Refractory obstetric hemorrhage as the initial presentation of acquired hemophilia: diagnostic limitations of viscoelastic testing in the presence of factor VIII inhibitors. A case report and literature review

Acquired hemophilia A is a rare autoimmune bleeding disorder caused by the development of autoantibodies against coagulation factor VIII. It is frequently associated with the postpartum period and may present as severe and persistent bleeding in patients without a prior history of coagulopathy, often leading to diagnostic delay. We report the case of a 26-year-old woman in the postpartum period following cesarean section for severe preeclampsia, who developed refractory hemorrhage despite multiple surgical interventions, including exploratory laparotomies, hematoma drainage, and abdominal packing. Laboratory evaluation revealed an isolated prolongation of activated partial thromboplastin time. Mixing studies showed incomplete correction, raising suspicion of a circulating inhibitor. Further testing confirmed severely reduced factor VIII activity and the presence of a factor VIII inhibitor. Serial thromboelastography demonstrated profound hypocoagulability with impaired thrombin generation and episodes of hyperfibrinolysis. The patient was treated with bypassing agents and combined immunosuppressive therapy, resulting in progressive reduction of inhibitor levels and recovery of factor VIII activity, ultimately achieving complete hematologic remission. This case highlights the diagnostic challenges of acquired hemophilia A in the postpartum setting and emphasizes the importance of early recognition of isolated coagulation abnormalities. Prompt diagnosis and a coordinated multidisciplinary approach are essential for effective bleeding control and inhibitor eradication in critically ill patients.