Frostbite injuries of the hand.

Frostbite may be defined as acute freezing of tissues as a result of exposure to temperatures below the freezing point of intact skin. Severity of injury is due to the degree of cold and the duration of exposure. Tissue injury occurs during freezing due to the actual formation of ice crystals within the extracellular fluid. In addition, ice crystals form in the blood and lead to sludging and cessation of capillary blood flow. However, the most severe tissue damage comes with rewarming the tissues. Reperfused capillaries, with their damaged endothelium, leak fluid and protein leading to edema. Blisters form, and prostaglandins and thromboxanes in the blister fluid cause platelet aggregation. Rapid rewarming of the part is now the acceptable practice. Immersion of the injured part in a whirlpool bath is recommended at a temperature of 100 to 108 degrees Fahrenheit. Eventual care may include debridement and tissue transfers if amputation is required. A case is presented of a woman with frostbitten hands.