Complete Recovery from AKI: A Rare Case of Postpartum Atypical Hemolytic Uremic Syndrome

Introduction: As a critical disease in pregnancy, atypical hemolytic uremic syndrome (aHUS) features thrombocytopenia, acute kidney injury and the non-immune microangiopathy degeneration of hemolytic anemia. Its clinical course is disruptive and progressive. Pregnancy-related aHUS mostly progresses to end-stage renal disease (ESRD) with a high incidence. Here, a pregnant woman who developed hemolytic anemia and acute renal failure after induced abortion was reported. Case Description: During her third month of pregnancy, a female aged 45 underwent an artificial abortion one month ago. One week after the abortion, she developed increased vaginal bleeding, abdominal pain and oliguria. Serum creatinine (Scr) increased from 36 to 1,114 umol/L. Laboratory examination showed hemolytic changes: increased proportions of helmet cells in peripheral blood (11%), significantly increased lactate dehydrogenase (LDH, 1,845 U/L), decreased haptoglobin (< 0.0706 g/L) and decreased platelets (38*10^9/L). The Coombs test was negative. She was diagnosed with thrombotic microangiopathy (TMA). Renal biopsy showed that renal tubule epithelial cells were granular denaturated and shed to form a bare basement membrane under a light microscope. In addition, electron microscopy showed endothelial cell swelling with loss of fenestrae and subendothelial electron-lucent widening. C5b-9 exhibited a significant increase by the quantitative detection of complement-related indicators, which was classified as aHUS. Corticosteroid impulse therapy combined with plasma exchange, the transfusion of fresh frozen plasma, hemodialysis and other treatments were given successively. Consequently, urine volume completely recovered, and Scr decreased from 1,184 to 78 umol/L. The patient was off dialysis, and hematological indicators were in complete remission. Discussion: Postpartum acute kidney injury can be caused by a variety of reasons, of which the rare cause of aHUS can be life-threatening. The outcome of complete renal function recovery in this case confirmed that timely identification and early treatment can save patients’ lives, preserve renal function, and avoid dialysis.