Heparin-associated thrombocytopenia

on 9.2.09 with 0 comments

  • Seen in 5% of adults getting unfractioned heparin; rare in those on LMWH

  • Associated with 2 kinds of thrombocytopenia

    • Type I

      • More common variant; onset rapidly after starting heparin therapy

      • This is modest in severity and is clinically insignificant

      • This is a result of the direct platelet aggregating effects of heparin

    • Type II

      • Much more severe; typically starts 5-14 days after starting heparin therapy

      • This is due to the production of circulating Abs to a heparin/platelet factor 4 complex

        • Abs bind to those complexes on platelets and endothelial cells resulting in platelet activation and endothelial damage

        • Systemic platelet aggregation leads to life-threatening venous and arterial thrombosis and infarction

  • People getting heparin therapy should always be watch for thrombocytopenia

  • Treatment involves stopping the unfractioned heparin and using LMWH or another anticoagulant

Category: Medical Subject Notes , Pathology Notes



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