[Two cases of acquired hemophilia A in elderly patients].

Acquired hemophilia A is a rare bleeding diathesis caused by autoantibodies against clotting factor VIII. The incidence of acquired hemophilia A increases with age. We report two cases of acquired hemophilia A in elderly patients and their clinical characteristics. Case 1: A 66-year-old man was referred to our hospital with massive subcutaneous and intramuscular hemorrhage. Prolonged APTT, low factor VIII activity and factor VIII inhibitor with high titer (42 BU/ml ) were observed, confirming the diagnosis of acquired hemophilia A. His hemorrhages disappeared soon after 50 mg/day oral prednisolone was administered. Although early steroid withdrawal lead to repeated prolongation of APTT, the addition of 20 mg/day oral prednisolone successfully decreased the inhibitor titer. The underlying disease was not identified. Case 2: An 85-year-old man with advanced gastric cancer was referred to our division because of severe bleeding. His factor VIII inhibitor titer was 64 BU/ml . Activated prothrombin complex concentrates were used to control the bleeding. Initially, he did not seem to respond to 20 mg/day oral prednisolone, but a further 12 weeks of 20 mg/day prednisolone finally achieved normalization of his hemostatic parameters. Subsequently, he successfully underwent surgery for cancer. The responses to immunosuppressive therapy were very different in the two cases, probably because of the difference in the underlying diseases. The immunosuppressive therapy of acquired hemophilia A should be strictly tailored to the patient's characteristics to minimize treatment-related adverse effects.