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Cold-related injuries have been described since antiquity in the medical and historical literature.1 Their occurrence depends on the degree of cold exposure, as well as environmental and individual factors. Cold-related injuries develop either directly, by tissue cooling, or secondarily, through cold-associated injuries causing straings, sprains, or other trauma and predisposing a person to frostbite and other local cold injuries. Injuries sustained in a cold environment may predispose a person to nonfreezing cold injuries, frostbite, or hypothermia (Figure 202-0.1). Hypothermia is discussed in Chapter 203, Hypothermia.

Figure 202-0.1.

Cold exposure and cold injuries algorithm.

Frostbite is the prototype freezing injury and is seen only when ambient temperatures are well below freezing. Nonfreezing cold injuries occur as a result of exposure to wet conditions when temperatures are above freezing. The most common nonfreezing cold injuries are trench foot and chilblains. Although frostbite may result in permanent tissue damage, nonfreezing cold injuries are characterized by usually mild but uncomfortable inflammatory lesions of the skin. This chapter describes the occurrence, risk factors, treatment, and prevention of the nonfreezing cold injuries—trench foot and immersion foot, chilblains or pernio, panniculitis, and cold urticaria—and the freezing injury—frostbite.

Trench Foot

Trench foot was given its current name because of the frequency with which it was diagnosed among World War I troops confined in trenches filled with standing cold water. Significant numbers of cases were also seen in the Falkland, Korean, and Vietnam wars. Immersion foot is a more severe variant of trench foot seen in downed pilots and shipwrecked sailors exposed for extended periods in life rafts in the North Atlantic Ocean. Trench foot and immersion foot, are rare in civilians, although they remain a significant problem in military operations. Nowadays, trench foot is occasionally seen in workers exposed to primitive wet circumstances (jungle rot), in victims of shipwreck who have spent several hours in lifeboats or on rafts, in those in military training, and in persons who have been hiking or camping or on an expedition.

The pathophysiology of trench foot is multifactorial but involves direct injury to soft tissue sustained from prolonged cooling, and it is accelerated by wet conditions. The peripheral nerves seem to be the most sensitive to this form of injury. Trench foot develops slowly over hours to days and is reversible initially but becomes irreversible if allowed to progress. Cold and wet conditions above freezing lower the skin temperature, which leads to vasoconstriction, red cell and thrombocyte plugging, tissue edema, and nerve and small-vessel injury. Individual sensitivity, including immunologic factors, likely contributes to the development of nonfreezing cold injury.

Clinical Features

Early symptoms progress from tingling to numbness of the affected tissues. On initial examination, the foot is pale, mottled, anesthetic, pulseless, and immobile, which initially does not ...

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