Venomous snakebites in the United States: management review and update.

Venomous snakebites, although uncommon, are a potentially deadly emergency in the United States. Rattlesnakes cause most snakebites and related fatalities. Venomous snakes in the United States can be classified as having hemotoxic or neurotoxic venom. Patients with venomous snakebites present with signs and symptoms ranging from fang marks, with or without local pain and swelling, to life-threatening coagulopathy, renal failure, and shock. First-aid techniques such as arterial tourniquets, application of ice, and wound incisions are ineffective and can be harmful; however, suction with a venom extractor within the first five minutes after the bite may be useful. Conservative measures, such as immobilization and lymphatic constriction bands, are now advocated until emergency care can be administered. Patients with snakebites should undergo a comprehensive work-up to look for possible hematologic, neurologic, renal, and cardiovascular abnormalities. Equine-derived antivenin is considered the standard of care; however, a promising new treatment is sheep-derived antigen binding fragment ovine (CroFab), which is much less allergenic. Although there is no universal grading system for snakebites, a I through IV grading scale is clinically useful as a guide to antivenin administration. Surgical intervention with fasciotomy is now reserved for rare cases. Snakebite prevention should be taught to patients.