Fibrinolysis as a feature of disseminated intravascular coagulation (DIC) after Pseudonaja textilis textilis envenomation

Abstract

Blood was obtained from four patients envenomated by the Australian common brown snake, Pseudonaja textilis textilis. This elapid snake has one of the most toxic venoms in the world, containing extremely potent neurotoxic and coagulant components. The latter is a potent complete prothrombinase, converting prothrombin to alpha-thrombin, and comprises more than 30% of the total venom protein. The four envenomated patients developed a typical consumption coagulopathy. Serial serum and plasma samples from patients were studied by immunoaffinity adsorption, 2-alanine precipitation of fibrinogen and fibrinogen-related products and 2-dimensional immunoelectrophoresis, and assayed for crosslinked fibrin degradation products as D dimer, using the monoclonal antibody, DD-3B6/22. These procedures showed the virtually complete disappearance of fibrinogen, accompanied by the appearance of large quantities of fibrinogen and fibrin degradation products consisting of both crosslinked and noncrosslinked species. With recovery, a homogeneous high molecular weight fibrinogen was observed. The data suggest that the prothrombin activator of this venom causes the generation of thrombin which subsequently converts fibrinogen to fibrin and stimulates partial crosslinking of both alpha and gamma-chains. The resultant disseminated intravascular coagulation is accompanied by very active secondary fibrinolysis which apparently limits the extent of any microvascular thrombosis but which may contribute to a bleeding tendency.