BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuEssential thrombocythemiaPrimary thrombocythemia; Essential thrombocytosisEssential thrombocythemia (ET) is a condition in which the bone marrow produces too many platelets. Platelets are a part of the blood that aids in blood clotting.No audio descriptionWith audio descriptionRelated video goes here for no-HTML5 browsersRelated video goes here for no-HTML5 browsers 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) Chronic myelogenous leukemiaChronic myelogenous leukemia (CML) is cancer that starts inside bone marrow. This is the soft tissue in the center of bones that helps form all bloo...ImageRead Article Now Book Mark Article Polycythemia vera (bone marrow disease that leads to an abnormal increase in the number of blood cells) Polycythemia veraPolycythemia vera (PV) is a bone marrow disease that leads to an abnormal increase in the number of blood cells. The red blood cells are mostly affe...Read Article Now Book Mark Article Primary myelofibrosis (disorder of the bone marrow in which the marrow is replaced by fibrous scar tissue) MyelofibrosisMyelofibrosis is a disorder of the bone marrow in which the marrow is replaced by fibrous scar tissue.Read Article Now Book Mark Article 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 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 strokeStrokesA stroke occurs when blood flow to a part of the brain stops. A stroke is sometimes called a "brain attack. " If blood flow is cut off for longer th...ImageRead Article Now Book Mark Article Transient ischemic attacksA transient ischemic attack (TIA) occurs when blood flow to a part of the brain stops for a brief time. A person will have stroke-like symptoms for ...ImageRead Article Now Book Mark Article If bleeding is a problem, symptoms may include any of the following:Easy bruising and nosebleeds BruisingBleeding into the skin can occur from broken blood vessels that form tiny red dots (called petechiae). Blood also can collect under the tissue in la...ImageRead Article Now Book Mark Article Bleeding from the gastrointestinal tract, respiratory system, urinary tract, or skin RespiratoryThe words "respiratory" and "respiration" refer to the lungs and breathing.ImageRead Article Now Book Mark Article 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:Bone marrow biopsy Bone marrow biopsyA bone marrow biopsy is the removal of marrow from inside bone. Bone marrow is the soft tissue inside bones that helps form blood cells. It is foun...ImageRead Article Now Book Mark Article Complete blood count (CBC) CBCA complete blood count (CBC) test measures the following:The number of red blood cells (RBC count)The number of white blood cells (WBC count)The tota...ImageRead Article Now Book Mark Article Genetic tests (to look for a change in the JAK2, CALR, or MPL gene) Treatment 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.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:Acute leukemia or myelofibrosis MyelofibrosisMyelofibrosis is a disorder of the bone marrow in which the marrow is replaced by fibrous scar tissue.Read Article Now Book Mark Article Severe bleeding (hemorrhage) Stroke, heart attack, or blood clotsStrokeA stroke occurs when blood flow to a part of the brain stops. A stroke is sometimes called a "brain attack. " If blood flow is cut off for longer th...ImageRead Article Now Book Mark Article Heart attackMost heart attacks are caused by a blood clot that blocks one of the coronary arteries. The coronary arteries bring blood and oxygen to the heart. ...ImageRead Article Now Book Mark Article When to Contact a Medical Professional Call your 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. Chest painChest pain is discomfort or pain that you feel anywhere along the front of your body between your neck and upper abdomen.ImageRead Article Now Book Mark Article Leg painLeg pain is a common problem. It can be due to a cramp, injury, or other cause.ImageRead Article Now Book Mark Article ConfusionConfusion is the inability to think as clearly or quickly as you normally do. You may feel disoriented and have difficulty paying attention, remembe...ImageRead Article Now Book Mark Article WeaknessWeakness is reduced strength in one or more muscles.Read Article Now Book Mark Article NumbnessNumbness and tingling are abnormal sensations that can occur anywhere in your body, but they are often felt in your fingers, hands, feet, arms, or le...ImageRead Article Now Book Mark Article Open ReferencesReferencesGotlib 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.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. 7th ed. Philadelphia, PA: Elsevier; 2018:chap 69.AllVideoImagesTogBlood cells - illustration Blood is comprised of red blood cells, platelets, and various white blood cells.Blood cellsillustrationBlood cells - illustration Blood is comprised of red blood cells, platelets, and various white blood cells.Blood cellsillustrationRelated Information Platelet count(Medical Test)Polycythemia vera(Condition)Chronic myelogenous leukemia (CML)(Condition)Myelofibrosis(Condition)Respiratory(Special Topic)Blood clots(Condition)Incidence(Special Topic)Stroke(Condition)Heart attack(Condition)Stroke(In-Depth)Heart attack and acute coronary syndrome(In-Depth) Review Date: 1/19/2021 Reviewed By: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, 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- © 1997- All rights reserved. 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.