Pit viper snakebite in the United States.

Pit viper snakebite is a relatively uncommon medical emergency which must be adequately diagnosed and treated to minimize local tissue destruction and systemic complications and to prevent death. Severity is highly variable and may range from minimal local pain and swelling to marked pain, edema, tissue necrosis, hemorrhage, shock, and death within one hour. By far, the most common complication is local tissue destruction often resulting in loss of function. Pit viper venom is extremely complex, containing factors which directly destroy muscle, blood vessels, and renal tissues. Other components anticoagulate blood and cause hypotension, local edema, and pain. Neurotoxicity is unusual, but respiratory paralysis may follow Mojave rattlesnake bites. Proper first aid consists of a proximal mildly constricting tourniquet, superficial incision at fang marks, and constant suction. Medical management consists of early intravenous antivenin in adequate dosage, after hypersensitivity testing. Other measures are largely supportive. The early use of corticosteroids is controversial. Cryotherapy is to be avoided. Fasciotomy may be necessary when edema is severe and impairs arterial perfusion. Promising developments include immunization trials against pit viper venom as well as studies on the antivenom activity of rattlesnake plasma.