Acute Kidney Injury USMLE Step 1 Practice Question
A 28-year-old woman with a 3-month history of systemic lupus erythematosus presents to the emergency department with a 5-day history of malaise, dyspnea, and dark urine. Her temperature is 38.2°C, blood pressure is 168/104 mmHg, and she has mild generalized edema. Laboratory studies show: Hemoglobin: 7.8 g/dL
Platelets: 42,000/μL
Creatinine: 2.9 mg/dL (baseline 0.8 mg/dL)
LDH: 720 U/L
Haptoglobin: <10 mg/dL (normal 30-200)
Direct antiglobulin test: Negative
Peripheral blood smear: Numerous schistocytes
PT/INR: 1.1 (normal)
Fibrinogen: 380 mg/dL (normal) Which of the following is the most likely diagnosis?
Answer choices
- ADisseminated intravascular coagulation secondary to SLE
- BLupus nephritis with immune-mediated hemolytic anemia
- CDrug-induced thrombocytopenia from hydroxychloroquine
- DAtypical hemolytic uremic syndrome with C3 dysregulation
- EThrombotic thrombocytopenic purpuraCorrect answer
- FSecondary immune thrombocytopenia without microangiopathic hemolytic anemia
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