Platelet count Estimate:Upper panel: normal platelet count.
Lower panel: severe thrombocytopeniaAfter you have finished the differential count, continue your blood smear analysis with an estimate of the platelet count as low, normal, or high. To estimate platelet number, determine the average number of platelets in 5 to 10 oil immersion fields. At this magnification, each platelet is approximately equal to 15,000 platelets/µl. The following guidelines are useful for this session:
The platelet estimate should be done in the part of the smear used for differential counting and evaluation of morphology. This method of estimating platelets is less precise if platelet clumps are present, though an estimate based on the dispersed platelets in such a smear does provide a 'not less than' estimate. On Cornell CBC's, the following reporting protocol is used:
Who gets ITP?
There are 2 types of ITP. One type affects children, and the other type affects adults. In children, the usual age for getting ITP is 2 to 4 years of age. Most adults with ITP are young women, but it can occur in anyone. ITP does not seem to be hereditary (run in families).
How does ITP affect children?ITP in children is usually mild and runs it course without the need for treatment. About 80% of children recover completely from ITP in about 6 months.
How is ITP treated in children? Because most children recover with no treatment, many doctors recommend just watching them carefully and taking care of the bleeding symptoms. Children don't have to go to the hospital if good care is available at home. However, some doctors recommend a short treatment with prednisone pills or intravenous infusions (given in a vein) of gamma globulin to increase the platelet count more quickly. Both medicines have some side effects.
How does ITP affect adults? In most adults, ITP lasts much longer than it does in children. At the time of diagnosis, most adults have noticed increased bleeding and easy bruising for several weeks or even months. In women, increased menstrual blood flow is a major sign.
Many adults have only mild thrombocytopenia. In fact, quite a few people have no bleeding symptoms. They are only diagnosed with ITP when their blood is checked for another reason and a low blood platelet count is found. Mild cases of ITP may not require treatment, just regular monitoring of the platelet levels.
How is ITP treated in adults?Treatment of ITP in adults is aimed at increasing the blood platelet count. This is not the same as curing the disease. Patients may take prednisone for several weeks or months. Prednisone raises the level of your platelet count. As your count rises and reaches a safe level, your doctor may gradually decrease your medicine until you are completely off of prednisone. However, when the medicine is stopped, the platelet count may decrease again.
If prednisone doesn't help enough, the spleen can be removed. The spleen makes most of the antibodies that destroy the blood platelets. It also destroys old or damaged blood cells. In an otherwise healthy person, removal of the spleen is not a serious operation. Laparoscopic removal of the spleen is now possible, further reducing surgical risk.
What about ITP in pregnant women?
Diagnosing ITP during pregnancy can be difficult, because platelet counts may be low for other reasons. About 5% of women have mildly low platelet counts at the end of a normal pregnancy. The cause of this is unknown. The platelet count goes back to normal right after delivery.
A baby born to a mother who has ITP may have a low blood platelet count a few days to a few weeks after birth. These babies are usually kept in the hospital for several days for observation (watching to make sure they are okay) before they go can home. If the baby's platelet count is very low, treatment is available to speed recovery.
What can I do if I have ITP?
If you have ITP, you should avoid medicines that may decrease your platelet count, such as over-the-counter drugs like aspirin and ibuprofen (some brands: Advil, Motrin). You should also limit alcohol because it can decrease the ability of your blood to clot