Acute Kidney Injury USMLE Step 1 Practice Question
A 34-year-old woman with a 6-year history of systemic lupus erythematosus presents to the emergency department with dyspnea and bilateral ankle edema. Her medications include prednisone and hydroxychloroquine. Vital signs: BP 158/96 mmHg, HR 88 bpm, RR 18, temperature 37.2°C. Laboratory values show serum creatinine 3.5 mg/dL (baseline 0.8 mg/dL), BUN 62 mg/dL, and eGFR 18 mL/min/1.73m². Urinalysis reveals RBC casts, dysmorphic red blood cells, and 2+ proteinuria. Serum complement C3 and C4 levels are both depressed. Renal ultrasound shows normal-sized kidneys without hydronephrosis. Which of the following is the most likely diagnosis?
Answer choices
- AAcute tubular necrosis from sepsis
- BPrerenal acute kidney injury from dehydration
- CAcute interstitial nephritis from drug reaction
- DAcute proliferative lupus nephritis (class IV)Correct answer
- EThrombotic thrombocytopenic purpura
- FMembranous lupus nephritis (class V)
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