Glomerular Diseases USMLE Step 1 Practice Question
A 45-year-old woman presents to the emergency department with a 1-week history of hemoptysis, progressive dyspnea, and cola-colored urine. She denies recent infections, drug use, or systemic symptoms. Physical examination reveals bilateral crackles on lung auscultation. Laboratory studies show serum creatinine 2.8 mg/dL (baseline 0.9 mg/dL), hemoglobin 9.2 g/dL, and urinalysis with 3+ proteinuria, dysmorphic RBCs, and RBC casts. Chest X-ray demonstrates bilateral alveolar infiltrates. Serum ANCA panel (c-ANCA, p-ANCA) and ANA are negative. Serum complement levels (C3, C4) are normal. Kidney biopsy shows segmental crescentic glomerulonephritis with linear IgG deposition along the glomerular basement membrane on immunofluorescence microscopy. Which of the following is the most likely diagnosis?
Answer choices
- AANCA-associated vasculitis (granulomatosis with polyangiitis)
- BImmune complex membranoproliferative glomerulonephritis
- CInfective endocarditis-associated glomerulonephritis
- DAnti-glomerular basement membrane diseaseCorrect answer
- ECryoglobulinemia-associated vasculitis
- FDrug-induced lupus with secondary glomerulonephritis
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