THROMBOCYTOPENIA FOLLOWING TIMBER RATTLESNAKE ENVENOMATION

Study objective: To better characterize timber rattlesnake venom-induc ed thrombocytopenia and coagulopathy and the response to therapy with Antivenin (Crotalidae) Polyvalent. Methods: We conducted a retrospecti ve multicenter review of timber rattlesnake envenomation. Results: We reviewed 18 cases at two institutions. Restoration of normal prothromb in time and partial thromboplastin time was achieved in all cases with antivenom therapy. In contrast, complete reversal of thrombocytopenia was not achieved, despite antivenom therapy. Conclusion: Antivenin (C rotalidae) Polyvalent was less effective in reversing thrombocytopenia than coagulopathy after timber rattlesnake envenomation, suggesting t hat a component of timber rattlesnake venom persists in the blood desp ite antivenom therapy. Persistent thrombocytopenia may be due to a ven om factor that the antivenom does not neutralize or to inadequate dosi ng of antivenom. Prompt reversal of thrombocytopenia following treatme nt of timber rattlesnake envenomation with this antivenom appears unli kely.