Idiopathic Thrombocytopenic Purpura (ITP)

Features:

• blood film: < 50,000 platelet count; often < 10,000
• bone marrow biopsy to exclude secondary cause
• commonest primary platelet disorder of childhood
• immunological basis ?
• decreased lifespan of platelets – sequestered and destroyed in spleen
  • acute
    • spontaneous remission in 4-6 weeks (75%)
    • high dose IV γ-globulin over 4-6 months (10-15%)
    • after exacerbations / remissions – year
  • 10%
    • show no recovery of platelet count
• high-dose γ-globulins (± steroids) not work after 6 months
  • splenectomy successful in 90%
  • but increase pneumococcal and Haemophilus influenzae infections
    • vaccinate