A Case Report on Emergency Medicine: Suspected Acquired Hemophilia A in an Older Adult Male.

Acquired hemophilia A (AHA) is a rare autoimmune disorder caused by autoantibodies against factor VIII, leading to severe bleeding. According to the European Acquired Hemophilia (EACH2) registry, AHA has an incidence of approximately 1.5 cases per million per year, most often presenting in the elderly population. This case report highlights the diagnostic challenges and multidisciplinary management of a high-titer inhibitor in an elderly male with delayed presentation. A 65-year-old male presented with persistent bleeding from a sutured laceration and new-onset atrial fibrillation. Laboratory findings revealed an isolated prolonged partial thromboplastin time (PTT) (unresponsive to mixing studies, with lupus anticoagulant excluded), factor VIII activity of 1%, and a high-titer inhibitor (268.3 BU via Nijmegen-Bethesda assay). The patient had experienced prolonged bleeding after dental surgery and testosterone implantation, which was initially overlooked. Emergency management included recombinant factor VIIa (rFVIIa) for hemostasis and methylprednisolone for immunosuppression, resulting in partial response (factor VIII activity: 3%; inhibitor titer: 92 BU). This case highlights that AHA should be suspected in patients with unexplained bleeding, even in the absence of a prior bleeding history. The study concluded that: (1) mixing studies and Bethesda assays are key for a diagnosis of AHA, (2) bypassing agents (e.g., rFVIIa) should be prioritized for acute bleeding, and (3) multidisciplinary efforts can improve outcomes in complex cases. The patient's delayed diagnosis despite prior bleeding episodes shows the need for increased clinical vigilance.