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Essential thrombocythemia

Show Alternative Names
Primary thrombocythemia
Essential thrombocytosis

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

Blood clotting - Animation

Ouch! Here's how platelets form clots. This small artery has a cut. Blood flowing past the cut includes red blood cells that carry oxygen, platelets that come from white blood cell fragments, and clotting factors that help blood clot. When a blood vessel is damaged, blood cells and plasma ooze into surrounding tissue. Platelets immediately stick to the edges of the cut and release chemicals that attract more platelets. Eventually, a platelet plug is formed, and the outside bleeding stops. On the inside, clotting factors cause a cascade of activity that includes strands of blood-borne material called fibrin sticking together to seal the inside of the wound. Eventually, the blood vessel heals, and several days later, the blood clot dissolves.

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:

  • Chronic myelogenous leukemia (an overproduction of white blood cells that starts in the bone marrow)
  • Polycythemia vera (bone marrow disease that leads to an abnormal increase in the number of red blood cells)
  • Primary myelofibrosis (disorder of the bone marrow in which the marrow is replaced by fibrous scar tissue)

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 sometimes be seen in younger people, especially women under age 40.

Symptoms

Symptoms may include any of the following:

  • Headache (most common)
  • Tingling, coldness, or blueness in the hands and feet
  • Feeling dizzy or lightheaded
  • Vision problems
  • Mini-strokes (transient ischemic attacks) or stroke

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

  • Easy bruising and nosebleeds
  • Bleeding from the gastrointestinal tract, respiratory system, urinary tract, or skin
  • Bleeding from the gums
  • Prolonged bleeding from surgical procedures or tooth removal

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 the number of  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

Contact your provider if:

Review Date: 2/2/2023

Reviewed By

Mark Levin, MD, Hematologist and Oncologist, Monsey, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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.

Marcellino BK, 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. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 71.

Disclaimer

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. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

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Blood clotting - Animation

Ouch!

Here's how platelets form clots. This small artery has a cut. Blood flowing past the cut includes red blood cells that carry oxygen, platelets that come from white blood cell fragments, and clotting factors that help blood clot. When a blood vessel is damaged, blood cells and plasma ooze into surrounding tissue. Platelets immediately stick to the edges of the cut and release chemicals that attract more platelets. Eventually, a platelet plug is formed, and the outside bleeding stops.

On the inside, clotting factors cause a cascade of activity that includes strands of blood-borne material called fibrin sticking together to seal the inside of the wound. Eventually, the blood vessel heals, and several days later, the blood clot dissolves.

 

Blood clotting - Animation

Ouch!

Here's how platelets form clots. This small artery has a cut. Blood flowing past the cut includes red blood cells that carry oxygen, platelets that come from white blood cell fragments, and clotting factors that help blood clot. When a blood vessel is damaged, blood cells and plasma ooze into surrounding tissue. Platelets immediately stick to the edges of the cut and release chemicals that attract more platelets. Eventually, a platelet plug is formed, and the outside bleeding stops.

On the inside, clotting factors cause a cascade of activity that includes strands of blood-borne material called fibrin sticking together to seal the inside of the wound. Eventually, the blood vessel heals, and several days later, the blood clot dissolves.

 
 
 
 

 

 
 

 
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