Essential Thrombocythemia

In this condition, the body produces too many platelets, cells that circulate in the blood and keep us from bleeding. This may result in abnormal clotting.


In its early stage, essential thrombocythemia (ET) may not cause any symptoms. However, some patients may experience the following:

  • Headaches
  • Burning or tingling in hands or feet
  • Redness and warmth in hands or feet
  • Vision or hearing problems
  • Clotting of the blood vessels and/or increased bleeding. These can cause serious health problems such as stroke or heart attack.


A physician may order the following tests to confirm a diagnosis of ET:

  • Complete blood count (CBC) to determine the number of platelets in the blood.
  • Blood smear. A blood sample is examined under a microscope to check the number and shape of the platelets.
  • Genetic testing for the JAK2 gene mutation. In ET, the calreticulin (CALR) and MPL genes can also be mutated.
  • Other blood tests to check the level of iron in the blood or look for inflammation. These tests help to rule out other causes of elevated platelet count.
  • Bone marrow aspiration. The physician uses a needle to remove a small amount of liquid bone marrow then examines it under a microscope for abnormal cells.
  • Bone marrow biopsy. The physician uses a needle to take a sample of solid bone marrow tissue then examines it under a microscope. Patients with ET have an elevated number of the large cells that make up platelets (megakaryocytes) in their bone marrow.

Risk Factors

Little is known about the risk factors for developing this disease. However, studies have shown a link between ET and exposures to hair dyes, living in a tuff house (made of hard volcanic rock), and working as an electrician.


Treatment for ET depends upon the patient’s risk for developing blood clots, age, and general cardiovascular health. Those at low risk for clots may be observed, while smokers and those with high blood pressure, high cholesterol, or diabetes may need to take aspirin to thin the blood and other medications such as:

  • Hydroxyurea, which decreases the production of blood cells, including platelets, in the bone marrow
  • Anagrelide (Agrylin) which decreases the production of platelets in the bone marrow
  • Interferon alfa-2B (Intron A) which can affect the growth of bone marrow cells that make platelets

Emergency Plateletpheresis

This procedure is warranted only after a stroke or other dangerous blood clotting to rapidly lower platelet count. An intravenous needle is inserted into a blood vessel. The patient’s blood flows through the tube and into a machine that removes platelets from your blood. The remaining portion of the blood is then returned to the body.