Effects of Puff-Adder Venom on Coagulation, Fibrinolysis and Platelet Aggregation in the Baboon

Abstract

The in vitro and in vivo haematological effects of puffadder (Bitis arietans) venom in the baboon (Papio ursinus) with regard to its effect on coagulation, fibrinolysis and platelet aggregation were studied. There is a delay in the intrinsic coagulation mechanism with fibrinolysis and in vitro fibrinogenolysis. Normal human platelets demonstrated an extreme susceptibility to puff-adder venom in vitro. The aggregation of platelets with small dosages of venom was irreversible. The effect is related to the dosage, and appears to be the result of multiple enzyme activities, some of which are heat-labile. In minimal amounts there is evidence of consumption of blood coagulation factors with sustained thrombocytopenia, but no fibrinolysis, where heparin therapy might have a beneficial effect. With larger dosages of venom the thrombocytopenia, haemorrhagic effects and shock are not prevented or corrected by heparin and heparinisation might even be harmful. The effect of heparin should be further investigated, since it might have a place in mildly affected cases of snakebite, where absorption into the blood has been slow or intermittent. It might be indicated when antivenene is not available or when patients are sensitive to serum.

S. Afr. Med. J., 48, 1205 (1974).