Envenoming by the common krait (Bungarus caeruleus) and Sri Lankan cobra (Naja naja naja): efficacy and complications of therapy with Haffkine antivenom.

In Anuradhapura, Sri Lanka, 5 patients proved to have been bitten by common kraits (Bungarus caeruelus) and 2 by Sri Lankan cobras (Naja naja naja) were investigated. In all the cases of krait bite the patients were bitten while they were asleep: local signs were negligible but 4 developed symptoms of systemic envenoming including paralysis, muscle pain and tenderness and abdominal pain. Mild myoglobinaemia was found in one case. Of the 2 patients bitten by cobras, one developed severe local swelling which progressed to necrosis and the other local swelling and respiratory paralysis. Response to polyspecific antivenom (Haffkine, India) was neither rapid nor convincing. Venom antigenaemia became undetectable within 2 h of the start of antivenom treatment, but recurred 25 and 65 h later in 2 cases. Among a group of 27 patients treated with this antivenom (including 21 bitten by Russell's vipers), the incidence of early anaphylactic and pyrogenic reactions was high at 52% and 65% respectively. Anticholinesterase did not improve paralysis in 2 patients bitten by kraits. The respiratory failure in 2 patients was successfully treated by mechanical ventilation for 8 and 30 h. These observations confirm the importance of neurotoxic symptoms following bites by these species but also suggest a contributory role of generalized rhabdomyolysis in krait victims and emphasize the problem of severe local tissue necrosis in cobra victims. There is a need for safer and more potent antivenoms for use in Sri Lanka.