Thrombocythaemia

        Thrombocythaemia is a disorder where the body produces too many platelets. When the cause is an underlying condition from infection, inflammation or iron deficiency it is called ‘reactive’ or ‘secondary’ thrombocytosis. Primary thrombocytosis is when there is no obvious or known cause for the high platelet count; also referred to as ‘primary’ or ‘essential’ thrombocythaemia (ET), which is a blood or bone marrow disease.

        Your bone marrow contains stem cells which develop into platelets, and the large number of platelets are produced when faulty or defective bone marrow cells don’t work properly. Thrombocythaemia is mostly caused by mutations or changes in the genes that control how your bone marrow forms platelets, and therefore is a condition which can be inherited.

        Myelofibrosis and polycythaemia vera (PV) are associated with primary thrombocytosis. Both ET and PV are myeloproliferative neoplasm disorders, which refers to when bone marrow produces blood cells in a rapid and uncontrolled way. Visit our website to read more about Polycythemia vera and Myelofibrosis.

        Statistics

        Essential thrombocythaemia is more common in women than men and usually between the ages of 50-70 years. In 2019, a review article reported the following data and clinical features associated with ET:

        • Incidence of ET was estimated at 1.2 to 3.0 per 100,000 population per year.
        • A retrospective study with 1076 patients with ET conducted by the Mayo Clinic, found the average age at diagnosis was 58 years; 67% were women; leukocytosis was documented in 26% of patients, and a history of thrombosis at or before diagnosis was present in 21%.
        • Other features included headaches, visual disturbances, light-headedness, dysesthesia (symptoms related to the skin – itching, burning, tingling, stinging, tickling, crawling or cold sensation, pain); and less frequently, erythromelalgia (a burning dysesthesia associated with red discoloration of the hands or feet).
        • After an average follow-up period of 10 years, death had occurred in 43%, myelofibrosis in 13%, and new thrombosis in 21%.

        Symptoms

        Most people do not have any symptoms and therefore the disorder is usually only discovered during blood tests for another condition. A high platelet count is linked to blood clots and bleeding.

        Blood clots generally occur in the brain, hands and feet, causing long-term chronic headaches and dizziness. The risk of a blood clot increases if you have clots in the past, smoke, have diabetes or high blood pressure. In severe cases there is the possibility of a transient ischaemic attack or stroke.

        Other possible symptoms associated with a blood clot include:

        • Hands and feet – numbness, burning feeling and throbbing pain.
        • Confusion or changes in speech
        • Migraines
        • Seizures
        • Upper body discomfort (jaw, neck, arms, back, abdomen)
        • Weakness
        • Chest pain
        • Enlarged spleen
        • Pregnancy complications

        Bleeding occurs as a result of the elevated platelet count causing ‘bad’ blood clots to develop and depleting the body platelet levels. Without this reservoir of platelets, the body cannot form a ‘good’ clot to seal off any cuts and so the risk of bleeding increases. Symptoms include:

        • Nosebleeds
        • Bruising
        • Bleeding in your mouth and gums
        • Blood in your stool
        • Cuts and breaks in blood vessels which don’t seal.

        Elevated platelet count and pregnancy

        Blood clots caused from an excessively high platelet count can hinder blood flow to the baby. Complications associated with clots and bleeding include:

        • High blood pressure
        • Slow growth of the unborn baby
        • Premature delivery
        • Separation of the placenta from the womb
        • Loss of pregnancy

        References

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        Author: Gina Rodgers

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