24th July 2024

Haemophilia A and B

These are X-linked recessive disorders, and therefore affect males. Haemophilia B is also called Christmas disease.

There is a deficiency or absence of factor VIII (haemophilia A) or factor IX (haemophilia B), which are important in the amplification of thrombin and thus fibrin production.

Clinical features of haemophilia

Symptoms include frequent bruising and bleeding into muscles and joints. Patients with complete absence of the factor present at an earlier age than those with milder disease.

Coagulation studies will show a prolonged APTT that normalises on mixing with normal pool plasma, suggesting factor deficiency rather than inhibition. Factor VIII and IX levels confirm the diagnosis.

Management of haemophilia

Factor replacement remains the cornerstone of treatment. It can be used prophylactically to prevent bleeding, both before procedures and in general to prevent major joint bleeds, which can lead to debilitating haemophilic arthropathy.

Repeated doses of factor concentrate can lead to inhibitor formation, reducing the efficacy of treatment. In these cases, bypassing agents are required. Desmopressin may be used for haemophilia A.