essential thrombocythemia

thrombocythemia /throm·bo·cy·the·mia/ (throm″bo-si-the´me-ah) thrombocytosis.

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essential thrombocythemia , hemorrhagic thrombocythemia a syndrome of repeated spontaneous hemorrhages, either external or into the tissues, and greatly increased number of circulating platelets.

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essential thrombocythemia.

See thrombocytosis.

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essential thrombocythemia

Essential thrombocytosis Hematology A primary myeloproliferative disorder of older–age 55-75–adults, or less commonly of young ♀, with a platelet count is > 600 x 109/L; ET has many clinical features of P vera; it affects the same age group, is accompanied by splenomegaly, has similar BM findings, intensity of leukocytosis Diagnosis Polycythemia Vera Study Group criteria Treatment Hydroxyurea, a myelosuppressant, prevents recurrent thromboses. See Polycythema vera.

Essential thrombocythemia-diagnostic criteria

1. Platelets > 1 x 10⁹ /L (US: < 1000/mm³)

2. Hb < 2.05 mmol/L (US < 13.0 g/dL)

3. Iron in BM or if absent, little ↑ in Hb after 1 month of oral iron therapy

4. Absent marrow fibrosis by biopsy and

5. Absent Philadelphia chromosome

Polycythemia Vera Study Group