Essential thrombocythemia; Essential thrombocytosis
Primary thrombocythemia is when the bone marrow is making too many platelets without a known cause. Platelets are essential for blood clotting.
Primary thrombocythemia is a disorder that is caused by too much growth of a type of cell that is used to make blood cells. Although the platelets are mostly affected, the red blood cells and white blood cells may also be involved. This condition slowly gets worse over time.
The disease is in the same family of disorders as:
Usually it affects people in middle age. It can also be seen in younger patients, especially females under age 40.
People with this condition make too many platelets and may have a problem with blood clots (thrombosis). Because these platelets do not work normally, bleeding is also a common problem.
The condition may even cause strokes in some people.
This condition is often detected on blood tests done for other reasons, before there are any symptoms.
A physical exam may show an enlarged spleen or liver. There may be abnormal blood flow in the toes or feet, as well as skin damage caused by that abnormal blood flow.
Other tests may include:
If a patient has life-threatening complications, a procedure to remove platelets directly from the blood (platelet pheresis) can quickly decrease the platelet count.
Long-term use of medications to decrease the platelet count can reduce both bleeding and clotting complications. The most commonly used medications include hydroxyurea, interferon-alpha, or anagrelide.
In patients who are at high risk for clotting (older patients, those with very high platelet levels or who have had past clotting episodes), aspirin at a low dose (81 to 100 mg per day) decreases clotting episodes.
Many patients do not need any treatment. However, the health care provider should monitor their condition.
The outcome varies. Most people go long periods of time without complications and have a normal life expectancy. In a very small number of patients, complications from bleeding (hemorrhage) and blood clots (thrombosis) can cause serious problems.
In a small number of patients, the disease will change into acute leukemia or myelofibrosis.
Finazzi G, Xu M, Barbui T, Hoffman R. Essential thrombocythemia. In: Hoffman R, Benz EJ Jr., Shattil SJ, et al, eds. Hoffman Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Churchill Livingstone Elsevier;2008:chap 127.
Tefferi A. Myeloproliferative disorders: Essential thrombocythemia and primary myelofibrosis. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 177.
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