Chronic Kidney Disease USMLE Step 1 Practice Question
A 45-year-old man with stage 3b chronic kidney disease (eGFR 34 mL/min/1.73m²) presents with BP 148/92 mmHg, HR 78/min, RR 16/min. Serum creatinine is 2.1 mg/dL with normal urinalysis. He takes lisinopril daily. A researcher administers an agent that selectively constricts the efferent arteriole. Renal plasma flow decreases modestly while glomerular capillary hydrostatic pressure initially rises. Which hemodynamic change occurs first?
Answer choices
- ANo change in filtration fraction
- BDecrease in filtration fraction
- CIncrease in free water clearance only
- DComplete loss of autoregulation with anuria
- EIncrease in filtration fractionCorrect answer
- FDecrease in glomerular filtration rate without change in renal plasma flow
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