Postpartum hemolytic uremic syndrome

This 22-year-old Caucasian female presented with acute renal failure and proteinuria five days after delivering her first child. The pregnancy was uneventful. Serum creatinine at presentation was 6.2 mg/dL (baseline of 0.8 mg/dL), hemoglobin 2.5 g/dL, platelets 22,000 and LDH 2300 U/L.

The biopsy shows glomeruli with endocapillary fibrin thrombi, associated with segmental mesangiolysis and red blood cell fragmentation.  These findings are diagnostic of a thrombotic microangiopathy (TMA).  Numerous etiologies may lead to a TMA, all of which show morphologic overlap with no morphologic finding specific for a single etiology.

Given the clinical history and the timing of disease presentation in relation to delivery, a postpartum hemolytic uremic syndrome diagnosis is favored. Patients affected by this disorder show a high incidence of mutations in genes involved in regulation of the alternative pathway of complement, leading to persistent activation by C3 convertase.