Health Encyclopedia

Primary thrombocythemia

Definition

Primary thrombocythemia is the overproduction of platelets without a recognizable cause. Platelets are essential for blood clotting.

Alternative Names

Essential thrombocythemia; Essential thrombocytosis

Causes, incidence, and risk factors

Primary thrombocythemia is a slowly progressing disorder, caused by overgrowth of a type of cell that is a precursor of blood cells. Although the platelets are primarily affected, the red blood cells and white blood cells are also involved.

The disease has similarities to polycythemia vera, chronic myelogenous leukemia, and myelofibrosis. Usually it affects people in middle age. Bleeding can occur from the gastrointestinal tract, respiratory system, urinary tract, or skin.

The formation of blood clots (thrombosis), may occur with bleeding episodes. It may even cause strokes in some people. Risk factors are unknown. The incidence is about 3 out of 100,000 people.

Symptoms

Bleeding from the gastrointestinal tract
Bleeding from the gums
Bloody stools
Dizziness
Easy bruising
Enlarged lymph nodes (rare)
Headache
Nosebleeds (epistaxis)
Numbness of hands or feet
Prolonged bleeding from surgical procedures or tooth extraction
Ulcers on fingers or toes

Signs and tests

Bone marrow aspiration
CBC that shows elevated platelet count
Physical examination may show enlarged spleen or liver
Uric acid level may be elevated

Treatment

If a patient has life-threatening complications, platelet pheresis, a procedure to remove platelets from the blood directly, can rapidly decrease the platelet count.

Long-term decrease of the platelet count using medications can reduce both bleeding and clotting complications. Most common medications include hydroxyurea, interferon-alpha, or anagrelide. For patients with a known clotting tendency, aspirin may help decrease clotting episodes.

Some patients do not need any treatment.

Expectations (prognosis)

The outcome varies. Some people have prolonged periods without complications, while complications related to hemorrhage and thrombosis lead to death in others.

Complications

Acute leukemia or myelofibrosis can develop in some patients
Severe hemorrhage
Thrombotic episodes (stroke, heart attack, or blood clots in extremities)

Calling your health care provider

Call your health care provider:

If unexplained or prolonged bleeding occurs
If chest pain, leg pain, confusion, weakness, numbness, or other new symptoms develop

References

Hoffman R, Benz Jr. EJ, Shattil SJ, et al., eds. Hematology: Basic Principles and Practice. 4th ed. Philladelphia, Pa: Churchill Livingston; 2005:1277-91.

Rakel RE. Textbook of Family Practice. 6th ed. Philadelphia, Pa: WB Saunders; 2002:1256.

Review Date:2/26/2007
Reviewed By:William Matsui, MD, Assistant Professor of Oncology, Division of Hematologic Malignancies, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD. Review provided by VeriMed Healthcare Network.

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