Idiopathic Thrombocytopenia Purpura

What is Idiopathic thrombocytopenia?

Idiopathic thrombocytopenia (ITP) is characterized by a low platelet count with no apparent underlying cause. Individuals with this disease have normal, functioning bone marrow. The platelets, meanwhile, are destroyed in the circulating blood by the body's own immune system (autoantibodies). Because it frequently follows a viral infection, it may be an autoimmune disorder in which the infection triggers the immune system to destroy the platelets.

Platelets play a vital role in stopping bleeding (they plug any small breaks occurring in blood vessel walls). A reduction in the number of platelets causes a tendency to bleed, especially from the smaller blood vessels.

There are two forms of idiopathic thrombocytopenia. One typically occurs in childhood, and the second occurs in adults between the ages of 20 and 50. Acute ITP is more common in children. The adult form, chronic ITP, does not usually follow an infection, is insidious (comes on in such a manner that the individual is not aware of its onset), and is chronic, rarely resolving without therapy. Females are twice as likely to be affected. The incident rate is 66 per one million adults.

How is it diagnosed?

Physical exam: The individual may have present with pinpoint bruises (petechiae) or large bruises. The rest of the exam will be normal.

Tests: A complete blood count (CBC) will be normal except for an abnormally low platelet count (usually 50 thousand or less). A bone marrow examination will reveal normal platelet production, appearance and increased platelet production. Taking into account history, physical, CBC and bone marrow findings, diagnosis of idiopathic thrombocytopenia is made by excluding other possible causes.

How is Idiopathic thrombocytopenia treated?

Adults are generally treated with anti-inflammatory (corticosteroid) drugs. If the individual is having an acute bleed, he or she is given IVIG (intravenous immunoglobulins) followed by a platelet transfusion. If the condition persists for many weeks or becomes recurrent, the spleen may need to be removed (splenectomy).

A splenectomy provides a lasting cure in about seventy five percent of the cases. Approximately one-quarter of all adults will not respond to either oral anti-inflammatory medication or a splenectomy. These individuals are then considered to have chronic refractory ITP. Various therapies have been tried with response rates between zero to 50% in effectiveness.

Medications

What might complicate it?

Complications from this disease include acute bleeding into any area of the body, including the brain (brain hemorrhage). Individuals who do not respond to therapy (chronic refractory ITP) are at risk of an acute bleed, resulting in a five-percent mortality rate.

Predicted outcome

Most adults respond to appropriate treatment, although the bleeding tendency may occur from time to time. Adults who do not respond to therapy (chronic refractory ITP) usually require continued management. If the ITP is secondary to another disease like lupus, the ultimate outcome will depend on treatment and biology of the underlying disease regardless of response of the platelet count to treatment. Acute bleeding into a vital organ, such as the brain, will compromise the outcome even if the process resolves.

Alternatives

Conditions with similar symptoms include acute infectious diseases, myelodysplastic syndrome, disseminated intravascular coagulation (DIC), drug-induced thrombocytopenia, and congenital thrombocytopenia.

Appropriate specialists

Hematologist, allergist and immunologist.

Last updated 28 May 2015