Venomous bites and stings

Abstract

Abstract Venomous bites and stings occur worldwide and are a particular problem for rural workers in the remote tropics. They are caused by a large variety of terrestrial and marine animals and are associated with both mortality and morbidity. Most snakebites occur on the lower limbs; not all bites by venomous species lead to envenoming, but they may result in both local and systemic effects. Clinical features depend on the species of snake; elapids tend to cause minimal local damage and neurotoxicity, whereas vipers may cause local swelling and necrosis in addition to coagulopathy and shock. Careful clinical observation of patients after snakebite is crucial; the 20-minute whole-blood clotting test is useful in the diagnosis of some viper bites. Intravenous infusion of antivenom is the mainstay of treatment in those with clear signs of envenoming; the antivenom used should be appropriate to the biting species and the geographical region. The dose of antivenom is the same for adults and children, and supportive care (e.g. fluid replacement in shock, respiratory support for severe neurotoxicity) is crucial. Scorpion stings commonly cause pain, but in children may lead to systemic envenoming with transmitter release from autonomic nerves; antivenom is effective in some regions. There are many venomous spider species; some cause local skin necrosis, others cause severe systemic envenoming. Many marine animals are venomous, often causing severe pain at the site of the sting. Some jellyfish (e.g. box jellyfish) can cause life-threatening systemic envenoming.