Definition of Immune thrombocytopenic purpura

Immune thrombocytopenic purpura: A blood disorder characterized by the destruction of blood platelets due to the presence of antiplatelet autoantibodies. (Autoantibodies are antibodies directed against the patient's own cells, in this disorder, the patient's own platelets.) Thrombocytopenia refers to a decrease in platelets (also known as thrombocytes). Purpura pertains to the visible hallmarks: purplish areas in the skin and mucous membranes (such as the mouth lining) where bleeding has occurred as a result of decreased platelets.

Immune thrombocytopenic purpura (ITP) can be triggered by drugs, or associated with infection, pregnancy, or immune disorders such as systemic lupus erythematosus. About half of all cases are classified as "idiopathic," meaning the cause is unknown.

The main clinical feature in ITP is bleeding. Aside from purpura, evidence of bleeding can include easy bruising ("ecchymosis") and tiny red dots on the skin or mucous membranes ("petechiae"). In some instances, bleeding from the nose, gums, gastrointestinal or urinary tracts may also occur. Bleeding within the brain is a rare but feared complication.

Acute ITP most commonly occurs in young children. Boys and girls are equally affected. Symptoms often, but do not necessarily, follow a viral infection. About 85% of children recover within 1 year and the problem does not return. ITP is considered chronic when it lasts more than 6 months. The onset of chronic ITP may be at any age. It peaks in adulthood and females are affected two to three times more often than males.

The treatment of ITP depends on the severity of the disease. No therapy is needed in some mild cases. In most cases, drugs that alter the immune system's attack on platelets are prescribed. These include corticosteroids (for example, prednisone) and/or IV immune globulin. Another treatment that usually results in an increased number of platelet is removal of the spleen, the organ that destroys antibody-coated platelet. Other drugs such as vincristine, azathioprine (Imuran), Danazol, cyclophosphamide, and cyclosporine are usually reserved for patients with sever ITP.

Lifestyle changes may be helpful for the prevention of bleeding due to injury. These changes include use of protective gear such as helmets and avoidance of contact sports in symptomatic patients or when platelet counts are less than 50,000.

The abbreviation "ITP" is much used. It stands for both immune thrombocytopenic purpura and idiopathic thrombocytopenic purpura.