Acute Kidney Injury USMLE Step 1 Practice Question
A 46-year-old woman presents with acute onset hematuria and rapidly rising creatinine (baseline 0.8 mg/dL, now 3.2 mg/dL). Vital signs: BP 156/94 mmHg, HR 92, RR 18, temp 37.2°C, SpO2 98%. Urinalysis shows dysmorphic RBCs and RBC casts. She denies arthralgia or rash. Kidney biopsy demonstrates crescent formation with fibrinoid necrosis, but immunofluorescence shows minimal immunoglobulin and complement deposition. Which mechanism most likely explains this disease process?
Answer choices
- APauci immune small vessel vasculitis associated with ANCACorrect answer
- BMesangial IgA immune complex deposition
- CSubepithelial immune complex deposition due to malignancy
- DPodocyte cytokine mediated foot process effacement
- EAnti basement membrane antibody mediated injury
- FImmune complex-mediated crescentic GN from hepatitis C cryoglobulinemia
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