Essential Thrombocythemia

Essential Thrombocythemia Overview

Essential thrombocythemia is an uncommon disorder in which your body produces too many platelets. Platelets are the part of your blood that sticks together to form clots.

This condition may cause you to feel fatigued and lightheaded and to experience headaches and vision changes. It also increases your risk of blood clots. Essential thrombocythemia is more common in people over age 60, though younger people can develop it too. It’s also more common in women than men.

Essential thrombocythemia is a chronic disease with no cure. If you have a mild form of the disease, you may not need treatment. If you have severe symptoms, you may need medicine that lowers your platelet count, blood thinners or both.

Essential Thrombocythemia Symptoms

You may not have any noticeable symptoms of essential thrombocythemia. The first indication you have the disorder may be the development of a blood clot. Clots can develop anywhere in your body, but with essential thrombocythemia they occur most often in your brain, hands and feet.

Signs and symptoms depend on where the clot forms. They include:

  • Headache
  • Dizziness or lightheadedness
  • Chest pain
  • Fainting
  • Temporary vision changes
  • Numbness or tingling of the hands and feet
  • Redness, throbbing and burning pain in the hands and feet

Less commonly, essential thrombocythemia may cause bleeding, especially if your platelet count is more than 1 million platelets per microliter of blood. Bleeding may take the form of:

  • Nosebleeds
  • Bruising
  • Bleeding from your mouth or gums
  • Bloody stool

Essential Thrombocythemia Causes

Essential thrombocythemia is a type of chronic myeloproliferative disorder. That means your bone marrow, the spongy tissue inside your bones, makes too many of a certain type of cell. In the case of essential thrombocythemia, the bone marrow makes too many cells that create platelets.

It’s not clear what causes this to happen. About 90% of people with the disorder have a gene mutation contributing to the disease.

If an underlying condition such as an infection or iron deficiency causes a high platelet count, it’s called secondary thrombocytosis. Compared with essential thrombocythemia, secondary thrombocytosis causes less risk of blood clots and bleeding.

Essential Thrombocythemia Diagnostics

If your blood count is above 450,000 platelets per microliter of blood, your doctor will look for an underlying condition. He or she will rule out all other causes of high platelet counts to confirm a diagnosis of essential thrombocythemia.

Blood tests

Samples of your blood will be checked for:

  • The number of platelets
  • The size of your platelets
  • Specific genetic flaws, such as the JAK2, CALR or MPL gene mutation
  • Iron levels
  • Markers of inflammation

Bone marrow tests

Your doctor may also suggest two bone marrow tests:

  • Bone marrow aspiration. Your doctor extracts a small amount of your liquid bone marrow through a needle. The sample is examined under a microscope for abnormal cells.
  • Bone marrow biopsy. Your doctor takes a sample of solid bone marrow tissue through a needle. The sample is examined under a microscope to determine whether your bone marrow has a higher than normal number of the large cells that make platelets.

Essential Thrombocythemia Treatment

Although there’s no cure for essential thrombocythemia, treatments can control symptoms and reduce the risk of complications. Life span is expected to be normal despite the disease.

Treatment of essential thrombocythemia depends on your risk of blood clots or bleeding episodes. If you’re younger than 60 and have had no signs or symptoms, you may simply need periodic medical checkups.

Your doctor may prescribe medication if:

  • You’re older than 60 and have had previous blood clots or TIAs
  • You have cardiovascular risk factors, such as high cholesterol, high blood pressure and diabetes


Your doctor may suggest one of the following prescription drugs, perhaps along with low-dose aspirin, to reduce your platelet count:

  • Hydroxyurea (Droxia, Hydrea.) This drug is the most common prescription used for essential thrombocythemia.
  • Anagrelide (Agrylin). Unlike hydroxyurea, anagrelide isn’t associated with an increased risk of leukemia, but it’s not considered as effective.
  • Interferon alfa-2b (Intron A) or peginterferon alfa-2a (Pegasys). These drugs are given by injection, and may cause worse side effects than hydroxyurea or anagrelide does. But it’s the best choice for some people.

Emergency procedure

A medical procedure called plateletpheresis is used only in emergencies, such as after a stroke or other dangerous blood clotting. It involves passing your blood through a device that removes platelets and then returns the blood to your body. This temporarily lowers your platelet count.