
     • It replaces the need for developmental screening at this age
     • It is used to diagnose a specific endocrine disorder at each visit
     • It tracks growth trends over time to detect faltering growth or abnormal patterns early

     Correct answer: It tracks growth trends over time to detect faltering growth or abnormal patterns early

     Routine plotting of weight, length or height, and head circumference tracks a child's growth trajectory so that faltering growth, excessive gain, or abnormal patterns are detected early. Growth monitoring is performed at every visit, not only when concern arises, and it complements rather than replaces developmental screening. Serial measurement, not a single value, is what gives growth charts their diagnostic value in preventive care.

379. A 72-year-old man with no acute complaints is seen for routine care. As part of geriatric preventive screening, which assessment is recommended to detect a common but frequently underrecognized sensory impairment that affects communication and safety?
     • Routine carotid duplex ultrasound
     • Pubertal Tanner staging
     • Genetic testing for dementia risk
     • Hearing impairment screening

     Correct answer: Hearing impairment screening

     Screening for hearing impairment is recommended in older adults because age-related hearing loss is common, often unrecognized, and contributes to social isolation, communication difficulty, and safety risks. Routine carotid duplex ultrasound, Tanner staging, and genetic dementia testing are not standard components of older-adult preventive screening. Sensory screening is part of comprehensive, developmentally appropriate geriatric assessment.

380. An 82-year-old woman living alone is seen for routine care. Her physician asks about unintentional weight loss, low mood, and difficulty with bathing and managing finances. Which geriatric screening domains are these questions primarily assessing?
     • Coronary risk and lipid status
     • Mood and functional status including activities of daily living
     • Pubertal development and growth velocity
     • Acute infectious symptoms only

     Correct answer: Mood and functional status including activities of daily living

     Questions about low mood screen for depression, while difficulty with bathing and managing finances assess basic and instrumental activities of daily living, together evaluating mood and functional status. These are core domains of comprehensive geriatric assessment and are not measures of coronary risk, pubertal development, or acute infection. Function- and mood-focused screening reflects the developmental priorities of later life.

381. A 75-year-old patient takes nine prescription medications managed by several specialists. As part of routine geriatric care, which intervention is most appropriate to address a key safety concern associated with this situation?
     • Automatically discontinuing all medications at once
     • Ordering routine whole-body imaging
     • Performing a medication review to identify polypharmacy and potentially inappropriate drugs
     • Deferring any change until an acute adverse event occurs

     Correct answer: Performing a medication review to identify polypharmacy and potentially inappropriate drugs

     A structured medication review to identify polypharmacy and potentially inappropriate medications is the appropriate response, because older adults are at high risk for drug interactions, adverse effects, and falls from excessive or inappropriate medications. Abruptly stopping all medications, ordering routine whole-body imaging, and waiting for an adverse event are unsafe or unhelpful. Medication review is a central element of preventive geriatric screening.

382. A trial reports that a vaccine lowers the one-season incidence of a respiratory infection from 15% to 9%. How many people must be vaccinated for one season to prevent a single infection?
     • About 17
     • About 11
     • About 6
     • About 40

     Correct answer: About 17

     The answer is about 17. The absolute risk reduction is 15% minus 9%, which equals 6% or 0.06, and the number needed to treat is the reciprocal of that value, so $\frac{1}{0.06} \approx 17$ people vaccinated to prevent one infection.

383. A reviewer reads that a therapy has a number needed to treat of 12 with a 95% confidence interval ranging from 9 to 18. What does this confidence interval primarily convey?
     • The probability that the therapy is harmful
     • The precision of the estimated treatment benefit per patient treated
     • The proportion of patients who adhered to therapy
     • The disease prevalence in the trial population

     Correct answer: The precision of the estimated treatment benefit per patient treated

     The answer is the precision of the estimated treatment benefit per patient treated. A confidence interval around a number needed to treat reflects the range of plausible values for the true benefit; an interval entirely within the benefit range, such as 9 to 18, indicates a precise and statistically significant effect.

384. A clinician knows a treatment produces an absolute risk reduction of 0.025 over two years. What is the number needed to treat over that period?
     • 25
     • 4
     • 40
     • 250

     Correct answer: 40

     The answer is 40. The number needed to treat is the reciprocal of the absolute risk reduction expressed as a proportion, so $\frac{1}{0.025} = 40$ patients treated over two years to prevent one event.

385. Two preventive drugs for the same outcome over the same period report a number needed to treat of 15 and a number needed to harm of 50. How is the balance of benefit and harm best summarized for a single such drug?
     • The two figures cannot be compared on the same scale
     • More patients are harmed than helped because the harm number is larger
     • Benefit and harm are equal because both are reciprocals of risk differences
     • More patients are helped than harmed because fewer must be treated to prevent an event than to cause one

     Correct answer: More patients are helped than harmed because fewer must be treated to prevent an event than to cause one

     The answer is that more patients are helped than harmed because fewer must be treated to prevent an event than to cause one. A number needed to treat of 15 that is smaller than the number needed to harm of 50 means beneficial events accrue more readily than harmful ones, favoring a net benefit.

386. A graphical tool lets a clinician draw a line from a pre-test probability through a likelihood ratio to read off the post-test probability of disease. What is this tool called?
     • A Fagan nomogram
     • A forest plot
     • A funnel plot
     • A Kaplan-Meier curve

     Correct answer: A Fagan nomogram

     The answer is a Fagan nomogram. It graphically applies Bayes theorem by connecting the pre-test probability and the likelihood ratio of a test result to estimate the post-test probability, sparing the clinician from manual odds calculations.

387. A test result carries a positive likelihood ratio of 5. As a general rule of thumb for clinical decision-making, how is a likelihood ratio of about 5 described?
     • It produces no meaningful change in probability
     • It produces a moderate increase in the probability of disease
     • It rules out disease
     • It is mathematically impossible

     Correct answer: It produces a moderate increase in the probability of disease

     The answer is that it produces a moderate increase in the probability of disease. By convention, positive likelihood ratios around 5 cause a moderate rise in post-test probability, ratios near 2 cause small shifts, and ratios of 10 or more cause large, often decisive increases.

388. A test has a sensitivity of 60% and a specificity of 80%. What is its negative likelihood ratio?
     • 0.25
     • 3.0
     • 0.5
     • 1.33

     Correct answer: 0.5

     The answer is 0.5. The negative likelihood ratio equals (1 minus sensitivity) divided by specificity, which is $\frac{1 - 0.60}{0.80} = \frac{0.40}{0.80} = 0.5$.

389. A clinician applies two independent tests in series, performing the second test only if the first is positive. Compared with either test alone, what does serial testing tend to do to overall specificity?
     • Make specificity equal to sensitivity
     • Decrease overall specificity
     • Leave specificity unchanged
     • Increase overall specificity

     Correct answer: Increase overall specificity

     The answer is increase overall specificity. Requiring both tests to be positive before calling a result positive reduces false positives, raising specificity and the positive predictive value, though it lowers overall sensitivity.

390. A diagnostic study compares a new test against a reference test considered the definitive standard for the disease. What is this reference test called?
     • The gold standard
     • The likelihood ratio
     • The confounder
     • The surrogate endpoint

     Correct answer: The gold standard

     The answer is the gold standard. It is the accepted definitive method for establishing the true disease status, against which a new test's sensitivity and specificity are measured.

391. A test has a sensitivity of 90%. What is the corresponding false-negative rate?
     • 90%
     • 10%
     • 1%
     • Cannot be determined without specificity

     Correct answer: 10%

     The answer is 10%. The false-negative rate is the proportion of truly diseased patients who test negative, equal to 1 minus sensitivity, so 1 minus 0.90 equals 0.10 or 10%.

392. A specificity of 85% corresponds to what false-positive rate for a diagnostic test?
     • 5%
     • 85%
     • 15%
     • Cannot be determined

     Correct answer: 15%

     The answer is 15%. The false-positive rate is the proportion of healthy individuals who test positive, equal to 1 minus specificity, so 1 minus 0.85 equals 0.15 or 15%.

393. On a receiver operating characteristic analysis, investigators select the cutoff that maximizes sensitivity plus specificity minus one. What is this optimizing index called?
     • The attributable fraction
     • Cohen's kappa
     • The hazard ratio
     • The Youden index

     Correct answer: The Youden index

     The answer is the Youden index. Defined as sensitivity plus specificity minus 1, it identifies the cutoff that gives the best overall balance of true-positive and true-negative classification on a receiver operating characteristic curve.

394. A disease has a prevalence of 10%. A test with sensitivity 90% and specificity 90% is applied to 1,000 people. Approximately what is the positive predictive value?
     • 50%
     • 90%
     • 10%
     • 75%

     Correct answer: 50%

     The answer is 50%. Of 100 diseased people, 90 test positive (true positives); of 900 healthy people, 90 test positive (false positives); the positive predictive value is $\frac{90}{90 + 90} = \frac{90}{180} = 0.50$ or 50%.

395. In the same population of 1,000 people with 10% prevalence, where a test with 90% sensitivity and 90% specificity yields 90 true positives, 90 false positives, 810 true negatives, and 10 false negatives, what is the negative predictive value?
     • 50%
     • About 99%
     • 90%
     • 81%

     Correct answer: About 99%

     The answer is about 99%. Negative predictive value equals true negatives divided by all negatives, which is $\frac{810}{810 + 10} = \frac{810}{820} \approx 0.988$ or about 99%.

396. A clinician reads that a positive test has a false discovery rate of 30%. How does this relate to the positive predictive value?
     • The two are unrelated quantities
     • The positive predictive value is also 30%
     • The positive predictive value is 70%, because false discovery rate equals 1 minus positive predictive value
     • The positive predictive value is 130%

     Correct answer: The positive predictive value is 70%, because false discovery rate equals 1 minus positive predictive value

     The answer is that the positive predictive value is 70%, because false discovery rate equals 1 minus positive predictive value. The false discovery rate is the proportion of positive results that are false, so its complement among positives is the proportion truly diseased, the positive predictive value.

397. A trial reports a control event rate of 30% and a treatment event rate of 21%. What is the relative risk of the outcome with treatment compared with control?
     • 0.3
     • 1.43
     • 0.09
     • 0.7

     Correct answer: 0.7

     The answer is 0.7. Relative risk is the treatment event rate divided by the control event rate, which is $\frac{0.21}{0.30} = 0.70$.

398. A treatment lowers an outcome from 16% to 4%. What is the relative risk reduction?
     • 75%
     • 12%
     • 25%
     • 4%

     Correct answer: 75%

     The answer is 75%. Relative risk reduction equals the absolute risk reduction divided by the control event rate, which is $\frac{0.16 - 0.04}{0.16} = \frac{0.12}{0.16} = 0.75$ or 75%.

399. A guideline states that a treatment achieves a relative risk reduction of 50% and an absolute risk reduction of 1%. What baseline control event rate is implied?
     • 1%
     • 2%
     • 50%
     • 0.5%

     Correct answer: 2%

     The answer is 2%. Absolute risk reduction equals the control event rate multiplied by the relative risk reduction, so $0.01 = \text{CER} \times 0.50$; solving gives a control event rate of 0.02 or 2%.

400. A medication produces an absolute risk increase of harm of 0.4% over one year. What is the number needed to harm?
     • 40
     • 25
     • 250
     • 400

     Correct answer: 250

     The answer is 250. The number needed to harm is the reciprocal of the absolute risk increase expressed as a proportion, so $\frac{1}{0.004} = 250$ patients treated for one additional harmful event.

401. Investigators study an exposure and a rare disease using a case-control design and report an odds ratio of 6. They state it approximates the relative risk. What assumption justifies this claim?
     • The assumption of equal group sizes
     • The assumption that exposure was randomized
     • The assumption that prevalence equals incidence
     • The rare-disease assumption, because the outcome is uncommon

     Correct answer: The rare-disease assumption, because the outcome is uncommon

     The answer is the rare-disease assumption, because the outcome is uncommon. When disease is rare, the odds of disease approximate the risk of disease, so the odds ratio from a case-control study closely approximates the relative risk.

402. A cohort study finds an incidence of 5% in exposed and 5% in unexposed participants. What relative risk does this represent and how is it interpreted?
     • A relative risk of 1.0, indicating no association between exposure and disease
     • A relative risk of 0.5, indicating protection
     • A relative risk of 2.0, indicating harm
     • A relative risk of 5.0, indicating strong harm

     Correct answer: A relative risk of 1.0, indicating no association between exposure and disease

     The answer is a relative risk of 1.0, indicating no association between exposure and disease. Relative risk is the exposed incidence divided by the unexposed incidence, $\frac{0.05}{0.05} = 1.0$, the null value showing no difference in risk.

403. An investigator collects data on a 2x2 table from a cohort study with 30 exposed cases, 70 exposed non-cases, 10 unexposed cases, and 90 unexposed non-cases. What is the odds ratio?
     • 3.0
     • About 3.9
     • 0.26
     • 1.0

     Correct answer: About 3.9

     The answer is about 3.9. The odds ratio is the cross-product ratio $\frac{30 \times 90}{70 \times 10} = \frac{2700}{700} \approx 3.9$.

404. An ecological study finds that countries with higher average fat intake have higher rates of heart disease, and a researcher concludes that individuals who eat more fat have more heart disease. What error has the researcher committed?
     • Lead-time bias
     • Recall bias
     • The ecological fallacy, inferring individual-level associations from group-level data
     • Confounding by indication

     Correct answer: The ecological fallacy, inferring individual-level associations from group-level data

     The answer is the ecological fallacy, inferring individual-level associations from group-level data. Ecological studies measure exposures and outcomes at the population level, so associations observed between group averages may not hold for individuals within those groups.

405. Investigators nest a case-control study within an existing prospective cohort, selecting cases and matched controls from the cohort after follow-up. What is a key advantage of this nested case-control design?
     • It removes all confounding without adjustment
     • It eliminates the need for any comparison group
     • It guarantees a rare-disease assumption is unnecessary
     • Exposure data were collected before disease developed, reducing recall bias

     Correct answer: Exposure data were collected before disease developed, reducing recall bias

     The answer is that exposure data were collected before disease developed, reducing recall bias. Because the parent cohort recorded exposures at baseline, a nested case-control study draws on prospectively gathered information, avoiding the retrospective recall problems of standard case-control studies while remaining efficient.

406. A factorial randomized trial assigns participants to two interventions simultaneously, such as drug A versus placebo and drug B versus placebo. What is the principal advantage of a factorial design?
     • It allows two interventions to be tested efficiently within one trial
     • It eliminates the need for randomization
     • It removes the possibility of interaction between treatments
     • It guarantees both drugs will be effective

     Correct answer: It allows two interventions to be tested efficiently within one trial

     The answer is that it allows two interventions to be tested efficiently within one trial. By crossing two randomized comparisons, a factorial design evaluates the effects of both treatments, and their possible interaction, using a single study population.

407. A trial randomizes entire clinics rather than individual patients to receive a quality-improvement intervention. What is this design called?
     • Crossover trial
     • Cluster randomized trial
     • Case-crossover study
     • Nested case-control study

     Correct answer: Cluster randomized trial

     The answer is a cluster randomized trial. Groups such as clinics, hospitals, or communities are the units of randomization rather than individuals, which suits interventions delivered at a group level and requires analysis that accounts for within-cluster correlation.

408. In a crossover trial, a washout period is inserted between treatment phases. What is the purpose of this washout?
     • To randomize participants a second time
     • To increase the disease prevalence
     • To allow the effect of the first treatment to dissipate before the second begins, reducing carryover
     • To eliminate the placebo effect

     Correct answer: To allow the effect of the first treatment to dissipate before the second begins, reducing carryover

     The answer is to allow the effect of the first treatment to dissipate before the second begins, reducing carryover. A washout interval ensures the first intervention no longer influences the participant when the second period starts, preserving the validity of the within-person comparison.

409. A study reports a 95% confidence interval for a number needed to treat that runs from 8 to 30, entirely within the benefit range. What does this interval indicate about the treatment effect?
     • The interval cannot be interpreted
     • The benefit is not statistically significant
     • The treatment is harmful
     • The benefit is statistically significant because the interval does not cross into harm

     Correct answer: The benefit is statistically significant because the interval does not cross into harm

     The answer is that the benefit is statistically significant because the interval does not cross into harm. When the entire confidence interval for the number needed to treat reflects benefit and does not extend into number needed to harm, the underlying absolute risk reduction excludes zero, indicating a significant effect.

410. A study reports a relative risk of 1.6 with a 95% confidence interval of 0.95 to 2.70. What is the correct conclusion about statistical significance?
     • It is not statistically significant because the interval includes 1.0
     • It is statistically significant because the point estimate exceeds 1.0
     • It is statistically significant because the interval is wide
     • Significance cannot be assessed from a relative risk

     Correct answer: It is not statistically significant because the interval includes 1.0

     The answer is that it is not statistically significant because the interval includes 1.0. Even though the point estimate suggests increased risk, the 95% confidence interval crosses the null value of 1.0, so the data remain compatible with no association.

411. An investigator distinguishes the standard error of the mean from the standard deviation. Which statement is correct?
     • The standard error always exceeds the standard deviation
     • The standard error estimates the precision of the sample mean, while the standard deviation describes the spread of individual values
     • The standard deviation decreases as the sample size grows
     • The two are identical for any sample

     Correct answer: The standard error estimates the precision of the sample mean, while the standard deviation describes the spread of individual values

     The answer is that the standard error estimates the precision of the sample mean, while the standard deviation describes the spread of individual values. The standard error equals the standard deviation divided by the $\sqrt{\text{sample size}}$, so it shrinks with larger samples, unlike the standard deviation.

412. A survival study reports a hazard ratio of 0.50 for a new therapy. Which statement most accurately interprets this value?
     • Survival time was reduced by half
     • Half of the patients survived
     • The instantaneous rate of the event is half that of the comparison group at any given time
     • The event rate increased by 50%

     Correct answer: The instantaneous rate of the event is half that of the comparison group at any given time

     The answer is that the instantaneous rate of the event is half that of the comparison group at any given time. A hazard ratio of 0.50 means the hazard, the instantaneous event rate, in the treatment group is half that of control, a 50% relative reduction in the rate of events.

413. An investigator checks whether the proportional hazards assumption holds by examining whether two Kaplan-Meier survival curves cross during follow-up. What does crossing of the curves suggest?
     • The data are perfectly censored
     • The hazard ratio is exactly 1.0
     • The study has high power
     • The proportional hazards assumption may be violated

     Correct answer: The proportional hazards assumption may be violated

     The answer is that the proportional hazards assumption may be violated. Crossing survival curves imply that the relative hazard between groups changes direction over time, so a single constant hazard ratio cannot adequately summarize the comparison.

414. A study sets a one-sided alpha of 0.05 rather than a two-sided alpha. Compared with a two-sided test, what is the chief consequence of a one-sided test?
     • It places the entire rejection region in one direction, ignoring effects in the opposite direction
     • It doubles the probability of a type II error
     • It eliminates type I error entirely
     • It requires no prespecified hypothesis

     Correct answer: It places the entire rejection region in one direction, ignoring effects in the opposite direction

     The answer is that it places the entire rejection region in one direction, ignoring effects in the opposite direction. A one-sided test allocates all of alpha to detecting an effect in a single prespecified direction and cannot detect a significant effect the other way, which is why two-sided tests are usually preferred.

415. A study runs many subgroup comparisons and applies a Bonferroni correction. What is the purpose of this correction?
     • To increase statistical power
     • To control the overall type I error rate across multiple comparisons
     • To convert relative risk into absolute risk
     • To correct for loss to follow-up

     Correct answer: To control the overall type I error rate across multiple comparisons

     The answer is to control the overall type I error rate across multiple comparisons. The Bonferroni method divides the significance threshold by the number of tests, lowering the chance that at least one false-positive result arises from performing many comparisons.

416. An investigator reports a Cohen's d of 0.8 for the difference between two group means. What does this statistic describe?
     • The disease prevalence
     • The probability of a type I error
     • A standardized measure of effect size
     • The sensitivity of an outcome measure

     Correct answer: A standardized measure of effect size

     The answer is a standardized measure of effect size. Cohen's d expresses the difference between two means in units of pooled standard deviation, allowing the magnitude of an effect to be judged independently of the original measurement scale and sample size.

417. An investigator compares a continuous outcome measured at three time points within the same patients. Which statistical test is most appropriate for these repeated measurements?
     • Log-rank test
     • Independent two-sample t-test
     • Chi-square test
     • Repeated-measures analysis of variance

     Correct answer: Repeated-measures analysis of variance

     The answer is repeated-measures analysis of variance. It compares means across multiple time points measured on the same subjects while accounting for the correlation between repeated observations within each individual.

418. An investigator compares a continuous, non-normally distributed outcome across three or more independent groups. Which nonparametric test is most appropriate?
     • Kruskal-Wallis test
     • Paired t-test
     • Pearson correlation
     • One-way analysis of variance

     Correct answer: Kruskal-Wallis test

     The answer is the Kruskal-Wallis test. As the nonparametric counterpart to one-way analysis of variance, it compares the distributions of a continuous outcome across three or more independent groups without assuming normality.

419. An investigator compares paired, non-normally distributed before-and-after measurements in the same patients. Which nonparametric test fits this paired design?
     • Mann-Whitney U test
     • Wilcoxon signed-rank test
     • Chi-square test
     • Independent t-test

     Correct answer: Wilcoxon signed-rank test

     The answer is the Wilcoxon signed-rank test. It is the nonparametric equivalent of the paired t-test, comparing matched or repeated measurements within subjects when the distribution of the differences is not normal.

420. A new randomized trial of an inexpensive drug aims to show it is no worse than the standard by more than a prespecified margin. An intention-to-treat analysis in this non-inferiority setting can bias results in which direction?
     • It removes all bias automatically
     • Toward falsely concluding superiority
     • Toward falsely concluding non-inferiority, because non-adherence dilutes differences
     • Toward overstating harm

     Correct answer: Toward falsely concluding non-inferiority, because non-adherence dilutes differences

     The answer is toward falsely concluding non-inferiority, because non-adherence dilutes differences. In non-inferiority trials, intention-to-treat analysis pushes results toward equivalence, so a per-protocol analysis is also examined to confirm the new treatment is genuinely not worse.

421. In a randomized trial, participants who dropped out before the outcome had their last available measurement carried forward into the final analysis to preserve the intention-to-treat principle. What is this imputation method called?
     • Inverse probability weighting
     • Per-protocol analysis
     • Propensity matching
     • Last observation carried forward

     Correct answer: Last observation carried forward

     The answer is last observation carried forward. It is a simple imputation that uses a participant's most recent measurement in place of a missing later value, often used to retain randomized participants in an intention-to-treat analysis, though it can bias results if dropout relates to outcome.

422. A trial is designed with a fixed effect size and a fixed alpha of 0.05. If the investigators want to raise power from 80% to 90%, what must generally happen to the sample size?
     • It must increase
     • It must decrease
     • It stays the same
     • It must drop to zero

     Correct answer: It must increase

     The answer is that it must increase. Achieving higher power while holding the effect size and alpha constant requires reducing the standard error, which is accomplished by enrolling more participants, so the sample size must grow.

423. A reviewer notes that a study with a very large sample size produced a statistically significant result for a tiny effect. Which error type is least likely to explain a false conclusion in this large, well-powered study, and why?
     • Type I error is impossible in large studies
     • Type II error is unlikely because high power makes missing a true effect improbable
     • Type II error is likely because power is low
     • Both error types are eliminated by large samples

     Correct answer: Type II error is unlikely because high power makes missing a true effect improbable

     The answer is that type II error is unlikely because high power makes missing a true effect improbable. Large samples confer high power, so failing to detect a real difference is uncommon; the relevant caution is instead that trivial effects can reach significance.

424. A study with adequate power reports a non-significant result. A clinician concludes there is good evidence of no clinically important difference. What feature most supports treating this as evidence of absence rather than absence of evidence?
     • The sample size was small
     • The p value is exactly 0.05
     • The confidence interval is narrow and excludes a clinically important difference
     • The study had low power

     Correct answer: The confidence interval is narrow and excludes a clinically important difference

     The answer is that the confidence interval is narrow and excludes a clinically important difference. A non-significant result is more credibly evidence of no meaningful effect when a precise confidence interval rules out differences large enough to matter, which requires adequate power.

425. An epidemiologist compares observed deaths in an occupational cohort to the number expected based on the general population, reporting the ratio. What is this measure called?
     • Incidence density
     • Case-fatality ratio
     • Attack rate
     • Standardized mortality ratio

     Correct answer: Standardized mortality ratio

     The answer is the standardized mortality ratio. It divides the observed number of deaths in a study group by the number expected if that group had the same age-specific mortality as a reference population, with a value above 1 indicating excess mortality.

426. An occupational cohort of workers appears healthier than the general population, biasing comparisons of mortality. Which phenomenon explains this?
     • The healthy worker effect
     • Lead-time bias
     • Recall bias
     • Berkson bias

     Correct answer: The healthy worker effect

     The answer is the healthy worker effect. Employed populations tend to be healthier than the general population, which includes the sick and disabled, so comparing worker mortality to the general population can mask occupational hazards.

427. A public health official tracks years of potential life lost to compare the burden of two diseases. What does this measure emphasize compared with simple death counts?
     • Only deaths in the elderly
     • Deaths occurring at younger ages, weighting premature mortality more heavily
     • The prevalence of disease
     • The sensitivity of death certificates

     Correct answer: Deaths occurring at younger ages, weighting premature mortality more heavily

     The answer is deaths occurring at younger ages, weighting premature mortality more heavily. Years of potential life lost sums the difference between a reference age and the age at death, so conditions killing younger people contribute more, highlighting premature mortality.

428. During a foodborne outbreak, epidemiologists calculate the proportion of dinner guests who fell ill among those who ate a specific dish. To find the likely source, they compare this measure across different dishes. What is this measure?
     • Standardized mortality ratio
     • Point prevalence
     • Food-specific attack rate
     • Incidence density

     Correct answer: Food-specific attack rate

     The answer is the food-specific attack rate. Comparing the attack rate among those who ate each food with the rate among those who did not helps identify the contaminated item responsible for an outbreak.

429. An outbreak epidemic curve shows a single sharp peak of cases clustered over a short interval. What pattern of transmission does this most likely indicate?
     • A pandemic
     • A propagated outbreak spread person to person
     • Endemic background transmission
     • A point-source outbreak from a common exposure

     Correct answer: A point-source outbreak from a common exposure

     The answer is a point-source outbreak from a common exposure. A single tight peak on the epidemic curve, with cases appearing within one incubation period, suggests everyone was exposed to the same source at about the same time.

430. An infectious disease has a basic reproduction number, R0, of 3. What does this value mean in a fully susceptible population?
     • Each infected person will, on average, infect three others
     • Three percent of the population will be infected
     • The disease lasts three days
     • Three doses of vaccine are required

     Correct answer: Each infected person will, on average, infect three others

     The answer is that each infected person will, on average, infect three others. The basic reproduction number R0 is the average number of secondary cases generated by one case in a wholly susceptible population, and values above 1 indicate the potential for an epidemic.

431. A vaccine confers herd immunity once enough of the population is immune. As the basic reproduction number of a disease rises, what happens to the herd immunity threshold needed to halt spread?
     • It falls, requiring fewer immune people
     • It rises, requiring a larger immune fraction
     • It stays constant regardless of transmissibility
     • It becomes zero

     Correct answer: It rises, requiring a larger immune fraction

     The answer is that it rises, requiring a larger immune fraction. The herd immunity threshold is approximately 1 minus the reciprocal of the basic reproduction number, so more transmissible diseases with higher R0 demand a greater proportion of immune individuals to stop sustained transmission.

432. A disease is consistently present at a relatively stable, expected level in a particular geographic region. Which term describes this pattern?
     • Pandemic
     • Epidemic
     • Endemic
     • Sporadic

     Correct answer: Endemic

     The answer is endemic. An endemic disease maintains a constant, predictable baseline presence within a defined population or area, in contrast to an epidemic, which is an increase above the expected level, or a pandemic, which spans multiple countries.

433. Investigators studying a chronic disease enroll prevalent (existing) cases rather than newly diagnosed cases. The exposure association is distorted because long-surviving patients are overrepresented. Which bias is this?
     • Spectrum bias
     • Recall bias
     • Lead-time bias
     • Prevalence-incidence (Neyman) bias

     Correct answer: Prevalence-incidence (Neyman) bias

     The answer is prevalence-incidence bias, also called Neyman bias. Studying existing cases preferentially includes those who survived longer and excludes those who died quickly or recovered, distorting the exposure-disease relationship relative to using incident cases.

434. In a study, only patients who survived long enough to receive a treatment could be counted in the treated group, falsely making the treatment appear protective. Which bias does this describe?
     • Immortal time bias
     • Recall bias
     • Hawthorne effect
     • Berkson bias

     Correct answer: Immortal time bias

     The answer is immortal time bias. It arises when a period during which the outcome cannot occur is misclassified or excluded, so that the treated group is guaranteed to survive until treatment, artificially inflating the apparent benefit.

435. In a trial of a surgical versus medical therapy, the clinicians assessing outcomes knew which treatment each patient received and rated outcomes more favorably for surgery. Which bias does this lack of blinding introduce?
     • Recall bias
     • Detection (observer) bias
     • Lead-time bias
     • Confounding by indication

     Correct answer: Detection (observer) bias

     The answer is detection bias, also called observer bias. When outcome assessors know the treatment assignment, their measurements can be systematically influenced, which blinding of outcome assessors is designed to prevent.

436. In an unblinded trial, patients who knew they received the active drug received more attentive co-interventions and follow-up than the control group. Which bias does this differential care represent?
     • Spectrum bias
     • Recall bias
     • Performance bias
     • Lead-time bias

     Correct answer: Performance bias

     The answer is performance bias. It occurs when groups receive systematically different care apart from the intervention being studied, often due to lack of blinding, distorting the comparison; blinding of patients and providers helps prevent it.

437. Survey respondents underreport their alcohol intake because heavy drinking is viewed unfavorably. Which type of information bias does this represent?
     • Confounding
     • Lead-time bias
     • Selection bias
     • Social desirability bias

     Correct answer: Social desirability bias

     The answer is social desirability bias. Respondents systematically misreport behaviors to align with socially approved norms, distorting self-reported exposure data, especially for sensitive topics such as alcohol, smoking, or risky behaviors.

438. An interviewer who knows the disease status of case-control participants probes cases more thoroughly about exposures than controls. Which bias does this differential questioning produce?
     • Interviewer (ascertainment) bias
     • Lead-time bias
     • Regression to the mean
     • Immortal time bias

     Correct answer: Interviewer (ascertainment) bias

     The answer is interviewer bias, a form of ascertainment bias. When data collectors aware of outcome status question groups differently, they introduce systematic differences in exposure measurement; blinding interviewers to case or control status mitigates this.

439. An exposure is mismeasured more often in cases than in controls, distorting the association in an unpredictable direction. What is this type of error called?
     • Nondifferential misclassification
     • Differential misclassification
     • Random sampling error
     • Regression to the mean

     Correct answer: Differential misclassification

     The answer is differential misclassification. When measurement error differs by outcome status, it can bias the estimated association either toward or away from the null, unlike nondifferential misclassification, which typically biases toward the null.

440. Investigators use multivariable regression to adjust the crude association between an exposure and outcome for several confounders measured in the data. What is this analytic strategy designed to accomplish?
     • Randomization after data collection
     • Elimination of unmeasured confounding
     • Statistical control of measured confounding at the analysis stage
     • Increasing the disease prevalence

     Correct answer: Statistical control of measured confounding at the analysis stage

     The answer is statistical control of measured confounding at the analysis stage. Multivariable adjustment estimates the exposure effect while holding measured confounders constant, but it cannot account for confounders that were not measured, unlike randomization.

441. An observational study uses propensity score matching to compare treated and untreated patients. What does the propensity score represent?
     • The hazard ratio of the comparison
     • The probability of the disease outcome
     • The sensitivity of the treatment
     • Each patient's estimated probability of receiving the treatment given their characteristics

     Correct answer: Each patient's estimated probability of receiving the treatment given their characteristics

     The answer is each patient's estimated probability of receiving the treatment given their characteristics. Matching or weighting on the propensity score balances measured confounders between treated and untreated groups, mimicking some advantages of randomization for measured variables only.

442. A clinician must choose a study design to test whether a new drug truly causes better outcomes than placebo, minimizing confounding. Which design provides the strongest causal evidence?
     • Randomized controlled trial
     • Cross-sectional survey
     • Case series
     • Ecological study

     Correct answer: Randomized controlled trial

     The answer is the randomized controlled trial. Random allocation balances measured and unmeasured confounders across groups, so it provides the strongest design for establishing that an intervention causes the observed difference in outcomes.

443. A descriptive study reports only a series of patients with an unusual presentation and their outcomes, without any comparison group. What is this study design?
     • Cohort study
     • Case series
     • Case-control study
     • Randomized trial

     Correct answer: Case series

     The answer is a case series. It describes characteristics and outcomes of a group of patients with a condition but lacks a comparison group, so it can generate hypotheses but cannot establish associations or causation.

444. A clinical research team wants to estimate the prevalence of a condition and its association with several characteristics by surveying a population at a single time point. Which design fits this goal?
     • Randomized controlled trial
     • Prospective cohort study
     • Cross-sectional study
     • Case-crossover study

     Correct answer: Cross-sectional study

     The answer is a cross-sectional study. By measuring exposures and outcomes simultaneously in a population at one point in time, it efficiently estimates prevalence and associations, though it cannot establish temporal sequence or causation.

445. A clinical preventive service is assigned a Grade D recommendation by a national task force. What does a Grade D recommendation indicate?
     • The service is strongly recommended
     • The service has substantial net benefit
     • There is insufficient evidence to assess
     • There is moderate or high certainty the service has no net benefit or that harms outweigh benefits, so it is discouraged

     Correct answer: There is moderate or high certainty the service has no net benefit or that harms outweigh benefits, so it is discouraged

     The answer is that there is moderate or high certainty the service has no net benefit or that harms outweigh benefits, so it is discouraged. A Grade D recommendation advises against routinely providing the service because the evidence shows it does more harm than good or no benefit.

446. A preventive service receives an I (insufficient) statement from a national task force. What does this signify?
     • The current evidence is inadequate to assess the balance of benefits and harms
     • The service is strongly recommended
     • The service causes definite harm
     • The service has a substantial net benefit

     Correct answer: The current evidence is inadequate to assess the balance of benefits and harms

     The answer is that the current evidence is inadequate to assess the balance of benefits and harms. An I statement means the available evidence is insufficient, conflicting, or of poor quality, so the task force cannot recommend for or against the service.

447. Vaccinating children before they are exposed to a pathogen, to keep disease from occurring at all, is an example of which level of prevention?
     • Secondary prevention
     • Primary prevention
     • Tertiary prevention
     • Quaternary prevention

     Correct answer: Primary prevention

     The answer is primary prevention. Primary prevention acts before disease onset to prevent its occurrence, as immunization does by reducing susceptibility, whereas secondary prevention detects early disease and tertiary prevention limits complications of established disease.

448. A mammography program detects breast cancer in asymptomatic women so it can be treated earlier. Which level of prevention does screening represent?
     • Tertiary prevention
     • Primary prevention
     • Secondary prevention
     • Health promotion only

     Correct answer: Secondary prevention

     The answer is secondary prevention. Screening asymptomatic individuals to detect disease at an early, more treatable stage is secondary prevention, distinct from primary prevention that prevents disease onset and tertiary prevention that reduces complications of existing disease.

449. A cardiac rehabilitation program helps patients who have already had a myocardial infarction avoid further decline and complications. Which level of prevention is this?
     • Screening
     • Primary prevention
     • Secondary prevention
     • Tertiary prevention

     Correct answer: Tertiary prevention

     The answer is tertiary prevention. Tertiary prevention aims to reduce disability and complications and improve function in people with established disease, as cardiac rehabilitation does after a myocardial infarction.

450. A reviewer evaluates whether a condition is appropriate for a screening program. According to classic screening principles, which characteristic of the disease is required?
     • There is a recognizable early or latent stage and effective treatment for early disease
     • The disease must be extremely rare
     • There must be no available treatment
     • The disease must have no detectable preclinical phase

     Correct answer: There is a recognizable early or latent stage and effective treatment for early disease

     The answer is that there is a recognizable early or latent stage and effective treatment for early disease. Classic screening criteria require a detectable preclinical phase during which intervention improves outcomes; without effective early treatment, earlier detection provides no benefit.

451. An investigator reports the incidence rate of an event as 12 per 1,000 person-years. What does the use of person-years in the denominator account for?
     • The prevalence of disease at baseline
     • Varying lengths of time that participants are observed and at risk
     • The sensitivity of the outcome measure
     • The number of confounders adjusted for

     Correct answer: Varying lengths of time that participants are observed and at risk

     The answer is varying lengths of time that participants are observed and at risk. Person-time denominators sum each participant's contributed time at risk, allowing an incidence rate to be computed even when individuals enter and leave the study at different times.

452. A meta-analysis combines studies but the authors worry that smaller studies with null results were never published, inflating the pooled effect. What is this concern called?
     • Confounding by indication
     • Recall bias
     • Publication bias
     • Lead-time bias

     Correct answer: Publication bias

     The answer is publication bias. It arises when studies with positive or significant findings are more likely to be published than those with null or negative results, so a synthesis of only published work can overstate the true effect.

453. A systematic review follows a structured, prespecified protocol to identify, appraise, and synthesize all relevant studies on a question. How does a systematic review differ from a narrative review?
     • It is lower on the evidence hierarchy than a case series
     • It includes only the author's preferred studies
     • It always pools data into a single estimate
     • It uses explicit, reproducible methods to minimize bias in selecting and combining studies

     Correct answer: It uses explicit, reproducible methods to minimize bias in selecting and combining studies

     The answer is that it uses explicit, reproducible methods to minimize bias in selecting and combining studies. A systematic review follows a predefined search and appraisal strategy, whereas a narrative review reflects subjective selection; a meta-analysis is the optional quantitative pooling step within a systematic review.

454. A trial uses a data safety monitoring board to review interim results. What is the primary role of this independent board?
     • To safeguard participants by monitoring safety and efficacy and recommending stopping if warranted
     • To increase the trial's sample size
     • To analyze only the final published data
     • To recruit additional participants

     Correct answer: To safeguard participants by monitoring safety and efficacy and recommending stopping if warranted

     The answer is to safeguard participants by monitoring safety and efficacy and recommending stopping if warranted. An independent data safety monitoring board reviews accumulating data during a trial and may recommend early termination for clear harm, overwhelming benefit, or futility.

455. A measurement tool is highly reliable but a validation study shows it does not actually measure the intended underlying concept. Which property is lacking?
     • Reliability
     • Validity
     • Precision
     • Reproducibility

     Correct answer: Validity

     The answer is validity. A tool can yield consistent, reproducible results, indicating good reliability, yet still fail to measure the true construct of interest, which is the separate property of validity, or accuracy.

456. Two physicians independently rate the severity of the same set of x-rays on a continuous scale, and investigators want to quantify the consistency of their continuous ratings. Which statistic is most appropriate?
     • Relative risk
     • Cohen's kappa
     • Intraclass correlation coefficient
     • Odds ratio

     Correct answer: Intraclass correlation coefficient

     The answer is the intraclass correlation coefficient. It assesses the reliability of continuous measurements made by different raters, whereas Cohen's kappa is used for categorical agreement between raters.

457. A diagnostic accuracy study enrolled a narrow, atypical spectrum of patients, so the reported sensitivity may not apply to the broader patient population. Which type of validity is most threatened?
     • Construct validity of the gold standard
     • Internal validity
     • Statistical conclusion validity
     • External validity

     Correct answer: External validity

     The answer is external validity. When the studied sample does not represent the range of patients seen in practice, the findings, though internally valid, may not generalize, which is a limitation of external validity, also called generalizability.

458. A study's internal validity is described as strong. What does strong internal validity indicate?
     • The observed effect is likely real within the study, with bias and confounding minimized
     • The results apply to all populations
     • The disease prevalence was high
     • The sample size was large

     Correct answer: The observed effect is likely real within the study, with bias and confounding minimized

     The answer is that the observed effect is likely real within the study, with bias and confounding minimized. Internal validity concerns whether the study accurately measures the effect it intends to within its own sample, distinct from external validity, which concerns generalizability.

459. A reviewer of a diagnostic test calculates the proportion of all patients, both diseased and healthy, that the test classifies correctly. Which measure is this?
     • Sensitivity
     • Accuracy
     • Positive predictive value
     • Likelihood ratio

     Correct answer: Accuracy

     The answer is accuracy. Diagnostic accuracy is the proportion of all tested individuals correctly classified, calculated as true positives plus true negatives divided by the total tested, summarizing overall performance but obscuring the separate sensitivity and specificity.

460. An investigator wants to display how the true-positive rate trades off against the false-positive rate across all possible cutoffs of a continuous diagnostic test. Which graphic accomplishes this?
     • Forest plot
     • Kaplan-Meier curve
     • Receiver operating characteristic curve
     • Funnel plot

     Correct answer: Receiver operating characteristic curve

     The answer is the receiver operating characteristic curve. It plots sensitivity against 1 minus specificity across every possible threshold, illustrating the inherent trade-off and allowing comparison of overall test discrimination through the area under the curve.

461. An advertisement reports only the relative risk reduction of a drug. Why do regulators and evidence reviewers prefer that both relative and absolute measures be reported?
     • Relative measures cannot be calculated from trials
     • Relative measures are always wrong
     • Absolute measures are easier to inflate
     • Absolute measures reveal the real-world magnitude of benefit at the patient's baseline risk

     Correct answer: Absolute measures reveal the real-world magnitude of benefit at the patient's baseline risk

     The answer is that absolute measures reveal the real-world magnitude of benefit at the patient's baseline risk. Reporting relative risk reduction alone can exaggerate perceived benefit when baseline risk is low, so absolute risk reduction and number needed to treat are needed for honest interpretation.

462. A treatment increases the absolute risk of a serious adverse event by 2 percentage points while reducing the absolute risk of the primary outcome by 5 percentage points. How should the net effect be framed for shared decision-making?
     • Weigh the number needed to treat of 20 against the number needed to harm of 50
     • Ignore the harm because the benefit is larger in relative terms
     • Conclude the treatment is harmful overall
     • The two cannot be compared

     Correct answer: Weigh the number needed to treat of 20 against the number needed to harm of 50

     The answer is to weigh the number needed to treat of 20 against the number needed to harm of 50. A 5% absolute benefit gives a number needed to treat of 20, while a 2% absolute harm gives a number needed to harm of 50, so fewer patients are needed to gain a benefit than to incur a harm, informing the risk-benefit discussion.

463. A researcher reports that an exposure has an odds ratio of 0.6 with a 95% confidence interval of 0.4 to 0.9. What is the best interpretation?
     • A harmful association because the odds ratio is positive
     • A statistically significant protective association because the interval lies entirely below 1.0
     • A non-significant result because the interval is narrow
     • No association because the odds ratio is less than 1.0

     Correct answer: A statistically significant protective association because the interval lies entirely below 1.0

     The answer is a statistically significant protective association because the interval lies entirely below 1.0. An odds ratio under 1.0 indicates lower odds of the outcome with exposure, and because the entire confidence interval excludes the null value of 1.0, the protective association is statistically significant.

464. A clinician converts a probability to odds for use with a likelihood ratio. A patient has a pre-test probability of disease of 20%. What are the corresponding pre-test odds?
     • 4 to 1 (4.0)
     • 1 to 5 (0.20)
     • 1 to 4 (0.25)
     • 1 to 1 (1.0)

     Correct answer: 1 to 4 (0.25)

     The answer is 1 to 4, or 0.25. Odds equal probability divided by (1 minus probability), so $\frac{0.20}{0.80} = 0.25$, expressed as odds of 1 to 4, the form needed to multiply by a likelihood ratio.

465. A team studies an acute, transient trigger of myocardial infarction by comparing each patient's exposure in the hour before the event to the same patient's exposure during an earlier control period. Which design is this?
     • Cross-sectional study
     • Prospective cohort study
     • Cluster randomized trial
     • Case-crossover study

     Correct answer: Case-crossover study

     The answer is a case-crossover study. Each case serves as their own control by comparing exposure just before the acute event with exposure during a prior reference window, which efficiently studies transient triggers of sudden-onset outcomes while controlling for stable individual characteristics.

466. A diagnostic study enrolls patients with the full spectrum of disease severity and a representative range of comorbidities seen in practice. What does this approach help avoid?
     • Spectrum bias, which inflates apparent test accuracy
     • Lead-time bias
     • Confounding by indication
     • Immortal time bias

     Correct answer: Spectrum bias, which inflates apparent test accuracy

     The answer is spectrum bias, which inflates apparent test accuracy. Including the realistic range of patients rather than only clearly diseased and clearly healthy subjects yields sensitivity and specificity estimates that reflect true real-world performance.

467. A study compares two treatments and reports a p value of exactly 0.05 with the chosen alpha set at 0.05. How is this result conventionally classified?
     • Clearly not significant
     • At the threshold of statistical significance, conventionally treated as borderline
     • Highly significant
     • Proof that the treatments are identical

     Correct answer: At the threshold of statistical significance, conventionally treated as borderline

     The answer is at the threshold of statistical significance, conventionally treated as borderline. A p value equal to alpha sits exactly at the predefined cutoff, so the result is marginal and should be interpreted cautiously alongside the effect size and confidence interval rather than as a definitive finding.

468. An investigator wants to control for a known confounder during the design phase by enrolling only nonsmokers so that smoking cannot confound the exposure-disease relationship. What is this design technique called?
     • Stratified analysis
     • Matching
     • Restriction
     • Standardization

     Correct answer: Restriction

     The answer is restriction. Limiting enrollment to a single level of a confounder, such as nonsmokers, prevents that variable from confounding the association, though it reduces generalizability and prevents study of the restricted variable's effect.

469. After data collection, an analyst examines the exposure-outcome association separately within levels of a third variable to control for it. What is this analytic technique?
     • Blinding
     • Restriction
     • Randomization
     • Stratification

     Correct answer: Stratification

     The answer is stratification. Analyzing the association within strata of a potential confounder, then combining the stratum-specific estimates, controls for that confounder at the analysis stage and can also reveal effect modification if the estimates differ across strata.

470. Stratified analysis reveals that an exposure increases risk in men but decreases risk in women, with clearly different stratum-specific estimates. What does this finding represent?
     • Effect modification by sex, which should be reported by stratum
     • Confounding by sex, which should be adjusted away
     • Random error only
     • Selection bias

     Correct answer: Effect modification by sex, which should be reported by stratum

     The answer is effect modification by sex, which should be reported by stratum. When the true effect of an exposure genuinely differs across levels of another variable, that variable is an effect modifier, and the distinct stratum-specific results should be presented rather than pooled into one estimate.

471. A study reports that a continuous biomarker is normally distributed. In such a distribution, how do the mean, median, and mode relate to one another?
     • The mean greatly exceeds the median
     • They are approximately equal
     • The median exceeds the mode by a wide margin
     • They are unrelated

     Correct answer: They are approximately equal

     The answer is that they are approximately equal. A symmetric normal distribution has its mean, median, and mode coinciding at the center, in contrast to skewed distributions where these measures of central tendency diverge.

472. A test is described as having high precision but poor accuracy. Which scenario fits this description?
     • Measurements are both close to the truth and reproducible
     • Repeated measurements scatter widely but average to the true value
     • Repeated measurements cluster tightly but are systematically offset from the true value
     • Measurements are random and untrustworthy in every way

     Correct answer: Repeated measurements cluster tightly but are systematically offset from the true value

     The answer is that repeated measurements cluster tightly but are systematically offset from the true value. High precision means reproducible, closely grouped results, while poor accuracy means a consistent bias away from the truth, illustrating that the two properties are independent.

473. A clinician reads that a screening test reduced disease-specific mortality in a randomized trial but did not change all-cause mortality. Why might evidence reviewers still scrutinize the benefit?
     • Screening trials do not require randomization
     • Disease-specific mortality is never a valid endpoint
     • All-cause mortality cannot be measured in trials
     • Lack of an all-cause mortality benefit raises the possibility that screening-related harms offset disease-specific gains

     Correct answer: Lack of an all-cause mortality benefit raises the possibility that screening-related harms offset disease-specific gains

     The answer is that lack of an all-cause mortality benefit raises the possibility that screening-related harms offset disease-specific gains. If fewer disease-specific deaths do not translate into fewer total deaths, harms such as overdiagnosis or complications of workup may counterbalance the benefit, warranting careful interpretation.

474. A screening program detects and treats many indolent cancers that would never have caused symptoms or death in the patient's lifetime. What is this phenomenon called?
     • Overdiagnosis
     • Lead-time bias
     • Confounding
     • Regression to the mean

     Correct answer: Overdiagnosis

     The answer is overdiagnosis. It occurs when screening identifies disease that would never have become clinically significant, leading to unnecessary treatment and harm without benefit, and it is a recognized limitation of screening programs.

475. A clinical trial registers its protocol and prespecifies its primary outcome before enrollment. How does prospective registration improve the integrity of the evidence?
     • It increases the sample size automatically
     • It deters selective outcome reporting and undisclosed changes to the primary endpoint
     • It guarantees a statistically significant result
     • It removes the need for a control group

     Correct answer: It deters selective outcome reporting and undisclosed changes to the primary endpoint

     The answer is that it deters selective outcome reporting and undisclosed changes to the primary endpoint. Publicly registering the protocol and prespecified outcomes makes it possible to detect when reported results deviate from the original plan, reducing outcome reporting bias.

476. Two trials of the same drug report relative risks of 0.78 and 0.81 with confidence intervals that overlap substantially. A meta-analyst notes low statistical heterogeneity. What does low heterogeneity support?
     • Publication bias is certainly present
     • The studies should not be combined
     • Pooling the studies into a single summary estimate is reasonable
     • The pooled estimate must be ignored

     Correct answer: Pooling the studies into a single summary estimate is reasonable

     The answer is that pooling the studies into a single summary estimate is reasonable. Low heterogeneity indicates that variation across study results is mostly due to chance rather than true differences, so combining them into one pooled effect is statistically appropriate.

477. A continuous outcome is summarized by its mean and standard deviation. Roughly what proportion of values lie within one standard deviation of the mean in a normal distribution?
     • About 50%
     • About 95%
     • About 99.7%
     • About 68%

     Correct answer: About 68%

     The answer is about 68%. Under the empirical rule for a normal distribution, approximately 68% of observations fall within one standard deviation of the mean, about 95% within two, and about 99.7% within three.

478. An investigator analyzing observational data uses an instrumental variable to estimate a treatment effect. What property must a valid instrumental variable have?
     • It influences treatment receipt but affects the outcome only through treatment, not directly
     • It is the same as the outcome
     • It must be a confounder of the exposure and outcome
     • It must be measured after the outcome

     Correct answer: It influences treatment receipt but affects the outcome only through treatment, not directly

     The answer is that it influences treatment receipt but affects the outcome only through treatment, not directly. A valid instrumental variable is associated with the exposure, is independent of confounders, and affects the outcome solely via the exposure, allowing estimation of causal effects from observational data under these assumptions.

479. A 68-year-old man with a history of ischemic cardiomyopathy presents with worsening dyspnea over two days, orthopnea, and a 4 kg weight gain. He is sitting upright, with crackles in both lung bases, jugular venous distension to the angle of the jaw, and 2+ pitting edema. His blood pressure is 148/88 mm Hg and oxygen saturation is 90% on room air. Which is the most appropriate initial pharmacologic therapy?
     • Intravenous loop diuretic such as furosemide
     • Oral metoprolol succinate uptitration
     • Intravenous normal saline bolus
     • Oral spironolactone as the sole agent

     Correct answer: Intravenous loop diuretic such as furosemide

     Intravenous loop diuretic such as furosemide is correct. This patient has acute decompensated heart failure with volume overload, and IV loop diuretics relieve congestion by promoting natriuresis and diuresis. Uptitrating a beta-blocker during acute decompensation can worsen low output and is deferred until euvolemic. A saline bolus would worsen fluid overload. Spironolactone alone produces inadequate diuresis for acute pulmonary congestion.

480. A 74-year-old woman with heart failure with reduced ejection fraction is admitted with acute decompensation. Despite escalating doses of intravenous furosemide, her urine output remains low and her creatinine is rising while she remains congested with persistent pulmonary edema. Her blood pressure is 132/80 mm Hg. Which strategy is most appropriate to overcome the inadequate diuretic response?
     • Switch to oral furosemide at the same dose
     • Add a thiazide-type diuretic such as metolazone to the loop diuretic
     • Stop all diuretics and start intravenous fluids
     • Begin dialysis immediately

     Correct answer: Add a thiazide-type diuretic such as metolazone to the loop diuretic

     Adding a thiazide-type diuretic such as metolazone to the loop diuretic is correct. Sequential nephron blockade with a thiazide augments diuresis in patients with diuretic resistance during acute decompensated heart failure. Switching to oral furosemide reduces bioavailability and worsens response. Stopping diuretics and giving fluids would worsen congestion. Dialysis is reserved for refractory cases with true diuretic failure or specific dialysis indications, not as the next step here.

481. A 60-year-old man presents with acute decompensated heart failure and severe dyspnea. His blood pressure is 196/110 mm Hg, he is markedly hypertensive, and chest imaging shows flash pulmonary edema. In addition to a loop diuretic and supplemental oxygen, which adjunctive agent most directly addresses the underlying hemodynamic problem?
     • Intravenous phenylephrine
     • Oral amlodipine
     • Intravenous nitroglycerin for afterload and preload reduction
     • Intravenous dopamine

     Correct answer: Intravenous nitroglycerin for afterload and preload reduction

     Intravenous nitroglycerin for afterload and preload reduction is correct. In hypertensive acute decompensated heart failure with flash pulmonary edema, vasodilators such as nitroglycerin rapidly reduce preload and afterload, improving forward flow and relieving congestion. Phenylephrine and dopamine raise blood pressure and increase afterload, worsening the situation. Oral amlodipine acts too slowly for this hypertensive emergency presentation.

482. A 55-year-old man with acute decompensated heart failure now has a blood pressure of 82/54 mm Hg, cool extremities, mottled skin, lactate of 4.2 mmol/L, and a rising creatinine, indicating cardiogenic shock with end-organ hypoperfusion. He remains congested. Which intervention is most appropriate at this point?
     • High-dose intravenous loop diuretic alone
     • Intravenous beta-blocker
     • Aggressive intravenous fluid resuscitation
     • An inotrope such as dobutamine to improve cardiac output

     Correct answer: An inotrope such as dobutamine to improve cardiac output

     An inotrope such as dobutamine to improve cardiac output is correct. In acute decompensated heart failure complicated by cardiogenic shock with hypoperfusion, an inotrope augments contractility and forward flow to restore perfusion. A loop diuretic alone will not address low output and may worsen hypotension. Beta-blockade further depresses contractility. Aggressive fluids worsen pulmonary congestion in a patient who is already volume overloaded.

483. A patient hospitalized for acute decompensated heart failure with reduced ejection fraction has been diuresed to euvolemia and is now comfortable on room air. He had been taking metoprolol and lisinopril as an outpatient, both held on admission. Which is the most appropriate approach to his guideline-directed medical therapy before discharge?
     • Resume and optimize guideline-directed medical therapy including the beta-blocker once euvolemic and hemodynamically stable
     • Discontinue the beta-blocker permanently because it caused the admission
     • Avoid all afterload-reducing agents indefinitely
     • Start an inotrope infusion for home use

     Correct answer: Resume and optimize guideline-directed medical therapy including the beta-blocker once euvolemic and hemodynamically stable

     Resuming and optimizing guideline-directed medical therapy including the beta-blocker once euvolemic and hemodynamically stable is correct. Beta-blockers, ACE inhibitors or ARNI, mineralocorticoid antagonists, and SGLT2 inhibitors reduce mortality in heart failure with reduced ejection fraction and should be continued or restarted before discharge once the patient is no longer congested. Permanently stopping the beta-blocker removes a survival benefit. Afterload reduction is beneficial. Home inotropes are reserved for select advanced or palliative cases.

484. A 72-year-old man with hypertension and diabetes is found to have asymptomatic atrial fibrillation on a routine ECG. His heart rate is 78 beats per minute and he is hemodynamically stable. His CHA2DS2-VASc score is 4. Which intervention most reduces his risk of stroke?
     • Daily aspirin 81 mg
     • Long-term oral anticoagulation with a direct oral anticoagulant
     • Rhythm control with antiarrhythmic drugs
     • Beta-blocker for rate control alone

     Correct answer: Long-term oral anticoagulation with a direct oral anticoagulant

     Long-term oral anticoagulation with a direct oral anticoagulant is correct. In atrial fibrillation, stroke prevention is guided by the CHA2DS2-VASc score, and a score of 4 in a man warrants anticoagulation, with DOACs preferred over warfarin in nonvalvular disease. Aspirin provides minimal stroke protection in atrial fibrillation. Rhythm control and rate control manage symptoms and heart rate but do not by themselves prevent thromboembolic stroke.

485. A 65-year-old woman with newly diagnosed atrial fibrillation has a heart rate of 132 beats per minute and reports palpitations. Her blood pressure is 128/76 mm Hg, she has no signs of decompensated heart failure, and she is otherwise stable. Which is the most appropriate initial strategy to control her ventricular rate?
     • Immediate synchronized cardioversion
     • Intravenous digoxin as the sole first agent
     • A beta-blocker or nondihydropyridine calcium channel blocker for rate control
     • Intravenous adenosine

     Correct answer: A beta-blocker or nondihydropyridine calcium channel blocker for rate control

     A beta-blocker or nondihydropyridine calcium channel blocker for rate control is correct. In stable atrial fibrillation with a rapid ventricular response, AV-nodal blockers such as metoprolol or diltiazem are first-line for rate control. Immediate cardioversion is reserved for hemodynamic instability. Digoxin is slower in onset and generally an adjunct, especially in heart failure. Adenosine briefly blocks the AV node but does not control the sustained rate of atrial fibrillation.

486. A 58-year-old man presents with atrial fibrillation, a heart rate of 168 beats per minute, blood pressure of 78/46 mm Hg, chest pain, and altered mental status. Which is the most appropriate immediate intervention?
     • Oral diltiazem and observation
     • Start warfarin and recheck in 3 weeks
     • Intravenous fluids alone
     • Synchronized electrical cardioversion

     Correct answer: Synchronized electrical cardioversion

     Synchronized electrical cardioversion is correct. Atrial fibrillation with hemodynamic instability such as hypotension, ischemic chest pain, or altered mental status requires immediate synchronized cardioversion regardless of duration. Oral diltiazem acts too slowly and could worsen hypotension. Starting warfarin and waiting does not address the unstable arrhythmia. Fluids alone will not terminate the arrhythmia causing the instability.

487. A 70-year-old woman with persistent atrial fibrillation for an estimated 6 weeks is scheduled for elective cardioversion to restore sinus rhythm. She is hemodynamically stable and has not been anticoagulated. Which approach minimizes her risk of thromboembolism around the procedure?
     • Either 3 weeks of therapeutic anticoagulation before cardioversion or a transesophageal echocardiogram to exclude left atrial thrombus, with anticoagulation continued afterward
     • Proceed to cardioversion immediately with no anticoagulation
     • Give a single aspirin dose immediately before cardioversion
     • Cardiovert now and start anticoagulation only if symptoms recur

     Correct answer: Either 3 weeks of therapeutic anticoagulation before cardioversion or a transesophageal echocardiogram to exclude left atrial thrombus, with anticoagulation continued afterward

     Either 3 weeks of therapeutic anticoagulation before cardioversion or a transesophageal echocardiogram to exclude left atrial thrombus, with anticoagulation continued afterward, is correct. For atrial fibrillation lasting 48 hours or longer or of unknown duration, this strategy prevents dislodging a left atrial thrombus, and anticoagulation continues for at least 4 weeks after cardioversion. Cardioverting without these precautions or relying on aspirin leaves the patient at high stroke risk.

488. A 63-year-old man with paroxysmal atrial fibrillation has persistent palpitations and reduced exercise tolerance despite adequate rate control with metoprolol, and he wishes to remain in sinus rhythm. His echocardiogram shows normal left ventricular function and no structural heart disease. Which is the most appropriate next step?
     • Add a second AV-nodal blocking agent only
     • Pursue a rhythm-control strategy with an antiarrhythmic drug such as flecainide or catheter ablation
     • Discontinue anticoagulation because he is symptomatic
     • Implant a permanent pacemaker

     Correct answer: Pursue a rhythm-control strategy with an antiarrhythmic drug such as flecainide or catheter ablation

     Pursuing a rhythm-control strategy with an antiarrhythmic drug such as flecainide or catheter ablation is correct. When symptoms persist despite rate control, rhythm control improves quality of life, and in a structurally normal heart a class IC agent or ablation is appropriate. Adding another rate-control agent does not address the symptomatic arrhythmia. Anticoagulation decisions follow CHA2DS2-VASc and are independent of rhythm. A pacemaker does not prevent or treat atrial fibrillation itself.

489. A 64-year-old man presents with 40 minutes of substernal chest pressure radiating to the left arm. His ECG shows ST-segment depression in the lateral leads without ST elevation, and his high-sensitivity troponin is elevated and rising. He is hemodynamically stable. In addition to aspirin and a high-intensity statin, which is the most appropriate next pharmacologic step?
     • Thrombolytic therapy with alteplase
     • Oral nifedipine alone
     • Anticoagulation plus a P2Y12 inhibitor as part of medical therapy for NSTEMI
     • No antithrombotic therapy until catheterization

     Correct answer: Anticoagulation plus a P2Y12 inhibitor as part of medical therapy for NSTEMI

     Anticoagulation plus a P2Y12 inhibitor as part of medical therapy for NSTEMI is correct. Non-ST-elevation myocardial infarction is managed with dual antiplatelet therapy (aspirin plus a P2Y12 inhibitor) and anticoagulation, along with anti-ischemic and statin therapy. Fibrinolytics are not indicated in NSTEMI and may cause harm. Nifedipine alone provides no benefit and can cause reflex tachycardia. Withholding antithrombotics increases ischemic risk.

490. A 70-year-old woman with an NSTEMI is started on dual antiplatelet therapy and anticoagulation. She has ongoing chest pain, dynamic ST depression, and a troponin that continues to rise, placing her at high ischemic risk. She is hemodynamically stable. Which is the most appropriate management decision regarding revascularization timing?
     • Discharge on medical therapy with outpatient stress testing in 6 weeks
     • Immediate fibrinolysis
     • Repeat ECG only and continue observation indefinitely
     • Early invasive strategy with coronary angiography, typically within 24 hours

     Correct answer: Early invasive strategy with coronary angiography, typically within 24 hours

     An early invasive strategy with coronary angiography, typically within 24 hours, is correct. High-risk NSTEMI features such as refractory ischemia, dynamic ECG changes, and rising troponin warrant early angiography with revascularization as appropriate. Discharge with delayed outpatient testing is unsafe in high-risk patients. Fibrinolysis is contraindicated in NSTEMI. Observation alone fails to address ongoing ischemia.

491. A 59-year-old man with an NSTEMI is being treated with aspirin, a P2Y12 inhibitor, and anticoagulation. His heart rate is 92 beats per minute, blood pressure is 138/82 mm Hg, and he has no signs of heart failure, bradycardia, or hypotension. Which additional medication most reduces myocardial oxygen demand and is indicated within the first 24 hours?
     • An oral beta-blocker
     • Intravenous fluids
     • A positive inotrope
     • A short-acting dihydropyridine calcium channel blocker

     Correct answer: An oral beta-blocker

     An oral beta-blocker is correct. In NSTEMI without contraindications such as decompensated heart failure, hypotension, or high-grade block, a beta-blocker started within 24 hours lowers heart rate, reduces myocardial oxygen demand, and decreases ischemia. Fluids do not reduce demand. An inotrope increases oxygen demand. Short-acting dihydropyridines can cause reflex tachycardia and are not first-line.

492. A 66-year-old man recovering from an NSTEMI treated with a drug-eluting stent is preparing for discharge. He is on aspirin, ticagrelor, a high-intensity statin, a beta-blocker, and an ACE inhibitor. Which statement about his antiplatelet regimen after the procedure is most accurate?
     • He should stop aspirin and continue ticagrelor alone for one week
     • He should continue dual antiplatelet therapy, generally for about 12 months unless bleeding risk dictates otherwise
     • He should stop both antiplatelet agents after 30 days
     • He needs only aspirin with no P2Y12 inhibitor after stenting

     Correct answer: He should continue dual antiplatelet therapy, generally for about 12 months unless bleeding risk dictates otherwise

     Continuing dual antiplatelet therapy, generally for about 12 months unless bleeding risk dictates otherwise, is correct. After NSTEMI with stenting, dual antiplatelet therapy with aspirin plus a P2Y12 inhibitor is recommended for approximately 12 months to prevent stent thrombosis and recurrent events, with duration adjusted for bleeding risk. The other options stop necessary therapy prematurely and increase the risk of stent thrombosis.

493. A 52-year-old man without diabetes or chronic kidney disease has an average office blood pressure of 150/96 mm Hg confirmed on repeat measurements and home monitoring. He is overweight and sedentary. After counseling on lifestyle modification, which is the most appropriate initial antihypertensive pharmacotherapy?
     • A loop diuretic
     • An alpha-blocker as first-line
     • A thiazide-type diuretic, ACE inhibitor, ARB, or calcium channel blocker
     • A central alpha-2 agonist such as clonidine as first-line

     Correct answer: A thiazide-type diuretic, ACE inhibitor, ARB, or calcium channel blocker

     A thiazide-type diuretic, ACE inhibitor, ARB, or calcium channel blocker is correct. For primary hypertension without compelling comorbidities, first-line agents are thiazide diuretics, ACE inhibitors, ARBs, or calcium channel blockers. Loop diuretics are reserved for volume overload or reduced kidney function. Alpha-blockers and clonidine are not first-line because of inferior outcomes and side effects.

494. A 58-year-old African American man with hypertension and no chronic kidney disease has a blood pressure of 154/94 mm Hg despite lifestyle changes. He has no compelling indication for a specific drug class. Which initial monotherapy is generally most effective for blood pressure lowering in this patient?
     • An ACE inhibitor alone
     • A beta-blocker alone
     • An ARB alone
     • A thiazide-type diuretic or a calcium channel blocker

     Correct answer: A thiazide-type diuretic or a calcium channel blocker

     A thiazide-type diuretic or a calcium channel blocker is correct. In Black adults without heart failure or chronic kidney disease, initial therapy with a thiazide diuretic or calcium channel blocker generally achieves greater blood pressure reduction than ACE inhibitors or ARBs as monotherapy. Beta-blockers are not preferred first-line for uncomplicated hypertension. Single-agent RAAS blockade tends to be less effective in this group when used alone.

495. A 60-year-old woman with type 2 diabetes and a urine albumin-to-creatinine ratio showing albuminuria has a blood pressure of 148/90 mm Hg. Which antihypertensive class is specifically preferred because of its added benefit on her kidney disease?
     • An ACE inhibitor or angiotensin receptor blocker
     • A nondihydropyridine calcium channel blocker
     • A thiazide diuretic
     • A beta-blocker

     Correct answer: An ACE inhibitor or angiotensin receptor blocker

     An ACE inhibitor or angiotensin receptor blocker is correct. In patients with diabetes and albuminuria, RAAS blockade with an ACE inhibitor or ARB reduces proteinuria and slows progression of diabetic kidney disease, making it the preferred agent. The other classes lower blood pressure but lack the same renal protective effect in this setting.

496. A 49-year-old man returns for follow-up on hypertension. Despite adherence to maximally tolerated doses of three antihypertensive agents from different classes, including a diuretic, his office blood pressure remains 156/98 mm Hg and is confirmed elevated at home. Which is the most appropriate next step?
     • Reassure him that this is acceptable control
     • Confirm adherence and evaluate for secondary causes of hypertension while considering adding a mineralocorticoid receptor antagonist
     • Stop all medications and restart from scratch
     • Switch all three drugs to a single beta-blocker

     Correct answer: Confirm adherence and evaluate for secondary causes of hypertension while considering adding a mineralocorticoid receptor antagonist

     Confirming adherence and evaluating for secondary causes of hypertension while considering adding a mineralocorticoid receptor antagonist is correct. Resistant hypertension, defined as uncontrolled pressure on three agents including a diuretic, warrants confirming adherence, excluding secondary causes such as primary aldosteronism, and adding spironolactone, which is often effective. Reassurance ignores uncontrolled disease, and the other options remove effective therapy.

497. A 45-year-old woman presents with a blood pressure of 215/130 mm Hg accompanied by a severe headache, blurred vision, and papilledema on fundoscopy, along with an elevated creatinine. Which describes the most appropriate management?
     • Rapidly normalize blood pressure to below 120/80 mm Hg within one hour
     • Prescribe an oral agent and follow up in one week
     • Admit and lower blood pressure in a controlled manner with intravenous agents, reducing it by roughly 10 to 20 percent in the first hour
     • Withhold treatment until repeat readings confirm the values

     Correct answer: Admit and lower blood pressure in a controlled manner with intravenous agents, reducing it by roughly 10 to 20 percent in the first hour

     Admitting and lowering blood pressure in a controlled manner with intravenous agents, reducing it by roughly 10 to 20 percent in the first hour, is correct. This is a hypertensive emergency with acute target-organ damage (encephalopathy, retinopathy, kidney injury), requiring careful intravenous reduction to avoid hypoperfusion. Overly rapid normalization can cause ischemic injury. Oral outpatient management or withholding treatment is unsafe with ongoing organ damage.

498. A 58-year-old man with no history of cardiovascular disease has an LDL cholesterol of 168 mg/dL and an estimated 10-year atherosclerotic cardiovascular disease risk of 14 percent. After a clinician-patient discussion, which is the most appropriate lipid-lowering therapy?
     • No pharmacotherapy because he has no prior cardiac event
     • A fibrate as first-line
     • Niacin monotherapy
     • A moderate- to high-intensity statin for primary prevention

     Correct answer: A moderate- to high-intensity statin for primary prevention

     A moderate- to high-intensity statin for primary prevention is correct. For a patient aged 40 to 75 without diabetes and with intermediate 10-year risk, a statin is indicated for primary prevention after shared decision-making, with intensity guided by risk. Withholding therapy ignores elevated risk. Fibrates and niacin are not first-line for lowering atherosclerotic risk and have not shown comparable event reduction.

499. A 62-year-old woman with a prior myocardial infarction is taking a moderate-intensity statin. Her most recent LDL cholesterol is 118 mg/dL and she tolerates the medication without symptoms. Which is the most appropriate adjustment to her therapy?
     • Intensify to a high-intensity statin to maximally lower LDL cholesterol
     • Stop the statin since she already had her event
     • Add a fibrate and keep the moderate-intensity statin
     • Switch to a bile acid sequestrant alone

     Correct answer: Intensify to a high-intensity statin to maximally lower LDL cholesterol

     Intensifying to a high-intensity statin to maximally lower LDL cholesterol is correct. Patients with established atherosclerotic cardiovascular disease should be on high-intensity statin therapy for secondary prevention to achieve maximal LDL reduction. Stopping the statin removes proven mortality benefit. Adding a fibrate does not address the need for higher-intensity statin and increases myopathy risk. A bile acid sequestrant alone is less effective.

500. A 70-year-old man on a high-intensity statin reports diffuse muscle aches several weeks after starting therapy. His creatine kinase is mildly elevated but less than three times the upper limit of normal, and he has no dark urine or weakness. Which is the most appropriate next step?
     • Immediately diagnose rhabdomyolysis and start dialysis
     • Continue the statin if symptoms are tolerable, or temporarily hold and rechallenge at a lower dose or alternate statin
     • Permanently avoid all statins for life
     • Replace the statin with high-dose niacin

     Correct answer: Continue the statin if symptoms are tolerable, or temporarily hold and rechallenge at a lower dose or alternate statin

     Continuing the statin if symptoms are tolerable, or temporarily holding and rechallenging at a lower dose or alternate statin, is correct. Mild statin-associated muscle symptoms without marked CK elevation or weakness are managed by reassurance, dose reduction, or switching agents, preserving the cardiovascular benefit. Mild CK elevation is not rhabdomyolysis. Permanent avoidance is unnecessary, and niacin is not an equivalent substitute.

501. A 55-year-old man with established coronary artery disease is on a maximally tolerated high-intensity statin, yet his LDL cholesterol remains 95 mg/dL, above his goal for very-high-risk secondary prevention. Which is the most appropriate next agent to add?
     • A short course of antibiotics
     • An additional statin from a second class
     • Ezetimibe and, if needed, a PCSK9 inhibitor
     • Vitamin E supplementation

     Correct answer: Ezetimibe and, if needed, a PCSK9 inhibitor

     Ezetimibe and, if needed, a PCSK9 inhibitor is correct. When LDL remains above goal on maximal statin therapy in very-high-risk patients, ezetimibe is added first, followed by a PCSK9 inhibitor if further lowering is needed, both of which reduce cardiovascular events. There is no role for antibiotics, a second statin is not used, and vitamin E does not lower LDL or cardiovascular risk.

502. A 47-year-old woman with type 2 diabetes and no known cardiovascular disease has an LDL cholesterol of 130 mg/dL and is 47 years old. Which statement best describes the indication for statin therapy in this patient?
     • Statins are not indicated because she has no prior cardiac event
     • A statin should be deferred until her LDL exceeds 190 mg/dL
     • Only a fibrate is appropriate given her diabetes
     • A statin is indicated because diabetes in adults aged 40 to 75 is itself an indication for at least moderate-intensity statin therapy

     Correct answer: A statin is indicated because diabetes in adults aged 40 to 75 is itself an indication for at least moderate-intensity statin therapy

     A statin is indicated because diabetes in adults aged 40 to 75 is itself an indication for at least moderate-intensity statin therapy. Diabetes substantially raises atherosclerotic risk, so guidelines recommend statin therapy in this age range regardless of a prior event, with high intensity if additional risk factors are present. Deferring until LDL exceeds 190 or using a fibrate first does not follow evidence-based diabetes lipid management.

503. A 58-year-old man presents 90 minutes after the onset of crushing substernal chest pain. His ECG shows 3 mm ST-segment elevation in leads II, III, and aVF. He is at a hospital with an on-site catheterization laboratory. Which is the most appropriate reperfusion strategy?
     • Primary percutaneous coronary intervention
     • Fibrinolytic therapy alone
     • Observation with serial troponins
     • Elective stress testing in the morning

     Correct answer: Primary percutaneous coronary intervention

     Primary percutaneous coronary intervention is correct. For ST-elevation myocardial infarction at a PCI-capable facility, primary percutaneous coronary intervention is the preferred reperfusion strategy when it can be performed promptly. Fibrinolytics are used when timely PCI is unavailable. Observation or elective testing dangerously delays reperfusion in an evolving infarct.

504. A 62-year-old woman presents with an inferior ST-elevation myocardial infarction. She becomes hypotensive after receiving sublingual nitroglycerin. Her lungs are clear, and ECG shows ST elevation also in the right-sided lead V4R. Which mechanism best explains her hypotension?
     • Acute mitral regurgitation from papillary muscle rupture
     • Right ventricular infarction with preload dependence worsened by nitrates
     • Cardiac tamponade from free wall rupture
     • Anaphylaxis to nitroglycerin

     Correct answer: Right ventricular infarction with preload dependence worsened by nitrates

     Right ventricular infarction with preload dependence worsened by nitrates is correct. Inferior STEMI with right-sided V4R elevation indicates right ventricular involvement, which is preload-dependent, so nitrates reduce preload and precipitate hypotension; treatment is intravenous fluids. Clear lungs argue against acute mitral regurgitation with pulmonary edema, and there is no evidence of tamponade or an allergic reaction.

505. A 60-year-old man reports predictable substernal chest pressure that occurs with exertion and resolves within minutes of rest, occurring over several months without change in frequency. His resting ECG is normal and he is hemodynamically stable. Which is the most appropriate initial diagnostic test?
     • Immediate coronary angiography
     • Empiric thrombolysis
     • A noninvasive stress test such as exercise treadmill testing
     • 24-hour ambulatory blood pressure monitoring

     Correct answer: A noninvasive stress test such as exercise treadmill testing

     A noninvasive stress test such as exercise treadmill testing is correct. Stable, exertional, reproducible chest pain suggests chronic stable angina, and noninvasive stress testing is the appropriate initial evaluation to assess for inducible ischemia. Coronary angiography is reserved for high-risk findings or refractory symptoms. Thrombolysis is for acute coronary occlusion. Ambulatory blood pressure monitoring evaluates hypertension, not ischemia.

506. A 64-year-old man with chronic stable angina has symptoms controlled on a beta-blocker but continues to have occasional exertional chest pain. He has no contraindication to additional anti-anginal therapy. Which medication is most appropriate to add for symptom relief?
     • A loop diuretic
     • An oral anticoagulant
     • A proton pump inhibitor
     • A long-acting nitrate or a calcium channel blocker

     Correct answer: A long-acting nitrate or a calcium channel blocker

     A long-acting nitrate or a calcium channel blocker is correct. When angina persists despite a beta-blocker, adding a long-acting nitrate or a calcium channel blocker provides additional anti-ischemic relief. Loop diuretics treat volume overload, not angina. Anticoagulants are not used for stable angina symptom control, and proton pump inhibitors treat acid-related disease.

507. A 74-year-old woman with hypertension and obesity has exertional dyspnea, lower extremity edema, and an elevated BNP. Echocardiography shows a left ventricular ejection fraction of 60 percent with evidence of diastolic dysfunction. Which is the cornerstone of managing her condition?
     • Control of blood pressure and volume status, treatment of comorbidities, and an SGLT2 inhibitor
     • High-dose digoxin
     • Long-term inotrope infusion
     • Aggressive afterload reduction to a systolic pressure below 90 mm Hg

     Correct answer: Control of blood pressure and volume status, treatment of comorbidities, and an SGLT2 inhibitor

     Control of blood pressure and volume status, treatment of comorbidities, and an SGLT2 inhibitor is correct. This is heart failure with preserved ejection fraction, managed by treating hypertension, controlling congestion with diuretics, managing comorbidities, and using an SGLT2 inhibitor, which reduces hospitalizations. Digoxin and chronic inotropes have no established role here, and excessive blood pressure lowering risks hypoperfusion.

508. A 76-year-old man reports exertional dyspnea and a syncopal episode. Examination reveals a harsh late-peaking systolic murmur at the right upper sternal border radiating to the carotids, with a diminished and delayed carotid upstroke. Which is the most likely diagnosis?
     • Mitral valve prolapse
     • Severe aortic stenosis
     • Tricuspid regurgitation
     • Pulmonic stenosis

     Correct answer: Severe aortic stenosis

     Severe aortic stenosis is correct. A late-peaking systolic ejection murmur radiating to the carotids with a slow-rising, delayed carotid upstroke (pulsus parvus et tardus) and the classic triad of angina, syncope, and dyspnea indicates severe aortic stenosis. Mitral prolapse produces a midsystolic click, tricuspid regurgitation a holosystolic murmur that increases with inspiration, and pulmonic stenosis a left upper sternal border murmur.

509. A 78-year-old man with severe symptomatic aortic stenosis and multiple comorbidities is evaluated for definitive treatment. He has exertional syncope and a mean transvalvular gradient consistent with severe disease. Which is the most appropriate definitive management?
     • Long-term medical therapy with diuretics alone
     • Chronic vasodilator therapy
     • Aortic valve replacement, either surgical or transcatheter depending on surgical risk
     • Watchful waiting until ejection fraction declines

     Correct answer: Aortic valve replacement, either surgical or transcatheter depending on surgical risk

     Aortic valve replacement, either surgical or transcatheter depending on surgical risk, is correct. Symptomatic severe aortic stenosis carries a poor prognosis without valve replacement, and the choice between surgical and transcatheter replacement depends on operative risk. Medical therapy and vasodilators do not relieve the fixed obstruction, and delaying intervention in a symptomatic patient increases mortality.

510. A 70-year-old man with chronic primary mitral regurgitation is asymptomatic, but serial echocardiograms now show a left ventricular ejection fraction of 58 percent that is declining toward the threshold for intervention, with progressive left ventricular dilation. Which is the most appropriate management?
     • Continue routine observation indefinitely
     • Start an inotrope infusion
     • Begin long-term antibiotic prophylaxis only
     • Refer for mitral valve surgery before irreversible left ventricular dysfunction develops

     Correct answer: Refer for mitral valve surgery before irreversible left ventricular dysfunction develops

     Referring for mitral valve surgery before irreversible left ventricular dysfunction develops is correct. In chronic severe primary mitral regurgitation, declining ejection fraction or progressive left ventricular enlargement is an indication for surgical repair or replacement even before symptoms become limiting. Continued observation risks irreversible damage, inotropes are not appropriate, and antibiotic prophylaxis does not treat the valve lesion.

511. A 36-year-old man who injects drugs presents with fever, malaise, and a new holosystolic murmur at the left lower sternal border that increases with inspiration. Blood cultures grow Staphylococcus aureus. Which is the most appropriate next diagnostic step?
     • Echocardiography to evaluate for vegetations
     • Chest radiograph alone
     • Exercise stress test
     • Coronary angiography

     Correct answer: Echocardiography to evaluate for vegetations

     Echocardiography to evaluate for vegetations is correct. Fever, a new regurgitant murmur, positive blood cultures for Staphylococcus aureus, and injection drug use strongly suggest infective endocarditis, and echocardiography is used to identify valvular vegetations and complications. A chest radiograph, stress test, or coronary angiography does not establish the diagnosis of endocarditis.

512. A 58-year-old woman with a prosthetic aortic valve develops persistent fevers, and blood cultures are positive for a typical endocarditis organism with echocardiographic evidence of a vegetation. While awaiting full susceptibilities, which is the most appropriate management?
     • Oral antibiotics for 7 days as an outpatient
     • Prolonged intravenous antibiotic therapy with monitoring for complications requiring possible surgery
     • Antipyretics alone
     • A single dose of intravenous antibiotic before discharge

     Correct answer: Prolonged intravenous antibiotic therapy with monitoring for complications requiring possible surgery

     Prolonged intravenous antibiotic therapy with monitoring for complications requiring possible surgery is correct. Infective endocarditis, particularly prosthetic valve endocarditis, requires extended intravenous antibiotics and close monitoring for indications for surgery such as heart failure, abscess, or persistent infection. Brief oral therapy, antipyretics alone, or a single dose are inadequate for this serious infection.

513. An 80-year-old woman presents with syncope. Her ECG shows progressive PR prolongation followed by a dropped QRS complex in a repeating pattern. She is otherwise asymptomatic at rest with a heart rate of 58 beats per minute. Which conduction abnormality does this describe?
     • Third-degree complete heart block
     • First-degree AV block
     • Mobitz type I (Wenckebach) second-degree AV block
     • Sinus arrhythmia

     Correct answer: Mobitz type I (Wenckebach) second-degree AV block

     Mobitz type I (Wenckebach) second-degree AV block is correct. Progressive PR prolongation culminating in a dropped beat is the hallmark of Mobitz type I block, which is usually benign and located in the AV node. Complete heart block shows AV dissociation, first-degree block shows a fixed prolonged PR without dropped beats, and sinus arrhythmia reflects respiratory variation in rate.

514. A 72-year-old man presents with fatigue and lightheadedness. His ECG shows complete dissociation between P waves and QRS complexes with a ventricular escape rate of 36 beats per minute, and he is symptomatic. Which is the most appropriate definitive management?
     • Reassurance and observation only
     • Long-term atropine therapy
     • Beta-blocker therapy
     • Permanent pacemaker placement

     Correct answer: Permanent pacemaker placement

     Permanent pacemaker placement is correct. Symptomatic third-degree (complete) heart block with a slow escape rhythm is an indication for permanent pacing. Observation leaves the patient at risk of syncope or asystole, atropine is only a temporizing measure and is often ineffective in infranodal block, and beta-blockers would further suppress the conduction system.

515. A 28-year-old woman presents with a sudden onset of palpitations. Her ECG shows a regular narrow-complex tachycardia at 185 beats per minute without discernible P waves. She is alert with a blood pressure of 118/74 mm Hg. After vagal maneuvers fail, which is the most appropriate next intervention?
     • Intravenous adenosine
     • Immediate synchronized cardioversion
     • Intravenous amiodarone bolus
     • Oral metoprolol and discharge

     Correct answer: Intravenous adenosine

     Intravenous adenosine is correct. A regular narrow-complex tachycardia consistent with paroxysmal supraventricular tachycardia in a stable patient is treated with vagal maneuvers first, then adenosine to transiently block the AV node and terminate the reentrant circuit. Cardioversion is reserved for instability or refractory cases, and amiodarone or oral metoprolol are not first-line for acute termination of stable SVT.

516. A 66-year-old man with prior myocardial infarction suddenly collapses. The monitor shows a wide-complex tachycardia at 200 beats per minute, and he is pulseless. Which is the most appropriate immediate intervention?
     • Synchronized cardioversion
     • Immediate defibrillation and CPR
     • Intravenous adenosine
     • Carotid sinus massage

     Correct answer: Immediate defibrillation and CPR

     Immediate defibrillation and CPR is correct. A pulseless wide-complex tachycardia such as ventricular tachycardia or ventricular fibrillation requires immediate unsynchronized defibrillation along with high-quality CPR. Synchronized cardioversion requires an organized rhythm with a pulse, and adenosine or carotid massage have no role in pulseless arrest.

517. A 70-year-old man with ischemic cardiomyopathy and a left ventricular ejection fraction of 28 percent despite optimal guideline-directed medical therapy is evaluated for prevention of sudden cardiac death. He has New York Heart Association class II symptoms and a reasonable life expectancy. Which intervention is most appropriate?
     • Daily aspirin alone
     • Routine antiarrhythmic drug prophylaxis alone
     • Implantable cardioverter-defibrillator for primary prevention
     • No additional intervention

     Correct answer: Implantable cardioverter-defibrillator for primary prevention

     An implantable cardioverter-defibrillator for primary prevention is correct. Patients with ischemic cardiomyopathy and an ejection fraction of 35 percent or less on optimal therapy with a reasonable life expectancy benefit from an ICD to prevent sudden cardiac death from ventricular arrhythmias. Aspirin and antiarrhythmic drugs alone do not provide this protection, and doing nothing leaves the patient at high arrhythmic risk.

518. A 34-year-old man presents with sharp, pleuritic chest pain that improves when he leans forward, following a recent viral illness. A friction rub is heard, and his ECG shows diffuse ST-segment elevation with PR-segment depression. Which is the most appropriate initial treatment?
     • Immediate thrombolysis
     • Urgent coronary angiography and stenting
     • Long-term anticoagulation
     • A high-dose NSAID plus colchicine

     Correct answer: A high-dose NSAID plus colchicine

     A high-dose NSAID plus colchicine is correct. Pleuritic chest pain relieved by leaning forward, a friction rub, and diffuse ST elevation with PR depression indicate acute pericarditis, treated with an NSAID and colchicine. Thrombolysis and emergent revascularization are for acute coronary occlusion, not pericarditis, and anticoagulation could increase the risk of hemorrhagic pericardial effusion.

519. A 50-year-old woman presents with dyspnea and hypotension. She has muffled heart sounds, jugular venous distension, and a 14 mm Hg drop in systolic blood pressure during inspiration. Echocardiography shows a large pericardial effusion with diastolic collapse of the right atrium. Which is the most appropriate immediate management?
     • Pericardiocentesis
     • Aggressive diuresis
     • Beta-blocker therapy
     • Oral NSAIDs and outpatient follow-up

     Correct answer: Pericardiocentesis

     Pericardiocentesis is correct. Muffled heart sounds, jugular venous distension, hypotension, pulsus paradoxus, and echocardiographic right-heart diastolic collapse indicate cardiac tamponade, which requires urgent drainage of the pericardial fluid. Diuresis reduces preload and worsens tamponade, beta-blockers blunt compensatory tachycardia, and outpatient management is unsafe in this emergency.

520. A 60-year-old man with poorly controlled hypertension presents with the sudden onset of severe tearing chest pain radiating to his back. His blood pressure is 188/104 mm Hg in the right arm and notably lower in the left arm. Which is the most appropriate initial pharmacologic therapy while pursuing definitive imaging?
     • Thrombolytic therapy
     • Intravenous beta-blockade to reduce heart rate and aortic wall stress
     • Aspirin and a P2Y12 inhibitor
     • Intravenous fluids to raise blood pressure

     Correct answer: Intravenous beta-blockade to reduce heart rate and aortic wall stress

     Intravenous beta-blockade to reduce heart rate and aortic wall stress is correct. Sudden tearing chest pain radiating to the back with a blood pressure differential between arms suggests aortic dissection, where rapid heart rate and blood pressure control with a beta-blocker reduces aortic shear stress. Thrombolytics and antiplatelet therapy could be catastrophic, and raising blood pressure would worsen the dissection.

521. A 65-year-old man who smokes reports cramping calf pain that reliably occurs after walking two blocks and resolves with rest. His pedal pulses are diminished and his ankle-brachial index is 0.7. Which is the most appropriate initial management for his symptoms in addition to risk-factor modification?
     • Immediate surgical bypass
     • Long-term oral anticoagulation alone
     • Supervised exercise therapy, smoking cessation, antiplatelet therapy, and a statin
     • Bed rest and leg elevation

     Correct answer: Supervised exercise therapy, smoking cessation, antiplatelet therapy, and a statin

     Supervised exercise therapy, smoking cessation, antiplatelet therapy, and a statin is correct. Intermittent claudication from peripheral arterial disease (ankle-brachial index of 0.90 or below) is initially managed with structured exercise, aggressive risk-factor control, antiplatelet therapy, and a statin. Surgical revascularization is reserved for lifestyle-limiting or critical limb ischemia, anticoagulation alone is not first-line, and leg elevation worsens arterial perfusion.

522. A 68-year-old man who has smoked one pack of cigarettes daily for 40 years comes in for routine care and has never been screened for an abdominal aortic aneurysm. Which is the most appropriate preventive recommendation?
     • Annual chest radiographs
     • Routine coronary calcium scoring
     • No screening is indicated
     • A one-time abdominal ultrasound to screen for abdominal aortic aneurysm

     Correct answer: A one-time abdominal ultrasound to screen for abdominal aortic aneurysm

     A one-time abdominal ultrasound to screen for abdominal aortic aneurysm is correct. Men aged 65 to 75 who have ever smoked should undergo one-time ultrasound screening for abdominal aortic aneurysm, which can detect an asymptomatic, potentially life-threatening dilation. Chest radiographs and coronary calcium scoring do not screen the abdominal aorta, and forgoing screening misses a guideline-based opportunity in this high-risk patient.

523. A 78-year-old man reports lightheadedness on standing. His blood pressure is 138/82 mm Hg supine and falls to 112/70 mm Hg within three minutes of standing, with reproduction of symptoms. He takes several antihypertensive medications. Which is the most appropriate initial step?
     • Review and reduce contributing medications and counsel on slow position changes and adequate hydration
     • Start a vasoconstrictor immediately as first-line
     • Increase his antihypertensive doses
     • Restrict all fluid intake

     Correct answer: Review and reduce contributing medications and counsel on slow position changes and adequate hydration

     Reviewing and reducing contributing medications and counseling on slow position changes and adequate hydration is correct. Orthostatic hypotension, a symptomatic drop of at least 20 mm Hg systolic on standing, is first addressed by removing offending medications and nonpharmacologic measures such as gradual rising and volume repletion. Pharmacologic vasoconstrictors are reserved for refractory cases, and increasing antihypertensives or restricting fluids would worsen symptoms.

524. A 19-year-old athlete experiences exertional syncope. Examination reveals a systolic murmur that increases in intensity with standing and Valsalva and decreases with squatting. There is a family history of sudden death. Which is the most likely underlying condition?
     • Chronic aortic regurgitation
     • Hypertrophic cardiomyopathy with outflow obstruction
     • Atrial septal defect
     • Mitral stenosis

     Correct answer: Hypertrophic cardiomyopathy with outflow obstruction

     Hypertrophic cardiomyopathy with outflow obstruction is correct. A murmur that intensifies with maneuvers that decrease preload (standing, Valsalva) and softens with increased preload (squatting), exertional syncope, and a family history of sudden death are characteristic of hypertrophic cardiomyopathy. Aortic regurgitation produces a diastolic murmur, an atrial septal defect causes fixed splitting of S2, and mitral stenosis produces a diastolic rumble.

525. A 75-year-old man on warfarin for atrial fibrillation presents with a major gastrointestinal hemorrhage and a markedly elevated INR. He is hemodynamically affected by the bleeding. Which is the most appropriate agent to rapidly reverse his anticoagulation?
     • Oral vitamin K alone
     • Protamine sulfate
     • Four-factor prothrombin complex concentrate plus intravenous vitamin K
     • Fresh frozen plasma is contraindicated and reversal should be withheld

     Correct answer: Four-factor prothrombin complex concentrate plus intravenous vitamin K

     Four-factor prothrombin complex concentrate plus intravenous vitamin K is correct. For life-threatening warfarin-associated bleeding, rapid reversal with four-factor prothrombin complex concentrate and intravenous vitamin K restores clotting factors quickly. Oral vitamin K works too slowly for an emergency, protamine reverses heparin rather than warfarin, and withholding reversal in major hemorrhage is dangerous.

526. A 60-year-old man is recovering from an acute myocardial infarction with a left ventricular ejection fraction of 38 percent and no contraindications. Which combination of medications is most appropriate to reduce his long-term mortality?
     • A calcium channel blocker and a fibrate only
     • An anticoagulant and a proton pump inhibitor only
     • A diuretic and a nitrate only
     • Antiplatelet therapy, a high-intensity statin, a beta-blocker, and an ACE inhibitor

     Correct answer: Antiplatelet therapy, a high-intensity statin, a beta-blocker, and an ACE inhibitor

     Antiplatelet therapy, a high-intensity statin, a beta-blocker, and an ACE inhibitor is correct. After myocardial infarction, particularly with reduced ejection fraction, these agents each reduce mortality and recurrent events and form the backbone of secondary prevention. The other combinations omit proven life-saving therapies and would not provide comparable benefit.

527. A 64-year-old woman with heart failure with reduced ejection fraction remains symptomatic on a beta-blocker and an ACE inhibitor with a low ejection fraction. Her potassium and renal function are normal. Which medication change most improves her survival?
     • Replace the ACE inhibitor with an angiotensin receptor-neprilysin inhibitor and add a mineralocorticoid receptor antagonist and an SGLT2 inhibitor
     • Add a long-acting nitrate as the sole change
     • Add digoxin to reduce mortality
     • Add a dihydropyridine calcium channel blocker

     Correct answer: Replace the ACE inhibitor with an angiotensin receptor-neprilysin inhibitor and add a mineralocorticoid receptor antagonist and an SGLT2 inhibitor

     Replacing the ACE inhibitor with an angiotensin receptor-neprilysin inhibitor and adding a mineralocorticoid receptor antagonist and an SGLT2 inhibitor is correct. The four pillars of guideline-directed therapy for heart failure with reduced ejection fraction (ARNI or ACE inhibitor/ARB, beta-blocker, mineralocorticoid antagonist, and SGLT2 inhibitor) each reduce mortality. Nitrates and digoxin improve symptoms but not survival in most patients, and dihydropyridine calcium channel blockers offer no mortality benefit.

528. A 44-year-old asymptomatic man has an in-office blood pressure of 142/90 mm Hg at a single visit and has no prior diagnosis of hypertension. Which is the most appropriate next step before initiating drug therapy?
     • Begin two antihypertensive drugs immediately
     • Confirm the diagnosis with out-of-office measurements such as home or ambulatory monitoring
     • Order coronary angiography
     • Ignore the reading as it is within normal limits

     Correct answer: Confirm the diagnosis with out-of-office measurements such as home or ambulatory monitoring

     Confirming the diagnosis with out-of-office measurements such as home or ambulatory monitoring is correct. A single elevated office reading should be confirmed with repeated or out-of-office measurements to exclude white-coat hypertension before committing to lifelong therapy. Starting two drugs immediately is premature for stage 1 hypertension after one reading, angiography is unrelated, and the value is clearly above normal and cannot be ignored.

529. An 80-year-old woman with atrial fibrillation and heart failure with reduced ejection fraction has a persistently elevated ventricular rate despite a beta-blocker, and she becomes hypotensive when the beta-blocker dose is increased. Which agent is most appropriate to add for additional rate control?
     • A nondihydropyridine calcium channel blocker such as diltiazem
     • A class IC antiarrhythmic such as flecainide
     • Digoxin
     • An additional dihydropyridine calcium channel blocker

     Correct answer: Digoxin

     Digoxin is correct. In atrial fibrillation with heart failure with reduced ejection fraction where a beta-blocker alone is insufficient and hypotension limits uptitration, digoxin provides additional rate control without significant negative inotropy. Nondihydropyridine calcium channel blockers are contraindicated in reduced ejection fraction, class IC agents are avoided in structural heart disease, and dihydropyridines do not control ventricular rate.

530. A 67-year-old woman with known coronary disease reports chest pain that now occurs at rest and is more frequent than her previous exertional pattern. Her ECG shows no ST elevation and her initial troponin is normal. Which best characterizes her presentation?
     • Stable angina
     • Aortic dissection
     • Acute pericarditis
     • Unstable angina

     Correct answer: Unstable angina

     Unstable angina is correct. Angina that is new at rest, accelerating, or occurring with less exertion, without ST elevation and with normal troponin, defines unstable angina, a form of acute coronary syndrome requiring admission and antithrombotic therapy. Stable angina has a predictable exertional pattern, aortic dissection presents with tearing pain, and pericarditis produces pleuritic, positional pain with diffuse ST changes.

531. A 62-year-old man after a large anterior myocardial infarction develops hypotension, cool clammy extremities, elevated jugular venous pressure, and pulmonary edema, with a low cardiac output and high filling pressures. Which type of shock does this represent?
     • Cardiogenic shock
     • Hypovolemic shock
     • Distributive (septic) shock
     • Obstructive shock from tension pneumothorax

     Correct answer: Cardiogenic shock

     Cardiogenic shock is correct. Hypotension with high filling pressures (elevated jugular venous pressure and pulmonary edema), cool extremities, and low cardiac output after a large myocardial infarction indicates cardiogenic shock from pump failure. Hypovolemic and septic shock are associated with low filling pressures, and a tension pneumothorax causes unilateral absent breath sounds and tracheal deviation.

532. A 48-year-old man with resistant hypertension is found to have hypokalemia, metabolic alkalosis, and a suppressed plasma renin with an elevated aldosterone level. Which secondary cause of hypertension is most likely?
     • Pheochromocytoma
     • Primary hyperaldosteronism
     • Renal artery stenosis from fibromuscular dysplasia
     • Cushing syndrome

     Correct answer: Primary hyperaldosteronism

     Primary hyperaldosteronism is correct. Resistant hypertension with spontaneous hypokalemia, an elevated aldosterone, and suppressed renin yielding a high aldosterone-to-renin ratio points to primary hyperaldosteronism. Pheochromocytoma causes episodic catecholamine symptoms, renal artery stenosis raises renin, and Cushing syndrome presents with characteristic body habitus and cortisol excess.

533. A 58-year-old man with chest pain consistent with stable angina mentions he took a phosphodiesterase-5 inhibitor for erectile dysfunction earlier that day. Which is the most important reason to avoid giving him nitrates now?
     • Nitrates will be ineffective after the medication
     • The combination causes hypertensive crisis
     • Concurrent use can cause severe, potentially life-threatening hypotension
     • The combination causes bradycardia

     Correct answer: Concurrent use can cause severe, potentially life-threatening hypotension

     Concurrent use can cause severe, potentially life-threatening hypotension is correct. Combining nitrates with phosphodiesterase-5 inhibitors causes profound vasodilation and dangerous hypotension, so nitrates must be avoided after recent PDE-5 inhibitor use. The interaction lowers, rather than raises, blood pressure, and the primary danger is hypotension rather than ineffectiveness or bradycardia.

534. A 68-year-old woman with atrial fibrillation and a mechanical mitral valve prosthesis requires anticoagulation for stroke prevention. Which anticoagulant is most appropriate for her?
     • A direct oral anticoagulant such as apixaban
     • Aspirin alone
     • A direct oral anticoagulant such as rivaroxaban
     • Warfarin with a target INR range

     Correct answer: Warfarin with a target INR range

     Warfarin with a target INR range is correct. Patients with atrial fibrillation and a mechanical heart valve require warfarin, because direct oral anticoagulants are contraindicated in mechanical valves due to increased thromboembolic and bleeding events shown in trials. Aspirin alone provides inadequate protection in this high-risk setting.

535. A 72-year-old man presenting with NSTEMI has a history of a recent gastrointestinal bleed and is at high bleeding risk, yet he needs antithrombotic therapy. Which approach best balances ischemic and bleeding risk?
     • Proceed with antiplatelet and anticoagulant therapy while taking measures to reduce bleeding risk, such as a proton pump inhibitor and careful dosing
     • Withhold all antithrombotic therapy permanently
     • Give full-dose fibrinolytics
     • Use triple antithrombotic therapy indefinitely

     Correct answer: Proceed with antiplatelet and anticoagulant therapy while taking measures to reduce bleeding risk, such as a proton pump inhibitor and careful dosing

     Proceeding with antiplatelet and anticoagulant therapy while taking measures to reduce bleeding risk, such as a proton pump inhibitor and careful dosing, is correct. NSTEMI still benefits from antithrombotic therapy even with elevated bleeding risk, so the goal is to mitigate bleeding rather than withhold proven therapy. Withholding therapy increases ischemic events, fibrinolytics are not indicated in NSTEMI, and prolonged triple therapy maximizes bleeding risk.

536. A 70-year-old man admitted with acute decompensated heart failure is undergoing aggressive intravenous diuresis. Which laboratory parameters most need close monitoring during this therapy?
     • Serum lipase and amylase
     • Serum electrolytes and renal function
     • Thyroid-stimulating hormone
     • Serum calcium and vitamin D

     Correct answer: Serum electrolytes and renal function

     Serum electrolytes and renal function is correct. Aggressive loop diuresis in acute decompensated heart failure can cause hypokalemia, hypomagnesemia, and worsening renal function, so electrolytes and creatinine require close monitoring. Pancreatic enzymes, thyroid function, and calcium or vitamin D are not the primary parameters affected by loop diuretic therapy.

537. A 58-year-old man with stable angina and asthma is started on anti-anginal therapy. Which class of medication should be used with caution because of the potential to provoke bronchospasm?
     • Long-acting nitrates
     • Dihydropyridine calcium channel blockers
     • Nonselective beta-blockers
     • Ranolazine

     Correct answer: Nonselective beta-blockers

     Nonselective beta-blockers is correct. Nonselective beta-blockers can precipitate bronchospasm in patients with asthma by blocking beta-2 receptors, so they should be used cautiously or avoided. Nitrates, dihydropyridine calcium channel blockers, and ranolazine do not cause bronchoconstriction and are reasonable anti-anginal alternatives in this patient.

538. A 45-year-old man with newly diagnosed atrial fibrillation has no hypertension, diabetes, vascular disease, prior stroke, or heart failure, giving him a CHA2DS2-VASc score of 0. Which is the most appropriate recommendation regarding stroke prevention?
     • Lifelong warfarin
     • Lifelong direct oral anticoagulant
     • Lifelong dual antiplatelet therapy
     • No antithrombotic therapy for stroke prevention is needed

     Correct answer: No antithrombotic therapy for stroke prevention is needed

     No antithrombotic therapy for stroke prevention is needed is correct. A CHA2DS2-VASc score of 0 in a man indicates a very low annual stroke risk, so anticoagulation is not recommended and its bleeding risk outweighs benefit. Warfarin, a direct oral anticoagulant, or dual antiplatelet therapy would expose this low-risk patient to unnecessary bleeding.

539. A 40-year-old woman who immigrated from a region with endemic rheumatic fever presents with exertional dyspnea and palpitations. Auscultation reveals a low-pitched diastolic rumble at the apex with an opening snap, and she is found to be in atrial fibrillation. Which valvular lesion is most likely?
     • Mitral stenosis
     • Aortic regurgitation
     • Tricuspid stenosis
     • Pulmonary regurgitation

     Correct answer: Mitral stenosis

     Mitral stenosis is correct. A low-pitched apical diastolic rumble with an opening snap, a history of rheumatic fever, and atrial fibrillation from left atrial enlargement are classic for rheumatic mitral stenosis. Aortic regurgitation causes an early decrescendo diastolic murmur, while tricuspid and pulmonary lesions produce distinct right-sided findings.

540. A 55-year-old man is noted to have a widened pulse pressure, bounding peripheral pulses, and a high-pitched early diastolic decrescendo murmur best heard at the left sternal border when he leans forward. Which valvular lesion does this describe?
     • Mitral stenosis
     • Chronic aortic regurgitation
     • Aortic stenosis
     • Tricuspid regurgitation

     Correct answer: Chronic aortic regurgitation

     Chronic aortic regurgitation is correct. A high-pitched early diastolic decrescendo murmur at the left sternal border with a widened pulse pressure and bounding (water-hammer) pulses reflects the large stroke volume and rapid diastolic runoff of aortic regurgitation. Mitral stenosis causes a diastolic rumble, aortic stenosis a systolic ejection murmur, and tricuspid regurgitation an inspiration-augmented holosystolic murmur.

541. A 50-year-old man with a prosthetic heart valve is scheduled for a dental procedure involving manipulation of the gingival tissue. Which is the most appropriate measure to reduce his risk of infective endocarditis?
     • No prophylaxis is ever indicated for dental work
     • Long-term daily antibiotics
     • Antibiotic prophylaxis before the dental procedure
     • Anticoagulation before the procedure

     Correct answer: Antibiotic prophylaxis before the dental procedure

     Antibiotic prophylaxis before the dental procedure is correct. Patients with high-risk cardiac conditions such as prosthetic heart valves should receive antibiotic prophylaxis before dental procedures that manipulate gingival tissue to reduce the risk of infective endocarditis. Routine long-term antibiotics are not used, anticoagulation does not prevent infection, and prophylaxis is indeed indicated in this high-risk group.

542. A 52-year-old man is found to have a blood pressure of 196/118 mm Hg at a clinic visit but has no headache, chest pain, visual changes, or other symptoms, and laboratory studies show no acute organ injury. Which best describes the appropriate management?
     • Admit for intravenous nitroprusside to normalize blood pressure within an hour
     • No treatment is needed
     • Immediate dialysis
     • This is hypertensive urgency; restart or adjust oral medications and arrange close follow-up without rapid intravenous lowering

     Correct answer: This is hypertensive urgency; restart or adjust oral medications and arrange close follow-up without rapid intravenous lowering

     This is hypertensive urgency; restart or adjust oral medications and arrange close follow-up without rapid intravenous lowering is correct. Severe hypertension without acute target-organ damage is hypertensive urgency, managed with oral therapy and gradual reduction over days rather than rapid intravenous lowering, which can cause harm. Doing nothing or dialysis is inappropriate for this presentation.

543. A 60-year-old woman started on an ACE inhibitor for hypertension develops a persistent dry cough that interferes with sleep. Her blood pressure is otherwise well controlled. Which is the most appropriate substitution?
     • Switch to an angiotensin receptor blocker
     • Add a cough suppressant and continue the ACE inhibitor indefinitely
     • Switch to a different ACE inhibitor
     • Discontinue all antihypertensive therapy

     Correct answer: Switch to an angiotensin receptor blocker

     Switch to an angiotensin receptor blocker is correct. ACE inhibitor-induced cough results from bradykinin accumulation, and switching to an ARB, which does not raise bradykinin, provides similar blood pressure control without the cough. The cough is a class effect, so a different ACE inhibitor would likely recur, masking with a suppressant ignores the cause, and stopping all therapy leaves hypertension untreated.

544. A 66-year-old man with heart failure with reduced ejection fraction is to begin beta-blocker therapy. Which beta-blockers have proven mortality benefit in this condition?
     • Atenolol or propranolol only
     • Carvedilol, metoprolol succinate, or bisoprolol
     • Esmolol infusion
     • Labetalol only

     Correct answer: Carvedilol, metoprolol succinate, or bisoprolol

     Carvedilol, metoprolol succinate, or bisoprolol is correct. Only these three beta-blockers have demonstrated mortality reduction in heart failure with reduced ejection fraction and are the recommended agents. Atenolol, propranolol, esmolol, and labetalol have not been shown to provide the same survival benefit in this setting.

545. Five days after an acute myocardial infarction, a 68-year-old man suddenly develops hypotension and a new harsh holosystolic murmur at the left lower sternal border with a palpable thrill, and an oxygen step-up is noted between the right atrium and right ventricle. Which mechanical complication is most likely?
     • Reinfarction without mechanical complication
     • Pulmonary embolism
     • Ventricular septal rupture
     • Aortic dissection

     Correct answer: Ventricular septal rupture

     Ventricular septal rupture is correct. A new harsh holosystolic murmur with a thrill, hemodynamic collapse, and an oxygen saturation step-up from left-to-right shunting days after a myocardial infarction indicate post-infarction ventricular septal rupture. Reinfarction would not produce a shunt, and pulmonary embolism and aortic dissection have different findings.

546. A 56-year-old man is started on a high-intensity statin for established coronary artery disease. Which is the most appropriate routine laboratory monitoring after initiation?
     • Monthly creatine kinase regardless of symptoms
     • Weekly liver function tests indefinitely
     • No follow-up testing is ever needed
     • Check a lipid panel in about 4 to 12 weeks to assess adherence and response

     Correct answer: Check a lipid panel in about 4 to 12 weeks to assess adherence and response

     Checking a lipid panel in about 4 to 12 weeks to assess adherence and response is correct. After starting a statin, a follow-up lipid panel in 4 to 12 weeks gauges adherence and LDL reduction. Routine scheduled creatine kinase and frequent liver tests are not recommended without symptoms, and some monitoring of response is appropriate rather than none.

547. A 55-year-old man with no prior cardiac history presents with new atrial fibrillation in the setting of thyrotoxicosis, with a suppressed TSH and elevated free T4. In addition to rate control, which intervention most directly addresses the underlying cause of his arrhythmia?
     • Treating the hyperthyroidism
     • Immediate catheter ablation
     • Long-term antiarrhythmic drug therapy
     • Permanent pacemaker placement

     Correct answer: Treating the hyperthyroidism

     Treating the hyperthyroidism is correct. Thyrotoxicosis is a reversible precipitant of atrial fibrillation, and treating the underlying hyperthyroidism often restores sinus rhythm, making it the priority alongside rate control and anticoagulation as indicated. Ablation, chronic antiarrhythmics, or a pacemaker do not correct the metabolic driver of the arrhythmia.

548. A 72-year-old woman with chronic heart failure is taught self-management to detect early decompensation at home. Which monitoring practice is most useful for early detection of fluid retention?
     • Monthly electrocardiograms
     • Daily weight measurement with reporting of rapid gains
     • Daily blood glucose checks
     • Weekly chest radiographs

     Correct answer: Daily weight measurement with reporting of rapid gains

     Daily weight measurement with reporting of rapid gains is correct. Daily weights detect fluid accumulation early, allowing timely diuretic adjustment and preventing hospitalization for decompensated heart failure. Periodic electrocardiograms, glucose checks, and chest radiographs do not provide the same early warning of volume retention.

549. A 70-year-old man with chest pain and an NSTEMI is being risk-stratified to guide management. Which combination of findings indicates high ischemic risk warranting an early invasive approach?
     • A single normal troponin and resolved symptoms
     • Isolated sinus tachycardia from anxiety
     • Recurrent or refractory angina, dynamic ST changes, hemodynamic instability, or a rising troponin
     • A normal ECG with no biomarker elevation

     Correct answer: Recurrent or refractory angina, dynamic ST changes, hemodynamic instability, or a rising troponin

     Recurrent or refractory angina, dynamic ST changes, hemodynamic instability, or a rising troponin is correct. These high-risk features in NSTEMI identify patients who benefit from an early invasive strategy. A single normal troponin with resolved symptoms, anxiety-related tachycardia, or a normal ECG without biomarker elevation suggest lower risk and do not by themselves mandate early angiography.

550. A 58-year-old man with hypertension and high cardiovascular risk is being managed to a blood pressure goal. According to current guidelines, which is an appropriate general target for most adults with hypertension?
     • Less than 160/100 mm Hg
     • Less than 150/90 mm Hg for all ages
     • Less than 110/60 mm Hg
     • Less than 130/80 mm Hg

     Correct answer: Less than 130/80 mm Hg

     Less than 130/80 mm Hg is correct. Current guidelines recommend a blood pressure target of less than 130/80 mm Hg for most adults with hypertension, particularly those with elevated cardiovascular risk. The higher thresholds are too permissive under current recommendations, and a goal below 110/60 risks hypoperfusion and is not a standard target.

551. A 76-year-old woman with atrial fibrillation taking a direct oral anticoagulant asks why she must continue it despite feeling well. Which explanation best reflects the purpose of her therapy?
     • It reduces the risk of a disabling cardioembolic stroke even though she has no symptoms
     • It controls her heart rate
     • It converts her rhythm back to normal
     • It treats her underlying coronary disease

     Correct answer: It reduces the risk of a disabling cardioembolic stroke even though she has no symptoms

     It reduces the risk of a disabling cardioembolic stroke even though she has no symptoms is correct. Anticoagulation in atrial fibrillation prevents thrombus formation in the left atrial appendage and the resulting embolic stroke, a benefit independent of symptoms. It does not control rate, restore rhythm, or treat coronary disease.

552. A 78-year-old man without cardiovascular disease and with a limited life expectancy due to advanced comorbidities asks whether he should start a statin for primary prevention. Which consideration most appropriately guides the decision?
     • Mandatory high-intensity statin regardless of life expectancy
     • Shared decision-making weighing limited remaining benefit against risks and patient preferences
     • Statins are absolutely contraindicated over age 75
     • Only a fibrate is appropriate at this age

     Correct answer: Shared decision-making weighing limited remaining benefit against risks and patient preferences

     Shared decision-making weighing limited remaining benefit against risks and patient preferences is correct. In older adults without established disease and with limited life expectancy, the benefit of primary-prevention statins is uncertain, so the decision should be individualized through shared decision-making. Statins are neither mandatory nor absolutely contraindicated in this age group, and fibrates are not a substitute for atherosclerotic risk reduction.

553. A 69-year-old woman with stable chronic heart failure with reduced ejection fraction is admitted with acute decompensation. She recently stopped her diuretic and started taking a daily NSAID for joint pain. Which factor most likely precipitated her decompensation?
     • Excessive diuretic effect
     • New-onset hyperthyroidism unrelated to medications
     • Sodium and fluid retention from the NSAID combined with diuretic nonadherence
     • Beta-blocker overdose

     Correct answer: Sodium and fluid retention from the NSAID combined with diuretic nonadherence

     Sodium and fluid retention from the NSAID combined with diuretic nonadherence is correct. NSAIDs promote sodium and water retention and blunt diuretic efficacy, and stopping the diuretic compounds volume overload, both common precipitants of acute decompensated heart failure. Excessive diuresis would cause volume depletion, and there is no evidence for hyperthyroidism or beta-blocker overdose here.

554. A 24-year-old man with Wolff-Parkinson-White syndrome presents with atrial fibrillation and a rapid, irregular wide-complex tachycardia. He is hemodynamically stable. Which medication should be avoided because it may accelerate conduction over the accessory pathway?
     • Procainamide
     • Intravenous fluids
     • Acetaminophen
     • AV-nodal blocking agents such as a calcium channel blocker, digoxin, or adenosine

     Correct answer: AV-nodal blocking agents such as a calcium channel blocker, digoxin, or adenosine

     AV-nodal blocking agents such as a calcium channel blocker, digoxin, or adenosine is correct. In atrial fibrillation with Wolff-Parkinson-White, blocking the AV node can shunt conduction down the accessory pathway and precipitate ventricular fibrillation, so these agents are avoided in favor of procainamide or cardioversion. Fluids and acetaminophen are not relevant to controlling this dangerous arrhythmia.

555. A 63-year-old man presents with rest chest pain and ST depression. Serial high-sensitivity troponins show a clear rise and fall above the 99th percentile reference limit. Which diagnosis does the troponin elevation establish in this context?
     • Non-ST-elevation myocardial infarction
     • Unstable angina
     • Stable angina
     • Pericarditis

     Correct answer: Non-ST-elevation myocardial infarction

     Non-ST-elevation myocardial infarction is correct. A rise and fall of troponin above the reference limit in the setting of ischemic symptoms and ST depression without ST elevation defines NSTEMI, distinguishing it from unstable angina, which has no troponin elevation. Stable angina and pericarditis do not fit this acute ischemic biomarker pattern.

556. A 65-year-old man with heart failure is being optimized on guideline-directed therapy. Which medication class reduces heart failure hospitalizations across the spectrum of ejection fraction, including both reduced and preserved ejection fraction?
     • Loop diuretics
     • SGLT2 inhibitors
     • Long-acting nitrates
     • Digoxin

     Correct answer: SGLT2 inhibitors

     SGLT2 inhibitors is correct. SGLT2 inhibitors reduce heart failure hospitalizations across the range of ejection fraction, benefiting patients with both reduced and preserved ejection fraction. Loop diuretics relieve congestion symptomatically but do not reduce hospitalizations as a disease-modifying therapy, and nitrates and digoxin lack this broad benefit.

557. A patient with an acute aortic dissection requires blood pressure and heart rate control. Why is a beta-blocker given before a pure vasodilator in this setting?
     • Because vasodilators are contraindicated in all dissections
     • To raise the heart rate
     • To prevent reflex tachycardia and increased aortic wall shear stress that a vasodilator alone could cause
     • To increase cardiac contractility

     Correct answer: To prevent reflex tachycardia and increased aortic wall shear stress that a vasodilator alone could cause

     To prevent reflex tachycardia and increased aortic wall shear stress that a vasodilator alone could cause is correct. In aortic dissection, a beta-blocker is given first so that subsequent vasodilator-induced reflex tachycardia does not increase the rate of rise of aortic pressure and propagate the dissection. Vasodilators are used after beta-blockade, and the goal is to reduce, not increase, heart rate and contractility.

558. A 67-year-old man with stable angina has persistent lifestyle-limiting symptoms despite optimal medical therapy with two anti-anginal agents, and stress testing shows a large area of inducible ischemia. Which is the most appropriate next step?
     • Add a third anti-anginal agent and continue indefinitely
     • Begin anticoagulation
     • Reassure and discontinue all therapy
     • Coronary angiography with consideration of revascularization

     Correct answer: Coronary angiography with consideration of revascularization

     Coronary angiography with consideration of revascularization is correct. Lifestyle-limiting angina refractory to optimal medical therapy with a large ischemic burden warrants angiography to guide revascularization. Endlessly stacking anti-anginal agents does not address refractory symptoms with a large ischemic territory, anticoagulation is not indicated, and discontinuing therapy would worsen ischemia.

559. A 78-year-old man with atrial fibrillation and a high stroke risk also has several bleeding risk factors. Which is the most appropriate approach to his bleeding risk when deciding on anticoagulation?
     • Identify and address modifiable bleeding risk factors rather than withholding indicated anticoagulation
     • Withhold anticoagulation because any bleeding risk outweighs stroke prevention
     • Use aspirin instead, which has no bleeding risk
     • Double the anticoagulant dose to ensure efficacy

     Correct answer: Identify and address modifiable bleeding risk factors rather than withholding indicated anticoagulation

     Identifying and addressing modifiable bleeding risk factors rather than withholding indicated anticoagulation is correct. Bleeding risk scores guide management of modifiable factors such as uncontrolled hypertension and concurrent NSAIDs, but they should not by themselves preclude anticoagulation when stroke risk is high. Aspirin still carries bleeding risk with less stroke protection, and overdosing increases harm.

560. A 50-year-old man with newly diagnosed stage 1 hypertension and low cardiovascular risk is counseled on nonpharmacologic management. Which lifestyle intervention has the strongest evidence for lowering blood pressure?
     • Increasing dietary sodium intake
     • A dietary pattern rich in fruits, vegetables, and low-fat dairy with reduced sodium, combined with weight loss and regular exercise
     • Daily alcohol consumption
     • A sedentary routine with high saturated fat intake

     Correct answer: A dietary pattern rich in fruits, vegetables, and low-fat dairy with reduced sodium, combined with weight loss and regular exercise

     A dietary pattern rich in fruits, vegetables, and low-fat dairy with reduced sodium, combined with weight loss and regular exercise, is correct. The DASH-style diet with sodium restriction, weight reduction, physical activity, and moderation of alcohol meaningfully lowers blood pressure and is first-line for low-risk stage 1 hypertension. The other choices raise blood pressure or cardiovascular risk.

561. A patient with an ST-elevation myocardial infarction arrives at a percutaneous coronary intervention-capable hospital. Which time-based goal best reflects optimal reperfusion care?
     • Performing intervention within 24 hours is sufficient in all cases
     • Waiting for troponin to peak before any intervention
     • Achieving primary percutaneous coronary intervention within 90 minutes of first medical contact
     • Scheduling intervention for the next available elective slot

     Correct answer: Achieving primary percutaneous coronary intervention within 90 minutes of first medical contact

     Achieving primary percutaneous coronary intervention within 90 minutes of first medical contact is correct. In STEMI, rapid reperfusion saves myocardium, and the goal at a PCI-capable center is a first-medical-contact-to-device time of 90 minutes or less. Delaying for troponin peaks or treating an acute STEMI as elective causes preventable myocardial loss.

562. A 62-year-old man with heart failure with reduced ejection fraction is being treated for comorbid conditions. Which medication should generally be avoided because it can worsen his heart failure?
     • An ACE inhibitor
     • A beta-blocker with proven benefit
     • An SGLT2 inhibitor
     • A nondihydropyridine calcium channel blocker such as verapamil

     Correct answer: A nondihydropyridine calcium channel blocker such as verapamil

     A nondihydropyridine calcium channel blocker such as verapamil is correct. Verapamil and diltiazem have negative inotropic effects that can worsen heart failure with reduced ejection fraction and should generally be avoided. ACE inhibitors, evidence-based beta-blockers, and SGLT2 inhibitors are beneficial components of guideline-directed therapy in this condition.

563. A 67-year-old patient with recently diagnosed symptomatic atrial fibrillation is counseled about early rhythm control. Which statement best reflects current evidence on early rhythm control in selected patients?
     • Early rhythm control can reduce cardiovascular outcomes in appropriately selected patients with recently diagnosed atrial fibrillation
     • Rhythm control eliminates the need for anticoagulation regardless of stroke risk
     • Rate control is always superior to rhythm control in every patient
     • Rhythm control is contraindicated in symptomatic patients

     Correct answer: Early rhythm control can reduce cardiovascular outcomes in appropriately selected patients with recently diagnosed atrial fibrillation

     Early rhythm control can reduce cardiovascular outcomes in appropriately selected patients with recently diagnosed atrial fibrillation is correct. Evidence supports early rhythm control to improve cardiovascular outcomes in selected patients diagnosed within the past year. Anticoagulation is still guided by stroke risk regardless of rhythm strategy, rate control is not universally superior, and rhythm control is appropriate for symptomatic patients.

564. A 65-year-old woman presents to the emergency department with chest pain and an evolving NSTEMI. Which medication should be administered first as soon as the diagnosis is suspected, assuming no contraindication?
     • A loop diuretic
     • Chewable aspirin
     • An oral anticoagulant for chronic stroke prevention
     • A proton pump inhibitor

     Correct answer: Chewable aspirin

     Chewable aspirin is correct. Aspirin given promptly in suspected acute coronary syndrome reduces mortality by inhibiting platelet aggregation and should be administered immediately unless contraindicated. A loop diuretic, chronic anticoagulation for stroke prevention, and a proton pump inhibitor are not the initial life-saving intervention in NSTEMI.

565. A 31-year-old woman on a statin for familial hypercholesterolemia reports that she is planning to become pregnant. Which is the most appropriate recommendation regarding her statin?
     • Continue the statin unchanged throughout pregnancy
     • Increase the statin dose to protect the fetus
     • Discontinue the statin before and during pregnancy
     • Switch to a higher-intensity statin

     Correct answer: Discontinue the statin before and during pregnancy

     Discontinuing the statin before and during pregnancy is correct. Statins are generally avoided in pregnancy, so women planning conception should stop the medication, and lipid management during pregnancy relies on diet and, if needed, other approaches. Continuing or increasing statin therapy in pregnancy is not recommended.

566. A 73-year-old man is being discharged after an admission for acute decompensated heart failure. Which intervention most reduces his risk of early readmission?
     • Discharging without any scheduled follow-up
     • Stopping all heart failure medications at discharge
     • Recommending a high-sodium diet to maintain blood pressure
     • Early follow-up, medication reconciliation, patient education, and ensuring he is on optimized guideline-directed therapy

     Correct answer: Early follow-up, medication reconciliation, patient education, and ensuring he is on optimized guideline-directed therapy

     Early follow-up, medication reconciliation, patient education, and ensuring he is on optimized guideline-directed therapy is correct. A structured transition of care with prompt follow-up, accurate medications, education on self-monitoring, and optimized guideline-directed therapy lowers heart failure readmissions. Omitting follow-up, stopping medications, or liberalizing sodium would increase the risk of decompensation.

567. A 56-year-old man has normal blood pressure readings in the clinic but reports consistently elevated readings on his validated home device, and he has left ventricular hypertrophy on echocardiography. Which condition does this pattern most likely represent?
     • Masked hypertension
     • White-coat hypertension
     • Orthostatic hypotension
     • Resistant hypertension

     Correct answer: Masked hypertension

     Masked hypertension is correct. Normal office readings with elevated out-of-office readings, especially with evidence of target-organ damage such as left ventricular hypertrophy, define masked hypertension, which carries elevated cardiovascular risk and warrants treatment. White-coat hypertension is the reverse pattern, and the other conditions describe different phenomena.

568. A 70-year-old man with chronic stable angina continues to have symptoms despite a beta-blocker, a calcium channel blocker, and nitrates, but his heart rate and blood pressure are already low, limiting further uptitration. Which additional anti-anginal agent works without significantly affecting heart rate or blood pressure?
     • An additional beta-blocker
     • Ranolazine
     • A high-dose long-acting nitrate added to the regimen
     • A nondihydropyridine calcium channel blocker added to the regimen

     Correct answer: Ranolazine

     Ranolazine is correct. Ranolazine reduces anginal symptoms by inhibiting the late sodium current without meaningfully lowering heart rate or blood pressure, making it useful when hemodynamics limit other agents. Adding another beta-blocker, more nitrate, or a rate-slowing calcium channel blocker would further reduce heart rate or blood pressure in an already hemodynamically constrained patient.

569. A 59-year-old man presents to a rural hospital with an acute ST-elevation myocardial infarction. The nearest catheterization laboratory is over two hours away by transfer. He has no contraindications to fibrinolytics. Which is the most appropriate reperfusion strategy?
     • Wait for the patient to be transferred for primary percutaneous coronary intervention regardless of delay
     • Give only aspirin and observe
     • Administer fibrinolytic therapy promptly while arranging transfer
     • Schedule elective angiography in one week

     Correct answer: Administer fibrinolytic therapy promptly while arranging transfer

     Administering fibrinolytic therapy promptly while arranging transfer is correct. When primary percutaneous coronary intervention cannot be performed within the recommended time window, fibrinolysis in an eligible STEMI patient restores perfusion and reduces mortality, followed by transfer. Waiting for prolonged transfer, observing on aspirin alone, or delaying to an elective procedure would forfeit salvageable myocardium.

570. A 68-year-old man is brought to the emergency department 90 minutes after the sudden onset of right-sided weakness and slurred speech. His blood pressure is 168/92 mm Hg and fingerstick glucose is 110 mg/dL. A non-contrast head CT shows no hemorrhage. Which of the following is the most appropriate next step in management?
     • Begin a heparin infusion
     • Administer intravenous alteplase
     • Give aspirin 325 mg orally
     • Schedule outpatient carotid ultrasound

     Correct answer: Administer intravenous alteplase

     Intravenous alteplase is the correct next step. The patient is within the 4.5-hour window for ischemic stroke, the CT excludes hemorrhage, glucose is normal, and blood pressure is below the 185/110 mm Hg threshold, so thrombolysis is indicated. Heparin is not used acutely, aspirin is deferred until after thrombolysis, and carotid imaging is not the immediate priority.

571. A 72-year-old woman presents 2 hours after onset of left hemiparesis. Her blood pressure is 210/115 mm Hg, glucose is 130 mg/dL, and non-contrast CT shows no bleed. The team plans intravenous thrombolysis. Which of the following must be addressed before alteplase can be given?
     • Correct the serum glucose to below 100 mg/dL
     • Lower the blood pressure to below 185/110 mm Hg
     • Obtain a CT angiogram of the neck
     • Confirm a platelet count above 200,000/microL

     Correct answer: Lower the blood pressure to below 185/110 mm Hg

     Lowering the blood pressure to below 185/110 mm Hg is required before thrombolysis. Persistent hypertension above this threshold is a contraindication because of increased hemorrhagic transformation risk, so a titratable agent such as labetalol or nicardipine is used. The glucose is acceptable, CT angiography is not a prerequisite, and the standard platelet threshold is above 100,000/microL.

572. A 60-year-old man with atrial fibrillation develops acute aphasia and right arm weakness. He last appeared normal 5 hours ago. CT shows no hemorrhage, and CT angiography reveals a left middle cerebral artery occlusion with a small core infarct. Which of the following is the most appropriate intervention?
     • Intravenous alteplase
     • Subcutaneous enoxaparin
     • Mechanical thrombectomy
     • Permissive hypertension and observation

     Correct answer: Mechanical thrombectomy

     Mechanical thrombectomy is the most appropriate intervention. He is beyond the 4.5-hour alteplase window but has a large-vessel occlusion with a small core and favorable imaging, making endovascular thrombectomy the indicated treatment up to 24 hours in selected patients. Alteplase is excluded by the time window, and anticoagulation or observation alone would forgo a reperfusion opportunity.

573. A 55-year-old man is admitted with an acute ischemic stroke not eligible for reperfusion therapy. He is neurologically stable. Which of the following antithrombotic strategies is most appropriate for secondary prevention in the first 48 hours?
     • Aspirin started within 24 to 48 hours
     • Therapeutic intravenous heparin immediately
     • Warfarin titrated to an INR of 2 to 3
     • No antithrombotic therapy for 2 weeks

     Correct answer: Aspirin started within 24 to 48 hours

     Aspirin started within 24 to 48 hours is correct. Early antiplatelet therapy reduces recurrent stroke risk after acute ischemic stroke once hemorrhage is excluded. Immediate full-dose heparin increases bleeding without benefit, warfarin alone is not first-line for noncardioembolic stroke, and withholding therapy for 2 weeks is inappropriate.

574. A 45-year-old woman has a generalized tonic-clonic seizure that has continued for 7 minutes without recovery of consciousness. Intravenous access is established. Which of the following is the most appropriate first-line pharmacologic therapy?
     • Intravenous lorazepam
     • Intravenous fosphenytoin
     • Intravenous valproate
     • Intravenous propofol

     Correct answer: Intravenous lorazepam

     Intravenous lorazepam is the first-line therapy. A benzodiazepine such as lorazepam aborts the majority of episodes of status epilepticus and is the initial step in the treatment ladder. Fosphenytoin and valproate are second-line agents given if seizures persist, and propofol is reserved for refractory status with intubation.

575. A 30-year-old man with epilepsy continues to seize despite two appropriate doses of intravenous lorazepam over 10 minutes. He remains unconscious and convulsing. Which of the following is the most appropriate next step?
     • Repeat lorazepam a third time
     • Begin a maintenance dose of oral levetiracetam
     • Obtain an outpatient EEG
     • Load intravenous fosphenytoin

     Correct answer: Load intravenous fosphenytoin

     Loading intravenous fosphenytoin is the next step. After benzodiazepines fail, a second-line antiseizure agent such as fosphenytoin, valproate, or levetiracetam is loaded to control ongoing status epilepticus. Repeating benzodiazepines a third time risks respiratory depression without added benefit, oral maintenance dosing is too slow, and outpatient EEG is inappropriate in an actively seizing patient.

576. A patient in convulsive status epilepticus continues to seize despite a benzodiazepine followed by a full dose of intravenous valproate. Which of the following best describes the current classification of this patient's seizure activity?
     • Established status epilepticus
     • Impending status epilepticus
     • Refractory status epilepticus
     • Super-refractory status epilepticus

     Correct answer: Refractory status epilepticus

     This is refractory status epilepticus. Seizures persisting after adequate doses of a benzodiazepine and a second-line agent define the refractory stage, which warrants continuous anesthetic infusion and intubation. Established status refers to seizures continuing after first-line therapy, and super-refractory status applies only when seizures continue beyond 24 hours of anesthetic therapy.

577. A 22-year-old college student presents with fever, severe headache, photophobia, and neck stiffness for 8 hours. He is alert. Which of the following is the most appropriate immediate sequence of management?
     • Perform lumbar puncture first, then start antibiotics only if CSF is abnormal
     • Obtain head CT and delay all antibiotics until imaging is complete
     • Start oral antibiotics and arrange outpatient follow-up
     • Draw blood cultures, start empiric antibiotics and dexamethasone, then perform lumbar puncture

     Correct answer: Draw blood cultures, start empiric antibiotics and dexamethasone, then perform lumbar puncture

     Drawing blood cultures, starting empiric antibiotics with dexamethasone, and then performing lumbar puncture is correct. In suspected bacterial meningitis without focal deficits or papilledema, empiric therapy must not be delayed, and adjunctive dexamethasone is given with or just before antibiotics. Delaying antibiotics for CSF results or imaging risks death, and oral outpatient therapy is unsafe.

578. A 70-year-old man with suspected bacterial meningitis has new papilledema and a focal neurologic deficit on examination. After blood cultures are drawn and empiric antibiotics with dexamethasone are given, which of the following should be done before lumbar puncture?
     • Brain MRI with contrast
     • Non-contrast head CT
     • Electroencephalography
     • Repeat antibiotic dosing

     Correct answer: Non-contrast head CT

     Non-contrast head CT before lumbar puncture is correct. Focal deficits, papilledema, or altered consciousness raise concern for elevated intracranial pressure and risk of herniation, so imaging is obtained before the tap. Importantly, antibiotics are still given first and are not delayed for the scan.

579. A 25-year-old woman with suspected bacterial meningitis has cerebrospinal fluid showing 4,000 neutrophils/microL, glucose of 20 mg/dL, and protein of 250 mg/dL. Which of the following CSF findings is most consistent with bacterial rather than viral meningitis?
     • Low CSF glucose with neutrophilic pleocytosis
     • Normal glucose with lymphocytic predominance
     • Elevated glucose with eosinophilia
     • Normal protein with absent pleocytosis

     Correct answer: Low CSF glucose with neutrophilic pleocytosis

     Low CSF glucose with neutrophilic pleocytosis is most consistent with bacterial meningitis. Bacteria consume glucose and trigger a neutrophil-predominant response with markedly elevated protein, whereas viral meningitis typically shows normal glucose and a lymphocytic predominance.

580. A previously healthy 19-year-old presents with fever, headache, and neck stiffness, and Gram stain of CSF shows gram-negative diplococci. After the patient is treated, which of the following is the most appropriate public health measure for close household contacts?
     • Chemoprophylaxis with rifampin or ciprofloxacin
     • Observation without prophylaxis
     • Vaccination only, without antibiotics
     • Empiric treatment-dose ceftriaxone for 7 days

     Correct answer: Chemoprophylaxis with rifampin or ciprofloxacin

     Chemoprophylaxis with rifampin or ciprofloxacin is appropriate for close contacts of meningococcal meningitis. Gram-negative diplococci indicate Neisseria meningitidis, and prophylaxis eradicates nasopharyngeal carriage to prevent secondary cases. Observation alone is insufficient, vaccination does not replace prophylaxis, and full treatment courses are not used for asymptomatic contacts.

581. A 28-year-old woman reports two episodes of neurologic dysfunction over the past year: one of right-eye painful vision loss and a later one of left leg numbness and weakness, each resolving over weeks. MRI shows periventricular white matter lesions. Which of the following best establishes the diagnosis?
     • A single enhancing lesion on MRI
     • Lesions disseminated in space and time
     • Elevated CSF glucose
     • Symmetric peripheral neuropathy on nerve conduction studies

     Correct answer: Lesions disseminated in space and time

     Lesions disseminated in space and time best establish multiple sclerosis. The diagnosis requires evidence of central nervous system demyelination in multiple locations occurring at different times, which her clinical episodes and MRI findings demonstrate. A single lesion is insufficient, CSF glucose is normal in MS, and peripheral neuropathy reflects a different process.

582. A 32-year-old woman with relapsing-remitting multiple sclerosis presents with 5 days of worsening right-sided weakness and an MRI showing a new enhancing lesion. Which of the following is the most appropriate treatment for this acute relapse?
     • Initiation of an interferon beta agent
     • Plasma exchange as first-line therapy
     • High-dose intravenous methylprednisolone
     • Oral gabapentin

     Correct answer: High-dose intravenous methylprednisolone

     High-dose intravenous methylprednisolone is the treatment for an acute multiple sclerosis relapse. Corticosteroids speed recovery from acute exacerbations. Disease-modifying agents such as interferon beta reduce future relapses but do not treat the acute attack, plasma exchange is reserved for steroid-refractory severe relapses, and gabapentin addresses neuropathic symptoms rather than the relapse.

583. A 35-year-old woman with multiple sclerosis describes a brief electric-shock sensation traveling down her spine when she flexes her neck forward. Which of the following best describes this finding?
     • Uhthoff phenomenon
     • Lhermitte sign
     • Internuclear ophthalmoplegia
     • Foster Kennedy syndrome

     Correct answer: Lhermitte sign

     This is Lhermitte sign, an electric-shock sensation down the spine with neck flexion that reflects demyelination of the cervical dorsal columns in multiple sclerosis. Uhthoff phenomenon is worsening of symptoms with heat, internuclear ophthalmoplegia is a gaze abnormality, and Foster Kennedy syndrome involves optic findings from a frontal mass.

584. A 67-year-old man has a 2-year history of resting tremor, slowed movements, and rigidity that began on the right side. His symptoms now interfere with buttoning his shirt. Which of the following is the most appropriate first-line pharmacologic therapy for his disabling symptoms?
     • Amantadine monotherapy
     • Carbidopa-levodopa
     • Benztropine alone
     • Quetiapine

     Correct answer: Carbidopa-levodopa

     Carbidopa-levodopa is the most effective first-line therapy for disabling Parkinson disease symptoms. It provides the greatest symptomatic benefit, particularly for bradykinesia and rigidity. Amantadine has modest effects, anticholinergics like benztropine mainly help tremor in younger patients, and quetiapine is used for psychosis rather than motor symptoms.

585. A 60-year-old man is evaluated for a resting tremor and slowness. On examination he has cogwheel rigidity, a shuffling gait, and decreased facial expression. Which of the following examination findings is most characteristic of Parkinson disease?
     • Intention tremor worsening near a target
     • Symmetric distal sensory loss
     • Bradykinesia with resting tremor
     • Spasticity with upgoing toes

     Correct answer: Bradykinesia with resting tremor

     Bradykinesia with a resting tremor is most characteristic of Parkinson disease. The core motor features are bradykinesia, resting tremor, and rigidity, typically beginning asymmetrically. An intention tremor suggests a cerebellar lesion, symmetric sensory loss indicates peripheral neuropathy, and spasticity with upgoing toes reflects an upper motor neuron process.

586. A 72-year-old man with advanced Parkinson disease develops visual hallucinations. He has no other acute illness, and review shows no recent medication changes other than escalation of his dopaminergic therapy. After reducing offending agents, which antipsychotic is preferred if pharmacologic treatment is needed?
     • Haloperidol
     • Risperidone
     • Quetiapine
     • Olanzapine

     Correct answer: Quetiapine

     Quetiapine is preferred because it has minimal extrapyramidal effects and is less likely to worsen parkinsonian motor symptoms. Typical antipsychotics such as haloperidol and higher-potency agents like risperidone and olanzapine can markedly worsen rigidity and bradykinesia in Parkinson disease and should be avoided.

587. A 58-year-old man presents with the worst headache of his life that began suddenly during exertion, accompanied by neck stiffness and brief loss of consciousness. Non-contrast head CT is unremarkable 8 hours after onset. Which of the following is the most appropriate next step?
     • Lumbar puncture looking for xanthochromia
     • Reassurance and discharge with analgesics
     • MRI of the cervical spine
     • Empiric triptan therapy

     Correct answer: Lumbar puncture looking for xanthochromia

     Lumbar puncture looking for xanthochromia is the next step. A thunderclap headache strongly suggests subarachnoid hemorrhage, and when CT is non-diagnostic, especially beyond 6 hours, CSF analysis for xanthochromia and red cells is required. Discharge is unsafe, cervical MRI does not address the suspected hemorrhage, and triptans are contraindicated when subarachnoid hemorrhage has not been excluded.

588. A 50-year-old woman is diagnosed with aneurysmal subarachnoid hemorrhage. On hospital day 5 she develops new confusion and a focal deficit, with vital signs stable. Which of the following medications is used to reduce the risk of this delayed complication?
     • Mannitol
     • Nimodipine
     • Phenytoin
     • Dexamethasone

     Correct answer: Nimodipine

     Nimodipine is used to reduce the risk of delayed cerebral ischemia from vasospasm after aneurysmal subarachnoid hemorrhage. This calcium channel blocker improves neurologic outcomes. Mannitol treats elevated intracranial pressure, phenytoin is not routinely used for prophylaxis, and corticosteroids have no role in preventing vasospasm.

589. A 26-year-old woman has recurrent unilateral throbbing headaches lasting most of a day, associated with nausea and photophobia, occurring four times per month and limiting her work. Acute therapy is only partially effective. Which of the following is the most appropriate addition to her regimen?
     • Increasing acute triptan use to daily dosing
     • Long-term daily opioid therapy
     • A daily preventive medication such as propranolol
     • Prophylactic antibiotics

     Correct answer: A daily preventive medication such as propranolol

     A daily preventive medication such as propranolol is appropriate. Frequent disabling migraines (generally four or more per month) warrant prophylaxis with agents like propranolol, topiramate, or amitriptyline. Daily triptan use risks medication-overuse headache, opioids are inappropriate for chronic migraine, and antibiotics have no role.

590. A 34-year-old man reports episodic headaches with visual zigzag lines and a spreading scintillating scotoma that resolve over 20 minutes, followed by a unilateral throbbing headache. Which of the following best describes this presentation?
     • Cluster headache
     • Tension-type headache
     • Trigeminal neuralgia
     • Migraine with aura

     Correct answer: Migraine with aura

     This presentation describes migraine with aura. The fully reversible visual aura of scintillating scotomata preceding a unilateral throbbing headache is characteristic. Cluster headache features severe orbital pain with autonomic signs, tension-type headache is bilateral and band-like without aura, and trigeminal neuralgia causes brief electric facial pains.

591. A 40-year-old man has recurrent attacks of excruciating, strictly unilateral periorbital pain lasting about an hour, with ipsilateral tearing, nasal congestion, and restlessness, occurring several times daily in clusters. Which of the following is the most appropriate acute treatment?
     • Oral acetaminophen
     • Daily oral verapamil
     • High-flow 100% oxygen
     • Prophylactic indomethacin

     Correct answer: High-flow 100% oxygen

     High-flow 100% oxygen is the most appropriate acute treatment for cluster headache, often combined with subcutaneous sumatriptan. Acetaminophen is ineffective for these severe attacks, verapamil is used for prevention rather than acute relief, and indomethacin is the treatment for paroxysmal hemicrania, a different syndrome.

592. A 62-year-old woman reports brief episodes of severe, lancinating pain over her right cheek triggered by chewing and light touch. Examination is normal. Which of the following is the most appropriate first-line medication?
     • Carbamazepine
     • Gabapentin
     • Amitriptyline
     • Prednisone

     Correct answer: Carbamazepine

     Carbamazepine is the first-line medication for trigeminal neuralgia. The brief, electric-shock-like facial pains triggered by light touch respond best to carbamazepine. Gabapentin and amitriptyline are alternatives but are less effective, and corticosteroids do not treat trigeminal neuralgia.

593. A 30-year-old man develops acute, isolated, right-sided facial droop affecting the forehead, with inability to fully close the right eye and loss of taste on the anterior tongue. The remainder of the neurologic examination is normal. Which of the following is the most appropriate treatment?
     • Intravenous thrombolysis
     • Long-term carbamazepine
     • Oral corticosteroids and eye protection
     • Surgical facial nerve decompression

     Correct answer: Oral corticosteroids and eye protection

     Oral corticosteroids with eye protection is the treatment for Bell palsy. Forehead involvement confirms a peripheral (lower motor neuron) facial nerve lesion, and early corticosteroids improve recovery while lubrication and a patch protect the cornea. Thrombolysis is for stroke, carbamazepine treats trigeminal neuralgia, and surgery is not first-line.

594. A 38-year-old man develops symmetric ascending weakness over 5 days, beginning in the legs, with absent deep tendon reflexes and minimal sensory loss two weeks after a diarrheal illness. Which of the following best confirms the diagnosis?
     • Elevated CSF white blood cell count with low glucose
     • Positive antinuclear antibody
     • CSF albuminocytologic dissociation
     • Markedly elevated creatine kinase

     Correct answer: CSF albuminocytologic dissociation

     CSF albuminocytologic dissociation, elevated protein with a normal cell count, best confirms Guillain-Barre syndrome in this postinfectious ascending paralysis with areflexia. A high CSF white count with low glucose suggests infection, antinuclear antibody points to autoimmune disease, and elevated creatine kinase indicates a myopathy.

595. A 40-year-old woman with Guillain-Barre syndrome develops a rising level of weakness, and her forced vital capacity is declining on serial measurement. Which of the following is the most important monitoring parameter to guide the need for intubation?
     • Serial blood pressure readings
     • Serial forced vital capacity
     • Daily creatine kinase levels
     • Repeated head CT scans

     Correct answer: Serial forced vital capacity

     Serial forced vital capacity is the most important parameter. Respiratory failure from diaphragmatic weakness is the major life threat in Guillain-Barre syndrome, and a falling vital capacity signals impending need for mechanical ventilation. Blood pressure, creatine kinase, and head imaging do not predict respiratory decline.

596. A 35-year-old woman reports fluctuating double vision and drooping eyelids that worsen toward the end of the day and after sustained activity, with improvement after rest. Which of the following best explains her symptoms?
     • Demyelination of central white matter tracts
     • Degeneration of dopaminergic neurons
     • Compression of the median nerve at the wrist
     • Antibodies against the acetylcholine receptor at the neuromuscular junction

     Correct answer: Antibodies against the acetylcholine receptor at the neuromuscular junction

     Antibodies against the acetylcholine receptor explain myasthenia gravis. Fatigable weakness of ocular and other muscles that worsens with use and improves with rest is the hallmark. Central demyelination causes multiple sclerosis, dopaminergic degeneration causes Parkinson disease, and median nerve compression causes carpal tunnel syndrome.

597. A 48-year-old man with myasthenia gravis develops worsening generalized weakness, dyspnea, and difficulty clearing secretions after an upper respiratory infection. His vital capacity is falling. Which of the following is the most appropriate acute treatment for this crisis?
     • Increase the dose of pyridostigmine only
     • Begin high-dose levodopa
     • Plasmapheresis or intravenous immunoglobulin
     • Start carbamazepine

     Correct answer: Plasmapheresis or intravenous immunoglobulin

     Plasmapheresis or intravenous immunoglobulin is the appropriate acute treatment for myasthenic crisis, together with respiratory support. These rapidly reduce circulating antibodies or modulate the immune response. Simply increasing pyridostigmine does not address the crisis adequately, and levodopa and carbamazepine are unrelated to neuromuscular junction disease.

598. A 55-year-old man presents with progressive limb weakness, muscle atrophy, and fasciculations along with brisk reflexes and a positive Babinski sign, but normal sensation and cognition. Which of the following best explains the combination of these findings?
     • An isolated peripheral sensory neuropathy
     • Degeneration of both upper and lower motor neurons
     • A demyelinating disorder of the central nervous system
     • A disorder of the neuromuscular junction

     Correct answer: Degeneration of both upper and lower motor neurons

     Degeneration of both upper and lower motor neurons explains amyotrophic lateral sclerosis. The mix of lower motor neuron signs (atrophy, fasciculations) and upper motor neuron signs (hyperreflexia, Babinski) with preserved sensation is characteristic. A sensory neuropathy would cause sensory loss, demyelination causes different patterns, and neuromuscular junction disease produces fatigable weakness without upper motor neuron signs.

599. An 80-year-old man presents with the classic triad of gait disturbance, urinary incontinence, and cognitive decline. MRI shows ventriculomegaly out of proportion to atrophy. Which of the following findings would most strongly predict benefit from ventriculoperitoneal shunting?
     • Elevated opening pressure on lumbar puncture
     • Improvement in gait after large-volume lumbar puncture
     • Markedly elevated CSF protein
     • Diffuse cortical atrophy on MRI

     Correct answer: Improvement in gait after large-volume lumbar puncture

     Gait improvement after a large-volume lumbar puncture most strongly predicts benefit from shunting in normal pressure hydrocephalus. A positive tap test identifies patients likely to respond to ventriculoperitoneal shunting. Opening pressure is typically normal, CSF protein is not predictive, and cortical atrophy argues against shunt benefit.

600. A 24-year-old man is struck on the side of the head and briefly loses consciousness, then has a lucid interval before rapidly deteriorating with a fixed dilated right pupil. CT shows a biconvex (lens-shaped) hyperdensity. Which of the following best describes this injury?
     • Epidural hematoma from middle meningeal artery injury
     • Subdural hematoma from bridging vein tearing
     • Diffuse axonal injury
     • Subarachnoid hemorrhage from aneurysm rupture

     Correct answer: Epidural hematoma from middle meningeal artery injury

     An epidural hematoma from middle meningeal artery injury best fits the lucid interval and the biconvex CT appearance. Arterial bleeding between the skull and dura expands rapidly and can cause uncal herniation with a blown pupil. Subdural hematomas are crescent-shaped, diffuse axonal injury lacks a focal collection, and aneurysmal hemorrhage is not lens-shaped.

601. An 82-year-old man on warfarin presents with progressive headache and confusion two weeks after a minor fall. CT shows a crescent-shaped hyperdensity over the right hemisphere with midline shift. Which of the following best describes this lesion?
     • Epidural hematoma
     • Subdural hematoma
     • Intraparenchymal hemorrhage
     • Subarachnoid hemorrhage

     Correct answer: Subdural hematoma

     A crescent-shaped collection in an elderly anticoagulated patient after minor trauma is a subdural hematoma from tearing of bridging veins. The crescentic shape crosses suture lines, distinguishing it from the lens-shaped epidural hematoma. Intraparenchymal and subarachnoid hemorrhages have different distributions.

602. A 65-year-old man with poorly controlled hypertension suddenly develops a severe headache, vomiting, and left-sided weakness. CT shows an acute hemorrhage in the right basal ganglia. Which of the following is the most important component of acute management?
     • Controlled lowering of systolic blood pressure
     • Immediate intravenous thrombolysis
     • Therapeutic anticoagulation
     • Lumbar puncture for diagnosis

     Correct answer: Controlled lowering of systolic blood pressure

     Controlled lowering of systolic blood pressure is a key component of managing acute hypertensive intracerebral hemorrhage, as it limits hematoma expansion. Thrombolysis and anticoagulation are contraindicated and would worsen bleeding, and lumbar puncture is unnecessary and unsafe when the diagnosis is clear on CT.

603. A 70-year-old woman has a transient episode of right arm weakness and slurred speech that fully resolves within 30 minutes. Her ABCD2 risk factors are present. Which of the following is the most appropriate next step in evaluation?
     • Reassurance because symptoms resolved
     • Outpatient follow-up in 3 months
     • Urgent carotid imaging and brain imaging to identify stroke etiology
     • Begin warfarin empirically

     Correct answer: Urgent carotid imaging and brain imaging to identify stroke etiology

     Urgent carotid and brain imaging to determine etiology is appropriate after a transient ischemic attack, because the short-term stroke risk is high. Rapid workup guides secondary prevention such as carotid revascularization or antiplatelet therapy. Reassurance or delayed follow-up is unsafe, and empiric warfarin is not first-line without a defined cardioembolic source.

604. A 60-year-old smoker reports brief episodes of painless monocular vision loss described as a curtain coming down over one eye, each lasting a few minutes. Which of the following is the most likely source of these episodes?
     • Carotid artery atherosclerotic emboli
     • Retinal detachment
     • Optic neuritis
     • Acute angle-closure glaucoma

     Correct answer: Carotid artery atherosclerotic emboli

     Carotid artery atherosclerotic emboli are the most likely source of amaurosis fugax, the transient monocular curtain-like vision loss. Emboli from the ipsilateral carotid transiently occlude the retinal circulation, so carotid evaluation is warranted. Retinal detachment causes persistent deficits with flashes and floaters, optic neuritis causes painful subacute loss, and angle-closure glaucoma causes a painful red eye.

605. A 28-year-old woman develops subacute vision loss in one eye over several days with pain on eye movement and an afferent pupillary defect; color vision is diminished. Which of the following is the most appropriate treatment?
     • Intravenous methylprednisolone
     • Oral prednisone alone
     • Topical antibiotic drops
     • Immediate enucleation

     Correct answer: Intravenous methylprednisolone

     Intravenous methylprednisolone is the appropriate treatment for optic neuritis, which often heralds multiple sclerosis. IV steroids speed visual recovery, whereas oral prednisone alone has been associated with increased recurrence. Topical antibiotics treat infection, and enucleation has no role.

606. A 65-year-old hypertensive man awakens with sudden, painless, severe loss of vision in the right eye. Funduscopy shows a pale retina with a cherry-red spot at the macula. Which of the following best explains this finding?
     • Central retinal artery occlusion
     • Central retinal vein occlusion
     • Vitreous hemorrhage
     • Open-angle glaucoma

     Correct answer: Central retinal artery occlusion

     Central retinal artery occlusion best explains sudden painless monocular vision loss with a pale retina and a cherry-red spot. The infarcted retina appears pale while the macula, supplied by the underlying choroid, retains its color. Vein occlusion shows hemorrhages, vitreous hemorrhage obscures the fundus, and open-angle glaucoma causes gradual peripheral loss.

607. A 68-year-old man with diabetes and hypertension reports sudden painless vision loss in one eye. Funduscopy reveals diffuse retinal hemorrhages in all four quadrants with dilated tortuous veins and disc edema. Which of the following best describes this presentation?
     • Central retinal artery occlusion
     • Retinal detachment
     • Acute angle-closure glaucoma
     • Central retinal vein occlusion

     Correct answer: Central retinal vein occlusion

     Central retinal vein occlusion best fits the blood-and-thunder fundus of widespread retinal hemorrhages, dilated tortuous veins, and disc edema. Artery occlusion instead produces a pale retina with a cherry-red spot, retinal detachment causes a curtain with flashes and floaters, and angle-closure glaucoma causes a painful red eye.

608. A 65-year-old woman presents with a sudden painful red eye, blurred vision with halos around lights, nausea, and a fixed mid-dilated pupil. Which of the following is the most likely diagnosis?
     • Open-angle glaucoma
     • Acute angle-closure glaucoma
     • Bacterial conjunctivitis
     • Optic neuritis

     Correct answer: Acute angle-closure glaucoma

     Acute angle-closure glaucoma is the likely diagnosis, presenting with a painful red eye, halos, a mid-dilated fixed pupil, and nausea due to abruptly elevated intraocular pressure. Open-angle glaucoma is painless and gradual, conjunctivitis lacks the pupillary findings and severe pain, and optic neuritis causes pain with movement rather than a red eye.

609. A 70-year-old man is found on routine screening to have elevated intraocular pressure, an enlarged optic cup-to-disc ratio, and asymptomatic peripheral visual field loss. Which of the following is the most likely diagnosis?
     • Acute angle-closure glaucoma
     • Cataract
     • Macular degeneration
     • Primary open-angle glaucoma

     Correct answer: Primary open-angle glaucoma

     Primary open-angle glaucoma is most likely given the painless, gradual peripheral field loss with optic disc cupping and elevated pressure detected on screening. Angle-closure glaucoma is acutely painful, cataract causes gradual central clouding, and macular degeneration affects central rather than peripheral vision.

610. A 78-year-old woman reports gradual, progressive loss of central vision with difficulty reading and distortion of straight lines, while peripheral vision is preserved. Funduscopy shows drusen at the macula. Which of the following is the most likely diagnosis?
     • Open-angle glaucoma
     • Diabetic retinopathy
     • Central retinal artery occlusion
     • Age-related macular degeneration

     Correct answer: Age-related macular degeneration

     Age-related macular degeneration is most likely, with central vision loss, metamorphopsia, and drusen at the macula in an older adult. Glaucoma causes peripheral loss, diabetic retinopathy typically occurs in diabetics with characteristic vascular changes, and artery occlusion causes sudden rather than gradual loss.

611. A 60-year-old man with type 2 diabetes for 15 years is due for an eye examination. Funduscopy shows microaneurysms, dot-blot hemorrhages, and hard exudates without neovascularization. Which of the following is the most appropriate ongoing management?
     • Immediate enucleation
     • Optimize glycemic and blood pressure control with regular ophthalmologic monitoring
     • Begin systemic corticosteroids
     • Discontinue all diabetes medications

     Correct answer: Optimize glycemic and blood pressure control with regular ophthalmologic monitoring

     Optimizing glycemic and blood pressure control with regular ophthalmologic monitoring is appropriate for nonproliferative diabetic retinopathy. Tight metabolic control slows progression, and surveillance detects advancement to proliferative disease. Enucleation and corticosteroids are inappropriate, and stopping diabetes therapy would worsen disease.

612. A 55-year-old man with poorly controlled diabetes is found to have proliferative diabetic retinopathy with neovascularization on the retina. Which of the following treatments most directly addresses the abnormal new vessels?
     • Topical antibiotic ointment
     • Oral acetazolamide
     • Cycloplegic eye drops
     • Panretinal photocoagulation or anti-VEGF injection

     Correct answer: Panretinal photocoagulation or anti-VEGF injection

     Panretinal photocoagulation or anti-VEGF injection most directly addresses neovascularization in proliferative diabetic retinopathy by reducing the angiogenic drive and the new vessels themselves. Topical antibiotics treat infection, acetazolamide lowers intraocular pressure, and cycloplegics relax the ciliary muscle, none of which treat neovascularization.

613. A 24-year-old man presents with a red, painful eye, photophobia, and tearing after wearing contact lenses overnight. Slit-lamp examination shows a corneal ulcer with fluorescein uptake. Which of the following is the most appropriate management?
     • Topical corticosteroids alone
     • Topical broad-spectrum antibiotics and urgent ophthalmology referral
     • Reassurance and patching for one week
     • Oral antihistamines

     Correct answer: Topical broad-spectrum antibiotics and urgent ophthalmology referral

     Topical broad-spectrum antibiotics with urgent ophthalmology referral is appropriate for a contact-lens-associated bacterial corneal ulcer, which threatens vision. Corticosteroids alone can worsen infection, simple patching is inappropriate and may promote infection, and antihistamines do not treat keratitis.

614. A 30-year-old man reports a unilateral red eye with a vesicular rash in a dermatomal distribution on the forehead and tip of the nose. Slit-lamp examination shows a branching dendritic corneal lesion. Which of the following is the most appropriate treatment?
     • Topical corticosteroids alone
     • Systemic antiviral therapy
     • Topical antibiotic drops only
     • Observation without treatment

     Correct answer: Systemic antiviral therapy

     Systemic antiviral therapy is appropriate for herpes zoster ophthalmicus, suggested by the dermatomal forehead rash, nasal tip involvement (Hutchinson sign), and dendritic keratitis. Antivirals reduce ocular complications. Corticosteroids alone can worsen viral keratitis, antibiotics do not treat the virus, and observation risks vision loss.

615. A 26-year-old man presents with redness, itching, and watery discharge in both eyes for several days, along with a recent upper respiratory infection and a palpable preauricular lymph node. Which of the following is the most likely cause?
     • Viral conjunctivitis
     • Bacterial conjunctivitis
     • Acute angle-closure glaucoma
     • Anterior uveitis

     Correct answer: Viral conjunctivitis

     Viral conjunctivitis is most likely given bilateral redness, watery discharge, an associated upper respiratory infection, and a preauricular node. Bacterial conjunctivitis typically causes thick purulent discharge, angle-closure glaucoma causes a painful red eye with vision changes, and uveitis causes pain and photophobia with a constricted pupil.

616. A 55-year-old man reports recurrent episodes of spinning sensation lasting under a minute, triggered by rolling over in bed or tilting his head back. Hearing is normal. The Dix-Hallpike maneuver reproduces transient torsional nystagmus. Which of the following is the most appropriate treatment?
     • Daily oral meclizine indefinitely
     • Epley canalith repositioning maneuver
     • Surgical labyrinthectomy
     • Systemic corticosteroids

     Correct answer: Epley canalith repositioning maneuver

     The Epley canalith repositioning maneuver is the appropriate treatment for benign paroxysmal positional vertigo, which features brief positional vertigo and a positive Dix-Hallpike test. The maneuver repositions displaced otoconia. Chronic meclizine is not curative, surgery is reserved for refractory cases, and corticosteroids are not indicated.

617. A 45-year-old woman has recurrent episodes of vertigo lasting hours accompanied by a sensation of ear fullness, low-frequency hearing loss, and tinnitus in one ear. Which of the following is the most likely diagnosis?
     • Meniere disease
     • Benign paroxysmal positional vertigo
     • Vestibular neuritis
     • Acoustic neuroma

     Correct answer: Meniere disease

     Meniere disease is most likely, characterized by episodic vertigo lasting minutes to hours with fluctuating low-frequency hearing loss, tinnitus, and aural fullness. Benign positional vertigo causes brief positional spells without hearing loss, vestibular neuritis causes a single prolonged episode, and acoustic neuroma causes progressive unilateral hearing loss without discrete vertigo attacks.

618. A 38-year-old man develops sudden severe continuous vertigo, nausea, and gait imbalance lasting several days after a viral illness, with normal hearing and no other neurologic deficits. Which of the following is the most likely diagnosis?
     • Meniere disease
     • Posterior circulation stroke
     • Benign paroxysmal positional vertigo
     • Vestibular neuritis

     Correct answer: Vestibular neuritis

     Vestibular neuritis is most likely, presenting as acute prolonged vertigo after a viral illness with preserved hearing and no central signs. Meniere disease is episodic with hearing loss, posterior circulation stroke would show additional neurologic deficits, and benign positional vertigo causes only brief positional spells.

619. A 55-year-old man reports progressive unilateral hearing loss and tinnitus over a year, with recent imbalance. MRI shows a mass at the cerebellopontine angle arising from the eighth cranial nerve. Which of the following is the most likely diagnosis?
     • Meniere disease
     • Otosclerosis
     • Vestibular schwannoma (acoustic neuroma)
     • Cholesteatoma

     Correct answer: Vestibular schwannoma (acoustic neuroma)

     Vestibular schwannoma, an acoustic neuroma, is most likely given progressive unilateral sensorineural hearing loss with a cerebellopontine angle mass on the eighth nerve. Meniere disease is episodic without a mass, otosclerosis causes conductive loss, and cholesteatoma is a middle ear lesion.

620. A 60-year-old man notes gradually worsening high-frequency hearing loss in both ears and difficulty understanding speech in noisy settings. Weber test does not lateralize and Rinne shows air conduction greater than bone conduction bilaterally. Which of the following is the most likely type of hearing loss?
     • Conductive hearing loss
     • Mixed hearing loss
     • Functional (nonorganic) hearing loss
     • Sensorineural hearing loss

     Correct answer: Sensorineural hearing loss

     Sensorineural hearing loss is most likely. Symmetric high-frequency loss with normal Rinne findings (air greater than bone) and a non-lateralizing Weber test is typical of presbycusis, an age-related sensorineural process. Conductive loss would show bone conduction greater than air and Weber lateralizing to the affected ear.

621. A 50-year-old man presents with sudden hearing loss in one ear over a few hours without trauma; the Weber test lateralizes to the unaffected ear and Rinne is air greater than bone in the affected ear. Audiometry confirms sensorineural loss. Which of the following is the most appropriate treatment?
     • Topical antibiotic ear drops
     • Cerumen removal
     • Systemic corticosteroids
     • Reassurance with observation alone

     Correct answer: Systemic corticosteroids

     Systemic corticosteroids are the appropriate treatment for sudden sensorineural hearing loss, an otologic emergency where early steroids improve recovery. Topical antibiotics and cerumen removal address external or conductive causes, and observation alone misses the treatment window.

622. A 7-year-old child has ear pain, fever, and decreased hearing. Otoscopy shows a bulging, erythematous tympanic membrane with reduced mobility. Which of the following is the most appropriate first-line treatment?
     • Topical fluoroquinolone drops
     • High-dose oral amoxicillin
     • Oral antihistamines
     • Immediate tympanostomy tube placement

     Correct answer: High-dose oral amoxicillin

     High-dose oral amoxicillin is the first-line treatment for acute otitis media presenting with a bulging, immobile, erythematous tympanic membrane. Topical drops are used for otitis externa or perforation, antihistamines are not effective, and tympanostomy tubes are reserved for recurrent or persistent effusions.

623. A 25-year-old swimmer has ear pain worsened by traction on the auricle, with a swollen, erythematous external ear canal and otorrhea. The tympanic membrane is normal where visible. Which of the following is the most appropriate treatment?
     • High-dose oral amoxicillin
     • Systemic antifungal therapy
     • Oral corticosteroids
     • Topical antibiotic ear drops

     Correct answer: Topical antibiotic ear drops

     Topical antibiotic ear drops are the treatment for otitis externa, indicated by pain on tragal or auricular traction with canal edema and discharge. Oral amoxicillin treats acute otitis media, systemic antifungals are not first-line, and corticosteroids alone do not treat the infection.

624. A 68-year-old woman with diabetes presents with severe persistent ear pain, purulent drainage, and granulation tissue in the ear canal, with elevated inflammatory markers. Which of the following is the most concerning diagnosis to evaluate for?
     • Simple cerumen impaction
     • Allergic contact dermatitis
     • Benign exostosis
     • Malignant (necrotizing) otitis externa

     Correct answer: Malignant (necrotizing) otitis externa

     Malignant (necrotizing) otitis externa is the most concerning diagnosis. In an elderly diabetic, severe pain with granulation tissue suggests invasive Pseudomonas infection that can spread to the skull base, requiring imaging and systemic antipseudomonal therapy. Cerumen impaction, contact dermatitis, and exostoses do not produce this invasive picture.

625. A 60-year-old man with new-onset right facial weakness affecting the forehead also has a vesicular rash in the external ear canal and decreased hearing. Which of the following best describes this syndrome?
     • Idiopathic Bell palsy
     • Acoustic neuroma
     • Trigeminal neuralgia
     • Ramsay Hunt syndrome from herpes zoster of the geniculate ganglion

     Correct answer: Ramsay Hunt syndrome from herpes zoster of the geniculate ganglion

     Ramsay Hunt syndrome from herpes zoster oticus best describes facial palsy with ear canal vesicles and hearing changes due to geniculate ganglion involvement. Bell palsy lacks the vesicular rash, acoustic neuroma causes progressive hearing loss without facial vesicles, and trigeminal neuralgia causes lancinating facial pain.

626. A 70-year-old woman with new headache reports jaw claudication, scalp tenderness, and transient visual blurring; her erythrocyte sedimentation rate is markedly elevated. Which of the following is the most appropriate immediate management to prevent vision loss?
     • Wait for temporal artery biopsy before any treatment
     • Start high-dose corticosteroids before biopsy results
     • Begin low-dose aspirin only
     • Obtain an MRI of the brain before any treatment

     Correct answer: Start high-dose corticosteroids before biopsy results

     Starting high-dose corticosteroids before biopsy is the appropriate immediate step in suspected giant cell arteritis, because delay risks irreversible blindness from anterior ischemic optic neuropathy. Temporal artery biopsy can still confirm the diagnosis after steroids are begun. Aspirin alone and waiting for imaging are inadequate to prevent vision loss.

627. A 45-year-old woman presents with a unilateral painful red eye, photophobia, blurred vision, and a small irregular pupil. Slit-lamp examination shows cells and flare in the anterior chamber. Which of the following is the most likely diagnosis?
     • Anterior uveitis
     • Bacterial conjunctivitis
     • Open-angle glaucoma
     • Cataract

     Correct answer: Anterior uveitis

     Anterior uveitis is most likely, presenting with a painful red eye, photophobia, and anterior chamber cells and flare, often with a constricted irregular pupil. Conjunctivitis causes discharge without these chamber findings, open-angle glaucoma is painless, and cataract causes painless gradual clouding.

628. A 30-year-old woman has chronic headaches and is found to have papilledema on funduscopy; she is obese and reports pulsatile tinnitus. MRI is normal and lumbar puncture shows elevated opening pressure with normal CSF composition. Which of the following is the most appropriate initial pharmacologic therapy?
     • Sumatriptan
     • Acetazolamide
     • Phenytoin
     • Levodopa

     Correct answer: Acetazolamide

     Acetazolamide is the initial pharmacologic therapy for idiopathic intracranial hypertension, reducing CSF production to lower pressure and protect vision; weight loss is also recommended. Sumatriptan treats migraine, phenytoin treats seizures, and levodopa treats Parkinson disease, none of which address the elevated intracranial pressure.

629. A 16-year-old boy is brought in after a witnessed generalized convulsion. He reports prior morning myoclonic jerks and a recent episode of staring. EEG shows generalized spike-and-wave discharges. Which of the following antiseizure medications is the most appropriate first-line choice for this generalized epilepsy?
     • Carbamazepine
     • Phenytoin
     • Valproate or levetiracetam
     • Vigabatrin

     Correct answer: Valproate or levetiracetam

     Valproate or levetiracetam is appropriate first-line therapy for a generalized epilepsy such as juvenile myoclonic epilepsy. Broad-spectrum agents control generalized seizures, whereas sodium channel blockers like carbamazepine and phenytoin can worsen myoclonic and absence seizures. Vigabatrin is not a first-line agent here.

630. A 7-year-old girl has frequent brief episodes of staring with eyelid fluttering lasting a few seconds, after which she resumes activity without confusion. Hyperventilation reproduces an episode, and EEG shows 3-Hz spike-and-wave discharges. Which of the following is the most appropriate first-line treatment?
     • Carbamazepine
     • Phenytoin
     • Gabapentin
     • Ethosuximide

     Correct answer: Ethosuximide

     Ethosuximide is the first-line treatment for childhood absence epilepsy, identified by brief staring spells without postictal confusion and 3-Hz spike-and-wave on EEG. Carbamazepine and phenytoin can worsen absence seizures, and gabapentin is ineffective for this syndrome.

631. A 30-year-old woman with a long history of recurrent severe headaches uses sumatriptan and over-the-counter combination analgesics nearly every day, and her headaches have become daily and refractory. Which of the following is the most appropriate management step?
     • Increase the frequency of triptan dosing
     • Add daily opioids
     • Withdraw the overused acute medications
     • Start prophylactic antibiotics

     Correct answer: Withdraw the overused acute medications

     Withdrawing the overused acute medications is the appropriate step for medication-overuse headache, which develops from frequent use of analgesics or triptans and improves once the offending agents are stopped. Increasing triptan dosing or adding opioids would perpetuate the problem, and antibiotics have no role.

632. A 58-year-old woman presents with a sudden severe occipital headache, vertigo, ataxia, and difficulty walking, with dysmetria on finger-to-nose testing. CT shows a cerebellar hemorrhage. Which of the following is the most important reason this location requires urgent neurosurgical evaluation?
     • High likelihood of spontaneous resolution
     • Low risk of clinical deterioration
     • Absence of any surgical options
     • Risk of brainstem compression and hydrocephalus

     Correct answer: Risk of brainstem compression and hydrocephalus

     Risk of brainstem compression and obstructive hydrocephalus makes cerebellar hemorrhage a neurosurgical emergency, as expansion in the posterior fossa can rapidly compress the brainstem and obstruct CSF flow. Such bleeds do not reliably resolve, can deteriorate quickly, and may be surgically evacuated, so urgent evaluation is essential.

633. A 24-year-old woman presents with double vision and difficulty with horizontal gaze. On attempted leftward gaze, the right eye fails to adduct while the left eye abducts with nystagmus; convergence is intact. Which of the following best explains this finding?
     • Lesion of the medial longitudinal fasciculus
     • Compression of the third cranial nerve
     • Lesion of the abducens nucleus
     • Damage to the optic chiasm

     Correct answer: Lesion of the medial longitudinal fasciculus

     A lesion of the medial longitudinal fasciculus explains internuclear ophthalmoplegia, with impaired adduction of one eye and abducting nystagmus of the other but preserved convergence; in a young woman this often indicates multiple sclerosis. A third nerve lesion causes a down-and-out eye with ptosis, an abducens problem impairs abduction, and a chiasmal lesion causes bitemporal field loss.

634. A 65-year-old diabetic man develops sudden binocular horizontal diplopia. Examination shows the left eye cannot abduct past the midline, and the pupil and eyelid are normal. Which of the following cranial nerves is most likely affected?
     • Oculomotor nerve (CN III)
     • Trochlear nerve (CN IV)
     • Optic nerve (CN II)
     • Abducens nerve (CN VI)

     Correct answer: Abducens nerve (CN VI)

     The abducens nerve is most likely affected, as it innervates the lateral rectus and its palsy causes impaired abduction with horizontal diplopia; microvascular ischemia in a diabetic is a common cause. Oculomotor palsy causes ptosis and a down-and-out eye, trochlear palsy causes vertical diplopia, and the optic nerve governs vision, not eye movement.

635. A 60-year-old man presents with sudden ptosis and a dilated, poorly reactive pupil on the right, with the right eye deviated down and out. Which of the following is the most concerning underlying cause to evaluate urgently?
     • Microvascular ischemia from diabetes
     • Myasthenia gravis
     • Compressive posterior communicating artery aneurysm
     • Horner syndrome

     Correct answer: Compressive posterior communicating artery aneurysm

     A compressive posterior communicating artery aneurysm is the most concerning cause of a pupil-involving third nerve palsy, because pupillary fibers run on the nerve's surface and are affected by external compression, signaling a potentially life-threatening aneurysm. Microvascular ischemia typically spares the pupil, and myasthenia and Horner syndrome do not produce a fixed dilated pupil with a down-and-out eye.

636. A 35-year-old woman is noted to have unilateral ptosis, miosis, and decreased sweating of the face on the same side. Which of the following best describes this constellation of findings?
     • Horner syndrome from disruption of sympathetic innervation
     • Third nerve palsy
     • Bell palsy
     • Myasthenia gravis

     Correct answer: Horner syndrome from disruption of sympathetic innervation

     Horner syndrome from disrupted sympathetic innervation best describes the triad of ptosis, miosis, and anhidrosis. The interrupted oculosympathetic pathway produces these ipsilateral findings, prompting a search for lesions along the pathway such as a Pancoast tumor. A third nerve palsy causes mydriasis, Bell palsy causes facial weakness, and myasthenia causes fatigable ptosis without miosis.

637. A 55-year-old man develops sudden vertigo, ipsilateral facial numbness, loss of pain and temperature sensation on the contralateral body, hoarseness, and Horner syndrome. Which of the following vascular territories is most likely involved?
     • Anterior cerebral artery
     • Middle cerebral artery
     • Lateral medulla (posterior inferior cerebellar artery)
     • Lenticulostriate arteries

     Correct answer: Lateral medulla (posterior inferior cerebellar artery)

     The lateral medulla, supplied by the posterior inferior cerebellar artery, is most likely involved, producing Wallenberg syndrome with crossed sensory loss, vertigo, dysphagia, hoarseness, and ipsilateral Horner syndrome. Anterior and middle cerebral artery strokes cause cortical deficits, and lenticulostriate occlusion causes lacunar syndromes.

638. A 70-year-old man with hypertension and diabetes develops pure motor hemiparesis of the right face, arm, and leg without sensory loss, visual deficit, or aphasia. CT later shows a small deep infarct. Which of the following best describes the most likely mechanism?
     • Lacunar infarct from small-vessel lipohyalinosis
     • Large-artery embolism to the cortex
     • Cardioembolism from atrial fibrillation
     • Watershed infarction from hypotension

     Correct answer: Lacunar infarct from small-vessel lipohyalinosis

     A lacunar infarct from small-vessel lipohyalinosis best explains a pure motor stroke affecting face, arm, and leg without cortical signs in a patient with chronic hypertension and diabetes. Cortical embolism and cardioembolism typically produce cortical deficits such as aphasia or neglect, and watershed infarcts follow systemic hypotension with different patterns.

639. A 45-year-old man sustains a cervical spinal cord injury and develops weakness and loss of proprioception on the right below the lesion, with loss of pain and temperature sensation on the left. Which of the following best describes this pattern?
     • Anterior cord syndrome
     • Central cord syndrome
     • Cauda equina syndrome
     • Brown-Sequard (cord hemisection) syndrome

     Correct answer: Brown-Sequard (cord hemisection) syndrome

     Brown-Sequard syndrome from cord hemisection best fits ipsilateral motor and dorsal-column loss with contralateral loss of pain and temperature, reflecting the crossing of the spinothalamic tract. Anterior cord syndrome spares proprioception, central cord syndrome causes upper-greater-than-lower extremity weakness, and cauda equina affects lumbosacral roots.

640. A 28-year-old man involved in a motor vehicle crash has acute back pain with bilateral leg weakness, saddle anesthesia, and new urinary retention. Which of the following is the most appropriate next step?
     • Outpatient physical therapy referral
     • Reassurance and bed rest
     • Oral NSAIDs and follow-up in 2 weeks
     • Emergent MRI of the spine and urgent surgical decompression

     Correct answer: Emergent MRI of the spine and urgent surgical decompression

     Emergent MRI and urgent surgical decompression is appropriate for cauda equina syndrome, signaled by saddle anesthesia, bilateral leg weakness, and urinary retention. Prompt decompression preserves neurologic and bladder function. Physical therapy, reassurance, and delayed follow-up risk permanent deficits.

641. A 58-year-old man with known metastatic prostate cancer develops progressive back pain that worsens at night, along with new leg weakness and a sensory level on the trunk. Which of the following is the most appropriate immediate management?
     • Start corticosteroids and obtain urgent spinal MRI
     • Schedule routine outpatient MRI
     • Begin physical therapy only
     • Provide oral analgesics and reassess in a week

     Correct answer: Start corticosteroids and obtain urgent spinal MRI

     Starting corticosteroids and obtaining urgent spinal MRI is appropriate for suspected metastatic epidural spinal cord compression. Dexamethasone reduces edema while imaging guides definitive radiation or surgery, and delay risks irreversible paralysis. Routine outpatient evaluation or analgesics alone would be unsafe.

642. A 4-year-old child develops fever, headache, and lethargy and on examination has nuchal rigidity. Lumbar puncture shows lymphocytic pleocytosis with normal glucose and modestly elevated protein, and bacterial cultures are negative. Which of the following is the most likely diagnosis?
     • Bacterial meningitis
     • Subarachnoid hemorrhage
     • Viral (aseptic) meningitis
     • Brain abscess

     Correct answer: Viral (aseptic) meningitis

     Viral (aseptic) meningitis is most likely given lymphocytic pleocytosis with normal glucose, mildly elevated protein, and negative bacterial cultures. Bacterial meningitis would show neutrophilic pleocytosis with low glucose, subarachnoid hemorrhage shows red cells and xanthochromia, and a brain abscess typically presents with focal findings and a ring-enhancing lesion.

643. A 45-year-old man presents with fever, headache, new-onset focal seizures, and behavioral changes. MRI shows temporal lobe involvement and CSF shows lymphocytic pleocytosis. Which of the following is the most appropriate empiric treatment to start immediately?
     • Intravenous acyclovir
     • Intravenous vancomycin alone
     • Oral valacyclovir at discharge
     • Corticosteroids without antivirals

     Correct answer: Intravenous acyclovir

     Intravenous acyclovir should be started immediately for suspected herpes simplex encephalitis, suggested by fever, seizures, behavioral change, and temporal lobe involvement; early treatment reduces mortality and is begun before confirmatory testing. Vancomycin targets bacteria, outpatient oral therapy is inadequate, and steroids alone do not treat the virus.

644. A 68-year-old man with a 40-pack-year smoking history and known COPD presents with three days of increased dyspnea, a change in sputum to a thick yellow color, and increased cough. His temperature is normal and a chest x-ray shows no infiltrate. Which combination of treatments is most appropriate for this COPD exacerbation?
     • Intravenous diuresis and supplemental potassium
     • Short-acting bronchodilators, a systemic corticosteroid course, and an antibiotic
     • Empiric antifungal therapy and immediate intubation
     • Inhaled corticosteroid monotherapy and chest physiotherapy

     Correct answer: Short-acting bronchodilators, a systemic corticosteroid course, and an antibiotic

     The answer is short-acting bronchodilators, a systemic corticosteroid course, and an antibiotic. A COPD exacerbation with increased dyspnea, sputum volume, and sputum purulence meets criteria for antibiotics, and bronchodilators plus a short systemic steroid course are the core of management.

645. A 72-year-old woman with severe COPD is admitted with a COPD exacerbation. Her arterial blood gas shows a pH of 7.30, a PaCO2 of 62 mmHg, and a PaO2 of 58 mmHg while alert and able to protect her airway. Which intervention is most appropriate to reduce her work of breathing and avoid intubation?
     • High-flow intravenous fluids
     • Noninvasive positive-pressure ventilation (BiPAP)
     • A loop diuretic infusion
     • Immediate cricothyrotomy

     Correct answer: Noninvasive positive-pressure ventilation (BiPAP)

     The answer is noninvasive positive-pressure ventilation. In a COPD exacerbation with respiratory acidosis and hypercapnia in an alert, airway-protecting patient, BiPAP reduces work of breathing and the need for intubation while ventilation improves.

646. A patient with a COPD exacerbation and chronic hypercapnia is placed on high-flow oxygen at a fraction far above what is needed, and over the next hour becomes progressively somnolent. Which mechanism best explains this deterioration?
     • Worsened ventilation-perfusion matching and reduced respiratory drive raised PaCO2, causing CO2 narcosis
     • Oxygen directly suppressed the cerebral cortex
     • Oxygen induced acute bronchospasm and air trapping
     • Excess oxygen caused acute hemolysis

     Correct answer: Worsened ventilation-perfusion matching and reduced respiratory drive raised PaCO2, causing CO2 narcosis

     The answer is worsened ventilation-perfusion matching and reduced respiratory drive raising PaCO2, causing CO2 narcosis. Excessive oxygen in chronically hypercapnic COPD patients increases dead-space ventilation and blunts drive, so oxygen should be titrated to a target saturation around 88 to 92 percent.

647. A patient hospitalized for a COPD exacerbation is improving and ready for discharge planning. Which intervention has been shown to most reduce the risk of future exacerbations and mortality in a current smoker with COPD?
     • Prophylactic continuous intravenous antibiotics
     • Smoking cessation
     • Chronic daily oral corticosteroids
     • Routine annual chest computed tomography

     Correct answer: Smoking cessation

     The answer is smoking cessation. Stopping smoking is the single most effective intervention to slow lung function decline and reduce exacerbations and mortality in COPD, making it the priority of discharge counseling.

648. A 70-year-old man with COPD has had two exacerbations in the past year despite using a long-acting muscarinic antagonist. He is now stable in clinic. Which step-up controller adjustment is most appropriate to reduce future exacerbations?
     • Start a daily oral antifungal
     • Add a daily systemic corticosteroid indefinitely
     • Add a long-acting beta-agonist, with consideration of an inhaled corticosteroid
     • Discontinue all inhalers and use only as-needed albuterol

     Correct answer: Add a long-acting beta-agonist, with consideration of an inhaled corticosteroid

     The answer is to add a long-acting beta-agonist, with consideration of an inhaled corticosteroid. For COPD with continued exacerbations on a long-acting muscarinic antagonist, escalating to dual long-acting bronchodilation, and adding an inhaled corticosteroid when exacerbations persist, is the guideline step-up.

649. A patient with stable severe COPD is found to have chronic resting hypoxemia with a PaO2 of 52 mmHg on room air. Which therapy has been proven to improve survival in this setting?
     • Chronic oral theophylline
     • Daily inhaled corticosteroids alone
     • Long-term home oxygen therapy
     • Routine prophylactic antibiotics

     Correct answer: Long-term home oxygen therapy

     The answer is long-term home oxygen therapy. In COPD patients with severe chronic hypoxemia, supplemental oxygen used at least 15 hours per day is one of the few interventions that improves survival.

650. A 55-year-old previously healthy man presents with fever, productive cough, and right-sided pleuritic chest pain for two days. Examination reveals bronchial breath sounds and crackles at the right base, and a chest x-ray shows a right lower lobe infiltrate. Which is the most likely diagnosis?
     • Spontaneous pneumothorax
     • Community-acquired pneumonia
     • Pulmonary embolism
     • Acute pericarditis

     Correct answer: Community-acquired pneumonia

     The answer is community-acquired pneumonia. Fever, productive cough, focal crackles with bronchial breath sounds, and a lobar infiltrate on chest x-ray in an otherwise healthy adult are the classic features of community-acquired pneumonia.

651. A 62-year-old man with community-acquired pneumonia is being assessed for disposition. He is confused, has a respiratory rate of 32, a blood pressure of 88/56 mmHg, and a blood urea nitrogen of 25 mg/dL. Using a standard severity tool, which disposition is most appropriate?
     • Outpatient follow-up in one week without treatment
     • Discharge home on oral antibiotics
     • Observation in the waiting room
     • Hospital admission, likely to an intensive care setting

     Correct answer: Hospital admission, likely to an intensive care setting

     The answer is hospital admission, likely to an intensive care setting. Confusion, elevated urea, a respiratory rate of 30 or more, and low blood pressure are CURB-65 criteria; with several criteria and hemodynamic instability, this patient needs inpatient and probable intensive care management.

652. A previously healthy 40-year-old woman is diagnosed with community-acquired pneumonia and judged suitable for outpatient treatment with no comorbidities and no recent antibiotics. Which empiric oral regimen is most appropriate for a healthy outpatient under current guidance?
     • Oral fluconazole
     • Intravenous vancomycin and cefepime
     • Amoxicillin, or a macrolide or doxycycline as an alternative
     • Oral acyclovir

     Correct answer: Amoxicillin, or a macrolide or doxycycline as an alternative

     The answer is amoxicillin, or a macrolide or doxycycline as an alternative. For a healthy outpatient with community-acquired pneumonia and no comorbidities or resistance risk, current guidelines favor amoxicillin or doxycycline, with a macrolide where local pneumococcal resistance is low.

653. A patient hospitalized for community-acquired pneumonia is started on appropriate antibiotics. By when should clinical improvement, such as defervescence and reduced respiratory distress, generally begin if therapy is effective?
     • Within the first 48 to 72 hours
     • Improvement is not expected until antibiotics are stopped
     • Only after 3 weeks of therapy
     • Within minutes of the first dose

     Correct answer: Within the first 48 to 72 hours

     The answer is within the first 48 to 72 hours. Most patients with community-acquired pneumonia who are on appropriate antibiotics show clinical improvement within two to three days, and failure to improve should prompt reassessment for complications or resistant organisms.

654. A 50-year-old man treated for community-acquired pneumonia has persistent fever and worsening pleuritic pain on day 4. Repeat imaging shows a moderate pleural effusion. Thoracentesis reveals pleural fluid pH of 7.05, low glucose, and a high lactate dehydrogenase. What is the most appropriate next step?
     • Continue current antibiotics without further intervention
     • Begin chronic oral corticosteroids
     • Tube thoracostomy (chest tube) drainage of the effusion
     • Switch to outpatient oral therapy and discharge

     Correct answer: Tube thoracostomy (chest tube) drainage of the effusion

     The answer is tube thoracostomy drainage of the effusion. A parapneumonic effusion with low pH, low glucose, and high lactate dehydrogenase represents a complicated effusion or empyema that requires chest tube drainage in addition to antibiotics.

655. An 80-year-old nursing-facility resident develops fever and a new infiltrate in the right lower lobe several days after an episode of impaired consciousness and vomiting. Which feature most suggests aspiration as the mechanism of this pneumonia?
     • Absence of any cough
     • Dependent lung-segment involvement in a patient with impaired airway protection
     • A bilateral upper-lobe distribution
     • A normal chest examination

     Correct answer: Dependent lung-segment involvement in a patient with impaired airway protection

     The answer is dependent lung-segment involvement in a patient with impaired airway protection. Aspiration pneumonia typically affects gravity-dependent segments, such as the right lower lobe when upright or posterior segments when supine, in patients with reduced consciousness or swallowing dysfunction.

656. A 30-year-old college student has a week of low-grade fever, malaise, and a persistent dry cough that is worse than the relatively unimpressive chest examination. A chest x-ray shows patchy bilateral interstitial infiltrates. Which organism is the most likely cause of this atypical (walking) pneumonia?
     • Staphylococcus aureus
     • Pseudomonas aeruginosa
     • Mycoplasma pneumoniae
     • Klebsiella pneumoniae

     Correct answer: Mycoplasma pneumoniae

     The answer is Mycoplasma pneumoniae. A young, otherwise healthy patient with a gradual dry cough, constitutional symptoms, and diffuse interstitial infiltrates out of proportion to examination findings is the classic picture of atypical pneumonia caused by Mycoplasma.

657. A 65-year-old man presents with sudden-onset dyspnea and pleuritic chest pain three days after a long flight. He has unilateral leg swelling. His heart rate is 110 and oxygen saturation is 91 percent. Pretest probability is calculated as high. What is the most appropriate next diagnostic step?
     • Observation with repeat examination in one week
     • Computed tomography pulmonary angiography
     • Empiric antibiotics for pneumonia
     • Order a D-dimer and discharge if negative

     Correct answer: Computed tomography pulmonary angiography

     The answer is computed tomography pulmonary angiography. With a high pretest probability for pulmonary embolism, a D-dimer is not useful to exclude disease, so definitive imaging with CT pulmonary angiography should be obtained directly.

658. A 45-year-old woman presents with mild pleuritic chest pain and dyspnea. Using the Wells criteria, her pretest probability for pulmonary embolism is low. Which test is most appropriate to safely exclude pulmonary embolism in this low-probability patient?
     • Bronchoscopy
     • A high-sensitivity D-dimer assay
     • Ventilation-perfusion scan in all cases
     • Immediate catheter pulmonary angiography

     Correct answer: A high-sensitivity D-dimer assay

     The answer is a high-sensitivity D-dimer assay. In a patient with low pretest probability for pulmonary embolism, a negative high-sensitivity D-dimer has a high negative predictive value and can safely exclude the diagnosis without imaging.

659. A 58-year-old man is diagnosed with an acute pulmonary embolism. He is hemodynamically stable with normal blood pressure and no right ventricular strain, and has normal renal function. Which initial treatment is most appropriate?
     • Systemic thrombolysis with alteplase
     • Therapeutic anticoagulation, such as a direct oral anticoagulant
     • Aspirin alone
     • Immediate surgical embolectomy

     Correct answer: Therapeutic anticoagulation, such as a direct oral anticoagulant

     The answer is therapeutic anticoagulation, such as a direct oral anticoagulant. A hemodynamically stable pulmonary embolism without right heart strain is treated with anticoagulation; thrombolysis is reserved for massive embolism with hemodynamic compromise.

660. A 60-year-old woman with an acute pulmonary embolism becomes hypotensive with a systolic blood pressure of 80 mmHg and signs of shock, and has no contraindication to thrombolytics. Which therapy is most appropriate for this massive pulmonary embolism?
     • Watchful waiting
     • An inhaled corticosteroid
     • Systemic thrombolytic therapy
     • Oral aspirin

     Correct answer: Systemic thrombolytic therapy

     The answer is systemic thrombolytic therapy. A massive pulmonary embolism causing hemodynamic instability, in the absence of contraindications, warrants thrombolysis to rapidly reduce clot burden and right ventricular afterload.

661. A patient with newly diagnosed acute pulmonary embolism has an acute gastrointestinal bleed and an absolute contraindication to anticoagulation. Which intervention is most appropriate to prevent further embolization?
     • Full-dose heparin infusion
     • Systemic thrombolysis
     • Inferior vena cava filter placement
     • A direct oral anticoagulant at reduced dose

     Correct answer: Inferior vena cava filter placement

     The answer is inferior vena cava filter placement. When anticoagulation is absolutely contraindicated, such as during active major bleeding, an inferior vena cava filter mechanically prevents lower-extremity thrombi from reaching the lungs.

662. A patient with suspected acute pulmonary embolism has an electrocardiogram. Which classic but uncommon electrocardiographic pattern is associated with acute right heart strain from pulmonary embolism?
     • U waves with a prolonged QT
     • An S1Q3T3 pattern
     • Diffuse ST elevation in all leads
     • Delta waves with a short PR interval

     Correct answer: An S1Q3T3 pattern

     The answer is an S1Q3T3 pattern. Although sinus tachycardia is the most common electrocardiographic finding in pulmonary embolism, the S1Q3T3 pattern reflects acute right ventricular strain and is the classically cited, though insensitive, finding.

663. A 35-year-old woman with mild persistent asthma uses her albuterol inhaler about four days per week and wakes at night with symptoms about three times per month. She currently uses no controller. Which step-up in therapy is most appropriate?
     • Add a daily oral corticosteroid
     • Add a daily low-dose inhaled corticosteroid
     • Begin a daily long-acting beta-agonist alone
     • Increase albuterol to scheduled four-times-daily dosing

     Correct answer: Add a daily low-dose inhaled corticosteroid

     The answer is to add a daily low-dose inhaled corticosteroid. Symptoms more than twice weekly with nighttime awakenings indicate persistent asthma, for which a daily inhaled corticosteroid is the preferred controller; a long-acting beta-agonist is never used as monotherapy.

664. A patient with asthma controlled on a low-dose inhaled corticosteroid continues to have daytime symptoms several times weekly and nighttime awakenings. Which adjustment best follows the step-up approach to asthma control?
     • Add a long-acting beta-agonist to the inhaled corticosteroid
     • Begin chronic daily oral prednisone
     • Switch to a long-acting beta-agonist alone
     • Stop the inhaled corticosteroid and use only albuterol

     Correct answer: Add a long-acting beta-agonist to the inhaled corticosteroid

     The answer is to add a long-acting beta-agonist to the inhaled corticosteroid. When low-dose inhaled corticosteroid alone fails to control asthma, combining it with a long-acting beta-agonist is the standard next step, always keeping the long-acting beta-agonist paired with an inhaled corticosteroid.

665. A 26-year-old presents to the emergency department with a severe asthma exacerbation, audible wheezing, and difficulty completing sentences. Which combination is the most appropriate initial treatment?
     • Empiric antibiotics and chest physiotherapy
     • Intravenous beta-blockers and diuretics
     • A long-acting beta-agonist alone
     • Inhaled short-acting beta-agonist, systemic corticosteroids, and supplemental oxygen

     Correct answer: Inhaled short-acting beta-agonist, systemic corticosteroids, and supplemental oxygen

     The answer is inhaled short-acting beta-agonist, systemic corticosteroids, and supplemental oxygen. Acute asthma exacerbations are managed with repeated short-acting beta-agonist bronchodilation, early systemic corticosteroids to reduce airway inflammation, and oxygen to maintain saturation.

666. A patient with a severe asthma exacerbation who was tachypneic and markedly wheezing now appears tired with a rising PaCO2 from a previously low value and a quieting chest. How should this change be interpreted?
     • The patient is improving and ready for discharge
     • A sign that bronchodilators should be stopped
     • Impending respiratory failure requiring escalation of care
     • Evidence of a resolved exacerbation

     Correct answer: Impending respiratory failure requiring escalation of care

     The answer is impending respiratory failure requiring escalation of care. A normalizing or rising PaCO2 during a severe asthma attack signals fatigue and worsening airflow obstruction, and a silent chest with tiring is an ominous sign that may require intubation.

667. A patient with asthma is being taught to monitor disease control at home. A drop in which measurement most directly reflects worsening airflow obstruction and can prompt action per an asthma action plan?
     • Resting heart rate
     • Oral temperature
     • Body weight
     • Peak expiratory flow rate

     Correct answer: Peak expiratory flow rate

     The answer is peak expiratory flow rate. Peak flow measures maximal expiratory airflow and falls as airway obstruction worsens, making it the standard home metric in an asthma action plan to guide self-management.

668. A 30-year-old with asthma undergoes spirometry. Which spirometric pattern, with reversibility after a bronchodilator, supports the diagnosis of asthma?
     • A reduced FEV1/FVC ratio that improves significantly after bronchodilator
     • A normal FEV1/FVC ratio with reduced total lung capacity
     • An increased FEV1/FVC ratio with reduced volumes
     • No change in flow with any maneuver

     Correct answer: A reduced FEV1/FVC ratio that improves significantly after bronchodilator

     The answer is a reduced FEV1/FVC ratio that improves significantly after bronchodilator. Asthma is an obstructive disease, so the FEV1/FVC ratio is low, and the hallmark distinguishing feature is reversibility, with a marked rise in FEV1 after a bronchodilator.

669. A 22-year-old tall, thin man develops sudden right-sided pleuritic chest pain and dyspnea at rest. Examination shows decreased breath sounds and hyperresonance on the right, with a chest x-ray confirming a small primary spontaneous pneumothorax without tension. He is hemodynamically stable. What is the most appropriate management?
     • Empiric broad-spectrum antibiotics
     • Observation with supplemental oxygen for a small, stable pneumothorax
     • Immediate pneumonectomy
     • Systemic anticoagulation

     Correct answer: Observation with supplemental oxygen for a small, stable pneumothorax

     The answer is observation with supplemental oxygen for a small, stable pneumothorax. A small primary spontaneous pneumothorax in a stable patient can be managed with observation and oxygen, which speeds reabsorption, reserving chest tubes for large or symptomatic pneumothoraces.

670. A trauma patient becomes acutely hypotensive with absent breath sounds and hyperresonance on the left, distended neck veins, and tracheal deviation to the right. Which immediate intervention is indicated?
     • Administer a bronchodilator
     • Immediate needle decompression followed by chest tube placement
     • Start intravenous antibiotics
     • Order a chest x-ray before any treatment

     Correct answer: Immediate needle decompression followed by chest tube placement

     The answer is immediate needle decompression followed by chest tube placement. Tension pneumothorax is a clinical diagnosis causing obstructive shock with tracheal deviation and distended neck veins, and it requires emergent decompression before imaging.

671. A 60-year-old man with a history of heart failure has progressive dyspnea. Examination shows dullness to percussion and decreased breath sounds at the right base. A chest x-ray shows blunting of the costophrenic angle. Which finding best confirms a pleural effusion at the bedside?
     • Increased tactile fremitus with bronchial breathing
     • Tracheal deviation toward the affected side
     • Hyperresonance to percussion
     • Dullness to percussion with decreased breath sounds and reduced tactile fremitus

     Correct answer: Dullness to percussion with decreased breath sounds and reduced tactile fremitus

     The answer is dullness to percussion with decreased breath sounds and reduced tactile fremitus. Fluid in the pleural space dampens sound transmission, producing dullness, diminished breath sounds, and decreased fremitus over the effusion.

672. A patient undergoes thoracentesis for a pleural effusion. The pleural fluid has a protein and lactate dehydrogenase ratio to serum that meets Light's criteria for an exudate. Which underlying process is most consistent with an exudative effusion?
     • Pneumonia or malignancy
     • Nephrotic syndrome
     • Hepatic hydrothorax from cirrhosis
     • Uncomplicated congestive heart failure

     Correct answer: Pneumonia or malignancy

     The answer is pneumonia or malignancy. Exudative effusions, identified by Light's criteria, result from increased capillary permeability or impaired lymphatic drainage, as occurs with infection or cancer, whereas transudates arise from heart failure, cirrhosis, or nephrotic syndrome.

673. A 70-year-old man with a 50-pack-year smoking history has a chronic cough, hemoptysis, and unintentional weight loss over three months. A chest x-ray shows a spiculated mass in the right upper lobe. Which is the most appropriate next step to establish a tissue diagnosis?
     • Start chemotherapy without confirmation
     • Begin empiric antibiotics and repeat imaging in 6 months
     • Reassure and discharge
     • Biopsy of the lesion, for example via bronchoscopy or transthoracic needle biopsy

     Correct answer: Biopsy of the lesion, for example via bronchoscopy or transthoracic needle biopsy

     The answer is biopsy of the lesion, for example via bronchoscopy or transthoracic needle biopsy. A spiculated mass with hemoptysis and weight loss in a heavy smoker is highly suspicious for lung cancer, and tissue confirmation is required before treatment.

674. A 65-year-old current smoker with a 30-pack-year history and no symptoms asks about lung cancer screening. Under current United States Preventive Services Task Force guidance, which screening test is recommended for eligible adults?
     • Annual chest x-ray
     • Sputum cytology every 6 months
     • Yearly bronchoscopy
     • Annual low-dose computed tomography of the chest

     Correct answer: Annual low-dose computed tomography of the chest

     The answer is annual low-dose computed tomography of the chest. Lung cancer screening with annual low-dose CT is recommended for adults aged 50 to 80 with a 20-pack-year history who currently smoke or quit within 15 years, as it reduces lung cancer mortality.

675. A patient with small cell lung cancer develops hyponatremia with low serum osmolality, inappropriately concentrated urine, and euvolemia. Which paraneoplastic syndrome best explains these findings?
     • Cushing syndrome from ectopic ACTH
     • Hypercalcemia of malignancy from parathyroid hormone-related peptide
     • Lambert-Eaton myasthenic syndrome
     • Syndrome of inappropriate antidiuretic hormone secretion

     Correct answer: Syndrome of inappropriate antidiuretic hormone secretion

     The answer is the syndrome of inappropriate antidiuretic hormone secretion. Small cell lung cancer can ectopically secrete antidiuretic hormone, causing euvolemic hyponatremia with low serum osmolality and inappropriately concentrated urine.

676. A 55-year-old asymptomatic patient has a 7 mm solid pulmonary nodule found incidentally on chest computed tomography. He is a former light smoker. According to current nodule-management guidance, which is the most appropriate next step?
     • Surveillance computed tomography to assess for interval growth
     • Immediate surgical resection
     • No further evaluation ever
     • Begin chemotherapy

     Correct answer: Surveillance computed tomography to assess for interval growth

     The answer is surveillance computed tomography to assess for interval growth. A small solid pulmonary nodule of intermediate size is typically followed with serial CT according to size and risk, since stability over time argues against malignancy and growth prompts biopsy.

677. A 45-year-old obese man reports loud snoring, witnessed apneas, and daytime sleepiness. His wife notes he gasps awake at night. Which diagnostic test is most appropriate to confirm obstructive sleep apnea?
     • Polysomnography (sleep study)
     • Spirometry
     • Arterial blood gas alone
     • Chest radiography

     Correct answer: Polysomnography (sleep study)

     The answer is polysomnography. Loud snoring, witnessed apneas, and daytime sleepiness suggest obstructive sleep apnea, which is confirmed by a sleep study measuring the apnea-hypopnea index and oxygen desaturations.

678. A patient is diagnosed with moderate-to-severe obstructive sleep apnea. Which therapy is the most effective first-line treatment for reducing apneic events and improving daytime symptoms?
     • A nightly sedative-hypnotic
     • Chronic supplemental nasal oxygen alone
     • Daily inhaled corticosteroids
     • Continuous positive airway pressure (CPAP)

     Correct answer: Continuous positive airway pressure (CPAP)

     The answer is continuous positive airway pressure. CPAP pneumatically splints the upper airway open during sleep and is the most effective first-line therapy for moderate-to-severe obstructive sleep apnea, alongside weight loss.

679. A 35-year-old recent immigrant has several weeks of cough, night sweats, low-grade fevers, and weight loss. A chest x-ray shows a right upper lobe cavitary infiltrate. Which initial step is most appropriate while pursuing the diagnosis?
     • Immediate lobectomy
     • Airborne isolation and collection of sputum for acid-fast bacilli
     • Discharge home on a short course of azithromycin
     • Start chronic corticosteroids

     Correct answer: Airborne isolation and collection of sputum for acid-fast bacilli

     The answer is airborne isolation and collection of sputum for acid-fast bacilli. An upper-lobe cavitary lesion with chronic constitutional symptoms in an at-risk patient is concerning for active pulmonary tuberculosis, mandating respiratory isolation and sputum testing.

680. A healthcare worker has a positive interferon-gamma release assay but is asymptomatic with a normal chest x-ray. This represents latent tuberculosis infection. Which is the most appropriate management?
     • A standard four-drug regimen as for active disease
     • No treatment because there are no symptoms
     • Treatment for latent tuberculosis infection, such as isoniazid with rifapentine or rifampin
     • Immediate lung biopsy

     Correct answer: Treatment for latent tuberculosis infection, such as isoniazid with rifapentine or rifampin

     The answer is treatment for latent tuberculosis infection, such as isoniazid with rifapentine or rifampin. A positive test with no symptoms and normal imaging indicates latent infection, treated with a shorter regimen to prevent progression rather than the full four-drug active-disease regimen.

681. A critically ill patient with sepsis develops acute severe hypoxemia, bilateral pulmonary infiltrates on chest x-ray, and a PaO2/FiO2 ratio of 150, without evidence of left atrial hypertension. Which diagnosis best fits this presentation?
     • Cardiogenic pulmonary edema from heart failure
     • Acute respiratory distress syndrome
     • Simple lobar pneumonia
     • Chronic obstructive pulmonary disease

     Correct answer: Acute respiratory distress syndrome

     The answer is acute respiratory distress syndrome. Acute onset of hypoxemia with bilateral infiltrates, a low PaO2/FiO2 ratio, and no primary cardiac cause within a week of an insult such as sepsis defines acute respiratory distress syndrome.

682. A patient with acute respiratory distress syndrome is intubated and mechanically ventilated. Which ventilator strategy has been shown to reduce mortality in this condition?
     • High tidal volumes to fully expand the lungs
     • Minimal positive end-expiratory pressure
     • Permissive hyperoxia with high FiO2 maintained indefinitely
     • Low tidal volume (lung-protective) ventilation

     Correct answer: Low tidal volume (lung-protective) ventilation

     The answer is low tidal volume, lung-protective ventilation. Using tidal volumes around 6 mL/kg of predicted body weight with limited plateau pressures reduces ventilator-induced lung injury and improves survival in acute respiratory distress syndrome.

683. A 50-year-old African American woman has dyspnea, dry cough, and bilateral hilar lymphadenopathy on chest x-ray. A biopsy of a lymph node shows noncaseating granulomas. Which diagnosis is most likely?
     • Sarcoidosis
     • Bacterial pneumonia
     • Small cell lung cancer
     • Active tuberculosis

     Correct answer: Sarcoidosis

     The answer is sarcoidosis. Bilateral hilar lymphadenopathy with noncaseating granulomas on biopsy, often in a younger adult with cough and dyspnea, is the classic presentation of pulmonary sarcoidosis.

684. A 62-year-old man has progressive exertional dyspnea and a dry cough over a year, with fine inspiratory crackles at the bases and clubbing. High-resolution computed tomography shows subpleural reticular changes with honeycombing. Which diagnosis is most consistent with these findings?
     • Pulmonary embolism
     • Acute bacterial pneumonia
     • Idiopathic pulmonary fibrosis
     • Asthma

     Correct answer: Idiopathic pulmonary fibrosis

     The answer is idiopathic pulmonary fibrosis. Insidious exertional dyspnea, dry cough, basal inspiratory crackles, clubbing, and subpleural honeycombing on high-resolution CT describe the usual interstitial pneumonia pattern of idiopathic pulmonary fibrosis.

685. A patient with chronic dyspnea undergoes pulmonary function testing showing a reduced FVC, a reduced total lung capacity, and a preserved or increased FEV1/FVC ratio. Which category of disease does this pattern represent?
     • Pure pulmonary vascular disease
     • Obstructive lung disease
     • Normal lung function
     • Restrictive lung disease

     Correct answer: Restrictive lung disease

     The answer is restrictive lung disease. Reduced lung volumes with a preserved or increased FEV1/FVC ratio indicate a restrictive pattern, as seen in interstitial lung disease, in contrast to the low ratio of obstructive disease.

686. A 68-year-old man with COPD has a chronically elevated PaCO2 and a near-normal pH on arterial blood gas, with an elevated serum bicarbonate. Which compensatory process explains the near-normal pH?
     • Acute respiratory alkalosis
     • Primary metabolic alkalosis from vomiting
     • Renal compensation with bicarbonate retention for chronic respiratory acidosis
     • Acute metabolic acidosis

     Correct answer: Renal compensation with bicarbonate retention for chronic respiratory acidosis

     The answer is renal compensation with bicarbonate retention for chronic respiratory acidosis. In chronic hypercapnia, the kidneys retain bicarbonate over days to buffer the retained carbon dioxide, returning the pH toward normal.

687. A 24-year-old presents with acute anxiety, perioral tingling, and carpopedal spasm after rapid deep breathing. An arterial blood gas shows a high pH and a low PaCO2. Which acid-base disturbance is present?
     • Metabolic acidosis with respiratory compensation
     • Chronic respiratory acidosis
     • Acute respiratory alkalosis
     • Metabolic alkalosis

     Correct answer: Acute respiratory alkalosis

     The answer is acute respiratory alkalosis. Hyperventilation lowers PaCO2 and raises pH, and the resulting fall in ionized calcium produces perioral tingling and carpopedal spasm, the classic picture of acute respiratory alkalosis.

688. A 6-month-old infant in winter has two days of cough, wheezing, tachypnea, and nasal congestion following an upper respiratory illness. Examination shows diffuse wheezes and crackles. Which is the most likely diagnosis?
     • Pulmonary embolism
     • Bacterial lobar pneumonia
     • Chronic obstructive pulmonary disease
     • Bronchiolitis, most often from respiratory syncytial virus

     Correct answer: Bronchiolitis, most often from respiratory syncytial virus

     The answer is bronchiolitis, most often from respiratory syncytial virus. A young infant with wintertime cough, wheeze, tachypnea, and a preceding upper respiratory infection has bronchiolitis, typically caused by respiratory syncytial virus, managed with supportive care.

689. A 2-year-old presents with a barking cough, inspiratory stridor, and hoarseness that worsen at night, following a mild upper respiratory illness. A neck x-ray shows subglottic narrowing (steeple sign). Which is the most likely diagnosis?
     • Croup (laryngotracheobronchitis)
     • Epiglottitis
     • Foreign body aspiration
     • Asthma

     Correct answer: Croup (laryngotracheobronchitis)

     The answer is croup. A barking cough, inspiratory stridor, hoarseness after a viral prodrome, and the steeple sign of subglottic narrowing characterize croup, which is usually viral and managed with corticosteroids and, if severe, nebulized epinephrine.

690. A 40-year-old woman with progressive dyspnea has an elevated estimated pulmonary artery systolic pressure on echocardiography, and right heart catheterization confirms elevated mean pulmonary artery pressure without left heart disease or lung disease. Which condition does this represent?
     • Acute bronchitis
     • Asthma
     • Simple pleural effusion
     • Pulmonary arterial hypertension

     Correct answer: Pulmonary arterial hypertension

     The answer is pulmonary arterial hypertension. Elevated mean pulmonary artery pressure confirmed by right heart catheterization, in the absence of left heart or significant lung disease, defines pulmonary arterial hypertension and guides targeted vasodilator therapy.

691. A patient with longstanding severe COPD develops lower-extremity edema, an elevated jugular venous pressure, and a loud pulmonic component of the second heart sound. Which complication of chronic lung disease does this represent?
     • Aortic stenosis
     • Acute pericardial tamponade
     • Left ventricular systolic failure
     • Cor pulmonale (right heart failure from lung disease)

     Correct answer: Cor pulmonale (right heart failure from lung disease)

     The answer is cor pulmonale, right heart failure from lung disease. Chronic hypoxic pulmonary vasoconstriction in severe COPD raises pulmonary pressures, straining and eventually failing the right ventricle, producing peripheral edema and elevated venous pressure.

692. A 28-year-old woman with cystic fibrosis has recurrent productive cough and frequent pulmonary infections. Imaging shows permanently dilated, thick-walled bronchi. Which structural lung condition is described?
     • Bronchiectasis
     • Pleural effusion
     • Pulmonary embolism
     • Lobar consolidation

     Correct answer: Bronchiectasis

     The answer is bronchiectasis. Chronic infection and inflammation, as in cystic fibrosis, permanently dilate and thicken the bronchi, producing recurrent infections and copious sputum, which is bronchiectasis.

693. A 30-year-old woman has episodic chest tightness and cough triggered by cold air and exercise, with normal findings between episodes. Spirometry is normal at baseline. Which test can help confirm airway hyperresponsiveness in suspected asthma?
     • An exercise stress echocardiogram
     • A methacholine challenge test
     • A D-dimer assay
     • Arterial blood gas at rest

     Correct answer: A methacholine challenge test

     The answer is a methacholine challenge test. When asthma is suspected but baseline spirometry is normal, a methacholine challenge demonstrating bronchoconstriction supports the diagnosis by revealing airway hyperresponsiveness.

694. A patient with a moderate COPD exacerbation is started on a short course of systemic corticosteroids. Which statement about the duration of corticosteroid therapy reflects current guidance?
     • At least 6 weeks of high-dose steroids is standard
     • Lifelong daily corticosteroids are required after every exacerbation
     • A short course of about 5 days is generally sufficient
     • A single dose is always adequate

     Correct answer: A short course of about 5 days is generally sufficient

     The answer is that a short course of about 5 days is generally sufficient. Evidence supports brief systemic corticosteroid courses for COPD exacerbations, which are as effective as longer courses while limiting steroid-related adverse effects.

695. A 75-year-old man with community-acquired pneumonia has risk factors including recent antibiotic use and significant comorbidities. Which outpatient empiric regimen better covers likely resistant pneumococcus and atypical pathogens in a patient with comorbidities?
     • A respiratory fluoroquinolone, or a beta-lactam plus a macrolide
     • No antibiotics, supportive care alone
     • Oral nystatin
     • Topical antibiotics only

     Correct answer: A respiratory fluoroquinolone, or a beta-lactam plus a macrolide

     The answer is a respiratory fluoroquinolone, or a beta-lactam plus a macrolide. Outpatients with comorbidities or recent antibiotics need broader coverage for resistant pneumococcus and atypicals, achieved with combination beta-lactam plus macrolide or a respiratory fluoroquinolone.

696. A patient with an unprovoked first pulmonary embolism has completed initial anticoagulation. When deciding on the duration of anticoagulation, which factor most favors extended (indefinite) anticoagulation?
     • The patient had a transient immobilization that has fully resolved
     • The embolism was clearly provoked by recent surgery
     • The embolism was unprovoked with a low bleeding risk
     • The patient has active major bleeding

     Correct answer: The embolism was unprovoked with a low bleeding risk

     The answer is that the embolism was unprovoked with a low bleeding risk. Unprovoked pulmonary embolism carries a high recurrence risk, so extended anticoagulation is favored when bleeding risk is low, whereas provoked events from a resolved transient factor often warrant a limited course.

697. A 19-year-old develops abrupt high fever, drooling, severe sore throat, and a muffled voice, sitting in a tripod position with stridor and looking toxic. Which condition is the most urgent concern, and what is the priority?
     • Asthma, with priority on a peak flow measurement
     • Allergic rhinitis, with priority on antihistamines
     • Viral croup, with priority on discharge home
     • Epiglottitis, with priority on securing the airway

     Correct answer: Epiglottitis, with priority on securing the airway

     The answer is epiglottitis, with priority on securing the airway. Rapid-onset fever, drooling, a muffled voice, and tripod positioning with a toxic appearance suggest epiglottitis, a potential airway emergency where airway management takes precedence over throat examination.

698. A 50-year-old shipyard worker with prior asbestos exposure presents with dyspnea, chest pain, and a unilateral pleural effusion with pleural thickening. Which malignancy is most associated with this exposure history?
     • Colon adenocarcinoma
     • Renal cell carcinoma
     • Malignant pleural mesothelioma
     • Thyroid carcinoma

     Correct answer: Malignant pleural mesothelioma

     The answer is malignant pleural mesothelioma. Asbestos exposure, often decades earlier, is the major risk factor for mesothelioma, which presents with dyspnea, chest pain, pleural thickening, and effusion.

699. A patient with acute hypoxemic respiratory failure has an oxygen saturation of 86 percent despite a non-rebreather mask, but remains alert with intact airway reflexes and is not in immediate need of intubation. Which oxygen-delivery method can provide high flows of heated, humidified oxygen to improve oxygenation?
     • High-flow nasal cannula
     • A venturi mask at 24 percent
     • Room air observation
     • A simple nasal cannula at 2 liters per minute

     Correct answer: High-flow nasal cannula

     The answer is high-flow nasal cannula. For hypoxemic respiratory failure in an alert patient, high-flow nasal cannula delivers heated, humidified oxygen at high flow rates with some positive airway pressure, improving oxygenation and comfort while avoiding intubation in selected patients.

700. A patient with severe pneumonia has an oxygen saturation reading of 98 percent on the pulse oximeter despite clinical cyanosis after a house fire with smoke exposure. Which condition can cause pulse oximetry to falsely read normal in this setting?
     • Mild dehydration
     • Sinus tachycardia alone
     • Simple iron deficiency anemia
     • Carbon monoxide poisoning

     Correct answer: Carbon monoxide poisoning

     The answer is carbon monoxide poisoning. Carboxyhemoglobin is read as oxyhemoglobin by standard pulse oximeters, producing a falsely normal saturation despite impaired oxygen delivery, so co-oximetry is needed after smoke inhalation.

701. A 3-year-old previously well child has sudden onset of coughing, choking, and unilateral wheezing after playing with small toys, with focal decreased breath sounds on the right. Which diagnosis should be suspected?
     • Foreign body aspiration
     • Bacterial pneumonia
     • Asthma exacerbation
     • Croup

     Correct answer: Foreign body aspiration

     The answer is foreign body aspiration. Abrupt coughing and choking with focal, unilateral wheeze and decreased breath sounds in a toddler points to an aspirated foreign body, frequently lodging in the right mainstem bronchus, requiring bronchoscopic removal.

702. A patient with a COPD exacerbation requires antibiotics. Which factor on history most strongly supports adding antibiotic therapy to bronchodilators and corticosteroids?
     • Isolated mild ankle swelling
     • A normal sputum that is unchanged
     • A single episode of palpitations
     • Increased sputum purulence and volume

     Correct answer: Increased sputum purulence and volume

     The answer is increased sputum purulence and volume. Antibiotics are indicated in COPD exacerbations when there is increased dyspnea together with increased sputum volume and purulence, the cardinal signs suggesting a bacterial trigger.

703. A patient recovering from community-acquired pneumonia asks how to prevent future episodes. Which preventive measure is most appropriate to recommend for an at-risk older adult?
     • Pneumococcal and influenza vaccination
     • Prophylactic daily antibiotics for life
     • Avoiding all physical activity
     • Routine annual bronchoscopy

     Correct answer: Pneumococcal and influenza vaccination

     The answer is pneumococcal and influenza vaccination. Immunization against pneumococcus and influenza reduces the incidence and severity of pneumonia in older and at-risk adults, making vaccination the cornerstone of prevention.

704. A patient is suspected of having a pulmonary embolism but cannot receive iodinated contrast because of a severe contrast allergy and acute kidney injury. Which alternative imaging study can evaluate for pulmonary embolism without iodinated contrast?
     • Coronary angiography
     • Ventilation-perfusion (V/Q) scan
     • Upper gastrointestinal series
     • Contrast-enhanced CT pulmonary angiography

     Correct answer: Ventilation-perfusion (V/Q) scan

     The answer is a ventilation-perfusion scan. When CT pulmonary angiography is contraindicated due to contrast allergy or renal impairment, a ventilation-perfusion scan can assess for pulmonary embolism by detecting mismatched perfusion defects.

705. A 65-year-old man with COPD is found to have a low FEV1 that does not improve much after bronchodilator and a reduced diffusing capacity for carbon monoxide. Which underlying pathology in emphysema best explains the reduced diffusing capacity?
     • Thickened airway smooth muscle alone
     • Excess pleural fluid
     • Destruction of alveolar walls reducing surface area for gas exchange
     • Increased alveolar surface area

     Correct answer: Destruction of alveolar walls reducing surface area for gas exchange

     The answer is destruction of alveolar walls reducing surface area for gas exchange. Emphysema destroys alveolar septa and the associated capillary bed, lowering the diffusing capacity for carbon monoxide, a feature that helps distinguish emphysema from asthma.

706. A patient hospitalized with severe community-acquired pneumonia has risk factors for Pseudomonas aeruginosa, including structural lung disease from bronchiectasis. Which empiric change best addresses this risk?
     • Include an antipseudomonal beta-lactam in the regimen
     • Use oral amoxicillin alone
     • Withhold antibiotics pending cultures
     • Use doxycycline monotherapy

     Correct answer: Include an antipseudomonal beta-lactam in the regimen

     The answer is to include an antipseudomonal beta-lactam in the regimen. Patients with structural lung disease such as bronchiectasis are at risk for Pseudomonas, so empiric therapy should add antipseudomonal coverage rather than relying on standard regimens.

707. A 50-year-old woman with no smoking history is incidentally found to have low serum alpha-1 antitrypsin and early basilar-predominant emphysema. Which inherited condition best explains emphysema in this nonsmoker?
     • Alpha-1 antitrypsin deficiency
     • Cystic fibrosis
     • Sarcoidosis
     • Primary ciliary dyskinesia

     Correct answer: Alpha-1 antitrypsin deficiency

     The answer is alpha-1 antitrypsin deficiency. This inherited deficiency leaves elastase unopposed, causing early-onset, often basilar emphysema in nonsmokers, and should be suspected when emphysema appears young or without a smoking history.

708. A 28-year-old woman at 33 weeks gestation presents with right upper quadrant pain, nausea, and a blood pressure of 162/108 mmHg. Laboratory studies show platelets of 78,000 per microliter, AST of 240 U/L, and lactate dehydrogenase of 820 U/L with a peripheral smear showing schistocytes. Which diagnosis best unifies these findings?
     • HELLP syndrome
     • Immune thrombocytopenic purpura
     • Cholelithiasis with biliary colic
     • Acute viral hepatitis

     Correct answer: HELLP syndrome

     HELLP syndrome is the unifying diagnosis. The triad of hemolysis (schistocytes, elevated LDH), elevated liver enzymes, and low platelets in a hypertensive pregnant woman defines HELLP, a severe variant of preeclampsia; isolated hepatitis, immune thrombocytopenia, or biliary colic would not produce this combination of microangiopathic hemolysis, transaminitis, and thrombocytopenia together with hypertension.

709. A 31-year-old woman at 30 weeks gestation with preeclampsia with severe features is receiving a magnesium sulfate infusion. The nurse reports that deep tendon reflexes are still present and respirations are 16 per minute. A magnesium level is drawn to confirm she is in the therapeutic range for seizure prophylaxis. Which serum magnesium range is generally considered therapeutic for this indication?
     • 0.5 to 1.5 mg/dL
     • 15 to 18 mg/dL
     • 10 to 12 mg/dL
     • 4 to 7 mg/dL

     Correct answer: 4 to 7 mg/dL

     A magnesium level of about 4 to 7 mg/dL is the therapeutic target. This range provides effective seizure prophylaxis while remaining below the levels at which toxicity appears, with loss of reflexes around 9 to 12 mg/dL and respiratory depression at higher levels; 0.5 to 1.5 mg/dL is the normal baseline and is subtherapeutic, while 10 mg/dL and above reflect toxic concentrations.

710. A 26-year-old woman at 39 weeks gestation suddenly develops a generalized tonic-clonic seizure during labor. She was previously diagnosed with preeclampsia with severe features. After protecting her airway and positioning her, which medication is the first-line treatment to control and prevent further seizures?
     • Intravenous lorazepam
     • Intravenous levetiracetam
     • Intravenous phenytoin
     • Intravenous magnesium sulfate

     Correct answer: Intravenous magnesium sulfate

     Magnesium sulfate is first-line for eclamptic seizures. It is superior to standard antiepileptics for both treating and preventing recurrent eclamptic seizures; benzodiazepines such as lorazepam and antiepileptics like phenytoin or levetiracetam are reserved for seizures refractory to magnesium rather than used as the initial agent in eclampsia.

711. A 30-year-old woman at 24 weeks gestation has a blood pressure of 150/96 mmHg confirmed on repeat, no proteinuria, normal platelets, normal liver enzymes, and no symptoms. She had a normal blood pressure before pregnancy and at her first-trimester visit. How is her condition best classified?
     • White coat hypertension only
     • Preeclampsia with severe features
     • Chronic hypertension
     • Gestational hypertension

     Correct answer: Gestational hypertension

     Gestational hypertension is the classification. New-onset hypertension after 20 weeks without proteinuria or other end-organ findings defines gestational hypertension; chronic hypertension would predate 20 weeks, preeclampsia requires proteinuria or severe features, and the persistence on repeat measurement makes white coat hypertension an inadequate explanation.

712. A 29-year-old woman is found to have a positive group B Streptococcus screening culture and receives intrapartum penicillin, but her newborn develops fever, lethargy, and respiratory distress at 18 hours of life with GBS isolated from blood. Which category of neonatal GBS disease does this represent?
     • Maternal GBS bacteriuria only
     • Late-onset GBS disease
     • Early-onset GBS disease
     • Congenital GBS osteomyelitis

     Correct answer: Early-onset GBS disease

     This is early-onset GBS disease. Early-onset disease presents within the first week of life, typically within 24 to 48 hours, as sepsis or pneumonia acquired around the time of delivery; late-onset disease appears after the first week and often presents as meningitis, and the scenario describes neonatal illness rather than maternal bacteriuria or bone infection.

713. A newborn is assessed one minute after delivery. The heart rate is 130 per minute, the infant cries vigorously, has active flexed movement, grimaces and pulls away with suctioning, and has pink trunk with bluish hands and feet. What is this newborn's Apgar score?
     • 7
     • 5
     • 10
     • 9

     Correct answer: 9

     The Apgar score is 9. Heart rate above 100 (2), strong respiratory effort with vigorous cry (2), active motion (2), and a grimace with active withdrawal (2) each earn full marks, while acrocyanosis with a pink body but blue extremities scores 1 for color; summing these gives 9 rather than a lower total or a perfect 10.

714. A 32-year-old woman with regular 28-day menstrual cycles reports that her last menstrual period began on March 10. Using Naegele rule, what is her estimated date of delivery?
     • December 17
     • November 30
     • January 3
     • December 31

     Correct answer: December 17

     The estimated date of delivery is December 17. Naegele rule adds 7 days to the first day of the last menstrual period and subtracts 3 months (equivalent to adding 9 months and 7 days): March 10 plus 7 days is March 17, and subtracting 3 months gives December 17, which is the correct estimate rather than the other dates.

715. A 27-year-old woman at 16 weeks gestation has a routine maternal serum alpha-fetoprotein that returns markedly elevated. A detailed ultrasound is being arranged. To reduce the risk that her fetus develops the defect most associated with this finding in future or current pregnancies, which preconception supplement is most important?
     • Folic acid
     • Calcium
     • Vitamin A
     • Vitamin C

     Correct answer: Folic acid

     Folic acid is the key supplement. An elevated maternal serum alpha-fetoprotein raises concern for an open neural tube defect, and periconceptional folic acid supplementation substantially reduces the risk of these defects; vitamin A in excess is actually teratogenic, and calcium and vitamin C do not prevent neural tube defects.

716. A laboring woman at 40 weeks is examined and the obstetrician determines that the bony presenting part of the fetal head is at the level of the maternal ischial spines. How should the fetal station be documented?
     • Station +3
     • Station -3
     • Station 0
     • Floating

     Correct answer: Station 0

     Station 0 is correct. Fetal station is measured relative to the maternal ischial spines, with the presenting part at the spines defined as station 0 (engaged); negative stations are above the spines, positive stations are below toward the introitus, and a floating head is well above the pelvis.

717. A 24-year-old woman who delivered vaginally 30 minutes ago has not yet delivered the placenta despite gentle controlled cord traction and signs of placental separation have not occurred. At what point is the third stage of labor generally considered prolonged, prompting consideration of manual removal?
     • After 5 minutes
     • After 30 minutes
     • After 2 hours
     • After 10 minutes

     Correct answer: After 30 minutes

     A third stage lasting beyond about 30 minutes is considered prolonged. Most placentas deliver within 30 minutes, and a retained placenta beyond this window raises the risk of hemorrhage and may warrant manual removal; 5 and 10 minutes are within the normal expected interval, and waiting 2 hours would unacceptably increase bleeding risk.

718. A 35-year-old woman undergoes an operative vaginal delivery and develops postpartum hemorrhage. The uterus is firm, the placenta is intact, and a steady stream of bright red blood is noted with a laceration extending into the anal sphincter and rectal mucosa. How is this perineal laceration classified?
     • First-degree laceration
     • Fourth-degree laceration
     • Third-degree laceration
     • Second-degree laceration

     Correct answer: Fourth-degree laceration

     This is a fourth-degree laceration. Extension through the anal sphincter complex and into the rectal mucosa defines a fourth-degree tear; a first-degree involves only the vaginal mucosa or perineal skin, a second-degree extends into the perineal muscles, and a third-degree involves the anal sphincter but spares the rectal mucosa.

719. A 22-year-old woman at 39 weeks gestation is in the second stage of labor with a reassuring fetal heart tracing and adequate maternal pushing. The obstetrician is deciding whether to perform a routine episiotomy. According to current evidence-based practice, which approach is most appropriate?
     • Routine midline episiotomy to prevent all tears
     • Routine episiotomy for all nulliparous women
     • Restrictive use of episiotomy, reserved for specific indications
     • Mandatory mediolateral episiotomy in every delivery

     Correct answer: Restrictive use of episiotomy, reserved for specific indications

     Restrictive use is the evidence-based approach. Routine episiotomy does not reduce severe perineal trauma and may increase third- and fourth-degree extensions, so episiotomy is now reserved for selected indications such as the need to expedite delivery; routine or mandatory episiotomy for all patients is no longer recommended.

720. A baby is born to a mother who used opioids throughout pregnancy. At 2 days of life the infant develops high-pitched crying, tremors, hypertonia, poor feeding, sweating, and frequent yawning and sneezing. Which condition do these findings represent?
     • Neonatal sepsis
     • Neonatal abstinence syndrome
     • Hypoglycemia of the newborn
     • Transient tachypnea of the newborn

     Correct answer: Neonatal abstinence syndrome

     Neonatal abstinence syndrome is the diagnosis. Withdrawal in an infant exposed to opioids in utero produces central nervous system irritability, autonomic signs such as sweating and yawning, and gastrointestinal disturbance; sepsis, hypoglycemia, and transient tachypnea do not produce this characteristic withdrawal constellation tied to maternal opioid use.

721. A pregnant woman is counseled about a congenital infection that is the most common infectious cause of congenital sensorineural hearing loss and may cause periventricular calcifications. Which organism is being described?
     • Cytomegalovirus
     • Treponema pallidum
     • Rubella virus
     • Toxoplasma gondii

     Correct answer: Cytomegalovirus

     Cytomegalovirus is the organism. Congenital CMV is the leading infectious cause of sensorineural hearing loss and classically causes periventricular calcifications, microcephaly, and petechiae; toxoplasmosis causes diffuse intracranial calcifications and chorioretinitis, syphilis causes bone and skin findings, and rubella causes the cardiac and cataract triad.

722. A nonimmune pregnant woman contracts a viral illness in the first trimester and her infant is later found to have patent ductus arteriosus, cataracts, and sensorineural deafness. Which congenital infection classically produces this triad?
     • Congenital rubella syndrome
     • Congenital Zika syndrome
     • Congenital varicella syndrome
     • Congenital toxoplasmosis

     Correct answer: Congenital rubella syndrome

     Congenital rubella syndrome is the classic cause. The triad of cardiac defects (often patent ductus arteriosus), cataracts, and sensorineural deafness is characteristic of first-trimester rubella infection; toxoplasmosis, varicella, and Zika produce different patterns such as chorioretinitis, limb defects, or microcephaly rather than this specific triad.

723. A pregnant woman travels to a region with active mosquito-borne transmission of a flavivirus associated with fetal brain anomalies. Her infant is later born with severe microcephaly and brain calcifications. Which infection is most likely responsible?
     • Parvovirus B19
     • Group B Streptococcus
     • Zika virus
     • Listeria monocytogenes

     Correct answer: Zika virus

     Zika virus is the likely cause. Maternal Zika infection, transmitted by Aedes mosquitoes, is strongly associated with congenital microcephaly and intracranial calcifications; parvovirus B19 causes fetal anemia and hydrops, Listeria causes neonatal sepsis and fetal loss, and group B Streptococcus causes neonatal sepsis rather than this congenital brain malformation pattern.

724. A 38-year-old woman with two prior unexplained second-trimester pregnancy losses and a history of an arterial thrombosis is evaluated for recurrent pregnancy loss. Laboratory studies show a persistently positive lupus anticoagulant and elevated anticardiolipin antibodies on testing 12 weeks apart. In her next pregnancy, which treatment is recommended to improve outcomes?
     • High-dose corticosteroids alone
     • No intervention beyond routine prenatal care
     • Warfarin throughout pregnancy
     • Low-dose aspirin combined with prophylactic heparin

     Correct answer: Low-dose aspirin combined with prophylactic heparin

     Low-dose aspirin plus heparin is recommended. Antiphospholipid syndrome with recurrent pregnancy loss is managed with combined low-dose aspirin and heparin to reduce thrombosis and improve live-birth rates; warfarin is teratogenic, corticosteroids are not the standard therapy for this indication, and no treatment would leave the high recurrence risk unaddressed.

725. A 30-year-old woman at 26 weeks gestation has an ultrasound showing a fetus with an abdominal circumference and estimated weight below the third percentile, but a normal head circumference, giving a head-sparing pattern. Which type of fetal growth restriction does this represent, and what does it suggest about the cause?
     • Symmetric growth restriction, suggesting an early chromosomal cause
     • Constitutionally small but healthy fetus with no pathology
     • Asymmetric growth restriction, suggesting later-onset placental insufficiency
     • Macrosomia from maternal diabetes

     Correct answer: Asymmetric growth restriction, suggesting later-onset placental insufficiency

     This is asymmetric growth restriction. A relatively spared head with a disproportionately small abdomen reflects redistribution of blood flow to the brain in response to placental insufficiency, typically later in pregnancy; symmetric restriction implies an early global insult such as a chromosomal or infectious cause, and the small size excludes a normally grown or macrosomic fetus.

726. A neonate is delivered with low-set ears, a flattened facial profile, limb contractures, and pulmonary hypoplasia, and the pregnancy was complicated by severe oligohydramnios from bilateral renal agenesis. Which clinical sequence explains these deformations?
     • Beckwith-Wiedemann syndrome
     • Fetal alcohol syndrome
     • Potter sequence
     • VACTERL association

     Correct answer: Potter sequence

     Potter sequence is the explanation. Inadequate fetal urine production from renal agenesis causes oligohydramnios, and the resulting compression produces the characteristic facies, limb contractures, and pulmonary hypoplasia; VACTERL is a different cluster of anomalies, fetal alcohol syndrome relates to alcohol exposure, and Beckwith-Wiedemann involves overgrowth rather than deformation from oligohydramnios.

727. A 33-year-old woman at 28 weeks gestation has an ultrasound showing a single deepest vertical amniotic fluid pocket of 1.5 cm. The membranes are intact and there is no leakage of fluid. How should this finding be interpreted?
     • Normal amniotic fluid volume
     • Anhydramnios
     • Polyhydramnios
     • Oligohydramnios

     Correct answer: Oligohydramnios

     This represents oligohydramnios. A single deepest vertical pocket less than 2 cm (or an amniotic fluid index below 5 cm) defines oligohydramnios, prompting evaluation for causes such as placental insufficiency or fetal renal anomalies; a normal pocket is 2 to 8 cm, polyhydramnios is excess fluid, and anhydramnios is the complete absence of measurable fluid.

728. A 19-year-old woman presents with lower abdominal pain, fever, mucopurulent cervical discharge, and exquisite cervical motion tenderness on bimanual exam. She is sexually active and not pregnant. What is the most appropriate empiric outpatient treatment for her pelvic inflammatory disease?
     • Topical clindamycin cream alone
     • Oral acyclovir for 7 days
     • A single dose of oral fluconazole
     • Ceftriaxone plus doxycycline, with metronidazole

     Correct answer: Ceftriaxone plus doxycycline, with metronidazole

     Ceftriaxone plus doxycycline with metronidazole is the recommended regimen. Pelvic inflammatory disease is polymicrobial, so empiric therapy covers gonorrhea with ceftriaxone and chlamydia and anaerobes with doxycycline and metronidazole; fluconazole treats yeast, acyclovir treats herpes, and topical clindamycin does not provide adequate coverage for upper genital tract infection.

729. A 24-year-old woman with pelvic inflammatory disease develops right upper quadrant pain, and laparoscopy reveals violin-string adhesions between the liver capsule and the abdominal wall. Which condition does this represent?
     • Meigs syndrome
     • Mittelschmerz
     • Acute cholecystitis
     • Fitz-Hugh-Curtis syndrome

     Correct answer: Fitz-Hugh-Curtis syndrome

     This is Fitz-Hugh-Curtis syndrome. Perihepatitis with characteristic violin-string adhesions is a complication of pelvic inflammatory disease, usually from chlamydial or gonococcal infection spreading to the liver capsule; acute cholecystitis involves the gallbladder, Meigs syndrome links an ovarian fibroma to ascites and effusion, and mittelschmerz is benign mid-cycle ovulatory pain.

730. A 27-year-old woman with pelvic inflammatory disease has persistent fever despite outpatient antibiotics, and transvaginal ultrasound reveals a multiloculated complex adnexal fluid collection. What complication has she most likely developed?
     • Ectopic pregnancy
     • Tubo-ovarian abscess
     • Endometrioma
     • Ovarian dermoid cyst

     Correct answer: Tubo-ovarian abscess

     A tubo-ovarian abscess is the likely complication. Failure to respond to oral antibiotics with a complex multiloculated adnexal mass indicates abscess formation, which generally requires inpatient intravenous antibiotics and possible drainage; an ectopic pregnancy requires a positive pregnancy test, an endometrioma has a homogeneous ground-glass appearance, and a dermoid contains fat and calcifications rather than purulent loculations.

731. A 21-year-old sexually active woman has a friable cervix with mucopurulent endocervical discharge on exam. Nucleic acid amplification testing confirms Chlamydia trachomatis. Besides treating her, which step is essential to prevent reinfection and complications?
     • Treat her sexual partners and counsel on STI prevention
     • Repeat the test daily for one week
     • Begin antifungal therapy
     • Schedule a hysteroscopy

     Correct answer: Treat her sexual partners and counsel on STI prevention

     Treating her partners is essential. Partner treatment and counseling prevent reinfection and onward transmission of chlamydial cervicitis, which can otherwise progress to pelvic inflammatory disease and tubal infertility; daily testing is not useful, antifungals do not treat chlamydia, and hysteroscopy is unrelated to managing cervicitis.

732. A 30-year-old woman presents with multiple soft, fleshy, cauliflower-like growths on the vulva. Biopsy is consistent with condyloma acuminatum. Which human papillomavirus types are most commonly responsible for these external genital warts?
     • HPV types 16 and 18
     • HPV types 6 and 11
     • HPV types 31 and 45
     • HPV types 1 and 2

     Correct answer: HPV types 6 and 11

     HPV types 6 and 11 cause most genital warts. These low-risk types are responsible for the majority of condyloma acuminatum, whereas high-risk types 16 and 18 (and others like 31 and 45) drive cervical and other anogenital cancers; types 1 and 2 cause common cutaneous warts rather than genital lesions.

733. A 62-year-old woman reports chronic vulvar itching, and exam reveals thin, white, parchment-like atrophic skin with a figure-eight distribution around the vulva and anus. Biopsy confirms the diagnosis. What is the first-line treatment for this lichen sclerosus?
     • Vulvectomy
     • Topical estrogen cream
     • Oral antifungal therapy
     • High-potency topical corticosteroids such as clobetasol

     Correct answer: High-potency topical corticosteroids such as clobetasol

     High-potency topical corticosteroids are first-line. Ultrapotent steroids such as clobetasol relieve symptoms and reduce scarring in lichen sclerosus, and patients require monitoring because of a small associated risk of vulvar squamous cell carcinoma; topical estrogen treats atrophy, antifungals treat candidiasis, and vulvectomy is far too aggressive for this benign condition.

734. A 70-year-old woman presents with a long-standing pruritic vulvar lesion that has become a firm, raised, ulcerated plaque on the labia majora. Biopsy is most likely to reveal which histology, the most common type of vulvar cancer?
     • Sarcoma
     • Squamous cell carcinoma
     • Melanoma
     • Adenocarcinoma

     Correct answer: Squamous cell carcinoma

     Squamous cell carcinoma is the most common vulvar cancer. The large majority of vulvar malignancies are squamous cell carcinomas, often arising in older women with chronic vulvar conditions or high-risk HPV; adenocarcinoma, melanoma, and sarcoma occur in the vulva but are far less common.

735. A 16-year-old girl presents with a rapidly enlarging unilateral adnexal mass and an elevated serum lactate dehydrogenase. Surgery reveals a solid ovarian tumor, and pathology shows sheets of uniform cells resembling primordial germ cells. Which ovarian tumor is most likely?
     • Dysgerminoma
     • Granulosa cell tumor
     • Brenner tumor
     • Serous cystadenocarcinoma

     Correct answer: Dysgerminoma

     Dysgerminoma is the most likely tumor. It is the most common malignant germ cell tumor of the ovary, occurs in young women, is often associated with elevated lactate dehydrogenase, and shows sheets of cells resembling primordial germ cells; serous cystadenocarcinoma and Brenner tumors are epithelial, and granulosa cell tumors are sex cord-stromal tumors producing estrogen.

736. A 24-year-old woman has an ovarian mass removed, and pathology describes a tumor containing hair, teeth, and sebaceous material derived from multiple germ layers. Which benign ovarian tumor is this?
     • Mature cystic teratoma (dermoid cyst)
     • Endometrioma
     • Theca lutein cyst
     • Krukenberg tumor

     Correct answer: Mature cystic teratoma (dermoid cyst)

     This is a mature cystic teratoma, or dermoid cyst. It is the most common benign ovarian germ cell tumor and contains tissues from multiple germ layers such as hair, teeth, and sebaceous glands; a Krukenberg tumor is a metastatic signet-ring tumor, an endometrioma contains old blood, and a theca lutein cyst is a functional cyst associated with high hCG states.

737. A 58-year-old woman with a history of gastric adenocarcinoma is found to have bilateral solid ovarian masses, and pathology shows mucin-filled signet-ring cells. Which diagnosis does this represent?
     • Krukenberg tumor
     • Mature teratoma
     • Primary serous ovarian carcinoma
     • Fibroma

     Correct answer: Krukenberg tumor

     A Krukenberg tumor is the diagnosis. This is a metastatic ovarian tumor, classically from a gastric or other gastrointestinal primary, characterized by mucin-secreting signet-ring cells and frequently bilateral involvement; a primary serous carcinoma, mature teratoma, and fibroma are primary ovarian tumors without signet-ring metastatic histology.

738. A 55-year-old woman is found to have a benign solid ovarian fibroma along with ascites and a right-sided pleural effusion, all of which resolve after the tumor is removed. Which eponymous syndrome describes this association?
     • Asherman syndrome
     • Sheehan syndrome
     • Meigs syndrome
     • Turner syndrome

     Correct answer: Meigs syndrome

     Meigs syndrome is the association. It is the classic triad of a benign ovarian fibroma, ascites, and pleural effusion that resolve after tumor removal; Asherman syndrome refers to intrauterine adhesions, Sheehan syndrome is postpartum pituitary necrosis, and Turner syndrome is a chromosomal disorder unrelated to this triad.

739. A 52-year-old postmenopausal woman presents with abnormal uterine bleeding and is found to have a solid ovarian mass; endometrial biopsy shows endometrial hyperplasia. Which ovarian tumor produces estrogen and can cause this endometrial change?
     • Mucinous cystadenoma
     • Granulosa cell tumor
     • Sertoli-Leydig cell tumor
     • Dysgerminoma

     Correct answer: Granulosa cell tumor

     A granulosa cell tumor is the answer. This estrogen-secreting sex cord-stromal tumor can cause endometrial hyperplasia or carcinoma and postmenopausal bleeding, and may be associated with elevated inhibin; a Sertoli-Leydig cell tumor secretes androgens causing virilization, while mucinous cystadenomas and dysgerminomas are not classically estrogenic.

740. A 30-year-old woman develops sudden right lower quadrant pain in the middle of her menstrual cycle, around day 14. The pain is mild to moderate, self-limited, and she has no fever, normal vital signs, and a negative pregnancy test. What is the most likely cause?
     • Appendicitis
     • Ovarian torsion
     • Mittelschmerz from ovulation
     • Ectopic pregnancy

     Correct answer: Mittelschmerz from ovulation

     Mittelschmerz is the most likely cause. Mid-cycle, self-limited unilateral pelvic pain around ovulation reflects follicular rupture and peritoneal irritation from follicular fluid; appendicitis causes progressive pain with systemic signs, ectopic pregnancy requires a positive pregnancy test, and ovarian torsion presents with severe persistent pain and an abnormal ultrasound.

741. A 26-year-old woman presents with sudden severe right lower quadrant pain after intercourse. Ultrasound shows a small amount of free fluid in the pelvis and a collapsed ovarian cyst, but normal ovarian Doppler flow, and she is hemodynamically stable with a negative pregnancy test. What is the most appropriate management?
     • Emergent laparotomy
     • Methotrexate therapy
     • Conservative management with analgesia and observation for a ruptured ovarian cyst
     • Immediate oophorectomy

     Correct answer: Conservative management with analgesia and observation for a ruptured ovarian cyst

     Conservative management is appropriate. A ruptured functional ovarian cyst in a stable patient with preserved ovarian flow and only a small amount of free fluid is managed with analgesia and observation; emergent surgery is reserved for hemodynamic instability or significant hemoperitoneum, methotrexate treats ectopic pregnancy, and oophorectomy is unnecessary.

742. A 48-year-old woman has heavy menstrual bleeding, and the clinician uses the standardized PALM-COEIN system to organize possible causes. Which of the following falls under the structural (PALM) category of this classification?
     • Leiomyoma
     • Coagulopathy
     • Ovulatory dysfunction
     • Iatrogenic causes

     Correct answer: Leiomyoma

     Leiomyoma is a structural cause. In the PALM-COEIN classification, the PALM categories are structural and include polyp, adenomyosis, leiomyoma, and malignancy or hyperplasia, while coagulopathy, ovulatory dysfunction, endometrial, iatrogenic, and not-otherwise-classified causes are the nonstructural COEIN group.

743. A 13-year-old girl is brought in by her mother because she has not yet started her menstrual periods. On exam she has Tanner stage 4 breast and pubic hair development. What is the most appropriate next step?
     • Start estrogen replacement therapy
     • Reassurance, as menarche typically follows breast development by about 2 to 3 years
     • Immediate karyotype analysis
     • Order an urgent pelvic MRI

     Correct answer: Reassurance, as menarche typically follows breast development by about 2 to 3 years

     Reassurance is appropriate. Menarche normally occurs roughly 2 to 3 years after the onset of breast development (thelarche), so advanced pubertal staging at 13 without menses is within the normal sequence; an evaluation for primary amenorrhea is reserved for age 15 with secondary sexual characteristics or absence of breast development by 13.

744. A 28-year-old woman with secondary amenorrhea and bilateral milky nipple discharge is found to have an elevated serum prolactin and a normal TSH and pregnancy test. MRI reveals a small pituitary adenoma. What is the most appropriate first-line treatment?
     • A dopamine agonist such as cabergoline
     • Levothyroxine
     • Transsphenoidal surgery
     • Combined oral contraceptives alone

     Correct answer: A dopamine agonist such as cabergoline

     A dopamine agonist is first-line. Cabergoline or bromocriptine lowers prolactin, shrinks most prolactinomas, and restores menses and ovulation, making it the preferred initial therapy; surgery is reserved for medication-resistant or large symptomatic tumors, levothyroxine treats hypothyroidism, and oral contraceptives do not address the underlying hyperprolactinemia.

745. A 17-year-old girl has never had a menstrual period and lacks breast development. She also reports she cannot smell, and laboratory testing shows low gonadotropins with low estrogen. Which diagnosis best explains anosmia with hypogonadotropic hypogonadism?
     • Turner syndrome
     • Kallmann syndrome
     • Polycystic ovary syndrome
     • Premature ovarian insufficiency

     Correct answer: Kallmann syndrome

     Kallmann syndrome is the diagnosis. It is hypogonadotropic hypogonadism caused by deficient gonadotropin-releasing hormone with associated anosmia from defective olfactory and GnRH neuron migration; Turner syndrome and premature ovarian insufficiency cause elevated gonadotropins, and polycystic ovary syndrome does not present with anosmia or absent puberty.

746. A 30-year-old woman with amenorrhea, hot flashes, and vaginal dryness is found to have an elevated FSH on two occasions and is diagnosed with premature ovarian insufficiency. Aside from fertility implications, which long-term health risk is most increased by her early estrogen deficiency, warranting hormone therapy until the typical age of menopause?
     • Hyperthyroidism
     • Colon cancer
     • Osteoporosis
     • Peptic ulcer disease

     Correct answer: Osteoporosis

     Osteoporosis is the key risk. Estrogen deficiency from premature ovarian insufficiency accelerates bone loss and also raises cardiovascular risk, so hormone therapy is generally recommended until about age 50 to protect bone and cardiovascular health; hyperthyroidism, colon cancer, and peptic ulcer disease are not driven by this estrogen deficiency.

747. A 55-year-old woman with postmenopausal bleeding undergoes endometrial biopsy showing endometrial adenocarcinoma. Which of the following is the strongest risk factor for the most common (type I, endometrioid) endometrial cancer?
     • Long-term combined oral contraceptive use
     • Unopposed estrogen exposure from obesity and chronic anovulation
     • Multiparity
     • A diet high in fiber

     Correct answer: Unopposed estrogen exposure from obesity and chronic anovulation

     Unopposed estrogen exposure is the strongest risk factor. Conditions that raise estrogen without adequate progesterone, such as obesity, chronic anovulation, and nulliparity, drive type I endometrioid endometrial cancer; multiparity and combined oral contraceptives are actually protective, and a high-fiber diet is not a recognized risk factor.

748. A 35-year-old woman has a cervical cytology result showing a high-grade squamous intraepithelial lesion. What is the most appropriate next step in her management?
     • Colposcopy with directed biopsy
     • Reassurance with no further testing
     • Repeat cytology in 3 years
     • Immediate hysterectomy

     Correct answer: Colposcopy with directed biopsy

     Colposcopy with directed biopsy is the next step. A high-grade squamous intraepithelial lesion on cytology carries a substantial risk of underlying cervical precancer or cancer and requires colposcopic evaluation with biopsy to guide treatment; routine repeat cytology, hysterectomy without diagnosis, and reassurance would all be inappropriate for a high-grade result.

749. A 29-year-old woman with biopsy-confirmed cervical intraepithelial neoplasia grade 3 (CIN 3) wishes to preserve fertility. Which procedure is an appropriate excisional treatment for this high-grade cervical precancer?
     • Pelvic exenteration
     • Total abdominal hysterectomy
     • Bilateral salpingo-oophorectomy
     • Loop electrosurgical excision procedure (LEEP)

     Correct answer: Loop electrosurgical excision procedure (LEEP)

     A loop electrosurgical excision procedure is appropriate. LEEP or cold-knife conization excises the transformation zone to treat CIN 3 while preserving the uterus and fertility; hysterectomy removes the uterus, bilateral salpingo-oophorectomy removes the ovaries and tubes, and pelvic exenteration is a radical operation reserved for advanced recurrent cancer.

750. A 42-year-old woman has bothersome heavy menstrual bleeding from a submucosal uterine fibroid distorting the endometrial cavity. She has completed childbearing but wishes to avoid hysterectomy, and a uterine-conserving outpatient procedure is considered. Which intervention is best suited to resect a submucosal fibroid through the cervix?
     • Hysteroscopic myomectomy
     • Abdominal hysterectomy
     • Endometrial ablation alone
     • Diagnostic laparoscopy

     Correct answer: Hysteroscopic myomectomy

     Hysteroscopic myomectomy is best suited. A submucosal fibroid projecting into the cavity can be resected transcervically under hysteroscopic guidance, preserving the uterus; hysterectomy removes the uterus entirely, endometrial ablation does not remove a distorting submucosal fibroid, and diagnostic laparoscopy is not a resection technique for an intracavitary fibroid.

751. A 25-year-old woman at 14 weeks gestation with a complete molar pregnancy has a markedly enlarged uterus and very high beta-hCG, and ultrasound shows bilateral multicystic ovarian enlargement. Which type of ovarian cyst accounts for this finding?
     • Dermoid cysts
     • Endometriomas
     • Theca lutein cysts from high hCG stimulation
     • Corpus luteum cyst of pregnancy

     Correct answer: Theca lutein cysts from high hCG stimulation

     Theca lutein cysts are responsible. Very high beta-hCG levels, as seen in molar pregnancy or multiple gestation, hyperstimulate the ovaries to form bilateral multicystic theca lutein cysts that regress as hCG falls; endometriomas and dermoids are unrelated to hCG, and a corpus luteum cyst is typically a single functional cyst.

752. A 23-year-old woman with a history of a complete hydatidiform mole now has a rising beta-hCG and a new lung lesion on imaging with vaginal metastases. Which malignancy of trophoblastic origin is most likely?
     • Choriocarcinoma
     • Cervical squamous cell carcinoma
     • Endometrial adenocarcinoma
     • Ovarian dysgerminoma

     Correct answer: Choriocarcinoma

     Choriocarcinoma is most likely. This aggressive trophoblastic malignancy can follow a molar pregnancy, produces beta-hCG, and characteristically spreads hematogenously to the lungs and vagina; endometrial and cervical carcinomas and ovarian dysgerminoma do not arise from trophoblast or follow this molar-to-metastatic pattern.

753. A 19-year-old woman at 8 weeks gestation has vaginal bleeding and passage of grape-like vesicular tissue. Beta-hCG is markedly elevated and ultrasound shows a snowstorm pattern with no fetus. Compared with a partial mole, which karyotype is characteristic of this complete mole?
     • 69,XXY triploid
     • 45,X
     • 47,XX,+21
     • 46,XX of entirely paternal origin

     Correct answer: 46,XX of entirely paternal origin

     A 46,XX entirely paternal karyotype is characteristic of a complete mole. It results from fertilization of an empty ovum so that all chromosomes are paternal with no fetal tissue; a triploid 69,XXY karyotype with some fetal tissue characterizes a partial mole, while 45,X is Turner syndrome and 47,XX,+21 is Down syndrome, neither of which describes a complete mole.

754. A 16-year-old girl presents with severe crampy pelvic pain with her periods that has been present since menarche, with a normal pelvic exam and no abnormalities on imaging. Which underlying mediator is primarily responsible for her primary dysmenorrhea?
     • An estrogen-secreting ovarian tumor
     • Excess prostaglandin production by the endometrium
     • Bacterial endometrial infection
     • Elevated thyroid hormone

     Correct answer: Excess prostaglandin production by the endometrium

     Excess prostaglandins are the primary mediator. In primary dysmenorrhea, endometrial prostaglandins trigger strong uterine contractions and ischemia causing cramping pain, which is why prostaglandin-inhibiting NSAIDs are effective; infection, hormone-secreting tumors, and thyroid disease are not the mechanism of primary dysmenorrhea.

755. A 34-year-old breastfeeding woman with persistent unilateral breast inflammation that does not improve after appropriate antibiotics and abscess drainage, with no fluctuant collection on repeat imaging, is concerning for a malignancy that can mimic infection. Which breast cancer presents with a red, warm, swollen breast with peau d'orange skin changes?
     • Inflammatory breast cancer
     • Phyllodes tumor
     • Lobular carcinoma in situ
     • Ductal carcinoma in situ

     Correct answer: Inflammatory breast cancer

     Inflammatory breast cancer is the concern. It presents with a rapidly progressive erythematous, warm, edematous breast and peau d'orange from dermal lymphatic invasion and can be mistaken for mastitis, so failure to respond to antibiotics warrants biopsy; ductal and lobular carcinoma in situ are noninvasive and usually asymptomatic, and a phyllodes tumor presents as a discrete enlarging mass.

756. A 22-year-old woman has a firm, smooth, mobile, nontender breast mass that is well-circumscribed on ultrasound. It is the most common benign solid breast tumor in young women. Which diagnosis is most likely?
     • Breast abscess
     • Fibroadenoma
     • Fat necrosis
     • Invasive ductal carcinoma

     Correct answer: Fibroadenoma

     A fibroadenoma is most likely. It is the most common benign solid breast tumor in young women, presenting as a firm, smooth, mobile, painless, well-circumscribed mass; invasive ductal carcinoma is typically hard, fixed, and irregular, an abscess is tender and fluctuant, and fat necrosis usually follows trauma or surgery.

757. A 45-year-old woman reports a breast lump that appeared after a seatbelt injury in a car accident. On exam there is a firm, irregular area with overlying skin retraction, and mammography shows oil cysts and calcifications. Biopsy shows fat necrosis. Which feature makes careful evaluation important in this case?
     • Fat necrosis always becomes malignant
     • Fat necrosis requires chemotherapy
     • Fat necrosis can mimic carcinoma on exam and imaging
     • Fat necrosis is contagious

     Correct answer: Fat necrosis can mimic carcinoma on exam and imaging

     Fat necrosis can mimic carcinoma. It may produce a firm irregular mass with skin retraction and suspicious calcifications that resemble cancer, so biopsy is often needed to confirm the benign diagnosis after trauma or surgery; it is benign and self-limited, does not require chemotherapy, is not contagious, and does not inevitably become malignant.

758. A 50-year-old woman has a newly diagnosed invasive breast cancer, and pathology reports the tumor is estrogen receptor positive and HER2 negative. Which class of adjuvant systemic therapy specifically targets this receptor status?
     • Topical corticosteroids
     • Trastuzumab monotherapy
     • Broad-spectrum antibiotics
     • Endocrine (hormonal) therapy such as tamoxifen or an aromatase inhibitor

     Correct answer: Endocrine (hormonal) therapy such as tamoxifen or an aromatase inhibitor

     Endocrine therapy is the targeted treatment. Estrogen receptor-positive tumors respond to hormonal therapy such as tamoxifen in premenopausal women or aromatase inhibitors in postmenopausal women; trastuzumab targets HER2-positive disease, which this tumor lacks, and antibiotics and topical steroids have no role in treating breast cancer.

759. A 27-year-old woman at 35 weeks gestation is found to have a fetus measuring large for gestational age. Which maternal condition is the most common cause of fetal macrosomia?
     • Maternal hypertension
     • Maternal diabetes
     • Maternal hypothyroidism
     • Maternal anemia

     Correct answer: Maternal diabetes

     Maternal diabetes is the most common cause. Maternal hyperglycemia drives fetal hyperinsulinemia and excessive growth, making pregestational and gestational diabetes the leading identifiable cause of macrosomia; maternal anemia and hypertension are more often associated with growth restriction, and hypothyroidism does not characteristically cause macrosomia.

760. A 30-year-old woman delivered a macrosomic infant after gestational diabetes. She is counseled about postpartum follow-up. When is she recommended to undergo a 75-gram oral glucose tolerance test to screen for persistent diabetes?
     • Never, since gestational diabetes always resolves
     • At about 4 to 12 weeks postpartum
     • Immediately at delivery
     • At 5 years postpartum

     Correct answer: At about 4 to 12 weeks postpartum

     Screening at 4 to 12 weeks postpartum is recommended. A 75-gram oral glucose tolerance test in this window detects persistent type 2 diabetes or impaired glucose tolerance after gestational diabetes, with ongoing periodic screening thereafter; testing at delivery is too early to reflect the postpartum state, waiting 5 years delays detection, and the elevated lifetime risk means screening is not omitted.

761. A 38-year-old woman at 12 weeks gestation with advanced maternal age has a positive cell-free DNA screen suggesting trisomy 21. She wants a definitive diagnostic test at this gestational age. Which procedure is most appropriate now?
     • Repeat cell-free DNA
     • A second-trimester quad screen
     • Chorionic villus sampling
     • Amniocentesis only at 20 weeks

     Correct answer: Chorionic villus sampling

     Chorionic villus sampling is most appropriate at this stage. It is an invasive diagnostic test available in the first trimester (about 10 to 13 weeks) that provides a fetal karyotype to confirm a positive screen; amniocentesis is diagnostic but performed later in the second trimester, and repeat cell-free DNA or a quad screen are screening tests rather than diagnostic confirmation.

762. A 28-year-old woman at 11 weeks gestation undergoes first-trimester ultrasound, and an increased nuchal translucency measurement is reported. What does an increased nuchal translucency primarily indicate?
     • Normal pregnancy with no further follow-up needed
     • An increased risk of fetal aneuploidy and cardiac defects warranting further testing
     • Confirmed Down syndrome requiring termination
     • Imminent miscarriage

     Correct answer: An increased risk of fetal aneuploidy and cardiac defects warranting further testing

     Increased nuchal translucency indicates elevated risk. A thickened nuchal translucency is a soft marker associated with aneuploidies such as trisomy 21 and with congenital heart defects, prompting additional screening or diagnostic testing; it is not diagnostic of Down syndrome by itself, does not indicate a normal pregnancy needing no follow-up, and does not mean imminent miscarriage.

763. A 32-year-old woman at 36 weeks gestation in a dichorionic twin pregnancy with both fetuses in vertex presentation and no complications is counseled about delivery. What is the most appropriate counseling regarding mode of delivery?
     • External cephalic version is required first
     • Vaginal delivery is contraindicated because of twin A being vertex
     • Cesarean delivery is mandatory for all twin pregnancies
     • A trial of vaginal delivery is reasonable when the presenting twin is vertex

     Correct answer: A trial of vaginal delivery is reasonable when the presenting twin is vertex

     A trial of vaginal delivery is reasonable. When the presenting twin is vertex in an otherwise uncomplicated twin pregnancy, vaginal birth can be attempted; twins are not an automatic indication for cesarean, a vertex presenting twin favors rather than contraindicates vaginal delivery, and external cephalic version of an already vertex presenting twin is unnecessary.

764. A 33-year-old woman at 18 weeks gestation in a monochorionic diamniotic twin pregnancy is found to have one twin with polyhydramnios and a large bladder and the other with oligohydramnios and a small bladder, described as a stuck twin. Which advanced therapy targets the underlying placental vascular connections in severe twin-twin transfusion syndrome?
     • Therapeutic maternal phlebotomy
     • Bed rest only
     • Fetoscopic laser photocoagulation of placental anastomoses
     • Maternal corticosteroids alone

     Correct answer: Fetoscopic laser photocoagulation of placental anastomoses

     Fetoscopic laser photocoagulation is the targeted therapy. In severe twin-twin transfusion syndrome, laser ablation of the shared placental vascular anastomoses interrupts the abnormal blood flow between the twins and improves outcomes; corticosteroids, maternal phlebotomy, and bed rest do not address the underlying placental connections driving the syndrome.

765. A 26-year-old woman at 39 weeks gestation has been fully dilated and pushing for two hours, and the fetal head is visible at the introitus with a reassuring tracing, but maternal exhaustion limits further pushing. The station is +3 and the position is occiput anterior. Which assisted delivery option is appropriate when criteria for a safe operative vaginal delivery are met?
     • External cephalic version
     • Fundal pressure as the definitive maneuver
     • Vacuum-assisted or forceps-assisted vaginal delivery
     • Immediate classical cesarean

     Correct answer: Vacuum-assisted or forceps-assisted vaginal delivery

     Operative vaginal delivery is appropriate. With the cervix fully dilated, membranes ruptured, the head engaged at a low station in a known position, and a reassuring tracing, vacuum or forceps can safely assist delivery; fundal pressure is not a definitive delivery maneuver, external cephalic version applies to malpresentation before labor, and cesarean is not required when operative vaginal criteria are met.

766. A 24-year-old woman in active labor has a fetal scalp electrode in place, and the obstetrician obtains a fetal scalp blood sample to assess acid-base status when the tracing is concerning. Which fetal scalp pH value is generally considered reassuring?
     • A pH of 7.25 or higher
     • A pH of 7.10
     • A pH below 7.0
     • A pH of 6.9

     Correct answer: A pH of 7.25 or higher

     A fetal scalp pH of 7.25 or higher is reassuring. Values at or above 7.25 generally indicate adequate fetal oxygenation, whereas a pH below 7.20 is concerning and below 7.0 reflects significant acidemia warranting expedited delivery; values like 7.10 or 6.9 indicate worsening acidosis rather than reassurance.

767. Immediately after delivery, umbilical cord blood gas analysis is performed on a depressed newborn. A markedly low umbilical artery pH with a high base deficit indicates which condition?
     • Significant intrapartum metabolic acidemia
     • Normal newborn acid-base status
     • Maternal hyperventilation with no fetal effect
     • Respiratory alkalosis only

     Correct answer: Significant intrapartum metabolic acidemia

     A low umbilical artery pH with a high base deficit reflects significant metabolic acidemia. This pattern indicates the fetus experienced impaired oxygen delivery during labor with anaerobic metabolism and lactate accumulation; it is not a normal result, is not a pure respiratory alkalosis, and reflects a true fetal disturbance rather than an isolated maternal effect.

768. A 29-year-old woman at 38 weeks gestation has a fetus that on Leopold maneuvers and ultrasound is in complete breech presentation, and she is in early labor. She has had no antenatal version. Considering current obstetric practice for a term singleton breech in labor, which mode of delivery is generally recommended?
     • Immediate external cephalic version during active labor
     • Vacuum-assisted vaginal delivery
     • Routine vaginal breech delivery for all
     • Planned cesarean delivery

     Correct answer: Planned cesarean delivery

     Planned cesarean delivery is generally recommended. For most term singleton breech presentations, planned cesarean reduces perinatal risk compared with routine vaginal breech delivery; external cephalic version is attempted before labor rather than during active labor, and vacuum extraction is not used for a breech presenting part.

769. A 31-year-old woman at 40 weeks gestation has prelabor rupture of membranes at term with clear fluid, a reassuring fetal heart tracing, and is group B Streptococcus negative, but she is not yet contracting after several hours. What is the most appropriate management?
     • Immediate cesarean delivery
     • Induction of labor with oxytocin
     • Expectant management for one week
     • Therapeutic tocolysis

     Correct answer: Induction of labor with oxytocin

     Induction of labor is appropriate. At term with ruptured membranes and no spontaneous labor, induction (commonly with oxytocin) reduces the risk of infection compared with prolonged expectant management; cesarean is not indicated without an obstetric reason, waiting a week increases infection risk, and tocolysis would inappropriately suppress labor.

770. A 25-year-old woman at 30 weeks gestation with a singleton pregnancy reports decreased fetal movement, and a nonstress test is nonreactive after 40 minutes despite vibroacoustic stimulation. What is the most appropriate next step?
     • Proceed immediately to cesarean delivery
     • Begin magnesium sulfate
     • Reassure and discharge with no further testing
     • Perform a biophysical profile or contraction stress test for further assessment

     Correct answer: Perform a biophysical profile or contraction stress test for further assessment

     Further assessment with a biophysical profile or contraction stress test is appropriate. A nonreactive nonstress test is not by itself diagnostic of fetal compromise, so additional testing clarifies fetal status before deciding on delivery; immediate cesarean is premature without confirmation, discharge ignores a concerning result, and magnesium is not indicated here.

771. A 23-year-old woman at 28 weeks gestation reports a recent exposure to a child with chickenpox, and she has no history of varicella or vaccination, with negative varicella IgG. What is the most appropriate intervention to reduce her risk of severe maternal varicella?
     • The live varicella vaccine now
     • No intervention is available
     • Oral valacyclovir prophylaxis indefinitely
     • Varicella-zoster immune globulin

     Correct answer: Varicella-zoster immune globulin

     Varicella-zoster immune globulin is appropriate. A nonimmune pregnant woman with significant varicella exposure should receive immune globulin promptly to reduce the risk of severe maternal varicella, which can include life-threatening pneumonia; the live vaccine is contraindicated during pregnancy, and immune globulin is the recommended postexposure measure rather than no intervention.

772. A 30-year-old woman at 12 weeks gestation is found to be hepatitis B surface antigen positive. To reduce perinatal transmission, what should be done for her newborn at birth?
     • Perform an immediate cesarean to prevent transmission
     • Give only oral antivirals to the infant
     • Administer hepatitis B vaccine and hepatitis B immune globulin
     • Withhold all immunization until 6 months

     Correct answer: Administer hepatitis B vaccine and hepatitis B immune globulin

     The newborn should receive both hepatitis B vaccine and immune globulin. Giving the vaccine plus hepatitis B immune globulin within hours of birth provides active and passive immunization that markedly reduces perinatal transmission from a surface antigen-positive mother; delaying immunization misses the critical window, cesarean does not reliably prevent transmission, and oral antivirals alone are not the neonatal prophylaxis.

773. A 34-year-old woman is scheduled for an elective laparoscopic cholecystectomy. Before she signs the consent form, what must the surgeon disclose for the consent to be considered valid informed consent?
     • Only the name of the procedure and the expected recovery time
     • The diagnosis, nature of the procedure, material risks and benefits, and reasonable alternatives including no treatment
     • Only the risks that are likely to cause death or permanent disability
     • The hospital's billing policy and the surgeon's complication statistics for the past year

     Correct answer: The diagnosis, nature of the procedure, material risks and benefits, and reasonable alternatives including no treatment

     The answer is disclosure of the diagnosis, nature of the procedure, material risks and benefits, and reasonable alternatives including no treatment. Valid informed consent requires that the patient understand what is wrong, what is proposed, the meaningful risks and benefits, and the available alternatives so the decision is genuinely informed and voluntary.

774. A 27-year-old man with appendicitis agrees to surgery after the surgeon explains the procedure, its risks, and the option of antibiotic therapy alone. Which element of informed consent does the discussion of antibiotic therapy specifically satisfy?
     • Voluntariness
     • Decision-making capacity
     • Disclosure of reasonable alternatives
     • Documentation requirement

     Correct answer: Disclosure of reasonable alternatives

     The answer is disclosure of reasonable alternatives. Presenting antibiotic therapy as another reasonable option addresses the requirement that the physician describe alternative courses of action, including their risks and benefits, so the patient can weigh choices.

775. A 19-year-old college student with intact mental status declines a recommended blood transfusion for symptomatic anemia after the physician carefully explains the risks of refusal. The physician believes the transfusion would clearly benefit him. What is the most appropriate next step?
     • Obtain a court order to compel the transfusion
     • Respect the patient's informed refusal and continue to offer supportive care
     • Ask the patient's parents to authorize the transfusion on his behalf
     • Sedate the patient and proceed with the transfusion in his best interest

     Correct answer: Respect the patient's informed refusal and continue to offer supportive care

     The answer is to respect the patient's informed refusal and continue supportive care. An adult with decision-making capacity has the right to refuse treatment even when refusal carries serious risk, and a properly informed refusal is the flip side of informed consent.

776. A surgeon obtains a patient's signature on a consent form by stating only that the operation is 'routine and very safe' without mentioning the risk of bowel injury, which is a recognized complication of the procedure. The patient later experiences a bowel injury. What deficiency best characterizes this consent process?
     • Inadequate disclosure of material risks
     • Lack of voluntariness
     • Absence of patient capacity
     • Failure to obtain a witness signature

     Correct answer: Inadequate disclosure of material risks

     The answer is inadequate disclosure of material risks. Informed consent requires disclosing risks that a reasonable patient would consider significant; omitting a recognized complication like bowel injury makes the consent legally and ethically deficient regardless of the signed form.

777. A previously healthy 45-year-old man is brought to the emergency department unconscious after a motor vehicle collision and has a tension pneumothorax requiring immediate needle decompression. No family is available. Under what principle may the physician proceed without obtaining signed consent?
     • Therapeutic privilege
     • Waiver of consent for research
     • Substituted judgment
     • Implied consent in an emergency

     Correct answer: Implied consent in an emergency

     The answer is implied consent in an emergency. When a patient lacks capacity, faces an immediate threat to life or limb, and no surrogate is available, consent is presumed because a reasonable person would want life-saving treatment, allowing the physician to act without delay.

778. During a clinic visit, a 60-year-old woman says, 'Just do whatever you think is best, doctor; I don't want to hear the details.' She has capacity and is not coerced. Which statement best describes the ethical handling of informed consent here?
     • Consent is invalid because she did not review the risks herself
     • A competent patient may waive the right to detailed disclosure
     • The physician must withhold the procedure until she reviews all risks
     • The physician should have a family member receive the disclosure instead

     Correct answer: A competent patient may waive the right to detailed disclosure

     The answer is that a competent patient may waive the right to detailed disclosure. A patient with capacity can voluntarily decline to receive specific risk information; the physician should document the waiver and confirm she understands she can change her mind and ask questions at any time.

779. A physician is deciding who must personally obtain informed consent for a complex spinal surgery. According to standard professional expectations, who is responsible for the informed consent discussion?
     • The nurse who hands the patient the consent form
     • Any available staff member, since the form is what matters
     • The hospital's billing department
     • The physician who will perform the procedure or who is appropriately knowledgeable about it

     Correct answer: The physician who will perform the procedure or who is appropriately knowledgeable about it

     The answer is the physician who will perform the procedure or who is appropriately knowledgeable about it. Informed consent is a physician-patient communication process, not merely a signature; the practitioner performing or directly responsible for the intervention should conduct the discussion.

780. A 16-year-old comes to a clinic alone requesting testing and treatment for a sexually transmitted infection and asks that her parents not be told. In most U.S. jurisdictions, what is the most appropriate approach to consent?
     • Refuse care until a parent provides consent
     • Treat only after obtaining a court order
     • Notify the parents immediately because she is a minor
     • Provide confidential evaluation and treatment under minor consent provisions for sexually transmitted infections

     Correct answer: Provide confidential evaluation and treatment under minor consent provisions for sexually transmitted infections

     The answer is to provide confidential evaluation and treatment under minor consent provisions. Most states allow minors to consent for diagnosis and treatment of sexually transmitted infections without parental involvement to remove barriers to care, so the adolescent can be treated confidentially.

781. A 70-year-old man with metastatic cancer asks his physician to make all of his medical decisions because he trusts the physician completely and finds the choices overwhelming. He clearly understands his situation. What does this scenario most directly illustrate about informed consent?
     • He lacks decision-making capacity and needs a surrogate
     • Consent is invalid whenever a patient defers to the physician
     • A patient with capacity may delegate decision-making to the physician through informed choice
     • The physician must refuse to make any decisions for the patient

     Correct answer: A patient with capacity may delegate decision-making to the physician through informed choice

     The answer is that a patient with capacity may delegate decision-making to the physician through informed choice. Choosing to entrust decisions to a trusted physician is itself an autonomous decision; the physician should confirm understanding, periodically check the patient's wishes, and act in his best interest.

782. Which statement most accurately distinguishes informed consent from a signed consent form?
     • Informed consent is a communication process, and the form merely documents it
     • A signed form is always sufficient proof that informed consent occurred
     • Informed consent and the consent form are legally identical
     • The form replaces the need for any discussion of risks

     Correct answer: Informed consent is a communication process, and the form merely documents it

     The answer is that informed consent is a communication process, and the form merely documents it. The signature records that a discussion took place, but valid consent depends on adequate disclosure, the patient's understanding, capacity, and voluntariness rather than on the paperwork alone.

783. A hospital convenes a multidisciplinary team after a patient received a tenfold insulin overdose to systematically identify why the error happened and what underlying system failures contributed. This structured retrospective investigation is best described as which patient-safety method?
     • Failure mode and effects analysis
     • Root cause analysis
     • Plan-do-study-act cycle
     • Peer review for disciplinary action

     Correct answer: Root cause analysis

     The answer is root cause analysis. Root cause analysis is a structured, retrospective review performed after an adverse event to uncover the underlying system and process failures that led to harm, rather than focusing on blaming individuals.

784. A quality team conducting a root cause analysis of a medication error repeatedly asks 'why' at each step until they reach a deficiency in the medication ordering system. What is the primary goal of identifying this underlying factor?
     • To assign disciplinary blame to the prescriber
     • To redesign the system so the same error is less likely to recur
     • To document the event for billing purposes
     • To determine the financial liability of the hospital

     Correct answer: To redesign the system so the same error is less likely to recur

     The answer is to redesign the system so the same error is less likely to recur. Root cause analysis aims to find correctable system-level causes and implement preventive changes, reflecting a non-punitive, systems-based approach to safety improvement.

785. Which feature most distinguishes root cause analysis from failure mode and effects analysis in patient safety work?
     • Root cause analysis is proactive while failure mode and effects analysis is retrospective
     • Both are performed only after a patient death
     • Root cause analysis is retrospective after an event, while failure mode and effects analysis is proactive before harm occurs
     • Failure mode and effects analysis assigns individual blame while root cause analysis does not

     Correct answer: Root cause analysis is retrospective after an event, while failure mode and effects analysis is proactive before harm occurs

     The answer is that root cause analysis is retrospective after an event, while failure mode and effects analysis is proactive before harm occurs. Root cause analysis investigates an error that already happened, whereas failure mode and effects analysis anticipates how a process could fail in order to prevent harm in advance.

786. After a surgical fire, a hospital's root cause analysis team includes representatives from surgery, anesthesia, nursing, biomedical engineering, and risk management. Why is this interdisciplinary composition important?
     • To ensure enough people are available to assign individual blame
     • To satisfy a requirement that ten people attend every meeting
     • To capture the perspectives needed to understand all system contributors to the event
     • To guarantee the analysis remains confidential from the patient

     Correct answer: To capture the perspectives needed to understand all system contributors to the event

     The answer is to capture the perspectives needed to understand all system contributors to the event. Adverse events usually arise from multiple interacting process and human factors, so an interdisciplinary team can map the full sequence of contributing causes that a single discipline might miss.

787. During a root cause analysis, the team concludes that a nurse administered the wrong dose because two medication vials had nearly identical labels stored side by side. What type of contributing factor does this finding represent?
     • An individual competency failure requiring retraining of that nurse only
     • An unavoidable random event with no preventable cause
     • A deliberate violation of policy
     • A latent system condition that predisposed to error

     Correct answer: A latent system condition that predisposed to error

     The answer is a latent system condition that predisposed to error. Look-alike packaging stored together is an underlying design flaw that sets up well-meaning clinicians to fail; correcting it (for example, separating or relabeling the vials) addresses the true root cause rather than the individual.

788. A patient-safety officer explains James Reason's model in which multiple layers of defense each have holes, and harm reaches the patient only when the holes momentarily align. Which model is being described?
     • The biopsychosocial model
     • The germ theory of disease
     • The Swiss cheese model of accident causation
     • The health belief model

     Correct answer: The Swiss cheese model of accident causation

     The answer is the Swiss cheese model of accident causation. This model depicts safety defenses as slices of cheese with holes representing weaknesses; an adverse event occurs only when holes in successive layers line up, allowing a hazard to pass through all defenses.

789. Using the Swiss cheese model, a hospital adds an independent pharmacist verification step and a barcode scan to its medication process. What is the safety rationale for adding these layers?
     • A single perfect barrier is more reliable than several imperfect ones
     • Adding layers eliminates the need to investigate errors
     • Multiple independent defenses make it less likely that all of their weaknesses align to allow harm
     • Each new layer guarantees zero errors on its own

     Correct answer: Multiple independent defenses make it less likely that all of their weaknesses align to allow harm

     The answer is that multiple independent defenses make it less likely that all of their weaknesses align to allow harm. In the Swiss cheese model, no single barrier is flawless, but layering several independent checks reduces the probability that a hazard passes through every gap simultaneously.

790. In the Swiss cheese model, the 'holes' in each defensive layer are best understood as representing what?
     • Active failures and latent conditions that weaken a defense
     • Patients who refuse treatment
     • The number of staff on a unit
     • Billing errors unrelated to clinical care

     Correct answer: Active failures and latent conditions that weaken a defense

     The answer is active failures and latent conditions that weaken a defense. The holes symbolize the unsafe acts at the sharp end and the hidden organizational or design flaws that, when aligned, permit a hazard to cause harm.

791. A risk manager argues that focusing only on punishing the last person who touched a process before an error is inconsistent with the Swiss cheese model. Why is this argument consistent with the model?
     • Because the model holds that errors are always intentional
     • Because the model recommends removing all human involvement in care
     • Because the model attributes harm to alignment of multiple system weaknesses, not a single individual
     • Because the model states that only the final actor can cause harm

     Correct answer: Because the model attributes harm to alignment of multiple system weaknesses, not a single individual

     The answer is that the model attributes harm to alignment of multiple system weaknesses, not a single individual. The Swiss cheese model emphasizes that adverse events result from many failed defenses lining up, so blaming the last clinician ignores the upstream latent conditions that allowed the error.

792. A clinician fully disclosing to a patient that an error occurred during care is acting on which professional and ethical obligation?
     • The duty of honesty and transparency with patients about errors that affect them
     • The duty to maximize hospital reputation
     • The duty to avoid documenting any complications
     • The duty to defer all communication to the legal department

     Correct answer: The duty of honesty and transparency with patients about errors that affect them

     The answer is the duty of honesty and transparency with patients about errors that affect them. Professionalism and patient autonomy require timely, truthful disclosure of harmful errors so patients can make informed decisions and the therapeutic relationship is preserved.

793. A resident administers a medication to which the patient has a documented allergy, and the patient develops a rash that resolves. The resident is anxious about telling the patient. What is the most appropriate course of action?
     • Avoid mentioning it since the rash resolved without lasting harm
     • Document it only in the chart but not tell the patient
     • Promptly and honestly disclose the error to the patient, express concern, and explain the plan
     • Tell the patient only if the patient specifically asks

     Correct answer: Promptly and honestly disclose the error to the patient, express concern, and explain the plan

     The answer is to promptly and honestly disclose the error to the patient, express concern, and explain the plan. Errors that reach and affect a patient should be disclosed regardless of whether harm is permanent, because honesty respects autonomy and maintains trust.

794. When disclosing a harmful medical error to a patient, which combination of elements is most consistent with recommended disclosure practice?
     • A vague acknowledgment with no apology and no plan
     • An explanation of what happened, an expression of empathy or apology, and a description of next steps
     • A statement blaming another department to protect oneself
     • A refusal to discuss the event until litigation concludes

     Correct answer: An explanation of what happened, an expression of empathy or apology, and a description of next steps

     The answer is an explanation of what happened, an expression of empathy or apology, and a description of next steps. Effective error disclosure provides factual information about the event, acknowledges the patient's experience with sincere empathy, and outlines how care will proceed and how recurrence will be prevented.

795. A senior physician tells a junior colleague that disclosing errors to patients should be avoided because it invites lawsuits. Which evidence-based response best refutes this view?
     • Disclosure has no effect on patient trust or litigation
     • Honest, empathetic disclosure tends to preserve trust and is ethically required even when harm occurred
     • Patients prefer not to be told about errors that affect them
     • Concealing errors is the standard recommended by professional bodies

     Correct answer: Honest, empathetic disclosure tends to preserve trust and is ethically required even when harm occurred

     The answer is that honest, empathetic disclosure tends to preserve trust and is ethically required even when harm occurred. Transparent communication maintains the therapeutic relationship and respects the patient's right to know, and concealment violates core professional duties.

796. A 58-year-old man hospitalized for pneumonia receives a unit of red blood cells intended for another patient due to a labeling mix-up. He shows no immediate reaction but the error is recognized. What is the physician's primary obligation regarding communication?
     • Wait to see if a delayed reaction develops before saying anything
     • Inform only the hospital risk-management team
     • Disclose the transfusion error to the patient and explain monitoring and follow-up
     • Tell the patient a different unit was given to avoid alarm

     Correct answer: Disclose the transfusion error to the patient and explain monitoring and follow-up

     The answer is to disclose the transfusion error to the patient and explain monitoring and follow-up. The patient was directly involved in an error with potential health implications, so prompt truthful disclosure with a clear monitoring plan is ethically required even if no reaction has yet occurred.

797. Decision-making capacity, as assessed by a treating physician, requires that a patient can do all of the following EXCEPT which one?
     • Be formally adjudicated competent by a judge
     • Understand the relevant information
     • Appreciate the situation and its consequences
     • Communicate a choice

     Correct answer: Be formally adjudicated competent by a judge

     The answer is being formally adjudicated competent by a judge. Capacity is a clinical determination based on the patient's ability to communicate a choice, understand information, appreciate consequences, and reason about options; competence is the legal counterpart decided by a court.

798. A 72-year-old woman with mild dementia refuses a recommended surgery. She can explain her diagnosis, the proposed operation, its risks, and her reasons, and she consistently maintains her choice. What is the correct interpretation of her decision-making capacity?
     • She lacks capacity because she has a dementia diagnosis
     • Capacity must be determined only by a psychiatrist before any decision
     • She retains capacity for this specific decision because she meets the functional criteria
     • Her refusal automatically proves she lacks capacity

     Correct answer: She retains capacity for this specific decision because she meets the functional criteria

     The answer is that she retains capacity for this specific decision because she meets the functional criteria. Capacity is decision-specific and functional; a diagnosis of dementia does not by itself remove capacity if the patient can understand, appreciate, reason, and communicate a stable choice.

799. Which statement best captures the difference between decision-making capacity and competence?
     • Capacity is a legal status determined by a court, and competence is a clinical judgment
     • The two terms are interchangeable and have identical meanings
     • Capacity is a clinical, decision-specific judgment, and competence is a legal status determined by a court
     • Both are determined solely by a patient's age

     Correct answer: Capacity is a clinical, decision-specific judgment, and competence is a legal status determined by a court

     The answer is that capacity is a clinical, decision-specific judgment, and competence is a legal status determined by a court. Physicians assess capacity at the bedside for a particular decision, while a judge determines global legal competence.

800. A patient consents readily to a low-risk blood draw but a clinician questions whether the same patient can refuse a high-risk life-saving surgery. How does the concept of capacity address this difference?
     • Capacity is all-or-nothing and applies equally to every decision
     • Capacity is irrelevant for low-risk procedures
     • The required level of capacity scales with the risk and complexity of the decision
     • A patient who consents to anything has capacity for everything

     Correct answer: The required level of capacity scales with the risk and complexity of the decision

     The answer is that the required level of capacity scales with the risk and complexity of the decision. A sliding-scale approach demands a higher degree of demonstrated understanding and reasoning for decisions with greater potential consequences, so a patient may have capacity for simple choices but require closer assessment for high-stakes ones.

801. An intoxicated 40-year-old man in the emergency department wants to leave against medical advice while still clinically intoxicated after a head injury. What is the most appropriate action regarding his capacity?
     • Conclude he lacks capacity at this time and provide care for safety while reassessing as intoxication resolves
     • Allow him to leave immediately because adults may refuse care
     • Declare him permanently incompetent and obtain a guardian
     • Force him to sign a consent form before he leaves

     Correct answer: Conclude he lacks capacity at this time and provide care for safety while reassessing as intoxication resolves

     The answer is to conclude he lacks capacity at this time and provide care for safety while reassessing as intoxication resolves. Acute intoxication can transiently impair the understanding and reasoning needed for capacity, so the patient should be kept safe and capacity reassessed once the impairment clears.

802. A previously healthy 68-year-old man is now unresponsive and intubated in the intensive care unit. He has a written advance directive and a designated health care proxy. Which document or person guides treatment decisions when his wishes for a specific situation are clearly stated in the directive?
     • The treating physician's personal preference
     • Whichever family member is most insistent
     • The hospital administrator's policy
     • The patient's previously expressed wishes documented in the advance directive

     Correct answer: The patient's previously expressed wishes documented in the advance directive

     The answer is the patient's previously expressed wishes documented in the advance directive. An advance directive lets a patient state treatment preferences in advance; when it clearly addresses the current situation, those documented wishes direct care to honor the patient's autonomy.

803. A patient's advance directive does not specifically address her current clinical situation, but she has a named health care proxy. How should the proxy make decisions on her behalf?
     • Based on what the proxy personally would want
     • Based on the least expensive option for the family
     • Based solely on the most aggressive treatment available
     • Based on substituted judgment, choosing what the patient would have wanted

     Correct answer: Based on substituted judgment, choosing what the patient would have wanted

     The answer is based on substituted judgment, choosing what the patient would have wanted. A surrogate or proxy should make decisions reflecting the patient's known values and prior statements; only when those are unknown does the standard shift to the patient's best interests.

804. What is the primary purpose of a durable power of attorney for health care, a type of advance directive?
     • To designate a person who will make medical decisions if the patient loses capacity
     • To manage the patient's bank accounts and property
     • To guarantee a specific treatment will always be provided
     • To transfer ownership of the patient's assets to the hospital

     Correct answer: To designate a person who will make medical decisions if the patient loses capacity

     The answer is to designate a person who will make medical decisions if the patient loses capacity. A durable power of attorney for health care names a trusted agent to speak for the patient on medical matters when the patient can no longer decide, which is distinct from financial powers of attorney.

805. A 55-year-old woman with capacity completes a living will stating she does not want mechanical ventilation if she becomes terminally ill with no reasonable chance of recovery. Two years later she is admitted with reversible pneumonia and is briefly hypoxic but expected to recover fully. How should the living will apply?
     • The living will does not apply because this is a reversible condition, not the terminal scenario she described
     • Withhold ventilation because the living will refuses it
     • Disregard the living will entirely since it is two years old
     • Transfer all decisions to the court

     Correct answer: The living will does not apply because this is a reversible condition, not the terminal scenario she described

     The answer is that the living will does not apply because this is a reversible condition, not the terminal scenario she described. Living wills specify preferences for defined circumstances such as terminal illness; a treatable acute illness with expected recovery falls outside the conditions she addressed, so standard care should proceed.

806. A patient's son insists that his comatose father would never want to be on a ventilator, but the father's valid written advance directive explicitly requests full life support in this situation. When the directive and the family disagree, what generally takes precedence?
     • The family's verbal opinion always overrides the written directive
     • The decision should be deferred until all relatives agree
     • The physician's clinical judgment regardless of the directive
     • The patient's clearly stated wishes in the valid advance directive

     Correct answer: The patient's clearly stated wishes in the valid advance directive

     The answer is the patient's clearly stated wishes in the valid advance directive. The directive is the patient's own autonomous voice; when it clearly addresses the situation, it takes precedence over a surrogate's contrary opinion, so the documented request for full support should be honored.

807. A 60-year-old man with a known terminal illness is admitted unconscious. He has no advance directive and no available family, and the treatment team is uncertain about life-sustaining measures. What standard should guide decisions in the absence of any expressed wishes or surrogate?
     • The physician's financial interest
     • The best-interest standard based on the patient's likely benefits and burdens
     • The default to withhold all treatment
     • The preference of the on-call administrator

     Correct answer: The best-interest standard based on the patient's likely benefits and burdens

     The answer is the best-interest standard based on the patient's likely benefits and burdens. When neither the patient's wishes nor a surrogate is available, decisions should be based on what a reasonable person would consider to be in the patient's best interest, weighing the benefits and burdens of treatment.

808. Under the Health Insurance Portability and Accountability Act (HIPAA) Privacy Rule, which of the following uses of protected health information generally does NOT require specific patient authorization?
     • Selling the patient's information to a marketing company
     • Posting the patient's diagnosis on social media
     • Disclosure for the patient's own treatment, payment, and health care operations
     • Sharing records with the patient's employer for a hiring decision

     Correct answer: Disclosure for the patient's own treatment, payment, and health care operations

     The answer is disclosure for the patient's own treatment, payment, and health care operations. HIPAA permits use and disclosure of protected health information for these core functions without separate authorization, while marketing, public posting, and employer disclosures generally require the patient's consent.

809. A physician receives a phone call from a man identifying himself as a patient's brother, asking for the patient's lab results. The patient never authorized this disclosure. Under HIPAA, what is the most appropriate response?
     • Provide the results because the caller is family
     • Confirm the diagnosis but not the specific numbers
     • Provide only the abnormal results
     • Decline to release the information without the patient's authorization

     Correct answer: Decline to release the information without the patient's authorization

     The answer is to decline to release the information without the patient's authorization. HIPAA protects against unauthorized disclosure of protected health information; being a relative does not by itself permit access, so the physician should not share results absent the patient's permission or another lawful exception.

810. Two physicians discuss a hospitalized patient's HIV status loudly in a crowded elevator where other patients and visitors can overhear. Which principle does this most clearly violate?
     • The HIPAA requirement to safeguard the confidentiality of protected health information
     • The duty to obtain informed consent
     • The duty to disclose medical errors
     • The requirement to perform root cause analysis

     Correct answer: The HIPAA requirement to safeguard the confidentiality of protected health information

     The answer is the HIPAA requirement to safeguard the confidentiality of protected health information. Discussing identifiable patient information where it can be overheard is an impermissible disclosure; clinicians must take reasonable safeguards to keep protected health information private.

811. A 24-year-old woman tells her physician she does not want her parents to know she is pregnant. Her mother later calls the office demanding information. The patient is an adult with capacity. Under HIPAA, what should the office do?
     • Tell the mother because she is the next of kin
     • Disclose the pregnancy but not the due date
     • Disclose only that the patient was seen but not why
     • Refuse to disclose any information without the patient's authorization

     Correct answer: Refuse to disclose any information without the patient's authorization

     The answer is to refuse to disclose any information without the patient's authorization. An adult patient with capacity controls her own protected health information; HIPAA bars releasing it to a parent or anyone else without the patient's consent or an applicable legal exception.

812. A nurse accesses the electronic medical record of a celebrity who is hospitalized on another unit, purely out of curiosity, and is not involved in that patient's care. How is this action best characterized under HIPAA?
     • Permissible because the nurse is a hospital employee
     • Required for hospital quality reporting
     • Allowed as long as the nurse does not share the information
     • An impermissible access of protected health information without a treatment, payment, or operations purpose

     Correct answer: An impermissible access of protected health information without a treatment, payment, or operations purpose

     The answer is an impermissible access of protected health information without a treatment, payment, or operations purpose. HIPAA limits access to the minimum necessary for a legitimate work-related reason; viewing records out of curiosity, even without further sharing, is an unauthorized access violation.

813. Which of the following is an example of a permitted HIPAA disclosure that may occur without individual patient authorization because it is required or allowed by law?
     • Posting de-identified jokes about a patient online with the name visible
     • Selling patient contact lists to a pharmaceutical company
     • Reporting a diagnosed case of tuberculosis to the public health department
     • Telling a neighbor about a patient's prognosis

     Correct answer: Reporting a diagnosed case of tuberculosis to the public health department

     The answer is reporting a diagnosed case of tuberculosis to the public health department. HIPAA permits disclosures required by law and for public health activities such as reportable communicable diseases, whereas selling, public posting, and casual gossip about identifiable patients are prohibited.

814. A patient asks to obtain a copy of her own complete medical record. Under HIPAA, what right does the patient have?
     • No right to view her own records
     • Access only to the billing portion of the record
     • Access only with a court order
     • The right to access and obtain a copy of her own protected health information

     Correct answer: The right to access and obtain a copy of her own protected health information

     The answer is the right to access and obtain a copy of her own protected health information. HIPAA grants patients the right of access to inspect and receive copies of their own records, with only narrow exceptions, supporting transparency and patient engagement in their care.

815. According to The Joint Commission, a sentinel event is best defined as which of the following?
     • Any medication error regardless of outcome
     • A patient safety event that reaches a patient and results in death, permanent harm, or severe temporary harm
     • A near miss that is intercepted before reaching the patient
     • A routine complication expected from a procedure

     Correct answer: A patient safety event that reaches a patient and results in death, permanent harm, or severe temporary harm

     The answer is a patient safety event that reaches a patient and results in death, permanent harm, or severe temporary harm. A sentinel event signals the need for immediate investigation and response because of its serious, often unexpected, outcome.

816. A surgical team operates on the wrong knee of a patient. Why is this classified as a sentinel event regardless of the ultimate clinical outcome?
     • Because it always results in patient death
     • Because it only involves a documentation issue
     • Because wrong-site surgery is a defined sentinel event that signals serious system failure requiring investigation
     • Because the patient consented to surgery

     Correct answer: Because wrong-site surgery is a defined sentinel event that signals serious system failure requiring investigation

     The answer is that wrong-site surgery is a defined sentinel event that signals serious system failure requiring investigation. Certain events such as wrong-site, wrong-procedure, and wrong-patient surgery are categorized as sentinel events by definition, triggering mandatory review even if the patient is not ultimately harmed.

817. Following an identified sentinel event in a hospital, what is the expected organizational response?
     • Conduct a thorough analysis such as a root cause analysis and develop an action plan to prevent recurrence
     • Conceal the event to protect the institution
     • Discipline the involved staff and take no further action
     • Wait for a lawsuit before reviewing the event

     Correct answer: Conduct a thorough analysis such as a root cause analysis and develop an action plan to prevent recurrence

     The answer is to conduct a thorough analysis such as a root cause analysis and develop an action plan to prevent recurrence. Sentinel events require timely, comprehensive investigation focused on systems improvement and a corrective action plan to reduce the risk of similar events.

818. A pharmacist intercepts a tenfold chemotherapy overdose before it reaches the patient. How is this event best categorized in patient-safety terminology?
     • A sentinel event
     • A near miss
     • A permanent harm event
     • An adverse drug reaction

     Correct answer: A near miss

     The answer is a near miss. Because the error was caught before reaching the patient and no harm occurred, it is a near miss rather than a sentinel event; near misses are still valuable to report because they reveal system vulnerabilities.

819. A hospital encourages staff to report near misses and adverse events through a non-punitive reporting system. What is the primary patient-safety rationale for a non-punitive approach?
     • It reduces the paperwork burden on administrators
     • It encourages honest reporting so system weaknesses can be identified and corrected
     • It allows the hospital to avoid investigating events
     • It shifts all responsibility to individual clinicians

     Correct answer: It encourages honest reporting so system weaknesses can be identified and corrected

     The answer is that it encourages honest reporting so system weaknesses can be identified and corrected. A just, non-punitive culture increases willingness to report errors and near misses, generating the information needed to fix latent system problems before they cause harm.

820. During a patient encounter, a physician uses open-ended questions, reflective listening, and silence to allow the patient to express concerns about a new cancer diagnosis. Which communication skill is the physician primarily demonstrating?
     • Patient-centered communication that elicits the patient's perspective
     • Directing the conversation to save time
     • Withholding information to reduce anxiety
     • Limiting the patient to yes-or-no answers

     Correct answer: Patient-centered communication that elicits the patient's perspective

     The answer is patient-centered communication that elicits the patient's perspective. Open-ended questions, reflective listening, and appropriate silence invite the patient to share concerns and emotions, building rapport and improving understanding and shared decision-making.

821. A physician must tell a patient that a biopsy shows metastatic cancer. Using a structured approach to breaking bad news, what should the physician do before disclosing the diagnosis?
     • Set up an appropriate private setting and assess what the patient already knows and wants to know
     • Deliver the news immediately in the hallway to save time
     • Ask a nurse to deliver the news instead
     • Minimize the seriousness to avoid distressing the patient

     Correct answer: Set up an appropriate private setting and assess what the patient already knows and wants to know

     The answer is to set up an appropriate private setting and assess what the patient already knows and wants to know. Structured bad-news frameworks begin by arranging privacy and gauging the patient's existing understanding and information preferences before the disclosure, so the conversation is tailored and compassionate.

822. A patient who speaks limited English needs to discuss a new diagnosis and treatment options. The patient's adult son offers to interpret. What is the most appropriate communication practice?
     • Use a trained professional medical interpreter to ensure accurate, confidential communication
     • Use the son because he knows the patient best
     • Proceed in English and hope the patient understands
     • Write everything down in English for the patient to read later

     Correct answer: Use a trained professional medical interpreter to ensure accurate, confidential communication

     The answer is to use a trained professional medical interpreter to ensure accurate, confidential communication. Professional interpreters reduce errors, protect confidentiality, and avoid the bias and omissions that can occur when family members interpret, supporting valid understanding and consent.

823. A patient becomes visibly tearful and says, 'I just don't know how I'll cope with this.' Which physician response best demonstrates an empathic communication technique?
     • 'Let's move on to your medication list.'
     • 'I can see this is overwhelming for you; tell me more about what worries you most.'
     • 'There's no reason to be upset about this.'
     • 'Most patients handle this without any problem.'

     Correct answer: 'I can see this is overwhelming for you; tell me more about what worries you most.'

     The answer is naming the emotion and inviting the patient to share more. Empathic statements that acknowledge and validate the patient's feelings, followed by an open invitation to elaborate, strengthen the therapeutic alliance and help address the patient's concerns.

824. A 35-year-old patient with a serious illness asks the physician directly, 'Am I going to die from this?' The patient appears calm and ready to talk. What is the most appropriate communication response?
     • Change the subject to avoid distressing the patient
     • Respond honestly and compassionately, exploring the patient's concerns and providing truthful information
     • Reassure the patient that everything will be fine regardless of the prognosis
     • Defer entirely to the family before answering

     Correct answer: Respond honestly and compassionately, exploring the patient's concerns and providing truthful information

     The answer is to respond honestly and compassionately, exploring the patient's concerns and providing truthful information. Truth-telling balanced with empathy respects autonomy; the physician should answer the direct question honestly while attending to the patient's emotional needs and hopes.

825. A 30-year-old woman with capacity is diagnosed with early breast cancer and asks the physician not to tell her elderly mother, who is also a patient at the practice, anything about it. What does respecting this request primarily reflect?
     • The principle of beneficence over autonomy
     • The physician's obligation to inform all family members
     • A violation of the duty to warn
     • The patient's right to confidentiality and control over her own information

     Correct answer: The patient's right to confidentiality and control over her own information

     The answer is the patient's right to confidentiality and control over her own information. A competent adult decides who may learn about her medical information; honoring her wish not to disclose to her mother upholds confidentiality, a core ethical and legal obligation.

826. A patient with newly diagnosed epilepsy continues to drive despite being advised not to, and the physician practices in a state with mandatory reporting of certain conditions to the licensing authority. How does this situation relate to confidentiality?
     • Confidentiality has limits, and disclosure may be permitted or required to protect the patient or public when mandated by law
     • Confidentiality is absolute and the physician may never disclose anything
     • The physician should publicly announce the diagnosis to warn others
     • The physician must obtain a court order for every disclosure

     Correct answer: Confidentiality has limits, and disclosure may be permitted or required to protect the patient or public when mandated by law

     The answer is that confidentiality has limits, and disclosure may be permitted or required to protect the patient or public when mandated by law. While confidentiality is fundamental, recognized exceptions include legally mandated reporting and serious threats to safety, balanced narrowly against the patient's privacy.

827. A psychiatric patient credibly threatens to seriously harm a specifically named third person. Under the duty to protect recognized in many jurisdictions, what may the physician be obligated to do?
     • Maintain absolute confidentiality and do nothing
     • Take reasonable steps to protect the identifiable potential victim, which may include warning or notifying authorities
     • Immediately publish the threat publicly
     • Discharge the patient without any intervention

     Correct answer: Take reasonable steps to protect the identifiable potential victim, which may include warning or notifying authorities

     The answer is to take reasonable steps to protect the identifiable potential victim. When a patient poses a serious, credible threat to an identifiable person, the duty to protect can override confidentiality, allowing or requiring actions such as warning the victim or notifying law enforcement.

828. A 17-year-old emancipated minor who lives independently, is married, and supports herself requests medical treatment. Regarding consent, how should she generally be treated?
     • She requires parental consent because she is under 18
     • She can consent only for emergency care
     • She needs a court order for any treatment
     • She may consent to her own medical care as an emancipated minor

     Correct answer: She may consent to her own medical care as an emancipated minor

     The answer is that she may consent to her own medical care as an emancipated minor. Emancipated minors, such as those who are married or self-supporting and living independently, are generally treated as adults for medical decision-making and may provide their own consent.

829. A hospital is redesigning its hand-off process between shifts after several errors occurred when key patient information was lost during transfers of care. Implementing a standardized structured hand-off tool primarily improves patient safety by doing what?
     • Eliminating the need for documentation
     • Standardizing communication so critical information is reliably transferred between clinicians
     • Reducing the number of patients each clinician sees
     • Assigning blame for prior errors

     Correct answer: Standardizing communication so critical information is reliably transferred between clinicians

     The answer is standardizing communication so critical information is reliably transferred between clinicians. Structured hand-off tools reduce omissions and miscommunication during transitions of care, a common source of error, by ensuring consistent transfer of essential patient information.

830. A surgical unit adopts a pre-procedure 'time out' in which the team verbally confirms the correct patient, procedure, and site before the first incision. This safety practice is primarily designed to prevent which category of harm?
     • Hospital-acquired infections
     • Delayed laboratory results
     • Medication interactions
     • Wrong-site, wrong-procedure, and wrong-patient surgery

     Correct answer: Wrong-site, wrong-procedure, and wrong-patient surgery

     The answer is wrong-site, wrong-procedure, and wrong-patient surgery. The surgical time out is a verification step in which the team confirms identity, procedure, and site to prevent these serious never events before the operation begins.

831. An institution introduces computerized provider order entry with automated allergy and dose-checking alerts. From a systems perspective, this intervention reduces errors mainly by which mechanism?
     • Building safeguards into the system so unsafe orders are flagged before reaching the patient
     • Increasing reliance on individual memory
     • Removing pharmacists from the medication process
     • Encouraging clinicians to work faster

     Correct answer: Building safeguards into the system so unsafe orders are flagged before reaching the patient

     The answer is building safeguards into the system so unsafe orders are flagged before reaching the patient. Forcing functions and automated checks within order entry catch dangerous orders such as allergies and overdoses, embedding error prevention into the system rather than relying on vigilance alone.

832. A patient on multiple medications is admitted to the hospital, and the team carefully compares the patient's home medication list with the inpatient orders to resolve discrepancies. This process is known as what, and why does it improve safety?
     • Formulary substitution, which selects cheaper drugs
     • Prior authorization, which lowers medication costs
     • Medication reconciliation, which prevents omissions, duplications, and dosing errors at transitions of care
     • Discharge planning, which arranges follow-up appointments

     Correct answer: Medication reconciliation, which prevents omissions, duplications, and dosing errors at transitions of care

     The answer is medication reconciliation, which prevents omissions, duplications, and dosing errors at transitions of care. Reconciling the patient's existing medications with new orders at admission, transfer, and discharge reduces preventable adverse drug events caused by miscommunication across care settings.

833. A physician privately disagrees with a colleague's management decision. The colleague's care, while not what the physician would have chosen, falls within accepted standards and is not harming the patient. What is the most appropriate professional response?
     • Recognize that reasonable clinicians may differ and avoid undermining the patient's trust in their care
     • Criticize the colleague in front of the patient
     • Document the colleague as incompetent in the chart
     • Immediately report the colleague to the licensing board

     Correct answer: Recognize that reasonable clinicians may differ and avoid undermining the patient's trust in their care

     The answer is to recognize that reasonable clinicians may differ and avoid undermining the patient's trust in their care. Professionalism calls for respectful collegial communication; when care is within the standard and safe, the physician should not disparage a colleague to the patient, addressing genuine concerns through appropriate channels instead.

834. A pharmaceutical representative offers a physician an expensive gift and a paid vacation in exchange for prescribing the company's new drug preferentially. What ethical principle is most directly threatened by accepting this offer?
     • Patient confidentiality
     • The duty to report sentinel events
     • The duty to obtain informed consent
     • The duty to avoid conflicts of interest that compromise patient-centered care

     Correct answer: The duty to avoid conflicts of interest that compromise patient-centered care

     The answer is the duty to avoid conflicts of interest that compromise patient-centered care. Accepting valuable inducements tied to prescribing can bias clinical judgment away from the patient's best interest, so physicians should avoid arrangements that create such conflicts of interest.

835. A 50-year-old man enrolled in a clinical trial of a new drug wishes to withdraw partway through because he no longer wants to participate. What does respect for his autonomy in research require?
     • He must complete the trial because he already consented
     • He may withdraw from the study at any time without penalty or loss of usual care
     • He can withdraw only with the sponsor's approval
     • He forfeits all medical care if he withdraws

     Correct answer: He may withdraw from the study at any time without penalty or loss of usual care

     The answer is that he may withdraw from the study at any time without penalty or loss of usual care. Voluntary participation is a cornerstone of research ethics; participants retain the right to withdraw at any point without jeopardizing their standard medical treatment.

836. A 48-year-old man presents to the emergency department with severe epigastric pain radiating to the back, nausea, and vomiting that began after a weekend of heavy alcohol use. His lipase is markedly elevated at more than three times the upper limit of normal. Which finding is required, in addition to characteristic pain and this lipase elevation, to confirm the diagnosis using the current diagnostic criteria for this condition?
     • No additional finding is required because two of the three accepted criteria are already met
     • A serum amylase that is also more than three times the upper limit of normal
     • Visible pancreatic necrosis on contrast-enhanced CT
     • A documented serum triglyceride level above 1000 mg/dL

     Correct answer: No additional finding is required because two of the three accepted criteria are already met

     No additional finding is required because two of the three accepted criteria are already met. Acute pancreatitis is diagnosed when at least two of three features are present: characteristic epigastric pain radiating to the back, lipase or amylase greater than three times the upper limit of normal, and characteristic imaging findings. This patient already satisfies the pain and enzyme criteria, so imaging is not needed for diagnosis. A confirmatory second elevated enzyme is not separately required, necrosis is a complication rather than a diagnostic criterion, and hypertriglyceridemia is only one possible etiology.

837. A 52-year-old man is admitted with acute pancreatitis secondary to gallstones. He is hemodynamically stable, has no nausea once antiemetics are given, and his pain is controlled. Which intervention is the most important early management step that improves outcomes in the first 24 hours?
     • Empiric broad-spectrum intravenous antibiotics to prevent infected necrosis
     • Aggressive goal-directed intravenous fluid resuscitation with monitoring of urine output
     • Strict bowel rest with nothing by mouth for at least seven days
     • Immediate ERCP regardless of bilirubin or cholangitis status

     Correct answer: Aggressive goal-directed intravenous fluid resuscitation with monitoring of urine output

     Aggressive goal-directed intravenous fluid resuscitation with monitoring of urine output is the cornerstone of early acute pancreatitis care and reduces the risk of organ failure. Prophylactic antibiotics are not recommended in the absence of infected necrosis or cholangitis. Prolonged bowel rest is outdated; early enteral feeding is favored once tolerated. Urgent ERCP is reserved for concurrent cholangitis or persistent biliary obstruction, not all gallstone pancreatitis.

838. A 60-year-old woman with acute gallstone pancreatitis develops worsening right upper quadrant pain, a fever of 39.2 C, jaundice, and hypotension on hospital day two. Her total bilirubin and alkaline phosphatase have risen sharply and a dilated common bile duct is seen on ultrasound. What is the most appropriate next step?
     • Proceed directly to open cholecystectomy
     • Continue supportive care and reassess in 48 hours
     • Urgent ERCP for biliary decompression
     • Start high-dose corticosteroids for the inflammatory response

     Correct answer: Urgent ERCP for biliary decompression

     Urgent ERCP for biliary decompression is indicated because this patient has acute pancreatitis complicated by ascending cholangitis, evidenced by the combination of fever, jaundice, and right upper quadrant pain with biliary obstruction. Decompression relieves the obstruction and treats the infection. Continued observation risks deterioration. Cholecystectomy is performed later, typically during the same admission once pancreatitis improves. Corticosteroids have no role here.

839. A 45-year-old man with acute pancreatitis is being assessed for severity on admission. Which laboratory or clinical parameter is most strongly associated with the development of severe disease and persistent organ failure?
     • A mildly elevated serum amylase that normalizes within a day
     • The absolute peak value of the serum lipase
     • The presence of a single episode of vomiting on arrival
     • A rising blood urea nitrogen and a persistently elevated hematocrit reflecting hemoconcentration

     Correct answer: A rising blood urea nitrogen and a persistently elevated hematocrit reflecting hemoconcentration

     A rising blood urea nitrogen and a persistently elevated hematocrit reflecting hemoconcentration are validated markers of severe acute pancreatitis and inadequate volume resuscitation, predicting organ failure. The magnitude of lipase elevation does not correlate with severity. Vomiting alone is nonspecific. A transiently elevated amylase does not predict a severe course.

840. A 55-year-old man recovering from severe necrotizing pancreatitis develops, three weeks after onset, recurrent abdominal pain, early satiety, and a persistent low-grade fever. CT shows a 7 cm encapsulated fluid collection adjacent to the pancreas. He is otherwise stable. What is the most appropriate initial management of this complication?
     • Observation, as many such collections resolve spontaneously over weeks
     • Immediate surgical excision of the entire collection
     • Long-term octreotide infusion to seal the pancreatic duct
     • Emergent percutaneous drainage in all cases regardless of symptoms

     Correct answer: Observation, as many such collections resolve spontaneously over weeks

     Observation, as many such collections resolve spontaneously over weeks, is appropriate for a stable patient with a pancreatic pseudocyst that is not infected, rapidly enlarging, or causing obstruction. Surgical excision and routine percutaneous drainage are reserved for symptomatic, infected, or complicated collections. Octreotide is not standard pseudocyst management. Intervention is guided by symptoms and complications rather than size alone.

841. A 50-year-old man with acute pancreatitis has been improving and now reports hunger. He has no nausea and his pain is well controlled. According to current guideline-based management, what is the recommended approach to nutrition?
     • Maintain nothing by mouth until lipase fully normalizes
     • Begin early oral feeding with a low-fat diet as tolerated
     • Initiate total parenteral nutrition as the preferred first route
     • Restrict to clear liquids only for a minimum of one week

     Correct answer: Begin early oral feeding with a low-fat diet as tolerated

     Begin early oral feeding with a low-fat diet as tolerated is recommended once a patient with mild acute pancreatitis is improving, because early enteral nutrition shortens hospital stay and lowers complications. Waiting for full enzyme normalization is unnecessary. Parenteral nutrition is reserved for those who cannot tolerate enteral feeding. Prolonged clear-liquid restriction provides no benefit.

842. A 38-year-old woman presents with recurrent acute pancreatitis. She does not drink alcohol, has no gallstones on ultrasound, and takes no medications. Her serum triglyceride level during the acute episode is 2,400 mg/dL. After acute stabilization, which long-term measure most directly addresses the underlying cause?
     • Scheduled elective cholecystectomy
     • Lifelong prophylactic antibiotics
     • Fibrate therapy with dietary fat restriction to lower triglycerides
     • Chronic proton pump inhibitor therapy

     Correct answer: Fibrate therapy with dietary fat restriction to lower triglycerides

     Fibrate therapy with dietary fat restriction to lower triglycerides directly treats hypertriglyceridemia-induced pancreatitis, which is the cause given a triglyceride level above 1,000 mg/dL with no gallstones or alcohol. Prophylactic antibiotics do not prevent recurrence. Cholecystectomy addresses gallstone disease, which is absent. Acid suppression does not treat the underlying lipid disorder.

843. A 62-year-old man with cirrhosis presents with hematemesis and melena. His heart rate is 118 and blood pressure is 92/58. After establishing two large-bore IVs, which combination of initial pharmacologic measures is most appropriate before and around endoscopy for this presentation?
     • Intravenous tranexamic acid as the primary therapy to stop the bleed
     • Intravenous calcium channel blockers to lower portal pressure
     • High-dose oral nonselective beta-blocker started immediately during active bleeding
     • An intravenous vasoactive agent such as octreotide plus prophylactic antibiotics

     Correct answer: An intravenous vasoactive agent such as octreotide plus prophylactic antibiotics

     An intravenous vasoactive agent such as octreotide plus prophylactic antibiotics is the correct early management of suspected variceal upper GI bleeding in cirrhosis; octreotide reduces splanchnic blood flow and antibiotics reduce infection and rebleeding. Calcium channel blockers are not used acutely. Beta-blockers are for prophylaxis, not active bleeding, where they would blunt the compensatory tachycardia. Tranexamic acid has not shown benefit and is not first-line.

844. A 70-year-old man on chronic NSAID therapy presents with coffee-ground emesis and a hemoglobin of 8.1 g/dL. He is hemodynamically stable after fluids. Upper endoscopy reveals a gastric ulcer with a visible non-bleeding vessel. After endoscopic hemostasis, which medication regimen most reduces the risk of rebleeding?
     • A high-dose intravenous proton pump inhibitor
     • An intravenous histamine-2 receptor antagonist alone
     • Sucralfate as monotherapy
     • Continued NSAID therapy with an added antacid

     Correct answer: A high-dose intravenous proton pump inhibitor

     A high-dose intravenous proton pump inhibitor is indicated after endoscopic treatment of a high-risk peptic ulcer because raising gastric pH stabilizes the clot and lowers rebleeding. Histamine-2 blockers are less effective for this purpose. Sucralfate alone does not provide adequate acid suppression. Continuing the offending NSAID would perpetuate ulcer disease and should be stopped.

845. A 65-year-old woman presents with melena. She is alert, with a heart rate of 84 and a blood pressure of 128/76. Her hemoglobin is 11.5 g/dL, blood urea nitrogen is normal, and she has no liver disease or syncope. Using a validated risk score for upper GI bleeding, what is the most appropriate disposition?
     • Immediate ICU admission with central venous monitoring
     • Consider outpatient management with early outpatient endoscopy given her very low-risk score
     • Emergent surgical consultation for laparotomy
     • Empiric blood transfusion to a hemoglobin target above 12 g/dL

     Correct answer: Consider outpatient management with early outpatient endoscopy given her very low-risk score

     Consider outpatient management with early outpatient endoscopy given her very low-risk score is appropriate because a low Glasgow-Blatchford score, reflecting normal vital signs, normal urea, and absence of high-risk features, identifies patients who can be safely managed without urgent hospitalization. ICU care and surgery are not warranted for a stable low-risk patient. Transfusion uses a restrictive threshold near 7 g/dL, so transfusing to above 12 is inappropriate.

846. A 58-year-old man with an active upper GI bleed and a hemoglobin of 6.5 g/dL has no cardiac disease and is hemodynamically stabilized. Based on current evidence for transfusion strategy in acute upper GI bleeding, what hemoglobin threshold should generally trigger red blood cell transfusion?
     • Transfusion only if the hemoglobin falls below 5 g/dL
     • A liberal threshold of approximately 10 g/dL
     • A restrictive threshold of approximately 7 g/dL
     • Transfusion to a target of 13 g/dL to maximize oxygen delivery

     Correct answer: A restrictive threshold of approximately 7 g/dL

     A restrictive threshold of approximately 7 g/dL is supported by randomized evidence showing improved survival and less rebleeding compared with liberal transfusion in acute upper GI bleeding without cardiovascular compromise. A liberal threshold of 10, withholding until 5, or targeting 13 all worsen or do not improve outcomes in this setting.

847. A 47-year-old man with known esophageal varices presents with massive hematemesis. After octreotide, antibiotics, and resuscitation, urgent endoscopy is performed. Which endoscopic intervention is the preferred definitive therapy for actively bleeding esophageal varices?
     • Argon plasma coagulation of the variceal columns
     • Endoscopic injection sclerotherapy as first-line over banding
     • Placement of a permanent metal esophageal stent
     • Endoscopic band ligation of the varices

     Correct answer: Endoscopic band ligation of the varices

     Endoscopic band ligation of the varices is the preferred endoscopic treatment for bleeding esophageal varices because it controls bleeding and has fewer complications than sclerotherapy. Sclerotherapy is now reserved for cases where banding is not feasible. Esophageal stents and argon plasma coagulation are not standard first-line therapies for variceal hemorrhage.

848. A 54-year-old man with decompensated cirrhosis is admitted with worsening abdominal distension. Diagnostic paracentesis is performed. Which ascitic fluid analysis result is most consistent with ascites due to portal hypertension from cirrhosis rather than another cause?
     • A serum-ascites albumin gradient of 1.5 g/dL or greater
     • A serum-ascites albumin gradient less than 1.1 g/dL
     • An ascitic fluid total protein greater than 4 g/dL
     • An ascitic fluid glucose markedly lower than serum glucose

     Correct answer: A serum-ascites albumin gradient of 1.5 g/dL or greater

     A serum-ascites albumin gradient of 1.5 g/dL or greater, being at or above the 1.1 g/dL cutoff, indicates portal hypertension and is consistent with cirrhotic ascites. A gradient below 1.1 suggests non-portal causes such as peritoneal malignancy or infection. A high ascitic total protein and a low glucose are seen in exudative or secondary peritonitis, not uncomplicated cirrhotic ascites.

849. A 60-year-old man with cirrhosis and ascites presents with diffuse abdominal pain and fever. Paracentesis shows an ascitic fluid absolute neutrophil count of 350 cells/mm3. He has no surgical source on imaging. What is the most appropriate management?
     • Observation with repeat paracentesis in 48 hours
     • Empiric intravenous third-generation cephalosporin and intravenous albumin
     • Immediate exploratory laparotomy
     • Oral antifungal therapy alone

     Correct answer: Empiric intravenous third-generation cephalosporin and intravenous albumin

     Empiric intravenous third-generation cephalosporin and intravenous albumin is the standard treatment for spontaneous bacterial peritonitis, diagnosed by an ascitic neutrophil count of 250 cells/mm3 or higher; albumin reduces renal failure and mortality. Delaying treatment risks death. Laparotomy is for secondary peritonitis with a surgical source. Antifungals are not indicated for typical bacterial SBP.

850. A 58-year-old man with cirrhosis is brought in confused and lethargic by his family. He has asterixis and a recent history of constipation. There is no focal neurologic deficit and a head CT is unremarkable. Which first-line therapy targets the underlying mechanism of his altered mental status?
     • High-protein nutritional supplementation
     • Intravenous mannitol to lower intracranial pressure
     • Lactulose to reduce intestinal ammonia absorption
     • Empiric benzodiazepines for agitation

     Correct answer: Lactulose to reduce intestinal ammonia absorption

     Lactulose to reduce intestinal ammonia absorption is first-line for hepatic encephalopathy because it acidifies the colon and promotes elimination of nitrogenous waste. Mannitol treats cerebral edema, which is not the issue here. Excess protein loading can worsen encephalopathy. Benzodiazepines can precipitate or deepen encephalopathy and should be avoided.

851. A 56-year-old man with cirrhosis and tense ascites that has been refractory to diuretics presents for recurrent large-volume paracentesis every two weeks. He has preserved renal function and no encephalopathy. Which intervention is most appropriate to address his refractory ascites and reduce the frequency of paracentesis?
     • High-dose intravenous albumin infusions on a daily basis
     • Lifelong empiric antibiotics
     • Permanent indwelling peritoneal drain left to continuous gravity drainage
     • Transjugular intrahepatic portosystemic shunt placement

     Correct answer: Transjugular intrahepatic portosystemic shunt placement

     Transjugular intrahepatic portosystemic shunt placement is an established option for refractory ascites, decreasing portal pressure and reducing the need for repeated paracentesis in selected patients with preserved liver and renal function and no encephalopathy. Empiric antibiotics do not treat ascites. A continuous indwelling drain risks infection and protein loss. Daily albumin alone is not a definitive solution.

852. A 63-year-old man with longstanding cirrhosis from chronic hepatitis C is undergoing surveillance. Which strategy is recommended to screen for the most important malignancy that complicates cirrhosis?
     • Abdominal ultrasound every six months, with or without alpha-fetoprotein
     • Annual colonoscopy
     • Yearly chest CT
     • Serum CA 19-9 measured monthly

     Correct answer: Abdominal ultrasound every six months, with or without alpha-fetoprotein

     Abdominal ultrasound every six months, with or without alpha-fetoprotein, is the recommended surveillance for hepatocellular carcinoma in patients with cirrhosis, allowing early detection. Colonoscopy screens for colorectal cancer, not liver cancer. Chest CT and serum CA 19-9 are not used for hepatocellular carcinoma surveillance.

853. A 59-year-old man with cirrhosis is found to have large esophageal varices on screening endoscopy but has never bled. He has no contraindications. Which intervention is most appropriate to reduce his risk of a first variceal hemorrhage?
     • A proton pump inhibitor taken indefinitely
     • A nonselective beta-blocker such as carvedilol or nadolol
     • Prophylactic transjugular intrahepatic portosystemic shunt
     • Chronic octreotide infusion at home

     Correct answer: A nonselective beta-blocker such as carvedilol or nadolol

     A nonselective beta-blocker such as carvedilol or nadolol is used for primary prophylaxis of variceal bleeding because it lowers portal pressure; endoscopic band ligation is an alternative. Proton pump inhibitors do not prevent variceal bleeding. A prophylactic shunt is not standard primary prophylaxis. Chronic octreotide is used in acute bleeding, not long-term prevention.

854. A 30-year-old man presents with months of bloody diarrhea, tenesmus, and lower abdominal cramping. Colonoscopy shows continuous inflammation beginning at the rectum and extending proximally without skip lesions, and biopsies show crypt abscesses limited to the mucosa. Which diagnosis best fits this pattern?
     • Ischemic colitis
     • Crohn disease
     • Ulcerative colitis
     • Celiac disease

     Correct answer: Ulcerative colitis

     Ulcerative colitis is characterized by continuous mucosal inflammation extending proximally from the rectum without skip lesions and limited to the colon, matching this presentation. Crohn disease shows skip lesions and transmural, often patchy involvement anywhere in the GI tract. Ischemic colitis typically affects watershed areas in older patients with vascular risk. Celiac disease affects the small bowel and does not cause this colonoscopic pattern.

855. A 26-year-old woman with Crohn disease has perianal fistulizing disease and frequent flares despite mesalamine. Her gastroenterologist plans to start an anti-tumor necrosis factor biologic agent. Which screening test is most important to perform before initiating this therapy?
     • A 24-hour urine protein collection
     • A bone mineral density scan
     • A fasting lipid panel
     • Testing for latent tuberculosis infection

     Correct answer: Testing for latent tuberculosis infection

     Testing for latent tuberculosis infection is essential before starting an anti-tumor necrosis factor agent because these drugs can reactivate latent tuberculosis, sometimes with disseminated disease. Bone density, lipids, and urine protein are not the critical pre-biologic safety screen for tuberculosis reactivation.

856. A 32-year-old man with a 10-year history of Crohn disease involving the terminal ileum presents with a fever, right lower quadrant pain, and a tender palpable mass. CT shows a walled-off fluid collection consistent with an abscess. What is the most appropriate next step in management?
     • Antibiotics and image-guided percutaneous drainage
     • Immediate escalation of corticosteroid dose
     • Start of an anti-tumor necrosis factor biologic now
     • Outpatient observation with oral mesalamine

     Correct answer: Antibiotics and image-guided percutaneous drainage

     Antibiotics and image-guided percutaneous drainage are appropriate because an intra-abdominal abscess is a complication of Crohn disease that requires source control, not immunosuppression. Increasing corticosteroids or starting a biologic in the setting of an undrained abscess can worsen infection. Outpatient observation is unsafe for an abscess with systemic signs.

857. A 24-year-old man with a moderate flare of ulcerative colitis limited to the left colon has not responded adequately to oral and topical mesalamine. He has no infection on stool testing. Which is the most appropriate next step to induce remission?
     • Long-term high-dose opioids for symptom control
     • A course of oral corticosteroids
     • Empiric metronidazole monotherapy
     • Immediate total colectomy

     Correct answer: A course of oral corticosteroids

     A course of oral corticosteroids is the standard next step to induce remission in a moderate ulcerative colitis flare that has failed mesalamine. Opioids can precipitate toxic megacolon and do not treat inflammation. Metronidazole alone does not treat ulcerative colitis. Colectomy is reserved for refractory disease, dysplasia, or complications, not as the immediate next step.

858. A 36-year-old woman has had extensive ulcerative colitis for 9 years that is well controlled. She asks how she should be monitored for the long-term risk of colorectal cancer. Which surveillance strategy is recommended for patients with longstanding extensive colitis?
     • No surveillance is needed unless symptoms change
     • Annual fecal occult blood testing as the sole screening method
     • Surveillance colonoscopy with biopsies beginning about 8 years after diagnosis, then at regular intervals
     • A single screening colonoscopy at age 50 as in average-risk patients

     Correct answer: Surveillance colonoscopy with biopsies beginning about 8 years after diagnosis, then at regular intervals

     Surveillance colonoscopy with biopsies beginning about 8 years after diagnosis, then at regular intervals, is recommended because longstanding extensive colitis substantially raises colorectal cancer risk and dysplasia must be detected early. Fecal occult blood testing alone, deferring until symptoms change, or following the average-risk age-50 single-screen approach all undertreat this elevated risk.

859. A 28-year-old man with severe ulcerative colitis is hospitalized with more than ten bloody stools daily, fever, tachycardia, and abdominal distension. An abdominal radiograph shows transverse colon dilation greater than 6 cm. What is the most appropriate immediate management in addition to bowel rest and fluids?
     • Scheduled colonoscopy to the cecum for assessment
     • Outpatient escalation of oral mesalamine
     • Antidiarrheal loperamide to reduce stool frequency
     • Intravenous corticosteroids, broad-spectrum antibiotics, and surgical consultation

     Correct answer: Intravenous corticosteroids, broad-spectrum antibiotics, and surgical consultation

     Intravenous corticosteroids, broad-spectrum antibiotics, and surgical consultation are required because this is toxic megacolon, a life-threatening complication. Outpatient mesalamine is inadequate. Antidiarrheals can precipitate or worsen toxic megacolon and are contraindicated. Full colonoscopy risks perforation and is contraindicated during acute toxic megacolon.

860. A 41-year-old woman with newly diagnosed inflammatory bowel disease develops painful red nodules on her shins during a flare and crusted oral ulcers. These findings resolve as her bowel disease is brought under control. Which statement best describes these findings?
     • They are extraintestinal manifestations whose activity often parallels bowel disease activity
     • They indicate a drug allergy to mesalamine requiring discontinuation
     • They represent metastatic spread of an undiagnosed colon cancer
     • They are unrelated to the inflammatory bowel disease and require dermatology biopsy of every lesion

     Correct answer: They are extraintestinal manifestations whose activity often parallels bowel disease activity

     They are extraintestinal manifestations whose activity often parallels bowel disease activity, as with erythema nodosum and aphthous oral ulcers in inflammatory bowel disease, which typically improve when intestinal inflammation is controlled. They are not a drug allergy, not metastatic cancer, and are recognized complications of the disease rather than incidental unrelated findings.

861. A 55-year-old woman presents with episodic right upper quadrant pain after fatty meals, lasting one to two hours and then resolving. She is afebrile with normal liver enzymes and white count. Ultrasound shows gallstones without wall thickening. Which diagnosis best explains her presentation?
     • Acute cholecystitis
     • Symptomatic cholelithiasis (biliary colic)
     • Ascending cholangitis
     • Choledocholithiasis with obstruction

     Correct answer: Symptomatic cholelithiasis (biliary colic)

     Symptomatic cholelithiasis, or biliary colic, presents with self-limited postprandial right upper quadrant pain, gallstones on imaging, and normal labs without fever or inflammation. Acute cholecystitis causes persistent pain with fever, leukocytosis, and gallbladder wall thickening. Cholangitis adds jaundice and fever from biliary infection. Choledocholithiasis with obstruction would elevate bilirubin and alkaline phosphatase.

862. A 60-year-old woman presents with right upper quadrant pain for 12 hours, fever, and nausea. She has a positive Murphy sign, leukocytosis, and ultrasound shows a thickened gallbladder wall with pericholecystic fluid and gallstones. What is the most appropriate definitive treatment?
     • Outpatient low-fat diet with reassessment in three months
     • Long-term ursodeoxycholic acid dissolution therapy
     • Laparoscopic cholecystectomy during the same admission
     • ERCP with sphincterotomy as definitive therapy

     Correct answer: Laparoscopic cholecystectomy during the same admission

     Laparoscopic cholecystectomy during the same admission is the definitive treatment for acute cholecystitis and is recommended early once the patient is stabilized. Ursodeoxycholic acid dissolution is slow and not appropriate for acute cholecystitis. Outpatient dietary management risks complications. ERCP treats common bile duct stones, not the inflamed gallbladder itself.

863. A 70-year-old man presents with right upper quadrant pain, jaundice, and a fever with rigors. His blood pressure is 88/54 and he is confused. Labs show leukocytosis and elevated bilirubin, and imaging shows a dilated common bile duct with a stone. After fluids and antibiotics, what is the most appropriate next step?
     • Oral ursodeoxycholic acid to dissolve the stone
     • Elective cholecystectomy in six weeks
     • Observation until the fever resolves
     • Urgent ERCP for biliary drainage

     Correct answer: Urgent ERCP for biliary drainage

     Urgent ERCP for biliary drainage is indicated because the patient has ascending cholangitis with hypotension and confusion, indicating the severe end of the spectrum requiring prompt decompression in addition to antibiotics and resuscitation. Delaying for elective surgery or observation risks death. Oral dissolution therapy does not relieve acute obstruction or infection.

864. A 45-year-old man presents with epigastric burning that improves with meals and worsens 2 to 3 hours afterward and at night. Testing confirms Helicobacter pylori infection. Which treatment approach is most appropriate?
     • A combination regimen including a proton pump inhibitor and two antibiotics
     • A proton pump inhibitor alone for four weeks
     • A single antibiotic course without acid suppression
     • An antacid as needed with no eradication therapy

     Correct answer: A combination regimen including a proton pump inhibitor and two antibiotics

     A combination regimen including a proton pump inhibitor and two antibiotics is required to eradicate Helicobacter pylori, which causes most duodenal ulcers and recurs without eradication. A proton pump inhibitor alone heals the ulcer but does not eradicate the organism. A single antibiotic promotes resistance and is insufficient. Antacids alone neither heal the ulcer reliably nor cure the infection.

865. A 50-year-old man treated for a Helicobacter pylori-associated peptic ulcer completes eradication therapy. He has no alarm features. Which approach is recommended to confirm that the infection has been successfully eradicated?
     • Repeat serology, since a falling antibody titer confirms cure within two weeks
     • A urea breath test or stool antigen test performed after stopping acid suppression for the recommended interval
     • No confirmatory testing is ever needed after treatment
     • Immediate repeat endoscopy regardless of symptoms

     Correct answer: A urea breath test or stool antigen test performed after stopping acid suppression for the recommended interval

     A urea breath test or stool antigen test performed after stopping acid suppression for the recommended interval reliably confirms Helicobacter pylori eradication; proton pump inhibitors must be held beforehand to avoid false negatives. Serology cannot distinguish active from prior infection because antibody titers persist. Confirmation is recommended for ulcer disease. Routine repeat endoscopy is not required unless other indications exist.

866. A 52-year-old man reports heartburn and regurgitation several times weekly for three months without dysphagia, weight loss, or anemia. Which initial management step is most appropriate?
     • An empiric course of antibiotics
     • Immediate upper endoscopy before any therapy
     • An empiric trial of a once-daily proton pump inhibitor with lifestyle modification
     • Twenty-four-hour ambulatory pH monitoring as the required first test

     Correct answer: An empiric trial of a once-daily proton pump inhibitor with lifestyle modification

     An empiric trial of a once-daily proton pump inhibitor with lifestyle modification is the standard initial management for typical gastroesophageal reflux disease without alarm features. Endoscopy is reserved for alarm symptoms or treatment failure. Antibiotics are not indicated. Ambulatory pH monitoring is used in selected cases, not as the routine first test.

867. A 58-year-old man with longstanding gastroesophageal reflux disease undergoes endoscopy that shows salmon-colored mucosa in the distal esophagus, and biopsy confirms intestinal metaplasia without dysplasia. Which is the most appropriate management?
     • A one-time endoscopy with no further follow-up
     • Immediate esophagectomy
     • Discontinuation of all acid suppression
     • Continued proton pump inhibitor therapy with periodic endoscopic surveillance

     Correct answer: Continued proton pump inhibitor therapy with periodic endoscopic surveillance

     Continued proton pump inhibitor therapy with periodic endoscopic surveillance is appropriate for Barrett esophagus without dysplasia, because it controls reflux and monitors for progression to dysplasia or adenocarcinoma. Esophagectomy is far too aggressive for nondysplastic disease. Stopping acid suppression worsens reflux. A single endoscopy without follow-up fails to monitor the premalignant condition.

868. A 64-year-old man presents with progressive difficulty swallowing solids that has worsened to include liquids, along with a 15-pound unintentional weight loss over two months. He has a long smoking and alcohol history. What is the most appropriate next diagnostic step?
     • Upper endoscopy with biopsy
     • Empiric proton pump inhibitor trial without further workup
     • Reassurance and dietary modification only
     • A barium swallow as the definitive test that excludes malignancy

     Correct answer: Upper endoscopy with biopsy

     Upper endoscopy with biopsy is the appropriate next step because progressive dysphagia from solids to liquids with weight loss in a patient with smoking and alcohol history is an alarm presentation concerning for esophageal cancer that requires tissue diagnosis. An empiric proton pump inhibitor trial or reassurance would dangerously delay diagnosis. A barium swallow may suggest a lesion but cannot provide tissue to exclude malignancy.

869. A 38-year-old woman reports difficulty swallowing both solids and liquids, regurgitation of undigested food, and chest discomfort. A barium esophagram shows a dilated esophagus with a tapered bird-beak narrowing at the gastroesophageal junction. Which test best confirms the underlying diagnosis?
     • A 24-hour pH study
     • Esophageal manometry
     • Serum gastrin level
     • Abdominal ultrasound

     Correct answer: Esophageal manometry

     Esophageal manometry confirms achalasia by demonstrating incomplete lower esophageal sphincter relaxation and absent peristalsis, consistent with the bird-beak esophagram. A pH study evaluates reflux, not motility. Serum gastrin assesses gastrin-secreting tumors. Abdominal ultrasound does not assess esophageal motor function.

870. A 30-year-old woman presents with chronic diarrhea, bloating, and iron-deficiency anemia. She has lost weight despite a normal appetite. Serologic testing shows elevated tissue transglutaminase IgA antibodies. What is the most appropriate next step to confirm the diagnosis before lifelong treatment?
     • Stool culture for bacterial pathogens
     • Immediate lifelong gluten-free diet without further testing
     • Duodenal biopsy via upper endoscopy while she remains on a gluten-containing diet
     • Colonoscopy with random biopsies

     Correct answer: Duodenal biopsy via upper endoscopy while she remains on a gluten-containing diet

     Duodenal biopsy via upper endoscopy while she remains on a gluten-containing diet confirms celiac disease by showing villous atrophy; testing while still consuming gluten avoids false negatives. Starting a gluten-free diet before confirmation undermines diagnostic accuracy. Stool culture targets infection, not celiac disease. Colonoscopy evaluates the colon, whereas celiac disease affects the small bowel.

871. A 45-year-old woman has recurrent abdominal pain associated with altered bowel habits that improves with defecation, present for more than six months. Workup including labs, celiac serology, and colonoscopy is unremarkable, and there are no alarm features. Which is the most appropriate diagnosis and approach?
     • Chronic mesenteric ischemia requiring revascularization
     • Inflammatory bowel disease requiring immunosuppression
     • Colon cancer requiring urgent resection
     • Irritable bowel syndrome managed with dietary modification and symptom-directed therapy

     Correct answer: Irritable bowel syndrome managed with dietary modification and symptom-directed therapy

     Irritable bowel syndrome managed with dietary modification and symptom-directed therapy fits recurrent abdominal pain related to defecation and altered bowel habits with a normal workup and no alarm features. Inflammatory bowel disease would show mucosal inflammation. Colon cancer is excluded by normal colonoscopy. Mesenteric ischemia causes postprandial pain in patients with vascular disease, not this pattern.

872. A 68-year-old man presents with severe, diffuse abdominal pain that is out of proportion to a relatively benign abdominal examination. He has atrial fibrillation and is not anticoagulated. His lactate is elevated. Which diagnosis must be urgently considered?
     • Acute mesenteric ischemia
     • Uncomplicated gastroenteritis
     • Functional dyspepsia
     • Simple constipation

     Correct answer: Acute mesenteric ischemia

     Acute mesenteric ischemia must be urgently considered because pain out of proportion to examination, atrial fibrillation predisposing to embolism, and an elevated lactate together suggest bowel ischemia that requires rapid imaging and intervention. Gastroenteritis, functional dyspepsia, and constipation do not produce this combination of embolic risk, severe pain with a benign exam, and lactic acidosis.

873. A 72-year-old man presents with left lower quadrant pain, low-grade fever, and a change in bowel habits. CT shows colonic wall thickening with surrounding fat stranding in the sigmoid colon and no abscess or free air. He tolerates oral intake. What is the most appropriate management?
     • Emergent colectomy
     • Outpatient antibiotics with bowel rest and close follow-up
     • Immediate colonoscopy during the acute episode
     • High-dose corticosteroids

     Correct answer: Outpatient antibiotics with bowel rest and close follow-up

     Outpatient antibiotics with bowel rest and close follow-up is appropriate for uncomplicated acute diverticulitis without abscess, perforation, or obstruction in a patient tolerating oral intake. Emergent colectomy is for complicated or perforated disease. Colonoscopy is deferred until after the acute inflammation resolves to avoid perforation. Corticosteroids are not used for diverticulitis.

874. A 74-year-old woman presents with sudden painless passage of a large amount of bright red blood per rectum. She is hemodynamically stable after fluids and has a history of diverticulosis. Bleeding stops spontaneously. Which is the most appropriate next diagnostic step once she is stabilized?
     • Exploratory laparotomy
     • Upper endoscopy as the first-line evaluation
     • Colonoscopy to identify and treat the source
     • Empiric long-term iron supplementation without any localization

     Correct answer: Colonoscopy to identify and treat the source

     Colonoscopy to identify and treat the source is the appropriate evaluation for lower GI bleeding, which painless hematochezia from likely diverticular or angiodysplastic sources represents, and it can both diagnose and treat. Upper endoscopy is first considered when an upper source is suspected, such as melena or hemodynamic instability with hematemesis. Laparotomy is not indicated for self-limited stable bleeding. Iron alone without localizing the source is inadequate.

875. A 58-year-old man undergoes screening colonoscopy that reveals three small tubular adenomas, all completely removed. Pathology shows no high-grade dysplasia or villous features. What is the most appropriate recommendation for his next surveillance colonoscopy?
     • Annual colonoscopy indefinitely
     • Repeat colonoscopy in ten years as for average-risk screening
     • No further colonoscopy is needed during his lifetime
     • Repeat colonoscopy in about three to five years based on the polyp findings

     Correct answer: Repeat colonoscopy in about three to five years based on the polyp findings

     Repeat colonoscopy in about three to five years based on the polyp findings is the recommended surveillance interval after removal of a few small tubular adenomas without advanced features. A ten-year interval applies to a normal screening exam, not after adenoma removal. Forgoing further surveillance ignores the increased risk. Annual colonoscopy is more frequent than indicated for low-risk adenomas.

876. A 62-year-old man at average risk asks about colorectal cancer screening options. He prefers a noninvasive stool-based test. Which statement most accurately describes appropriate screening?
     • Colorectal cancer screening should begin at age 45 for average-risk adults, and a positive stool test must be followed by colonoscopy
     • Screening should begin only at age 60 for all adults
     • A positive stool-based test requires no further evaluation
     • Stool-based testing replaces the need for any colonoscopy even when results are abnormal

     Correct answer: Colorectal cancer screening should begin at age 45 for average-risk adults, and a positive stool test must be followed by colonoscopy

     Colorectal cancer screening should begin at age 45 for average-risk adults, and a positive stool test must be followed by colonoscopy to evaluate and remove any lesions. Beginning at 60 misses the recommended start age. A positive stool test always requires colonoscopy. Stool testing does not eliminate the need for colonoscopy when results are abnormal.

877. A 70-year-old man presents with progressive fatigue and is found to have iron-deficiency anemia. He has no overt bleeding, no menstrual losses, and is a man over 50. Which evaluation is most appropriate to identify the source?
     • Empiric oral iron with no further investigation
     • Endoscopic evaluation of the gastrointestinal tract, including colonoscopy, to exclude a GI malignancy
     • Bone marrow biopsy as the first step
     • Reassurance, since iron deficiency in older men is usually dietary

     Correct answer: Endoscopic evaluation of the gastrointestinal tract, including colonoscopy, to exclude a GI malignancy

     Endoscopic evaluation of the gastrointestinal tract, including colonoscopy, to exclude a GI malignancy is essential because unexplained iron-deficiency anemia in an older man strongly suggests occult GI blood loss, classically from colorectal cancer. Empiric iron without a workup can mask a cancer. Bone marrow biopsy is not the first step for typical iron deficiency. Dietary iron deficiency is uncommon in this group, making reassurance inappropriate.

878. A 19-year-old man presents with periumbilical pain that migrated to the right lower quadrant, anorexia, and a low-grade fever. He has rebound tenderness at McBurney point and a mild leukocytosis. What is the most appropriate management?
     • Empiric antiparasitic therapy
     • Outpatient antacids and follow-up in one week
     • Surgical evaluation for appendectomy
     • A trial of antidiarrheal medication

     Correct answer: Surgical evaluation for appendectomy

     Surgical evaluation for appendectomy is appropriate because migratory right lower quadrant pain with anorexia, fever, focal tenderness, and leukocytosis is a classic presentation of acute appendicitis requiring prompt surgical management to prevent perforation. Antacids, antiparasitics, and antidiarrheals do not treat appendicitis and would dangerously delay care.

879. A 65-year-old woman presents with crampy abdominal pain, abdominal distension, vomiting, and obstipation. She has a prior abdominal surgery. Imaging shows dilated small-bowel loops with air-fluid levels and a transition point, without signs of strangulation or perforation. What is the most appropriate initial management?
     • Oral contrast challenge followed by immediate discharge
     • Immediate exploratory laparotomy in all cases
     • Outpatient stool softeners and discharge
     • Nasogastric decompression, intravenous fluids, and bowel rest with serial reassessment

     Correct answer: Nasogastric decompression, intravenous fluids, and bowel rest with serial reassessment

     Nasogastric decompression, intravenous fluids, and bowel rest with serial reassessment constitute the appropriate initial management of an uncomplicated adhesive small-bowel obstruction without ischemia or perforation, because many resolve without surgery. Immediate laparotomy is reserved for strangulation, perforation, or failure to improve. Outpatient discharge is unsafe for an obstruction with vomiting. Discharging after contrast without monitoring ignores the risk of deterioration.

880. A 60-year-old man with cirrhosis is admitted with new-onset ascites and rising creatinine. His urine sodium is very low, there is no proteinuria or hematuria, and renal function does not improve after stopping diuretics and giving a volume challenge with albumin. Which diagnosis best explains his renal failure?
     • Hepatorenal syndrome
     • Acute tubular necrosis from a nephrotoxin
     • Glomerulonephritis
     • Postrenal obstruction

     Correct answer: Hepatorenal syndrome

     Hepatorenal syndrome best explains progressive renal failure in advanced cirrhosis with avid sodium retention, a bland urine sediment, and no improvement after volume expansion and stopping diuretics. Acute tubular necrosis typically shows granular casts and a higher urine sodium. Glomerulonephritis produces proteinuria and hematuria. Postrenal obstruction would be evident on imaging.

881. A 48-year-old woman with cirrhosis is being evaluated for prognosis and transplant priority. Which scoring system, based on bilirubin, creatinine, and the international normalized ratio, is used to estimate mortality and prioritize liver transplantation?
     • The CURB-65 score
     • The MELD score
     • The Glasgow-Blatchford score
     • The Wells score

     Correct answer: The MELD score

     The MELD score uses bilirubin, creatinine, and the international normalized ratio to estimate short-term mortality in cirrhosis and prioritize liver transplant allocation. The CURB-65 score assesses pneumonia severity. The Glasgow-Blatchford score risk-stratifies upper GI bleeding. The Wells score estimates the probability of venous thromboembolism.

882. A 35-year-old woman presents with fatigue and pruritus and is found to have a markedly elevated alkaline phosphatase with a positive antimitochondrial antibody. Bilirubin is near normal and she has no biliary obstruction on imaging. Which first-line therapy is recommended for this cholestatic liver disease?
     • Lifelong broad-spectrum antibiotics
     • High-dose corticosteroids
     • Ursodeoxycholic acid
     • Immediate liver transplantation

     Correct answer: Ursodeoxycholic acid

     Ursodeoxycholic acid is first-line therapy for primary biliary cholangitis, indicated by cholestatic enzyme elevation, antimitochondrial antibodies, and no mechanical obstruction; it slows disease progression. Corticosteroids are used in autoimmune hepatitis, not this condition. Chronic antibiotics are not indicated. Transplantation is reserved for advanced disease, not initial management.

883. A 42-year-old obese woman with type 2 diabetes is found to have mildly elevated aminotransferases. She drinks minimal alcohol and viral hepatitis serologies are negative. Ultrasound shows a fatty-appearing liver. Which intervention most effectively addresses the underlying liver disease?
     • Lifelong oral corticosteroids
     • A short course of oral antibiotics
     • Immediate referral for liver biopsy in all such patients before any treatment
     • Weight loss through diet and exercise to reduce hepatic fat

     Correct answer: Weight loss through diet and exercise to reduce hepatic fat

     Weight loss through diet and exercise to reduce hepatic fat is the most effective intervention for nonalcoholic fatty liver disease associated with obesity and diabetes, and it can reverse steatosis and improve inflammation. Antibiotics do not treat the condition. Liver biopsy is selective, not universally required before treatment. Corticosteroids are not standard therapy for fatty liver disease.

884. A 28-year-old man presents with right upper quadrant pain, nausea, and jaundice. He recently returned from travel and ate at street vendors. Labs show markedly elevated aminotransferases and a positive IgM antibody to hepatitis A. He is otherwise stable. What is the most appropriate management?
     • Supportive care, as acute hepatitis A is typically self-limited
     • Lifelong antiviral therapy
     • Immediate liver transplant evaluation
     • A prolonged course of corticosteroids

     Correct answer: Supportive care, as acute hepatitis A is typically self-limited

     Supportive care, as acute hepatitis A is typically self-limited, is appropriate because hepatitis A is an acute self-resolving infection that does not become chronic and requires only symptom management with monitoring. Lifelong antivirals are used for chronic hepatitis B or C, not hepatitis A. Transplant evaluation is reserved for the rare case of fulminant failure. Corticosteroids are not indicated.

885. A 55-year-old man with chronic hepatitis B and no cirrhosis has a high viral load and persistently elevated alanine aminotransferase. Which class of therapy is recommended to suppress viral replication and reduce the risk of cirrhosis and hepatocellular carcinoma?
     • A short course of empiric antibiotics
     • A nucleos(t)ide analogue such as tenofovir or entecavir
     • A proton pump inhibitor
     • Lactulose

     Correct answer: A nucleos(t)ide analogue such as tenofovir or entecavir

     A nucleos(t)ide analogue such as tenofovir or entecavir suppresses hepatitis B viral replication and reduces progression to cirrhosis and hepatocellular carcinoma in patients with active disease. Antibiotics treat bacterial infections, not viral hepatitis. A proton pump inhibitor reduces acid but has no antiviral effect. Lactulose treats hepatic encephalopathy, not the underlying viral infection.

886. A 30-year-old woman presents with fatigue and elevated aminotransferases. She has a high titer of antinuclear and anti-smooth muscle antibodies, elevated IgG, and a liver biopsy showing interface hepatitis. Viral serologies are negative. Which therapy is first-line for this condition?
     • Tenofovir
     • Ursodeoxycholic acid alone
     • Corticosteroids, often with azathioprine
     • Phlebotomy

     Correct answer: Corticosteroids, often with azathioprine

     Corticosteroids, often with azathioprine, are first-line for autoimmune hepatitis, indicated by autoantibodies, elevated IgG, interface hepatitis, and negative viral serologies. Ursodeoxycholic acid is used in primary biliary cholangitis. Tenofovir treats hepatitis B. Phlebotomy treats hereditary hemochromatosis, a different cause of liver injury.

887. A 50-year-old man presents with fatigue, joint pain, bronze skin, and new-onset diabetes. Labs show an elevated transferrin saturation and ferritin. Genetic testing confirms a hereditary iron-overload disorder. Which is the cornerstone treatment to reduce iron burden?
     • Corticosteroids
     • Oral iron supplementation
     • Ursodeoxycholic acid
     • Therapeutic phlebotomy

     Correct answer: Therapeutic phlebotomy

     Therapeutic phlebotomy is the cornerstone treatment for hereditary hemochromatosis, removing excess iron and preventing organ damage including cirrhosis. Oral iron would worsen the overload and is contraindicated. Ursodeoxycholic acid treats cholestatic liver disease, not iron overload. Corticosteroids have no role in iron removal.

888. A 60-year-old woman with diabetes presents with severe epigastric pain radiating to the back consistent with acute pancreatitis, but she does not drink alcohol and an ultrasound shows no gallstones. Her triglycerides are normal. She started a new medication recently. Which additional historical detail most directly identifies a likely etiology?
     • Recent initiation of a drug known to cause pancreatitis
     • A family history of colon cancer
     • A recent upper respiratory infection
     • A history of seasonal allergies

     Correct answer: Recent initiation of a drug known to cause pancreatitis

     Recent initiation of a drug known to cause pancreatitis most directly identifies an etiology when gallstones, alcohol, and hypertriglyceridemia are excluded, because numerous medications can trigger acute pancreatitis. A family history of colon cancer, a recent respiratory infection, and seasonal allergies are not established causes of acute pancreatitis in this scenario.

889. A 55-year-old man with a history of repeated bouts of alcohol-related pancreatitis now has chronic epigastric pain, weight loss, greasy foul-smelling stools, and new diabetes. Imaging shows pancreatic calcifications. Which therapy most directly addresses his malabsorptive symptoms?
     • A proton pump inhibitor as the sole treatment
     • Pancreatic enzyme replacement therapy
     • Broad-spectrum antibiotics
     • Increased dietary fiber alone

     Correct answer: Pancreatic enzyme replacement therapy

     Pancreatic enzyme replacement therapy directly treats the steatorrhea and malabsorption of chronic pancreatitis caused by exocrine insufficiency, as suggested by greasy stools, weight loss, and calcifications. A proton pump inhibitor may be an adjunct but does not replace missing enzymes. Antibiotics do not treat malabsorption. Added fiber does not correct fat malabsorption.

890. A 40-year-old woman with a history of gallstones develops acute pancreatitis. After her acute episode resolves and she is recovering well, what is the recommended definitive measure to prevent recurrent gallstone pancreatitis?
     • Permanent dietary fat elimination as the only intervention
     • Lifelong proton pump inhibitor therapy
     • Cholecystectomy, ideally during the same hospitalization for mild disease
     • Routine prophylactic ERCP every six months

     Correct answer: Cholecystectomy, ideally during the same hospitalization for mild disease

     Cholecystectomy, ideally during the same hospitalization for mild disease, prevents recurrent gallstone pancreatitis by removing the source of stones and is recommended once the patient recovers. A proton pump inhibitor does not prevent gallstone pancreatitis. Dietary fat restriction alone does not address the stones. Routine prophylactic ERCP is not a standard preventive strategy and carries its own risks.

891. A 33-year-old man presents with watery diarrhea that began during a hospitalization where he received clindamycin. He now has crampy abdominal pain and a low-grade fever. Stool testing is positive for Clostridioides difficile toxin. Which is the most appropriate first-line treatment for an initial non-severe episode?
     • Reassurance with no antimicrobial therapy
     • Continuation of clindamycin with added loperamide
     • Intravenous metronidazole as the preferred single agent
     • Oral fidaxomicin or oral vancomycin and discontinuation of the inciting antibiotic

     Correct answer: Oral fidaxomicin or oral vancomycin and discontinuation of the inciting antibiotic

     Oral fidaxomicin or oral vancomycin and discontinuation of the inciting antibiotic is the current first-line approach to an initial Clostridioides difficile infection, replacing oral metronidazole for most cases. Continuing the offending antibiotic perpetuates the infection, and loperamide can worsen colitis. Intravenous metronidazole alone is reserved for special situations like ileus. Withholding treatment is inappropriate for confirmed symptomatic infection.

892. A 25-year-old man presents with several days of bloody diarrhea, abdominal cramps, and fever after a barbecue with undercooked poultry. He is well-hydrated and not toxic-appearing. Stool studies are pending. Which management principle is most appropriate for this likely inflammatory infectious diarrhea?
     • Supportive hydration with judicious use of antibiotics guided by severity and pathogen
     • Routine antimotility agents to stop the bloody diarrhea quickly
     • Empiric high-dose corticosteroids
     • Immediate colectomy

     Correct answer: Supportive hydration with judicious use of antibiotics guided by severity and pathogen

     Supportive hydration with judicious use of antibiotics guided by severity and pathogen is appropriate for acute inflammatory infectious diarrhea, because many cases are self-limited and antibiotic decisions depend on the organism and severity. Antimotility agents can be harmful in invasive bloody diarrhea by prolonging illness. Corticosteroids are not indicated for infectious diarrhea. Colectomy is not a treatment for uncomplicated infectious colitis.

893. A 47-year-old woman is found to have a markedly elevated unconjugated bilirubin with normal aminotransferases and alkaline phosphatase. There is no evidence of hemolysis, and the elevation worsens with fasting or illness but causes no other problems. Which condition best explains this benign finding?
     • Acute viral hepatitis
     • Gilbert syndrome
     • Choledocholithiasis with biliary obstruction
     • Primary sclerosing cholangitis

     Correct answer: Gilbert syndrome

     Gilbert syndrome best explains an isolated unconjugated hyperbilirubinemia with normal liver enzymes and no hemolysis, often worsened by fasting or stress, reflecting reduced bilirubin conjugation; it is benign and requires no treatment. Acute viral hepatitis raises aminotransferases. Choledocholithiasis causes a conjugated, obstructive pattern with elevated alkaline phosphatase. Primary sclerosing cholangitis produces cholestatic enzyme abnormalities.

894. A 58-year-old man is diagnosed with an acute proximal deep vein thrombosis. He is started on apixaban as a single-drug oral regimen. The patient asks why he is taking a higher dose twice daily for the first week before reducing the dose. Which explanation best describes the rationale for this initial lead-in dosing?
     • The higher early dose provides intensified anticoagulation during the period of greatest clot burden, after which a lower maintenance dose suffices
     • The higher dose is needed permanently and will never be reduced
     • The first week's dose compensates for a required heparin bridge
     • The early dose is higher only to monitor the INR more accurately

     Correct answer: The higher early dose provides intensified anticoagulation during the period of greatest clot burden, after which a lower maintenance dose suffices

     The higher early dose providing intensified anticoagulation during the period of greatest clot burden is correct. Apixaban for acute venous thromboembolism uses a higher twice-daily lead-in dose for the first 7 days to cover the period of highest thrombotic risk, then steps down to a standard maintenance dose. The reduction is planned rather than permanent, apixaban requires no heparin bridge, and direct oral anticoagulants are not titrated by INR.

895. A 47-year-old woman develops acute left leg swelling and is found on ultrasound to have an extensive iliofemoral deep vein thrombosis with marked limb pain, cyanosis, and tense swelling threatening tissue viability. Which intervention should be considered in addition to anticoagulation for this limb-threatening presentation?
     • Switch from anticoagulation to aspirin
     • Catheter-directed thrombolysis
     • Apply a tight compression wrap and observe
     • Elevate the leg and defer all intervention

     Correct answer: Catheter-directed thrombolysis

     Catheter-directed thrombolysis is correct. Phlegmasia cerulea dolens, a massive iliofemoral thrombosis with cyanosis and threatened limb viability, is one of the few situations where thrombolysis (often catheter-directed) is added to anticoagulation to rapidly restore venous outflow and save the limb. Substituting aspirin is inadequate, a tight wrap can worsen ischemia, and elevation alone does not address impending limb loss.

896. A 33-year-old woman who is 16 weeks pregnant develops a confirmed proximal deep vein thrombosis. She has normal renal function and no bleeding. Which anticoagulant is the most appropriate choice during her pregnancy?
     • Warfarin titrated to an INR of 2 to 3
     • A direct oral factor Xa inhibitor
     • Low-molecular-weight heparin
     • Aspirin alone

     Correct answer: Low-molecular-weight heparin

     Low-molecular-weight heparin is correct. It does not cross the placenta and is the standard anticoagulant for venous thromboembolism in pregnancy. Warfarin is teratogenic and crosses the placenta, direct oral anticoagulants are not recommended in pregnancy because of limited safety data and placental transfer, and aspirin is inadequate for treating an established clot.

897. A 25-year-old man presents with calf pain and swelling, and a validated clinical prediction tool yields a low pretest probability for deep vein thrombosis. Which next step is the most appropriate and resource-efficient to safely rule out the diagnosis?
     • Obtain a high-sensitivity D-dimer
     • Proceed directly to contrast venography
     • Begin empiric anticoagulation immediately
     • Order serial CT scans of the legs

     Correct answer: Obtain a high-sensitivity D-dimer

     Obtaining a high-sensitivity D-dimer is correct. In a patient with low pretest probability, a negative high-sensitivity D-dimer reliably excludes deep vein thrombosis without imaging, sparing unnecessary ultrasound. Venography is invasive and rarely needed, empiric anticoagulation before confirming the diagnosis exposes a low-risk patient to bleeding, and CT is not the appropriate test for leg DVT.

898. A 70-year-old woman with a remote history of an unprovoked deep vein thrombosis completed anticoagulation 2 years ago. She now presents with new acute leg swelling. Compression ultrasound shows a clot in the same vein, but it is unclear whether this is new thrombosis or residual chronic change. Which finding best supports an acute recurrent deep vein thrombosis rather than old residual thrombus?
     • A fully compressible vein with thin walls
     • A new increase in residual vein diameter or a previously normal segment that is now noncompressible
     • Calcified valve leaflets only
     • A normal D-dimer with no symptoms

     Correct answer: A new increase in residual vein diameter or a previously normal segment that is now noncompressible

     A new noncompressible segment or an increase in residual vein diameter is correct. Recurrence in a previously affected vein is suggested when a segment that was patent becomes noncompressible or the residual thrombus diameter increases compared with prior imaging, since chronic residual changes alone can mimic clot. A fully compressible vein argues against acute clot, calcification reflects chronicity, and a normal D-dimer in an asymptomatic patient does not indicate acute recurrence.

899. A 60-year-old man with sepsis from gram-negative bacteremia develops disseminated intravascular coagulation. The team wants to understand the initiating molecular event that triggers the widespread coagulation. Which mechanism most directly initiates the coagulopathy in sepsis-associated disseminated intravascular coagulation?
     • Endotoxin-induced expression of tissue factor that activates the coagulation cascade
     • A hereditary deficiency of factor IX
     • Autoantibodies directed against platelets
     • Mechanical shearing of red cells by a heart valve

     Correct answer: Endotoxin-induced expression of tissue factor that activates the coagulation cascade

     Endotoxin-induced tissue factor expression is correct. In sepsis, inflammatory mediators and bacterial endotoxin induce tissue factor on monocytes and endothelium, activating the extrinsic coagulation pathway and generating widespread thrombin, the central trigger of disseminated intravascular coagulation. A hereditary factor IX deficiency causes hemophilia B, antiplatelet autoantibodies cause immune thrombocytopenia, and mechanical red cell shearing causes a macroangiopathic hemolytic anemia, none of which initiate this consumptive coagulopathy.

900. A 44-year-old woman is suspected of having disseminated intravascular coagulation. Serial labs are ordered to assess the trend. Which single serial laboratory trend is considered the most sensitive early marker of evolving disseminated intravascular coagulation?
     • A rising white blood cell count
     • A falling platelet count on serial measurements
     • A rising hemoglobin
     • A stable fibrinogen

     Correct answer: A falling platelet count on serial measurements

     A falling platelet count on serial measurements is correct. A progressive decline in platelets is one of the earliest and most sensitive signs of evolving disseminated intravascular coagulation because consumption begins before fibrinogen falls dramatically. A rising white count is nonspecific, a rising hemoglobin is not expected, and a stable fibrinogen would argue against active consumption.

901. A 55-year-old man with disseminated intravascular coagulation has a fibrinogen that remains low despite cryoprecipitate, but his thrombotic complications predominate over bleeding. The team weighs adding heparin. Which statement best describes the appropriate use of low-dose heparin in disseminated intravascular coagulation?
     • Heparin is appropriate when thrombosis predominates and there is no major active bleeding
     • Heparin should be given to every patient with disseminated intravascular coagulation
     • Heparin is the treatment of choice for actively hemorrhaging patients
     • Heparin permanently cures the underlying coagulopathy

     Correct answer: Heparin is appropriate when thrombosis predominates and there is no major active bleeding

     Heparin being appropriate when thrombosis predominates without major active bleeding is correct. In the thrombotic-predominant form of disseminated intravascular coagulation, low-dose heparin can dampen ongoing thrombin generation, but it is hazardous in actively bleeding patients. It is not given universally, it is contraindicated as first-line in major hemorrhage, and it does not cure the coagulopathy, which resolves only when the underlying trigger is treated.

902. A 30-year-old woman with severe placental abruption develops bleeding from multiple sites with a low fibrinogen, prolonged PT and aPTT, thrombocytopenia, and elevated D-dimer. The team recognizes the obstetric trigger of her disseminated intravascular coagulation. Which is the single most important intervention to resolve her coagulopathy?
     • Lifelong anticoagulation
     • Delivery of the fetus and placenta to remove the procoagulant source
     • High-dose corticosteroids
     • Plasma exchange

     Correct answer: Delivery of the fetus and placenta to remove the procoagulant source

     Delivery to remove the procoagulant source is correct. Obstetric disseminated intravascular coagulation from abruption is driven by release of placental tissue factor, so prompt delivery of the fetus and placenta removes the trigger and is essential for resolution, alongside blood-product support. Anticoagulation, corticosteroids, and plasma exchange do not address the underlying obstetric driver.

903. A 62-year-old man with chronic iron deficiency anemia from slow gastrointestinal blood loss is treated with oral ferrous sulfate. After 2 weeks of therapy, which laboratory finding is the earliest expected indicator that the iron is working?
     • Normalization of the mean corpuscular volume
     • A rise in the reticulocyte count
     • Normalization of ferritin
     • A rise in total iron-binding capacity

     Correct answer: A rise in the reticulocyte count

     A rise in the reticulocyte count is correct. After effective iron repletion, a reticulocytosis appears within about a week as the marrow resumes red cell production, preceding the slower rise in hemoglobin and normalization of indices. The mean corpuscular volume and ferritin normalize over weeks to months, and total iron-binding capacity falls rather than rises as stores are replenished.

904. A 28-year-old woman with iron deficiency anemia is prescribed oral iron but reports poor absorption. Which counseling point best optimizes oral iron absorption?
     • Take the iron with a calcium supplement and an antacid
     • Take the iron with vitamin C and avoid taking it with tea, dairy, or proton pump inhibitors
     • Take the iron only with large meals high in dairy
     • Take the iron immediately after antacids to reduce stomach upset

     Correct answer: Take the iron with vitamin C and avoid taking it with tea, dairy, or proton pump inhibitors

     Taking iron with vitamin C and avoiding tea, dairy, and acid-suppressing agents is correct. An acidic environment and ascorbic acid enhance iron absorption, whereas calcium, dairy, tea tannins, antacids, and proton pump inhibitors reduce it. Pairing iron with calcium, antacids, or dairy impairs uptake.

905. A 38-year-old man is found to have iron deficiency anemia. His ferritin is borderline, making interpretation difficult, and he has a coexisting inflammatory condition that can elevate ferritin. Which additional test best clarifies whether true iron deficiency is present in this setting?
     • Soluble transferrin receptor level
     • Serum vitamin B12
     • Reticulocyte hemoglobin alone in isolation from iron studies
     • Direct antiglobulin test

     Correct answer: Soluble transferrin receptor level

     Soluble transferrin receptor level is correct. Because ferritin is an acute-phase reactant that rises with inflammation and can mask iron deficiency, the soluble transferrin receptor, which increases with true iron deficiency and is unaffected by inflammation, helps distinguish iron deficiency from anemia of chronic disease. Vitamin B12 and the direct antiglobulin test address unrelated processes.

906. A 65-year-old man with severe sepsis is being resuscitated. Despite adequate fluids and norepinephrine, he remains hypotensive and is found to have a low random cortisol with refractory shock. Which adjunctive therapy is most appropriate for this vasopressor-refractory septic shock?
     • High-dose insulin
     • Low-dose intravenous hydrocortisone
     • Therapeutic anticoagulation
     • Broad-spectrum antifungal therapy alone

     Correct answer: Low-dose intravenous hydrocortisone

     Low-dose intravenous hydrocortisone is correct. In septic shock that remains refractory to adequate fluids and vasopressors, low-dose corticosteroids are recommended to help restore vascular responsiveness. Insulin, anticoagulation, and empiric antifungals do not address vasopressor-refractory shock in this context.

907. A 72-year-old woman is admitted with suspected sepsis. The clinical team wants to rapidly identify whether she has organ dysfunction at the bedside outside the ICU. Which bedside scoring tool is most appropriate for quickly flagging patients at higher risk of poor outcomes from sepsis?
     • The quick Sequential Organ Failure Assessment (qSOFA) score
     • The CHA2DS2-VASc score
     • The Wells score for pulmonary embolism
     • The Child-Pugh score

     Correct answer: The quick Sequential Organ Failure Assessment (qSOFA) score

     The quick Sequential Organ Failure Assessment score is correct. It uses three simple bedside criteria, altered mental status, a high respiratory rate, and low systolic blood pressure, to rapidly flag patients with suspected infection who are at higher risk of poor outcomes. CHA2DS2-VASc estimates stroke risk in atrial fibrillation, the Wells score assesses pulmonary embolism probability, and Child-Pugh grades liver disease.

908. A 27-year-old woman with a previous anaphylactic reaction to a wasp sting is being counseled on long-term risk reduction. Beyond carrying epinephrine, which intervention can reduce her risk of future severe reactions to insect stings?
     • Daily oral antihistamines for life
     • Venom immunotherapy (allergen desensitization)
     • Routine prophylactic corticosteroids
     • Avoiding all outdoor activity permanently

     Correct answer: Venom immunotherapy (allergen desensitization)

     Venom immunotherapy is correct. For patients with a history of systemic anaphylaxis to insect stings, allergen-specific immunotherapy substantially reduces the risk and severity of future sting reactions. Daily antihistamines and prophylactic corticosteroids do not prevent anaphylaxis, and complete avoidance of the outdoors is neither practical nor reliable.

909. A 34-year-old man is treated for anaphylaxis with intramuscular epinephrine and recovers fully within an hour. The physician counsels him to remain monitored for several hours. Which phenomenon justifies a period of observation after apparent recovery from anaphylaxis?
     • The risk of a biphasic reaction with recurrence of symptoms hours later
     • The need to repeat allergy skin testing during the same visit
     • A delayed hemolytic reaction
     • Development of iron deficiency

     Correct answer: The risk of a biphasic reaction with recurrence of symptoms hours later

     The risk of a biphasic reaction is correct. Anaphylaxis can recur hours after the initial episode despite an apparent resolution, so a period of observation is recommended to detect and treat a biphasic reaction. Repeat skin testing during the acute visit is not done, and delayed hemolysis and iron deficiency are unrelated to anaphylaxis monitoring.

910. A 19-year-old man receiving a routine blood transfusion has had several prior febrile nonhemolytic transfusion reactions. To prevent recurrence at his next transfusion, which intervention is most appropriate?
     • Transfuse only fresh whole blood
     • Use leukoreduced blood products
     • Premedicate with epinephrine
     • Warm the blood to body temperature before infusion

     Correct answer: Use leukoreduced blood products

     Using leukoreduced blood products is correct. Febrile nonhemolytic reactions are caused largely by recipient antibodies against donor leukocytes and accumulated cytokines, so leukoreduction reduces their recurrence. Whole blood does not prevent the reaction, epinephrine is for anaphylaxis, and warming blood prevents hypothermia from massive transfusion rather than febrile reactions.

911. A 6-year-old boy with congenital T-cell immunodeficiency requires a red cell transfusion. The blood bank takes a special precaution to prevent a specific fatal complication in this immunocompromised recipient. Which transfusion modification is most important?
     • Irradiation of the cellular blood products
     • Rapid infusion over 10 minutes
     • Using only the freshest available units regardless of irradiation
     • Adding extra plasma to each unit

     Correct answer: Irradiation of the cellular blood products

     Irradiation of cellular blood products is correct. Severely immunocompromised recipients are at risk for transfusion-associated graft-versus-host disease, in which viable donor lymphocytes attack host tissues; irradiating cellular products inactivates these lymphocytes and prevents this nearly always fatal complication. Faster infusion, simply using fresh units, or adding plasma does not prevent graft-versus-host disease.

912. A 50-year-old man with hereditary hemochromatosis is undergoing serial therapeutic phlebotomy. Which laboratory parameter is most appropriate to monitor to guide the frequency of phlebotomy and assess when maintenance can begin?
     • Serum ferritin
     • Serum sodium
     • White blood cell count
     • Serum albumin

     Correct answer: Serum ferritin

     Serum ferritin is correct. Ferritin reflects total body iron stores, so it is followed during therapeutic phlebotomy to gauge iron depletion and to determine when the patient transitions from the de-ironing phase to less frequent maintenance phlebotomy. Sodium, white count, and albumin do not track iron burden.

913. A 45-year-old man with hereditary hemochromatosis is counseled about dietary and lifestyle measures. Which recommendation is most appropriate to limit further iron accumulation and protect his liver?
     • Take large doses of vitamin C with meals
     • Avoid alcohol and avoid iron and vitamin C supplements
     • Increase red meat intake substantially
     • Begin a daily iron supplement

     Correct answer: Avoid alcohol and avoid iron and vitamin C supplements

     Avoiding alcohol and iron and vitamin C supplements is correct. Alcohol accelerates hepatic injury in iron overload, and supplemental iron and vitamin C (which enhances iron absorption) worsen iron accumulation, so all should be avoided. Increasing red meat or taking iron supplements would add iron, the opposite of what is needed.

914. A 24-year-old man with sickle cell disease is seen for routine care. Which vaccination and prophylaxis strategy is most important to reduce his risk of life-threatening infection given his functional asplenia?
     • No additional vaccines beyond routine childhood schedule
     • Vaccination against encapsulated organisms such as pneumococcus and meningococcus, with penicillin prophylaxis in early childhood
     • Annual influenza vaccine only, with no other measures
     • Lifelong daily antifungal prophylaxis

     Correct answer: Vaccination against encapsulated organisms such as pneumococcus and meningococcus, with penicillin prophylaxis in early childhood

     Vaccination against encapsulated organisms with childhood penicillin prophylaxis is correct. Repeated splenic infarction in sickle cell disease produces functional asplenia, raising the risk of overwhelming infection by encapsulated bacteria, so pneumococcal, meningococcal, and Haemophilus vaccines plus penicillin prophylaxis in young children are essential. Routine childhood vaccines alone are insufficient, influenza vaccine alone is inadequate, and antifungal prophylaxis is not indicated.

915. A 5-year-old child with sickle cell disease presents with sudden pallor, lethargy, and a rapidly enlarging spleen, with a hemoglobin that has dropped sharply and a high reticulocyte count. Which acute complication has most likely occurred?
     • Aplastic crisis from parvovirus
     • Acute splenic sequestration crisis
     • Iron deficiency anemia
     • Vaso-occlusive bone crisis

     Correct answer: Acute splenic sequestration crisis

     Acute splenic sequestration crisis is correct. Sudden pooling of blood in the spleen causes rapid splenomegaly, a precipitous hemoglobin drop, and hypovolemia, with a high reticulocyte count reflecting intact marrow response; it is a pediatric emergency requiring transfusion. An aplastic crisis from parvovirus causes a low reticulocyte count, iron deficiency develops slowly, and a vaso-occlusive crisis causes pain without acute splenic enlargement.

916. An 8-year-old child with sickle cell disease develops sudden severe pallor and fatigue with a hemoglobin far below baseline and a reticulocyte count that is inappropriately low. Recent exposure to a viral illness with a slapped-cheek rash is noted. Which cause best explains this aplastic crisis?
     • Parvovirus B19 infection suppressing red cell production
     • Acute splenic sequestration
     • Iron overload
     • Cold agglutinin disease

     Correct answer: Parvovirus B19 infection suppressing red cell production

     Parvovirus B19 infection is correct. The virus infects erythroid precursors and transiently halts red cell production, causing an aplastic crisis with a sharp hemoglobin drop and a low reticulocyte count in patients with chronic hemolysis. Splenic sequestration shows a high reticulocyte count and splenomegaly, iron overload does not cause acute anemia, and cold agglutinin disease causes hemolysis rather than marrow suppression.

917. A 30-year-old man with HIV and a CD4 count of 45 cells/microliter is being optimized on antiretroviral therapy. In addition to Pneumocystis prophylaxis, which prophylaxis is indicated at this very low CD4 count to prevent a common disseminated opportunistic infection?
     • Prophylaxis against Mycobacterium avium complex is no longer routinely recommended when starting effective antiretroviral therapy
     • Lifelong amphotericin B
     • Routine ganciclovir for all patients
     • Daily acyclovir to prevent toxoplasmosis

     Correct answer: Prophylaxis against Mycobacterium avium complex is no longer routinely recommended when starting effective antiretroviral therapy

     The recognition that routine Mycobacterium avium complex prophylaxis is no longer recommended when effective antiretroviral therapy is promptly started is correct. Current guidance has moved away from routine azithromycin prophylaxis for disseminated Mycobacterium avium complex in patients who are starting effective antiretroviral therapy, since immune reconstitution provides protection. Lifelong amphotericin, routine ganciclovir, and acyclovir for toxoplasmosis are not appropriate strategies.

918. A healthcare worker is evaluated after a needlestick from a source patient whose HIV status is unknown but who has no risk factors and is ultimately confirmed HIV negative by rapid testing. The exposed worker has not yet started any medication. Which is the most appropriate management?
     • Begin a 4-week course of antiretroviral prophylaxis regardless of source testing
     • Give HIV immune globulin
     • No HIV postexposure prophylaxis is indicated once the source is confirmed HIV negative
     • Start lifelong antiretroviral therapy for the worker

     Correct answer: No HIV postexposure prophylaxis is indicated once the source is confirmed HIV negative

     No HIV postexposure prophylaxis once the source is confirmed negative is correct. When rapid testing confirms the source patient is HIV negative, the risk of transmission is negligible and prophylaxis is not warranted or can be stopped if already begun. Treating regardless of negative source testing exposes the worker to needless toxicity, there is no HIV immune globulin, and lifelong therapy is not indicated.

919. A 32-year-old woman of childbearing age is newly diagnosed with HIV and wishes to prevent transmission to a future infant. Which intervention most effectively reduces the risk of mother-to-child HIV transmission?
     • Maternal iron supplementation
     • Effective antiretroviral therapy achieving viral suppression during pregnancy
     • Cesarean delivery alone without antiretrovirals
     • Breastfeeding to transfer maternal antibodies

     Correct answer: Effective antiretroviral therapy achieving viral suppression during pregnancy

     Effective antiretroviral therapy achieving viral suppression is correct. Maintaining an undetectable maternal viral load with antiretroviral therapy throughout pregnancy is the most powerful way to reduce perinatal HIV transmission. Iron does not affect transmission, cesarean delivery alone without viral suppression is less effective, and breastfeeding can transmit HIV rather than protect the infant.

920. A 45-year-old man is exposed to a sexual partner with known HIV during condomless intercourse 18 hours ago and presents to an urgent care clinic. Which intervention is most appropriate to reduce his risk of acquiring HIV?
     • Begin nonoccupational HIV postexposure prophylaxis as soon as possible, within 72 hours
     • Wait 3 months and test before any treatment
     • Administer HIV vaccine
     • Give a single dose of an antiviral and stop

     Correct answer: Begin nonoccupational HIV postexposure prophylaxis as soon as possible, within 72 hours

     Beginning nonoccupational postexposure prophylaxis within 72 hours is correct. After a high-risk nonoccupational exposure, a multidrug antiretroviral regimen started as soon as possible and within 72 hours, continued for 28 days, reduces the chance of seroconversion. Delaying until testing reduces efficacy, there is no effective HIV vaccine, and a single antiviral dose is inadequate.

921. A 60-year-old woman with newly diagnosed multiple myeloma is being managed. She has anemia, lytic bone lesions, and bone pain. Which supportive medication reduces skeletal complications such as fractures and bone pain in this disease?
     • Oral iron
     • A bisphosphonate such as zoledronic acid
     • Erythropoietin alone for bone protection
     • Vitamin K

     Correct answer: A bisphosphonate such as zoledronic acid

     A bisphosphonate such as zoledronic acid is correct. Bisphosphonates reduce skeletal-related events, including pathologic fractures and bone pain, in multiple myeloma by inhibiting osteoclast-mediated bone destruction. Iron does not protect bone, erythropoietin addresses anemia rather than skeletal events, and vitamin K is unrelated.

922. A 68-year-old man with suspected multiple myeloma has anemia and renal insufficiency. Which combination of laboratory and protein studies is most appropriate to establish the diagnosis?
     • Serum and urine protein electrophoresis with immunofixation and serum free light chains, plus a bone marrow biopsy
     • A peripheral smear for schistocytes only
     • A direct antiglobulin test alone
     • Iron studies alone

     Correct answer: Serum and urine protein electrophoresis with immunofixation and serum free light chains, plus a bone marrow biopsy

     Serum and urine protein electrophoresis with immunofixation, free light chains, and a bone marrow biopsy is correct. Diagnosing multiple myeloma requires demonstrating a monoclonal protein and clonal marrow plasma cells, accomplished with protein electrophoresis, immunofixation, free light chain assays, and marrow examination. A smear for schistocytes, a direct antiglobulin test, and iron studies do not establish a plasma cell dyscrasia.

923. A 70-year-old man with multiple myeloma develops acute confusion, constipation, polyuria, and a serum calcium of 13.5 mg/dL. Which is the most appropriate initial treatment for his hypercalcemia of malignancy?
     • Fluid restriction
     • Aggressive intravenous normal saline hydration
     • Oral calcium supplementation
     • Immediate hemodialysis as first-line

     Correct answer: Aggressive intravenous normal saline hydration

     Aggressive intravenous normal saline hydration is correct. Symptomatic hypercalcemia from myeloma is initially treated with vigorous saline hydration to restore volume and promote calcium excretion, with bisphosphonates added for durable control. Fluid restriction and oral calcium would worsen hypercalcemia, and dialysis is reserved for severe refractory cases or renal failure.

924. A 22-year-old man receiving induction chemotherapy for acute lymphoblastic leukemia is at risk for tumor lysis syndrome despite hydration and allopurinol. The team reviews electrolyte targets. Which electrolyte abnormality of tumor lysis syndrome poses the most immediate threat of fatal cardiac arrhythmia?
     • Hyperphosphatemia
     • Hyperuricemia
     • Hyperkalemia
     • Hypocalcemia

     Correct answer: Hyperkalemia

     Hyperkalemia is correct. Among the metabolic derangements of tumor lysis syndrome, a rapidly rising potassium is the most immediately life-threatening because it can precipitate fatal cardiac arrhythmias. Hyperphosphatemia and hyperuricemia drive renal injury more gradually, and hypocalcemia, while it can cause symptoms, is generally less acutely lethal than severe hyperkalemia.

925. A 16-year-old boy with infectious mononucleosis is found to have moderate splenomegaly. His parents ask when he may safely return to playing contact sports. Which counseling point is most accurate?
     • He may return immediately because the spleen is not affected
     • He must avoid all activity permanently
     • He may return as soon as his fever resolves regardless of spleen size
     • He should avoid contact and collision sports for at least about 3 to 4 weeks given splenic rupture risk

     Correct answer: He should avoid contact and collision sports for at least about 3 to 4 weeks given splenic rupture risk

     Avoiding contact and collision sports for about 3 to 4 weeks is correct. The splenomegaly of mononucleosis predisposes to rupture, so contact and collision activities are restricted for several weeks until the spleen returns to normal size. Immediate return ignores the rupture risk, permanent restriction is unnecessary, and resolution of fever alone does not indicate the spleen has shrunk.

926. A 24-year-old patient with suspected infectious mononucleosis is mistakenly given amoxicillin for presumed bacterial pharyngitis and develops a widespread maculopapular rash. Which best explains this reaction?
     • A true IgE-mediated penicillin allergy that contraindicates all beta-lactams for life
     • An acute hemolytic reaction
     • Stevens-Johnson syndrome in every case
     • A characteristic morbilliform rash precipitated by aminopenicillins in Epstein-Barr virus infection, not a true penicillin allergy

     Correct answer: A characteristic morbilliform rash precipitated by aminopenicillins in Epstein-Barr virus infection, not a true penicillin allergy

     A characteristic aminopenicillin-associated rash in Epstein-Barr virus infection is correct. Patients with mononucleosis frequently develop a benign morbilliform rash when given aminopenicillins, which does not reflect a true lifelong penicillin allergy. It is not an IgE-mediated reaction, not hemolysis, and not necessarily a severe blistering reaction.

927. A 25-year-old man requires emergency transfusion, but his blood type is unknown and there is no time for full typing and crossmatching. Which red cell product is the safest universal choice in this emergency?
     • Group AB Rh-positive red cells
     • Group A Rh-positive red cells
     • Group B Rh-negative red cells
     • Group O Rh-negative red cells

     Correct answer: Group O Rh-negative red cells

     Group O Rh-negative red cells are correct. Group O cells lack A and B antigens and Rh-negative cells lack the D antigen, so they can be given to almost any recipient without causing immediate hemolysis, making them the universal red cell donor in emergencies before typing is available. The other groups carry A, B, or D antigens that could trigger a hemolytic reaction in an incompatible recipient.

928. A blood bank prepares to transfuse a patient and reviews plasma compatibility. For fresh frozen plasma rather than red cells, which donor group is the universal plasma donor that can be given to recipients of any ABO type?
     • Group AB plasma
     • Group O plasma
     • Group A plasma
     • Group B plasma

     Correct answer: Group AB plasma

     Group AB plasma is correct. Because plasma carries antibodies rather than antigens, group AB plasma contains neither anti-A nor anti-B antibodies and is therefore the universal plasma donor, compatible with recipients of any ABO type. Group O plasma, by contrast, contains both anti-A and anti-B and is the universal red cell donor's plasma but not a universal plasma donor; groups A and B each carry one antibody.

929. A 19-year-old woman with known systemic lupus erythematosus develops worsening fatigue, a rising creatinine, hematuria, and red cell casts on urinalysis with active urinary sediment. Which complication of her multisystem autoimmune disease has most likely developed?
     • Iron deficiency anemia
     • Hereditary angioedema
     • Lupus nephritis
     • Benign gestational change

     Correct answer: Lupus nephritis

     Lupus nephritis is correct. Worsening renal function with hematuria and red cell casts indicates immune complex-mediated glomerular involvement, a serious organ manifestation of systemic lupus erythematosus that requires prompt evaluation and often a renal biopsy to guide immunosuppression. Iron deficiency, angioedema, and benign change do not produce an active nephritic urinary sediment.

930. A 28-year-old woman with systemic lupus erythematosus is started on hydroxychloroquine as a foundational therapy. Which long-term monitoring is most important specifically because of a recognized toxicity of this drug?
     • Periodic ophthalmologic (retinal) examinations
     • Routine bone marrow biopsies
     • Frequent serum ferritin checks
     • Monthly chest radiographs

     Correct answer: Periodic ophthalmologic (retinal) examinations

     Periodic ophthalmologic examinations are correct. Long-term hydroxychloroquine can cause a dose- and duration-dependent retinopathy, so baseline and periodic retinal screening is recommended to detect early changes. Routine marrow biopsies, ferritin monitoring, and monthly chest films are not the targeted monitoring for hydroxychloroquine toxicity.

931. A 30-year-old woman is found to have a positive antinuclear antibody on a screening test ordered for nonspecific fatigue. She has no other symptoms or signs of autoimmune disease. Which interpretation of this result is most appropriate?
     • A positive antinuclear antibody alone confirms systemic lupus erythematosus
     • It mandates immediate immunosuppressive therapy
     • It indicates an inherited bleeding disorder
     • A low-titer positive antinuclear antibody is common in healthy people and is not diagnostic without clinical features

     Correct answer: A low-titer positive antinuclear antibody is common in healthy people and is not diagnostic without clinical features

     A low-titer positive antinuclear antibody being common in healthy people and not diagnostic alone is correct. Antinuclear antibodies can be positive in many healthy individuals, so the test must be interpreted with clinical features and more specific antibodies before diagnosing an autoimmune disease. A positive result alone does not confirm lupus, mandate treatment, or indicate a bleeding disorder.

932. A 26-year-old woman presents with dry eyes, dry mouth, dental caries, and bilateral parotid enlargement, with positive anti-Ro and anti-La antibodies. Which systemic autoimmune disease best explains these findings?
     • Systemic lupus erythematosus
     • Disseminated intravascular coagulation
     • Sjogren syndrome
     • Hemophilia A

     Correct answer: Sjogren syndrome

     Sjogren syndrome is correct. Lymphocytic infiltration of exocrine glands causes dry eyes and dry mouth with parotid enlargement and dental decay, and anti-Ro and anti-La antibodies support the diagnosis of this multisystem autoimmune disorder. The sicca symptoms with these specific antibodies are not features of lupus alone, a consumptive coagulopathy, or a clotting factor deficiency.

933. A 35-year-old woman has progressive skin thickening of her fingers and hands, Raynaud phenomenon, and difficulty swallowing, with anti-centromere antibodies. Which multisystem connective tissue disease best fits?
     • Iron deficiency anemia
     • Hemophilia B
     • Polycythemia vera
     • Systemic sclerosis (scleroderma)

     Correct answer: Systemic sclerosis (scleroderma)

     Systemic sclerosis is correct. Skin thickening, Raynaud phenomenon, esophageal dysmotility, and anti-centromere antibodies characterize the limited form of this connective tissue disease, which causes multisystem fibrosis and vasculopathy. Iron deficiency, hemophilia, and polycythemia vera do not produce sclerodermatous skin changes with these autoantibodies.

934. A 50-year-old man receiving a massive transfusion of more than 10 units of packed red cells for trauma develops perioral tingling, muscle twitching, and a prolonged QT interval. Which complication of massive transfusion best explains these findings?
     • Hyperkalemia
     • Iron overload
     • Citrate-induced hypocalcemia
     • Hypernatremia

     Correct answer: Citrate-induced hypocalcemia

     Citrate-induced hypocalcemia is correct. The citrate anticoagulant in stored blood binds calcium, and during massive transfusion citrate can accumulate faster than the liver clears it, lowering ionized calcium and producing paresthesias, tetany, and QT prolongation. Hyperkalemia from stored cells causes different ECG changes, iron overload develops chronically, and hypernatremia does not explain this picture.

935. A 40-year-old woman is found to have lymphadenopathy, and the clinician must decide whether tissue sampling is needed. Which lymph node location is generally considered the most concerning for serious underlying pathology and warrants prompt evaluation?
     • A small tender inguinal node after a foot infection
     • A small mobile axillary node after a hand laceration
     • A tender submandibular node during pharyngitis
     • A supraclavicular lymph node

     Correct answer: A supraclavicular lymph node

     A supraclavicular lymph node is correct. Supraclavicular adenopathy carries a high likelihood of underlying malignancy, including thoracic and abdominal cancers and lymphoma, and warrants prompt investigation. Tender inguinal, axillary, and submandibular nodes appearing in response to local infections are typically reactive and benign.

936. A 6-year-old boy presents with high fever for 6 days, bilateral nonexudative conjunctivitis, cracked red lips and a strawberry tongue, a polymorphous rash, cervical lymphadenopathy, and swollen hands and feet. Which diagnosis must be recognized, and which therapy reduces the risk of its most serious complication?
     • Streptococcal pharyngitis; penicillin
     • Allergic drug reaction; antihistamines
     • Kawasaki disease; intravenous immunoglobulin and aspirin
     • Iron deficiency anemia; oral iron

     Correct answer: Kawasaki disease; intravenous immunoglobulin and aspirin

     Kawasaki disease treated with intravenous immunoglobulin and aspirin is correct. This systemic vasculitis of childhood presents with prolonged fever, conjunctivitis, mucosal changes, rash, lymphadenopathy, and extremity changes, and prompt intravenous immunoglobulin reduces the risk of coronary artery aneurysms, with aspirin for its antiinflammatory and antiplatelet effects. The other diagnoses and treatments do not address this vasculitis or its cardiac risk.

937. A 55-year-old man with newly diagnosed cancer and a deep vein thrombosis has been on anticoagulation but develops a recurrent clot despite therapeutic dosing of a direct oral anticoagulant. He has been adherent. Which adjustment is most appropriate for this cancer patient with breakthrough thrombosis?
     • Stop all anticoagulation
     • Add aspirin only
     • Reduce the anticoagulant dose
     • Switch to or escalate low-molecular-weight heparin

     Correct answer: Switch to or escalate low-molecular-weight heparin

     Switching to or escalating low-molecular-weight heparin is correct. Recurrent thrombosis in cancer despite therapeutic anticoagulation is managed by switching to low-molecular-weight heparin or increasing its dose, given its reliability in malignancy-associated hypercoagulability. Stopping anticoagulation, adding only aspirin, or reducing the dose would all increase the thrombotic risk.

938. A 33-year-old man with hemophilia A is scheduled for an elective dental extraction. He has mild disease and no inhibitor. Which adjunctive measure can reduce bleeding at the mucosal surgical site by inhibiting clot breakdown?
     • Aspirin
     • Heparin
     • An antifibrinolytic agent such as tranexamic acid
     • Warfarin

     Correct answer: An antifibrinolytic agent such as tranexamic acid

     An antifibrinolytic agent such as tranexamic acid is correct. Antifibrinolytics stabilize clots at mucosal sites, where high local fibrinolytic activity promotes rebleeding, and are useful adjuncts for dental and oral procedures in bleeding disorders. Aspirin, heparin, and warfarin all impair hemostasis and would worsen bleeding.

939. A 40-year-old woman is incidentally found on a routine complete blood count to have an absolute lymphocytosis. She is asymptomatic and the finding is isolated. Which initial test is most appropriate to determine whether this represents a clonal lymphoproliferative disorder?
     • A bone marrow transplant evaluation
     • An immediate splenectomy
     • A direct antiglobulin test
     • Peripheral blood flow cytometry

     Correct answer: Peripheral blood flow cytometry

     Peripheral blood flow cytometry is correct. Flow cytometry can identify whether a lymphocytosis is reactive or a clonal population, distinguishing benign causes from disorders such as chronic lymphocytic leukemia without invasive procedures. Transplant evaluation and splenectomy are premature without a diagnosis, and a direct antiglobulin test assesses hemolysis rather than clonality.

940. A 70-year-old man with chronic lymphocytic leukemia and recurrent sinopulmonary infections is found to have low serum immunoglobulin levels (hypogammaglobulinemia). Which intervention can reduce his frequency of serious bacterial infections?
     • Therapeutic phlebotomy
     • Iron supplementation
     • Immunoglobulin replacement therapy
     • Anticoagulation

     Correct answer: Immunoglobulin replacement therapy

     Immunoglobulin replacement therapy is correct. Chronic lymphocytic leukemia commonly causes secondary hypogammaglobulinemia, and immunoglobulin replacement reduces recurrent serious bacterial infections in affected patients. Phlebotomy, iron, and anticoagulation do not address antibody deficiency.

941. A 50-year-old woman is found to have a markedly elevated white cell count driven by neutrophilia with a left shift and toxic granulation during a severe bacterial infection. There is no basophilia, and the leukocyte alkaline phosphatase score is high. Which best explains this blood picture?
     • Chronic myeloid leukemia
     • Acute myeloid leukemia
     • Polycythemia vera
     • A leukemoid reaction to infection

     Correct answer: A leukemoid reaction to infection

     A leukemoid reaction to infection is correct. A reactive, marked neutrophilia with a left shift, toxic granulation, and a high leukocyte alkaline phosphatase score reflects a benign response to severe infection, distinguishing it from chronic myeloid leukemia, which classically shows basophilia and a low leukocyte alkaline phosphatase score with the BCR-ABL fusion. Acute myeloid leukemia shows blasts, and polycythemia vera shows erythrocytosis.

942. A 60-year-old man with a deep vein thrombosis and a high risk of bleeding is treated with anticoagulation. The team weighs the use of a validated bleeding-risk assessment in his venous thromboembolism management. What is the primary purpose of assessing bleeding risk in a patient on anticoagulation for venous thromboembolism?
     • To decide whether to withhold all anticoagulation permanently in every high-risk patient
     • To determine the patient's blood type
     • To guide decisions about anticoagulation intensity, duration, and the need for closer monitoring while weighing recurrence risk
     • To diagnose the cause of the clot

     Correct answer: To guide decisions about anticoagulation intensity, duration, and the need for closer monitoring while weighing recurrence risk

     Guiding decisions about intensity, duration, and monitoring while weighing recurrence risk is correct. Bleeding-risk assessment helps balance the benefit of preventing recurrent thrombosis against the harm of hemorrhage, informing how long and how intensely to anticoagulate and whether closer follow-up is needed. It does not by itself mandate withholding therapy from everyone, identify blood type, or diagnose the clot's cause.

943. A 45-year-old man develops an enlarging, painless, rubbery lymph node and is found on biopsy to have a follicular lymphoma, an indolent non-Hodgkin lymphoma. He is asymptomatic with low tumor burden. Which management approach is appropriate for low-burden, asymptomatic indolent lymphoma?
     • Immediate aggressive combination chemotherapy in all cases
     • Urgent splenectomy
     • Lifelong corticosteroids alone
     • Active surveillance (watchful waiting)

     Correct answer: Active surveillance (watchful waiting)

     Active surveillance is correct. Asymptomatic, low-burden indolent (follicular) lymphoma can be observed because early treatment does not improve survival, with therapy initiated when symptoms, organ compromise, or high tumor burden develop. Immediate aggressive chemotherapy, splenectomy, and chronic corticosteroids alone are not appropriate initial management for low-burden indolent disease.

944. A 24-year-old man is diagnosed with Burkitt lymphoma, a highly aggressive B-cell lymphoma with an extremely high proliferation rate. As chemotherapy is initiated, which complication is he at especially high risk of developing because of the rapid tumor cell turnover?
     • Iron deficiency anemia
     • Hereditary hemochromatosis
     • Tumor lysis syndrome
     • Cold agglutinin disease

     Correct answer: Tumor lysis syndrome

     Tumor lysis syndrome is correct. Burkitt lymphoma has one of the highest proliferation rates of any tumor, so initiating chemotherapy releases massive amounts of intracellular contents, placing the patient at very high risk for tumor lysis syndrome with hyperkalemia, hyperphosphatemia, hyperuricemia, and acute kidney injury. The other conditions are unrelated to rapid chemotherapy-induced cell lysis.

945. A 30-year-old woman with severe iron deficiency anemia and ongoing menorrhagia is hemodynamically stable but symptomatic with a hemoglobin of 6.5 g/dL and signs of cardiac strain on exertion. Which is the most appropriate management for her symptomatic severe anemia?
     • Oral iron alone with no other intervention
     • Observation without therapy
     • Erythropoietin alone
     • Red cell transfusion to relieve symptoms followed by iron repletion and treatment of the bleeding source

     Correct answer: Red cell transfusion to relieve symptoms followed by iron repletion and treatment of the bleeding source

     Transfusion to relieve symptoms followed by iron repletion and treatment of the bleeding source is correct. Severe symptomatic anemia with cardiac strain may warrant red cell transfusion for immediate relief, but the underlying iron deficiency and the menorrhagia driving it must then be corrected to prevent recurrence. Oral iron alone is too slow for symptomatic severe anemia, observation is unsafe, and erythropoietin does not address iron deficiency or acute symptoms.

946. A 19-year-old man undergoing chemotherapy is profoundly neutropenic and remains febrile after 5 days of broad-spectrum antibacterial therapy with no source identified and persistently negative cultures. Which is the most appropriate next step in management?
     • Stop all antibiotics and observe
     • Switch to oral antibiotics and discharge
     • Add empiric antifungal therapy
     • Give a blood transfusion to treat the fever

     Correct answer: Add empiric antifungal therapy

     Adding empiric antifungal therapy is correct. Persistent fever in a profoundly neutropenic patient despite several days of broad-spectrum antibacterial coverage raises concern for invasive fungal infection, so empiric antifungal therapy is added. Stopping antibiotics or discharging the patient is unsafe during ongoing neutropenic fever, and transfusion does not treat the infection.

947. A 35-year-old woman with no prior bleeding suddenly develops severe spontaneous bruising and soft-tissue hematomas. She has a markedly prolonged aPTT that does NOT correct on a mixing study, a normal PT, and a normal platelet count, with very low factor VIII activity. Which diagnosis best explains this newly acquired bleeding disorder?
     • Hereditary hemophilia A
     • Von Willebrand disease
     • Vitamin K deficiency
     • Acquired hemophilia from a factor VIII autoantibody

     Correct answer: Acquired hemophilia from a factor VIII autoantibody

     Acquired hemophilia from a factor VIII autoantibody is correct. New-onset severe bleeding in an adult with an isolated prolonged aPTT that fails to correct on mixing and low factor VIII indicates an acquired inhibitor (autoantibody) against factor VIII, rather than an inherited deficiency, which would correct on mixing. von Willebrand disease and vitamin K deficiency produce different laboratory patterns and typically correct or affect the PT.

948. A 40-year-old man on chronic warfarin is admitted with an unrelated infection and started on a new antibiotic. Several days later his INR rises sharply to 7 without bleeding. Which mechanism most likely explains this interaction?
     • The antibiotic directly activates platelets
     • The antibiotic causes immune destruction of red cells
     • The antibiotic enhances warfarin effect by inhibiting its metabolism or suppressing vitamin K-producing gut flora
     • The antibiotic chelates iron

     Correct answer: The antibiotic enhances warfarin effect by inhibiting its metabolism or suppressing vitamin K-producing gut flora

     Enhancement of warfarin effect by inhibiting metabolism or suppressing gut flora is correct. Many antibiotics potentiate warfarin by inhibiting the enzymes that metabolize it and by killing intestinal bacteria that produce vitamin K, raising the INR and bleeding risk. The other mechanisms do not explain a rising INR on warfarin.

949. A 28-year-old woman with a mechanical heart valve becomes pregnant. The team must choose an anticoagulation strategy that balances maternal valve thrombosis risk against fetal harm. Which statement best reflects an appropriate consideration in managing her anticoagulation during pregnancy?
     • Aspirin alone provides adequate protection against mechanical valve thrombosis
     • Anticoagulation can be safely stopped for the entire pregnancy
     • Warfarin is most effective for the valve but is teratogenic, so low-molecular-weight heparin is often used, particularly in the first trimester, with careful monitoring
     • No anticoagulation is needed because pregnancy is protective against clotting

     Correct answer: Warfarin is most effective for the valve but is teratogenic, so low-molecular-weight heparin is often used, particularly in the first trimester, with careful monitoring

     The recognition that warfarin is most effective for the valve but teratogenic, prompting use of low-molecular-weight heparin especially in the first trimester with careful monitoring, is correct. Mechanical valves demand uninterrupted, effective anticoagulation, but warfarin's teratogenicity, particularly in the first trimester, requires balancing strategies with close monitoring. Aspirin alone is inadequate, stopping anticoagulation risks fatal valve thrombosis, and pregnancy is prothrombotic rather than protective.

950. A 5-year-old boy with leukemia who is severely immunocompromised is found to have a household measles exposure. He has no documented immunity and cannot receive a live vaccine. Which intervention is most appropriate to reduce his risk of severe measles?
     • Administer the live measles vaccine immediately
     • Give oral iron
     • Provide no intervention and observe
     • Provide immunoglobulin for postexposure passive immunization

     Correct answer: Provide immunoglobulin for postexposure passive immunization

     Providing immunoglobulin for postexposure passive immunization is correct. A susceptible, severely immunocompromised child exposed to measles should receive immunoglobulin, since the live vaccine is contraindicated in significant immunosuppression and passive antibody can prevent or attenuate disease. Iron and watchful waiting leave him unprotected.

951. A 60-year-old man with metastatic adenocarcinoma develops a microangiopathic hemolytic anemia with schistocytes and thrombocytopenia, but his PT, aPTT, and fibrinogen are normal and ADAMTS13 activity is only modestly reduced. Which underlying mechanism best explains this cancer-associated thrombotic microangiopathy?
     • A hereditary factor VIII deficiency
     • Autoimmune attack on platelets only
     • Tumor emboli and microvascular involvement causing mechanical red cell fragmentation
     • Iron deficiency from chronic disease

     Correct answer: Tumor emboli and microvascular involvement causing mechanical red cell fragmentation

     Tumor emboli and microvascular involvement causing mechanical fragmentation is correct. Disseminated malignancy can produce a microangiopathic hemolytic anemia when tumor cells and microthrombi obstruct the microvasculature, shearing red cells into schistocytes, with relatively preserved coagulation studies. A hereditary factor deficiency, isolated antiplatelet autoimmunity, and iron deficiency do not cause schistocyte-laden microangiopathy.

952. A 45-year-old woman is found to have an isolated mild thrombocytosis with a platelet count of 480,000/microliter that developed after she was treated for iron deficiency anemia and an acute infection. She has no JAK2 mutation and is asymptomatic. Which is the most appropriate interpretation?
     • Essential thrombocythemia requiring cytoreduction
     • Acute leukemia
     • Immune thrombocytopenic purpura
     • Reactive (secondary) thrombocytosis that typically resolves as the underlying condition improves

     Correct answer: Reactive (secondary) thrombocytosis that typically resolves as the underlying condition improves

     Reactive (secondary) thrombocytosis that resolves with the underlying condition is correct. Iron deficiency, infection, and inflammation commonly drive a mild reactive thrombocytosis that subsides as the trigger resolves, distinguishing it from a clonal disorder. The absence of a clonal marker and a clear reactive context argue against essential thrombocythemia, leukemia, or a thrombocytopenic process.