Thrombotic Microangiopathy And Hypertensive Emergency After Cocaine Use: A Case Report.

A patient in her early 60s presented with hypertensive emergency, microangiopathic hemolytic anemia, thrombocytopenia, and non-oliguric acute kidney injury (AKI) after recent cocaine use. The evaluation demonstrated schistocytes, a Coombs-negative hemolysis pattern, and preserved ADAMTS13 activity, making TTP unlikely. Kidney biopsy confirmed acute thrombotic microangiopathy (TMA) and excluded alternative intrinsic renal pathologies. Autoimmune and infectious workup was unrevealing. Although cocaine exposure temporally preceded presentation, malignant hypertension and complement activation may represent overlapping and potentially synergistic mechanisms rather than a single unifying etiology. Blood pressure control improved hemodynamics, but kidney function continued to worsen, and soluble C5b-9 (sC5b-9) was elevated. Eculizumab was initiated empirically after appropriate vaccination due to persistent renal dysfunction despite blood pressure optimization, recognizing that sC5b-9 is not specific for atypical HUS and may be elevated in secondary TMAs. Renal function subsequently stabilized, and the patient remained dialysis-free at three-month follow-up.