ENVIRONMENTAL DAMAGE OF THE EXTREMITIES



Both freezing (frostbite) and nonfreezing inju­ries may damage the extremities. The presence of dampness or peripheral vascular disease en­hances the tissue loss for any given temperature reduction or duration of exposure. Tissue damage is probably due to a combination of direct freezing and marked vasoconstriction. Cold produces numbness in tissues that may allow freezing with­out warning, so that the first indication of frostbite may be a prickling feeling. The affected area in­itially looks pale or waxy yellow and may be an­esthetic In severe frostbite, edema and bullae for­mation occur with thawing, and gangrene may result. Frostbite should be treated immediately by rewarming, but excessive warming, massage, and exercise should be avoided. Infection is the great­est danger and the affected areas must be handled with aseptic technique.

Prolonged immersion of extremities in water leads to a syndrome known as immersion foot or trench foot. Wetness plus cold produces the most serious form of the syndrome. It does not neces­sarily require freezing temperatures and is due in part to direct and reflex vasoconstriction.