Haemophilia

The term haemophilia has been used in reference to
haemophilia A, haemophilia B and von Willebrand disease.
Haemophilia A is the most common bleeding disorder
affecting 1 in 5000 to 1 in 10 000 males. It is an X-linked
recessive disorder due to deficiency of coagulation factor VIII.
Clinical severity varies considerably and correlates with residual
factor VIII activity. Activity of 1% leads to severe disease that
occurs in about half of affected males and may present at birth.
Activity of 1–5% leads to moderate disease, and 5–25% to mild
disease that may not require treatment. Affected individuals
have easy bruising, prolonged bleeding from wounds, and
bleeding into muscles and joints after relatively mild trauma.
Repeated bleeding into joints causes a chronic inflammatory
reaction leading to haemophiliac arthropathy with loss of
cartilage and reduced joint mobility. Treatment using human
plasma or recombinant factor VIII controls acute episodes and
is used electively for surgical procedures. Up to 15% of treated
individuals develop neutralising antibodies that reduce the
efficiency of treatment.