Idiopathic thrombocytopenic purpura
What is ITP?
“Thrombo” refers to the blood cells called platelets that help prevent bleeding by clotting and sealing small cuts or breaks in blood vessels and tissues.
“Cytopenia” is a term meaning low blood counts. Thus “thrombocytopenia” refers to conditions of low platelets. When the platelet count is low, more bleeding may occur particularly bleeding from the linings in the mouth and GI tract and in the skin (bruising or ecchymosis).
“Purpura” is another term to describe the purple rash of bruises. Low platelets may be caused by many process including medications, infections, enlarged spleens, and cancers. In medicine, when we don’t know or can’t find the cause we use the term “idiopathic”.
Therefore, idiopathic thrombocytopenia purpura (ITP) refers to conditions of low platelets where we cannot find another cause. We now know that the cause of the low platelets in ITP is due to an immune response to the platelets with the production of antibodies that bind the platelets and result in their early destruction. Sometimes ITP is now called immune thrombocytopenia purpura.
Symptoms and Diagnosis of ITP
People with ITP may have nosebleeds and may bleed from the gums when they have dental work done, and/or other bleeding that’s hard to stop. Women with ITP may have heavy menstrual bleeding. Sometimes, the only evidence the platelets are low are tiny bruises most commonly on the front of the leg called petechiae. The diagnosis is by careful history and physical exam and blood tests including a CBC and blood smear. Unfortunately, we do not have a good specific test for ITP and we have to assume the diagnosis based on the history and lack of other causes. A bone marrow biopsy is only necessary when other causes seem likely or patients fail to respond to treatment
Treatment of ITP
Acute ITP is the most common type and occurs most often in children, lasting less than 6 months and often goes away on its own without treatment within a few weeks or months and doesn’t return. It often occurs after an infection caused by a virus. Chronic ITP is longer (6 months or more) and affects adult women more often than adult men, and rarely children and teenagers.
Treatment depends on how severe the bleeding is and the platelet count as well as the age of the patient. In mild cases, treatment may not be needed. Effective treatments include prednisone and pooled immunoglobulins from donors. For severe disease that fails prednisone, treatments options include splenectomy (surgical removal of spleen), low dose chemotherapy, immunosuppressant therapy and the anti-lymphocyte antibody rituximab used in the treatment of lymphomas. Newer agents that directly stimulate platelet productions term TPO-mimetic because they mimic the platelet hormone, TPO, have been FDA approved and are useful in the very difficult to treat cases but do not cure the disease.