PLATELET-AGGREGATION IN PATIENTS BITTEN BY THE BRAZILIAN SNAKE BOTHROPS-JARARACA

Patients bitten by the lancehead snake Bothrops jararaca usually devel op systemic bleeding. Our aim was to evaluate platelet function in who le blood of 17 human patients bitten by this snake in Sao Paulo State, Brazil, Bleeding occurred in 71% of these patients, and thrombocytope nia in 53% of them. On admission, most of the patients presented with hypoaggregation to 50 mu M ADP and 1.2 mg/ml ristocetin, and only 35% of them to 5 mu g/ml collagen. Abnormal plasma levels of fibrinogen an d fibrin(ogen) degradation products (FDP/fdp) were also observed. Twen ty-four hours of finishing serumtherapy, bleeding had already ceased, fibrinogen and FDP/fdp levels returned to hemostatic levels, and value s for platelet aggregation returned to the reference range of controls , except for ADP that still remained decreased. These findings evidenc e that disturbances of platelet function are also an important factor for the development of bleeding in Bothrops envenomation, as well as o ther known hemostatic disturbances that occur concomitantly. (C) 1997 Elsevier Science Ltd.