Recurrent coagulopathy after antivenom treatment of crotalid snakebite

Background. We studied whether recurrence of coagulopathy, defined as the return of a coagulation abnormality after initial normalization, occurred after the use of antivenin (Crotalidae) polyvalent. Methods. A retrospective, blinded, descriptive analysis of 354 consecutive cases of North American crotalid snake envenomation was done. Inclusion criteria were documented clinical evidence of crotalid snakebite, presence of a coagulopathy (platelet count < 150,000/mm³, prothrombin time above normal, or fibrinogen level <150 mg/dL), and treatment with antivenin (Crotalidae) polyvalent. Results. Of 112 cases with a coagulopathy extending beyond 6 hours after envenomation, 31 had sufficient coagulopathy testing to detect recurrence. Fourteen of these patients (45%) had recurrence of coagulopathy, and two cases were severe (fibrinogen level 29 mg/dL; platelet count 36,000/mm³). Conclusion. Recurrence of coagulopathy after envenomation by North American crotalid snakes may occur after use of antivenin (Crotalidae) polyvalent and can result in severe coagulation abnormalities.