Epidemiology and clinical picture of the Russell's viper (Daboia russelii russelii) bite in Anuradhapura, Sri Lanka: a prospective study of 336 patients.

Russell's viper (Daboia russelii russelii) bite is associated with a high incidence of morbidity and mortality in Sri Lanka. Hence, this study enrolled all consecutive Russell's viper bite admissions to the 'Unit A' of General Hospital, Anuradhapura, over a two year period from January 1996, to describe the epidemiology, clinical picture, treatment and outcome. There were 336 cases which showed the following results. The male: female ratio was 5:1; 75% of patients were below the age of 40 years. Biting occurred mainly in paddy fields 41%, and on footpaths 29% at dusk or dawn. Envenoming manifested in 310 (92%) of patients as follows: local swelling 92%, local necrosis 8.9%, coagulopathy 77%, neurotoxicity 78%, nephrotoxicity 18%, cardiac effects 3-12% and myotoxicity 14%. Coagulopathy appeared within 30 minutes to 12 hours after the bite and was corrected within 1 hour to 48 hours (mode 20 hours). Neurotoxicity recovered spontaneously in 1 to 5 days (mode 3 days): however, eight patients needed mechanical ventilation. Thirteen (4%) of patients were managed with peritoneal dialysis because of hyperkalemia caused by a hypercatabolic state (7) and acute renal failure (6). The mortality rate of the series was 2.6% (9 patients). Rural dry zone paddy farmers are the common victims of Russell's viper bite in Sri Lanka and its' envenoming leads to diverse clinical manifestations. Therefore, practically feasible preventive measures should be developed to minimize the incidence of bite and an evidence based management guideline should be developed for hospital practice.