Idiopathic thrombocytopenic purpura (idiopathic means the exact cause of the disease is unkown) is a bleeding disorder characterized by low platelet numbers resulting from platelet destruction by the immune system.

Alternative Names

Immune thrombocytopenic purpura; ITP

Causes, incidence, and risk factors

The disease occurs when immune system cells called lymphocytes produce antibodies against platelets . The presence of antibodies on platelets leads to destruction in the spleen. Skin hemorrhage, easy bruising , abnormal menstrual bleeding , or sudden and severe loss of blood from the gastrointestinal tract may occur. Usually, no other abnormal findings are present. In children, the disease is sometimes preceded by a viral infection and runs its course without treatment. In adults, it is usually a chronic disease and rarely follows a viral infection. ITP affects women more frequently than men, and is more common in children than adults. There is no sex difference in children. Risk factors are unknown.

Signs and tests

Tests include:

Treatment

In children, the disease often runs its course without treatment. In adults, initial treatment with prednisone is given. A splenectomy (removal of the spleen) is indicated if the person does not respond to prednisone. The spleen is the major site of platelet destruction, so a splenectomy will resolve the thrombocytopenia in most people. Other treatments (when the disease does not respond to initial treatment) are oral danazol, high dose gamma globulin injections, drugs that suppress the immune system, and passage of the blood over a Protein A (Prosorba) column (which filters antibodies out of the blood stream). Anti-RhD therapy, which destroys cells carrying a specific blood cell molecule, is also useful in some people. People with ITP should avoid taking aspirin or ibuprofen, because these drugs interfere with platelet function, and bleeding may occur.

Expectations (prognosis)

The chance of remission (a symptom-free period) is good with prednisone or a splenectomy . Rarely, ITP may become a chronic ailment in adults and reappear even after remission.

Complications

Calling your health care provider

Go to the emergency room or call the local emergency number (such as 911) if severe bleeding occurs or other new symptoms develop.

Prevention

The causes and risk factors are unknown (except in children when it may be related to a viral infection). Therefore, prevention is unknown.