[Alterations in the coagulation mechanisms of patients bitten by Bothrops asper (Terciopelo)].

Blood from eighteen patients bitten by B. asper were studied for effects on coagulation. All showed alterations in the levels of fibrinogen and of factors II, V, VIII, IX, X and XI, as well as in anti-thrombin-III and plasminogen. The number of platelets and the concentrations of factors VII and XII did not show significant variations in comparison with the controls. The biological assay of fibrinogen, the quantitation of fibrinogen degradation products and of factor II and the general coagulation tests, such as prothrombin and partial thromboplastin times, showed a good correlation with the severity of the envenomation. In snakebites by B. asper there is a severe hypofibrinogenemia, with fibrin degradation by activation in the fibrinolytic system and with activation and consumption of factor II. Intramuscular emergency treatment with small quantities of antivenom did not prevent the above noted alterations in coagulation.