USMLE Clinical Medicine 2 — Questions and Answers
Question 1: A 50-year-old man with a history of GERD presents with progressive dysphagia, first to solids then liquids, and weight loss. Endoscopy shows a mucosal irregularity. What is the most likely diagnosis?
- Esophageal carcinoma (Correct answer)
- Achalasia
- Esophageal spasm
- Zenker diverticulum
Correct answer: Esophageal carcinoma
Progressive dysphagia starting with solids then progressing to liquids combined with weight loss is the classic presentation of esophageal carcinoma; GERD is a risk factor for adenocarcinoma.
Question 2: A patient taking lithium develops signs of toxicity including coarse tremor, confusion, and cardiac arrhythmias. What electrolyte abnormality predisposes to lithium toxicity?
- Hyponatremia (Correct answer)
- Hypernatremia
- Hypokalemia
- Hyperkalemia
Correct answer: Hyponatremia
Hyponatremia (from diuretics, low-sodium diet, or dehydration) causes the kidney to reabsorb lithium in place of sodium in the proximal tubule, increasing lithium levels and toxicity.
Question 3: A patient presents with periorbital and peripheral edema, massive proteinuria (>3.5 g/day), hypoalbuminemia, and hyperlipidemia. What is this syndrome?
- Nephrotic syndrome (Correct answer)
- Nephritic syndrome
- Acute glomerulonephritis
- Chronic kidney disease
Correct answer: Nephrotic syndrome
Nephrotic syndrome is defined by the triad of massive proteinuria (>3.5 g/day), hypoalbuminemia, and edema, with hyperlipidemia and lipiduria as secondary features.
Question 4: A patient with suspected meningitis undergoes lumbar puncture. CSF shows low glucose, high protein, and predominantly lymphocytes. What is the most likely etiology?
- Viral (aseptic) meningitis
- Bacterial meningitis
- Fungal meningitis
- Tuberculous meningitis (Correct answer)
Correct answer: Tuberculous meningitis
Tuberculous meningitis typically shows low glucose, high protein, and lymphocytic pleocytosis in CSF, along with a subacute course, compared to the acute neutrophilic presentation of bacterial meningitis.
Question 5: A 25-year-old woman has amenorrhea, elevated prolactin, and bitemporal hemianopia. MRI shows a pituitary mass. What is the diagnosis?
- Prolactinoma (Correct answer)
- Craniopharyngioma
- Empty sella syndrome
- Acromegaly
Correct answer: Prolactinoma
Prolactinoma (most common pituitary adenoma) secretes excess prolactin causing galactorrhea, amenorrhea/infertility in women, and compresses the optic chiasm causing bitemporal hemianopia.
Question 6: A patient with heart failure is given furosemide. Which electrolyte disturbance requires monitoring?
- Hypokalemia (Correct answer)
- Hyperkalemia
- Hyponatremia
- Hypercalcemia
Correct answer: Hypokalemia
Loop diuretics like furosemide cause urinary potassium wasting by increasing tubular flow to the collecting duct where K+ is secreted, leading to hypokalemia.
USMLE Clinical Medicine 2
A 50-year-old man with a history of GERD presents with progressive dysphagia, first to solids then liquids, and weight loss.
Endoscopy shows a mucosal irregularity.
What is the most likely diagnosis?