COVID-19-Associated Acquired Hemophilia A With an Exceptionally High Inhibitor Titer: A Case of Remission and Overwhelming Sepsis.

Acquired hemophilia A (AHA) is a rare autoimmune bleeding disorder caused by autoantibodies against factor VIII. COVID-19 infection has emerged as a potential trigger, though reported cases remain limited, with variable inhibitor titers. We report a 70-year-old African American man who developed AHA following documented COVID-19 infection in October 2023, presenting with an exceptionally high factor VIII inhibitor titer of 561 Bethesda Units (BU) that peaked at 677 BU during initial treatment. His course was complicated by migratory spontaneous hematomas and a massive chest wall hematoma leading to hemorrhagic shock and pulseless electrical activity (PEA) cardiac arrest, which he survived. Despite the severity, he achieved complete immunological remission with factor VIII normalization to 343% and inhibitor eradication (0 BU) following treatment with FEIBA, rituximab, cyclophosphamide, and corticosteroids. However, approximately three months after his initial diagnosis, he died from multiorgan failure secondary to overwhelming sepsis (procalcitonin 747.64 ng/mL) in the setting of profound treatment-induced immunosuppression. This case represents one of the highest reported inhibitor titers in COVID-19-associated AHA and demonstrates that complete remission is achievable even in severe cases. Yet this case underscores a critical therapeutic paradox: the aggressive immunosuppression necessary for inhibitor eradication carries a substantial risk of infectious mortality. Emerging therapies such as emicizumab may help mitigate this paradox by allowing reduced-intensity immunosuppression, though cost and off-label status currently limit accessibility.