Evidence that Crotalus durissus terrificus (South American rattlesnake) envenomation in humans causes myolysis rather than hemolysis.

The venom of the South American rattlesnake Crotalus durissus terrificus was originally reported to have a pathophysiological activity mainly involving hemolysis and neurotoxicity. The systemic myotoxic action of this venom was demonstrated in 1985. In the present paper we report clinical and laboratory data concerning three patients bitten by C. durissus terrificus and treated at the University Hospital of Ribeirão Preto, University of São Paulo. The normal haptoglobin levels detected in the serum of these patients during the first 48 hr after the accident, as well as the absence of hemoglobin in darkened urine samples as evaluated by immunodiffusion against anti-hemoglobin serum, rule out the occurrence of intravascular hemolysis. These data permit us to conclude that the signs and symptoms observed in human envenomation with C. durissus terrificus are due to a myotoxic and neurotoxic action of the venom.