Locations Main Campus: Chesterfield, MO 63017   |   Locations
314-434-1500 314-434-1500   |   Contact Us

Multimedia Encyclopedia

E-mail Form
Email Results


Primary thrombocythemia

Essential thrombocythemia; Essential thrombocytosis


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



Primary thrombocythemia is caused by the overproduction of platelets. If untreated, this condition gets worse over time. Because these platelets do not work normally, bleeding is a common problem.

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

  • Chronic myelogenous leukemia
  • Polycythemia vera
  • Primary myelofibrosis

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




Symptoms may include any of the following:

  • Bleeding from the gastrointestinal tract, respiratory system, urinary tract, or skin
  • Bleeding from the gums
  • Bleeding (prolonged) from surgical procedures or tooth removal
  • Dizziness and headaches
  • Easy bruising and nosebleeds (epistaxis)
  • Numbness of the hands or feet
  • Ulcers on the fingers or toes

The condition can even cause strokes in some people.


Exams and Tests


Most of the time, this condition is found through blood tests done for other conditions before symptoms appear.

Your health care provider may notice an enlarged liver or spleen on physical examination. You may also have abnormal blood flow in the toes or feet that causes skin damage in these areas.

Other tests may include:

  • Bone marrow biopsy
  • CBC
  • Genetic tests (to look for a change in the JAK2 gene)
  • Uric acid level




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. In some people with a JAK2 mutation, specific inhibitors of the JAK2 protein may be used.

In people who are at a high risk for clotting, aspirin at a low dose (81 to 100 mg per day) decreases clotting episodes. People who may benefit from this treatment include older people and people with very high platelet levels or who have had past clotting episodes.

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


Outlook (Prognosis)


While outcomes can 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:

  • Acute leukemia or myelofibrosis
  • Severe bleeding (hemorrhage)
  • Thrombotic episodes ( stroke , heart attack , or blood clots in the hands or feet)


When to Contact a Medical Professional


Call your health care provider if:

  • You have unexplained bleeding that continues longer than it should.
  • You notice chest pain , leg pain , confusion , weakness , numbness , or other new symptoms.




Hoffman R, Kremyanskaya M, Najfeld V, et al. Essential thrombocythemia. In: Hoffman R, Benz EJ Jr, Silberstein LE, Heslop HE, Weitz JI, Anastasi J, eds. Hematology: Basic Principles and Practice . 6th ed. Philadelphia, PA: Elsevier Saunders; 2013:chap 68.

Tefferi A. Polycythemia vera, essential thrombocytoemia, and primary myelofibrosis. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 166.

  • Blood cells - illustration

    Blood is comprised of red blood cells, platelets, and various white blood cells.

    Blood cells


    • Blood cells - illustration

      Blood is comprised of red blood cells, platelets, and various white blood cells.

      Blood cells


    A Closer Look


      Talking to your MD


        Self Care


          Tests for Primary thrombocythemia



            Review Date: 2/13/2015

            Reviewed By: Rita Nanda, MD, Assistant Professor of Medicine, Section of Hematology/Oncology, University of Chicago Medicine, Chicago, IL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

            The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.




            A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.

            Content is best viewed in IE9 or above, Firefox and Google Chrome browser.