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?
- A)Thin descending limb
- B)Thick ascending limb
- C)Medullary collecting duct
- D)Distal convoluted tubule
- E)Proximal tubuleGABARITO
Explicação
Acetazolamide inhibits carbonic anhydrase in the proximal tubule, reducing bicarbonate reabsorption and causing bicarbonaturia. The resulting mild metabolic acidosis helps stimulate ventilation and is useful for altitude sickness prophylaxis. Ver explicação completa e trilha adaptativa →