Hyponatraemia and seizures in Merrem’s hump-nosed pit viper (Hypnale hypnale) envenoming: a case report

BACKGROUND: Hump-nosed pit vipers (Genus: Hypnale) are medically important snakes in Sri Lanka and South India. Merrem’s Hump-nosed pit viper (Hypnale hypnale) frequently leads to potentially fatal envenomings in Sri Lanka and India. Venom-induced consumption coagulopathay (VICC), local envenoming and acute kidney injury (AKI) are the commonest effects of the envenoming by this snake. CASE PRESENTATION: We report a previously unreported presentation of H. hypnale envenoming, with an isolated urinary salt loss leading to moderate hyponatraemia resulting seizures. The patient was treated with careful fluid and electrolyte management. No antivenom is currently available for H. hypnale envenoming. CONCLUSION: In the absence of any evidence of venom induced consumptive coagulopathy, acute kidney injury and cerebral haemorrhage, we hypothesize that this effect is likely due to the presence of a natriuretic peptide in H. hypnale venom, similar to the natriuretic peptides identified in few other snake venoms.