About Your Diagnosis

Idiopathic thrombocytopenia purpura (ITP) is a disorder of the immune system that affects the platelets. Platelets are small cellular particles the function of which is to help form blood clots. Platelets are formed in the bone marrow and then circulate in the peripheral blood. In ITP, platelets are made normally, but while circulating in the blood, they become coated by antibodies or immune complexes and are destroyed by the patient’s spleen. This causes patients with ITP to have too few platelets in their blood, and their blood may not clot normally. ITP may be associated with other autoimmune disorders, such as systemic lupus erythematosus or immune thyroid disease, with malignant disease of the lymphocytes, or with human immunodeficiency virus (HIV) infection. However, many patients with ITP have no associated predisposing disease, and for these patients, the cause is unknown. ITP among children usually is caused by a viral infection. ITP is diagnosed among 66 adults per 1,000,000 population per year and 10 to 40 children per 1,000,000 population per year. Childhood ITP affects boys and girls equally, but ITP is more common among adult women than men. ITP is not contagious. There are very rare reports of ITP occurring in families, and some patients with ITP have family members with autoimmune disease. However, ITP is not considered a hereditary disease. The diagnosis of ITP is made by means of finding a low platelet count in a blood test and normal to increased platelet precursors (megakaryocytes) at bone marrow biopsy. After the diagnosis is made, some patients may be undergo tests for conditions that are associated with ITP, such as autoimmune disorders and HIV infection. ITP among children usually resolves on its own within 6 months. ITP among adults almost never resolves without treatment. Many adult patients with ITP can be cured with available medical and surgical therapies. Most patients who are not cured can have a platelet count maintained at a high enough level to allow a normal lifestyle.

Living With Your Diagnosis
Patients with ITP have too few platelets in their blood. If your platelet count is very low, your blood may not clot normally. You may bruise easily or bleed from the nose and gums. You may have very heavy menstrual flow. You also may have “blood blisters” and tiny red spots on your skin (petechiae), which are caused by bleeding into the skin or mucous membranes. You also may have serious bleeding in the gastrointestinal tract or brain, but this is rare.

Treatment
Patients with ITP whose platelets are low enough to place them at risk for spontaneous bleeding need treatment. First-line therapy for ITP is prednisone, a steroid, in the form of daily pills. Prednisone suppresses the immune destruction of platelets. More than half of patients with ITP respond to prednisone. However, because of the many side effects of prednisone, permanent treatment is not desirable, and about half of persons who respond have relapses as the drug is tapered. Side effects of prednisone include weight gain, fluid retention, stomach irritation, mood swings, and insomnia. Patients with diabetes or high blood pressure may have worsening of these conditions, necessitating an increase in medication. Some patients who do not have preexisting diabetes or high blood pressure may have them while taking prednisone. Prednisone pills suppress the body’s normal production of steroids. Therefore, patients receiving prednisone cannot simply stop taking it; the drug must be tapered slowly to allow the body time to adjust. The suppression of the immune system caused by prednisone can make patients susceptible to infection. Prednisone also masks fevers, making infections more difficult to detect. Long-term use of steroids can lead to many complications, including ulcers, cataracts, glaucoma, muscle weakness, osteoporosis, and development of a moon-shaped face. The most commonly used treatment option for patients who have relapses after taking prednisone is surgical removal of the spleen (splenectomy), which eliminates the site of platelet destruction. About two thirds of patients who undergo splenectomy respond, and responses usually occur within 1 week of the operation. Patients who have undergone splenectomy are at increased risk for infection with certain types of bacteria. Therefore they should receive a pneumococcal vaccine before the
operation. A new treatment option for patients with ITP is intravenous administration of Rho (D) immune globulin (eg, WinRho D). This drug, an antibody to the Rh antigen on red blood cells, binds to the patient’s red blood cells. The patient’s immune system becomes occupied with destroying the antibody- coated red blood cells and leaves the platelets alone. The drug is given intravenously over a half hour or less. Its effects last for 3 to 6 weeks. Rho (D) is effective only for Rh-positive patients who have not undergone splenectomy. Its main side effect is anemia, a decrease in red blood cells.

The DOs
• Undertake therapy for ITP as prescribed.
• Take only acetaminophen (eg, Tylenol) for pain or fever. Other over-the-counter pain and fever medications can damage platelet function.
• Eat a healthful, balanced diet.
• Brush your teeth with a soft toothbrush and shave only with an electric razor.
• Inform your surgeon or dentist that you have ITP before undergoing any surgical procedure or tooth extraction.

The DON’Ts
• Do not take aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs; eg, Motrin) because these can damage platelet function.
• Do not play contact sports if your platelet count is low enough to place you at increased risk for bleeding. If your platelet count is only slightly below normal, you may not have to restrict your activities.

When to Call Your Doctor
• If you have bleeding that does not resolve after application of pressure to the area for 5 minutes.

Websites:
MedMark Hematology: http://medmark.bit.co.kr/hematol.html