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Essential thrombocythemia

Primary thrombocythemia; Essential thrombocytosis

Essential thrombocythemia (ET) is a condition in which the bone marrow produces too many platelets. Platelets are a part of the blood that aids in blood clotting.

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Blood cells

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Blood clotting

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Causes

ET results from an overproduction of platelets. As these platelets do not work normally, blood clots and bleeding are common problems. Untreated, ET worsens over time.

ET is part of a group of conditions known as myeloproliferative disorders. Others include:

Many people with ET have a mutation of a gene (JAK2, CALR, or MPL).

ET is most common in middle-aged people. It can also be seen in younger people, especially women under age 40.

Symptoms

Symptoms may include any of the following:

If bleeding is a problem, symptoms may include any of the following:

Exams and Tests

Most of the time, ET is found through blood tests done for other health problems before symptoms appear.

Other tests may include:

Treatment

If you have life-threatening complications, you may have a treatment called platelet pheresis. It quickly reduces platelets in the blood.

Long-term, medicines are used to decrease the platelet count to avoid complications. The most common medicines used include hydroxyurea, interferon-alpha, or anagrelide.

Aspirin at a low dose (81 to 100 mg per day) may decrease clotting episodes.

Many people do not need any treatment, but they must be followed closely by their provider.

Outlook (Prognosis)

Outcomes may vary. Most people can go for long periods without complications and have a normal lifespan. In a small number of people, complications from bleeding and blood clots can cause serious problems.

In rare cases, the disease can change into acute leukemia or myelofibrosis.

Possible Complications

Complications may include:

When to Contact a Medical Professional

Call your provider if:

Related Information

Platelet count
Polycythemia vera
Chronic myelogenous leukemia (CML)
Myelofibrosis
Respiratory
Blood clots
Incidence
Stroke
Heart attack

References

Gotlib J. Polycythemia vera, essential thrombocythemia, and primary myelofibrosis. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 157.

Mascarenhas J, Iancu-Rubin C, Kremyanskaya M, Najfeld V, Hoffman R. Essential thrombocythemia. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 7th ed. Philadelphia, PA: Elsevier; 2018:chap 69.

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Review Date: 1/19/2021  

Reviewed By: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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