Chronic Kidney Disease USMLE Step 1 Practice Question
A 28-year-old man presents for evaluation before a high-altitude mountaineering expedition. Vital signs: BP 118/76 mmHg, HR 72 bpm, RR 16 breaths/min, SpO2 98% at sea level. He is prescribed acetazolamide to prevent altitude sickness through bicarbonate diuresis and mild metabolic acidosis, stimulating compensatory hyperventilation. Serum bicarbonate is 18 mEq/L. He denies kidney disease. The drug's primary mechanism involves inhibition of which nephron segment?
Answer choices
- AThin descending limb
- BThick ascending limb
- CMedullary collecting duct
- DDistal convoluted tubule
- EProximal tubuleCorrect answer
- FCortical collecting duct
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