Bleeding Disorders

Key points

• • Bleeding disorders fall into two broad groups: platelet or vessel problems that cause small skin and mucosal bleeds, and clotting-factor problems that cause deep bleeds into joints and muscles.
• • Haemophilia A is a lack of clotting factor VIII and haemophilia B a lack of factor IX; both are X-linked recessive, so they predominantly affect males and cause bleeding into joints.
• • Von Willebrand disease is the commonest inherited bleeding disorder, caused by a deficiency or dysfunction of von Willebrand factor, which helps platelets stick and also carries factor VIII, so both are affected.
• • Immune thrombocytopenic purpura is a low platelet count caused by the immune system destroying platelets, which gives petechiae and easy bruising.
• • Disseminated intravascular coagulation is a dangerous state in which widespread clotting uses up platelets and clotting factors, so bleeding and clotting happen together.
• • The pattern of bleeding gives a clue: platelet problems cause petechiae and mucosal bleeding, whereas factor problems cause bleeding into joints and muscles.