Acquired hemophilia: a case report and review of the literature.

Acquired hemophilia A (AHA) is a rare bleeding disorder caused by autoantibodies against clotting factor VIII (FVIII). FVIII autoantibody is characterized as polyclonal immunoglobulin G directed against the FVIII procoagulant activity. This disease occurs most commonly in the elderly population and with preponderance of men in nonpregnancy-related AHA. There are well-established clinical associations with AHA such as malignancy, other autoimmune diseases and pregnancy. However, up to 50% of reported cases remain idiopathic. The clinical manifestation of AHA includes mostly spontaneous hemorrhages into skin, muscles and soft tissues, or mucous membranes. AHA should be suspected when a patient with no previous history of bleeding presents with bleeding and an unexplained prolonged activated partial thromboplastin time. The diagnosis is confirmed in the laboratory by the subsequent identification of reduced FVIII levels and FVIII inhibitor titration. There is a high mortality, making prompt diagnosis and treatment vitally important. The principles of treatment consist in controlling the bleeding and eradicating the inhibitor. Because of the overall high relapse rate (15-33%), it is also recommended to follow up these patients. The review summarizes what is currently known about the epidemiology, pathogenesis, clinical features, diagnosis, treatment and prognosis of AHA and starts with a case report.