Essential Thrombocythaemia
Essential thrombocythaemia (ET) is a myeloproliferative blood cancer in which clonal bone-marrow cells produce persistently excessive platelets.
Key takeaways
- Infection, iron deficiency, inflammation and cancer can cause reactive thrombocytosis and must be excluded before diagnosing ET.
- Clot risk depends on age, prior thrombosis, cardiovascular factors and mutations rather than platelet count alone.
- Very high platelets can paradoxically increase bleeding through acquired von Willebrand dysfunction.
The listings below are not automatically appropriate for a high platelet count; haematology should confirm diagnosis and risk category.
Confirming ET and risk
Serial blood counts, blood film, iron and inflammation tests and molecular testing for JAK2, CALR or MPL contribute to diagnosis. Bone-marrow examination distinguishes ET from related myeloproliferative disorders. Symptoms may include headache, visual disturbance or burning hands and feet, but many people are asymptomatic.
Preventing clots without excess bleeding
Low-dose aspirin and cytoreductive therapy have risk-based roles. Hydroxycarbamide, interferon or other agents are selected around age, pregnancy, tolerance and clot history. Blood counts and adverse effects require monitoring, and aspirin may be unsuitable when bleeding risk or acquired von Willebrand disease is present.
When to seek urgent care
Call emergency services for sudden weakness or speech difficulty, chest pain, severe breathlessness, a painful swollen leg, unusual severe headache or uncontrolled bleeding.