Acute Kidney Injury USMLE Step 1 Practice Question
A 58-year-old woman hospitalized with infective endocarditis receives intravenous gentamicin therapy. After 7 days, she develops oliguria with BP 128/82 mmHg, HR 92/min, and SpO2 98% on room air. Serum creatinine rises from 0.8 to 2.1 mg/dL; BUN is 38 mg/dL. Urinalysis reveals muddy brown casts and renal tubular epithelial cells. Urine output remains adequate at 800 mL/day. Which nephron segment is most vulnerable to this aminoglycoside-induced toxic injury?
Answer choices
- AGlomerular mesangium
- BProximal tubuleCorrect answer
- CDistal tubule
- DThin descending limb
- ECollecting duct
- FThick ascending limb of the loop of Henle
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.