Snakebite in tropical Australia: a prospective study in the "Top End" of the Northern Territory

Objective: To describe the epidemiology of snakebite in the "Top End" of the Northern Territory, and the envenoming syndromes of individual snake species. Study design: Prospective collection of clinical data and snake identity. Setting: Royal Darwin Hospital (RDH), a 300-bed tertiary hospital servicing a population of 140 000 spread over 522 561 km2. Patients: All patients with bites by confirmed snake species between September 1989 and March 2003, and all suspected snakebite cases between September 1989 and March 1998. Outcome measures: Incidence rates of definite snakebite and envenoming. Clinical features of bites from defined snake species. Results: There were 348 suspected snakebites over 8.6 years, with 114 aerial evacuations to RDH, 216 patients (62%) definitely bitten (23.2/100 000 per year) and 79 (23%) envenomed (7.6/100 000 per year). There were 156 bites from confirmed species over 13.6 years: 31 (20%) from western brown snakes (Pseudonaja nuchalis), with early collapse in 14 (45%), consumptive coagulopathy in 26 (84%) and 25 (81%) given antivenom; 21 from death adders (Acanthophis spp.), with neurotoxicity in 8 (38%) and 6 (29%) given antivenom; and 20 from mulga snakes (Pseudechis australis), with local swelling in 19 (95%), myotoxicity in 12 (60%) and 15 (75%) given antivenom. In 34 bites from less venomous species, there was no life-threatening envenoming. There were no deaths. Conclusions: Snakebite still causes morbidity in tropical Australia, but, with access to hospital and antivenom, deaths are rare. This study has enabled further definition of the envenoming syndromes of three highly venomous Australasian elapids.