injuries poisoning
Snakebites
Key Points
In the US, common venomous snakes include rattlesnakes, copperheads, and cottonmouths (all pit vipers), but rattlesnakes account for most bites and almost all deaths. Pit viper envenomation can cause local effects (eg, pain, progressive swelling, ecchymosis) and systemic effects (eg, vomiting, diaphoresis, confusion, bleeding, fever, chest pain, dyspnea, paresthesias, hypotension). Features that can help differentiate pit vipers from nonvenomous snakes include an elliptical pupil, a triangular head, retractable fangs, heat-sensing pits between the eyes and nose, and a single row of subcaudal plates extending from the anal plate on the underside of the tail. In the field, remove the patient out of striking distance from the snake, arrange rapid transport, wrap a bitten limb loosely, immobilize it in a position at about heart level, and remove constricting devices such as rings and watches; do not incise bite wounds or apply tourniquets. Monitor patients with pit viper bites serially for at least 8 hours, longer if any findings suggest envenomation. Treat wounds and symptoms, and consult a poison center. Give antivenom early and at adequate doses, including full adult doses for children. 