What is Essential Thrombocythemia?

Essential Thrombocythemia (ET) is a Myeloproliferative Disorder.  There are 4 Myeloproliferative Disorders:

  • Essential Thrombocythemia — The overproduction of the platelet cells by the bone marrow
  • Polycythemia Vera — The overproduction of red blood cells by the bone marrow
  • Idiopathic Myelofibrosis  overproduction of collagen or fibrous tissue in the bone marrow, which impairs bone marrow’s ability to produce blood cells
  • Chronic Leukemia   A cancer of the bone marrow that produces abnormal white blood cells in the bone marrow.  There are 3 types of Chronic Leukemia.

ET is a rare disease that affects about 1.5 people out of every 100,000.  In 2005, the Janus Kinase 2 (JAK-2) test was developed to diagnose this disease.  Prior to 2005, a bone marrow biopsy was used (bone marrow biopsies are still used to monitor the disease).  The JAK-2 is positive in about one half of all patients with ET.

ET is caused when the gene responsible for production and regulation of the stem cells that produce platelets mutates.  The gene then produces mutated stem cells within the bone marrow which in turn produce mutated platelets.  In addition, the gene can no longer regulate platelet production and does not ‘turn off’.  The platelets continue to be produced beyond a safe level.  Because they are mutated, the platelets are ‘sticky’, and instead of being evenly dispersed throughout the blood are clumped and pose a great risk of clotting.  It is not known what causes this mutation.  It occurs at some point during the patient’s life and is not present from birth.

ET is also a Hematologic Malignancy.  Is it cancer?  Yes, Essential Thrombocythemia is a blood cancer.  However, it manifests itself differently than most cancers, and for this reason is not commonly referred to as cancer.  Most cancers are cancerous cells that multiply and invade a body’s systems and, ideally, can be removed surgically or destroyed by chemotherapy or radiation.  They are also very aggressive.  To the contrary, ET is caused by a mutated gene.  For this reason it cannot be removed completely.  Also, while excess platelets can be destroyed by chemotherapy or removed by plateletpheresis (filtering the blood mechanically) they will be replaced again.  On the other hand, with proper monitoring and treatment, most ET patients can live a full life span.

Normal platelet count is 150,000 to 450,000.  Diagnosis for ET includes platelet count above 600,000.  About half of all ET patients also have an enlarged spleen.  Only about one-third of patients have other symptoms, which could include intestinal bleeding, nosebleeds, headaches, dizziness, fatigue, bruising and numbness and pain in the hands and feet.  Common treatment for ET is low-dose aspirin and oral chemotherapy, which are taken daily for the remainder of the patient’s life.  Treatments in more serious or extreme cases include plateletpheresis and bone marrow transplant.  ET also has the risk of developing into Acute Leukemia as it may alter to affect production of other blood cells.

So, what does a person with ET face?  ET presents a high risk for abnormal clotting, which can cause problems such as stroke, heart attack, pulmonary embolisms or small clots blocking the circulation in the hands and feet.  It also presents high risk for hemorrhaging, internal bleeding, uncontrolled bleeding during surgeries or from trauma and brain aneurisms.  ET patients usually have their blood tested on a monthly basis to monitor platelet levels.


Some links that I have found to be very informative are:








~ by julie70 on January 5, 2009.

4 Responses to “What is Essential Thrombocythemia?”

  1. I was diagnosed with JAK-2 ET in April 2009. I am a 78 year old female also dealing with atrial fibrilation. The Jak-2 diagnosis was a surprise. I knew I had been feeling more tired than usual but then I am dealing with a heart condition. The thought of my age never entered the picture. I was taken to a hospital emergency room with my A-fib acting up – into ICU – when the blood work was done was asked if I had had a recent infection. No. Well, then, this is what you have.??? a mystery to me. Went to a Hematologist – blood drawn – diagnosis of Jak-2. Put on Hydrea. Initial platelet count was – JAK2 V617F tumor load os 12254.14 pg. Blood drawn 5/8/09 count 1063 – Went on 500 MG Hydroxyura per day. Over time dose has increased to 500 MG four days 1,000 MG three days. Latest platelet count 11/06/09 is 473 -still high. Have kept a copy of every test. Reaction to meds has been severe itching. I have kept this under control by taking an over the counter allergy med from Rite Aid Drug store – Chlorpheniramine. 4 Mg. taken as needed. Also use Eucerin Calming Cream and Smoothing Essentials. I have set up a chart to follow mhe counts. Very interesting.
    I take Coumadin and Digoxin for my heart. The Hydrrea is cauing the platelet count to drop but is also interfering with the blood thinning meds. Great time testing and adjusting.

  2. Hi Sara,
    I’m wondering if the itching is caused by the meds or the ET itself? One symptom of ET can be severe itching, because ET raises your histamine levels. How is the Chlorpheniramine working for you? I have the same issue. I used to scratch myself raw, and it wasn’t until I was diagnosed that I learned it was the ET. I take a Zyrtec tablet (Citrizine HCL 10mg) every day and it has really helped.
    Thanks for commenting, and I hope they are able to get your meds sorted out. The adjusting can really be a pain.

  3. Most of the times blogs are the same but i think you have a unique blog. Bravo !

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