[Diagnosis and management of hemophilia]

Hemophilia A and B are hereditary coagulation disorders caused by functional and quantitative abnormalities of coagulation factor VIII (FVIII) in hemophilia A and coagulation factor IX (FIX) in hemophilia B. A definitive diagnosis is made through the measurement of FVIII or FIX activity and ruling out other pathological conditions or diseases with decreased FVIII or FIX activity. Severity is classified as severe, moderate, and mild according to factor activity level. Moreover, as frequency of hemorrhage and severity are usually correlated, severe patients have a high risk of intracranial hemorrhage during infancy as well as joint damage due to recurrent hemarthrosis. However, there are some non-severe patients who have symptoms like bleeding and joint damage. Therefore, it is necessary to determine the treatment strategy not only based on severity but also on bleeding symptoms. The treatment for hemophilia is mainly replacement therapy using clotting factor concentrates (standard or extended half-life), such as prophylaxis or on-demand therapy for bleeding. However, there are also clinical problems, such as venous access and development of inhibitors. Recently, a non-factor agent has emerged as a new treatment option. Thus, the management of hemophilia is on a turning point.