A 78-year-old female presented with a hemoglobin of 5.3g/dL. CT scan showed a soft tissue hematoma within the left gluteus medius muscle. She reported skin bruising and hematuria. Activated partial prothrombin time (aPTT) was elevated at 78s and mixing study showed incomplete correction to 51.3s. Factor VIII activity was low at 3% with an inhibitor of 17.5 Bethesda Units (BU). A diagnosis of acquired hemophilia was made and factor VIII inhibitor bypassing agent (FEIBA) was initiated. Cyclophosphamide and prednisone were started for immunosuppression. Initially, the hematuria resolved, and aPTT and hematoma size remained stable. Suddenly on day fourteen, Hb dropped by 2g/dL and a repeat CT showed an intramuscular hematoma of the left iliopsoas with hemorrhagic tracking into the pelvis. Cyclophosphamide was switched to rituximab and recombinant Factor VIIa (rFVIIa) was added to FEIBA. Unfortunately, the patient went into hemorrhagic shock, multi-organ failure, and passed away.

Keywords: Hemophilia A; Autoantibodies; Bleeding disorders; Coagulation cascade