Prognostic factors for amputation in the case of envenoming by snakes of the Bothrops genus (Viperidae).

The prognostic factors for amputation following envenoming by snakes of the Bothrops genus were identified from the medical records of 3139 patients. Each of these patients had been bitten by Bothrops sp. and treated in the Hospital Vital Brazil, in São Paulo, Brazil, between 1981 and 1990. The 21 (0.67%) of the patients who had undergone amputation were compared with the 3118 who had not, with respect to the characteristics of the accident, the snake, the victim, the local and systemic manifestations of the envenoming and the treatment. There was an association between amputation and the month of the accident, the time of day when the accident happened, the length of the attacking snake, the anatomical region bitten, systemic bleeding and renal failure. Patients bitten in the fingers, during the cooler months, between 00.00 and 12.00 hours and/or by snakes > 60 cm in length, who developed blisters and abscesses at the site of the bite, systemic bleeding and/or renal failure underwent amputation more frequently than the others (P < 0.05 for each).