Syndromic Approach to Treatment of Snake Bite in Sri Lanka Based on Results of a Prospective National Hospital-Based Survey of Patients Envenomed by Identified Snakes

Of 860 snakes brought to 10 hospitals in Sri Lanka with the patients they had bitten, 762 (89%) were venomous. Russell's vipers (Daboia russelii) and hump-nosed pit vipers (Hypnale hypnale) were the most numerous and H. hypnale was the most widely distributed. Fifty-one (6%) were misidentified by hospital staff, causing inappropriate antivenom treatment of 13 patients. Distinctive clinical syndromes were identified to aid species diagnosis in most cases of snake bite in Sri Lanka where the biting species is unknown. Diagnostic sensitivities and specificities of these syndromes for envenoming were 78% and 96% by Naja raja, 66% and 100% by Bungarus caeruleus, 14% and 100% by Daboia russelii, and 10% and 97% by Hypnale hypnale, respectively. Although only polyspecific antivenoms are used in Sri Lanka. species diagnosis remains important to anticipate life-threatening complications such as local necrosis, hemorrhage and renal and respiratory failure and to identify likely victims of envenoming by H. hypnale who will not benefit from existing antivenoms. The technique of hospital-based collection, labeling and preservation of dead snakes brought by bitten patients is recommended for rapid assessment of a country's medically-important herpetofauna.