Postpartum thrombotic microangiopathy with acute kidney injury: A diagnostic challenge between TTP and atypical HUS

Abstract

Background: Pregnancy-associated thrombotic microangiopathy (TMA) is a diagnostic challenge because postpartum thrombotic thrombocytopenic purpura (TTP), atypical hemolytic uremic syndrome (aHUS), HELLP syndrome, and secondary TMAs can overlap clinically. ADAMTS13 activity is central to distinguishing TTP from other TMAs, but borderline reductions may not be definitive in pregnancy.

Case Presentation: A 21-year-old primigravida at 33 weeks gestation presented with intrauterine fetal demise and developed postpartum anuric acute kidney injury, severe thrombocytopenia, and microangiopathic hemolytic anemia. She had no hypertension or neurological symptoms. Laboratory evaluation showed elevated LDH (2576 U/L), thrombocytopenia (30,000/µL), anemia (Hb 5.7 g/dL), schistocytes (1.6%), and ADAMTS13 activity of 23%. Liver enzymes were mildly elevated without features of HELLP syndrome.She was treated with hemodialysis and plasma exchange, with subsequent improvement in platelet count and renal function.

Conclusion: This case highlights the diagnostic challenge of postpartum pregnancyassociated thrombotic microangiopathy when ADAMTS13 activity is reduced but not severely deficient. Early recognition, prompt plasma exchange, and renal support were associated with haematologic and renal recovery, emphasizing the need for timely empiric treatment in similar cases despite uncertainty between TTP and aHUS.