Thrombocytosis - Clinical History

  • Reactive / Secondary (75%)
    - infections ; malignancies ; collagen vascular diseases ; iron deficiency ; post splenectomy

  • Primary or clonal (25%)
    - myeloproliferative diseases: essential thrombocythemia, agnogenic myeloid metaplasia, polycythemia vera, chronic myelogenous leukemia
    - myelodysplasia (rare)

    • Most investigators believe that secondary thrombocytosis is rarely symptomatic in comparison to primary thrombocytosis (Schafer,2004).
      - thrombocytosis is usually not as severe with secondary thrombocytosis, although occasionally platelet counts of several million have been reported in association with neoplasm.

    • Patients should be questioned carefully for :
      - systemic and specific symptoms which might suggest infection or neoplasm, for example, fever, weight loss, night sweats, cough, hemoptysis, melena or hematuria
      - symptoms of bleeding and / or ischemia (for example transient cerebral ischemic symptoms, chest pain or burning / paresthesias of the fingers or toes suggestive of digital ischemia).

    • Treatment of thrombocytosis is controversial. Even in patients with platelet counts > 1,000,000 / ul, treatment is usually withheld until symptoms occur.

    • Hydroxyurea treatment appears effective in high-risk patients with primary (essential) thrombocytosis i.e. patients over 60 years old, or who have already had a thrombotic event (Cortelazzo et al, 1995).

      Recombinant interferon-alpha and anagrelide are other drugs under evaluation (Barbui, 2003)

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