Essential thrombocythaemia

Essential thrombocythaemia (ET) is a chronic myeloproliferative neoplasm (MPN) associated with an increase in number and size of circulating platelets.

Clinical presentation includes vasomotor symptoms and complications from thrombosis and bleeding. Approximately 40% to 50% of patients are asymptomatic at diagnosis, and thrombocytosis is an incidental finding on routine blood testing.

There are no pathognomonic features and it is a diagnosis of exclusion.

Patients can be stratified into four risk groups to help guide treatment: very low-risk, low-risk, intermediate-risk, and high-risk.

Treatment approach should be individualised and may include lifestyle modification and observation, antiplatelet and anticoagulant therapy, and cytoreductive therapy.

Hydroxycarbamide is the preferred cytoreductive agent in most patients. Peginterferon alfa-2a, busulfan, and anagrelide are alternative treatments.

Life expectancy is reported to be modestly reduced compared with that of the general population. Patients require life-long blood count monitoring.

ET (also known as primary thrombocythaemia) is a chronic myeloproliferative neoplasm. It is characterised by proliferation of abnormal megakaryocytes in the bone marrow, resulting in an increase in number and size of circulating platelets.