Acquired haemophilia

Acquired haemophilia (AH) is a severe bleeding diathesis that affects both males and females. It is caused by suddenly appearing autoantibodies that interfere with coagulation factor VIII (FVIII) activity. Although some conditions such as autoimmune diseases, cancer and puerperium seem likely to induce AH, in more than half of the observed cases autoantibodies to FVIII are idiopathic. The clinical picture is characterized by spontaneous and post-traumatic subcutaneous bleeds as well as massive mucosal membrane hemorrhages (from the genitourinary and gastrointestinal tracts). Typical abnormalities in AH are prolonged activated partial thromboplastin time and normal results of the other haemostatic tests (platelet count, prothrombin and thrombin times, fibrinogen concentration). Acquired haemophilia is definitely confirmed by quantification of FVIII neutralizing antibodies. Bleeds are usually treated with activated prothrombin complex concentrates and activated recombinant factor VII. In most patients with AH, the use of immunosupressive agents results in autoantibody elimination and restoration of normal FVIII plasma activity.