frostbite

frostbite /frost·bite/ (frost´bīt″) injury to tissues due to exposure to cold.

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frost·bite (frôstbt)

n.

Injury or destruction of skin and underlying tissue, most often that of the nose, ears, fingers, or toes, resulting from prolonged exposure to freezing or subfreezing temperatures.

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frostbite

Etymology: AS, frost + bitan

a traumatic effect of extreme cold on skin and subcutaneous tissues that is first recognized by distinct pallor of exposed skin surfaces, particularly the nose, ears, fingers, and toes. Vasoconstriction and damage to blood vessels impair local circulation and cause anoxia, edema, vesiculation, and necrosis. Gentle warming is appropriate first-aid treatment; rubbing of the affected part is avoided. Later therapy is similar to treatment of thermal burns. Iatrogenic frostbite is the result of excessive use of ethyl chloride sprays for local anesthesia for the relief of muscle and tendon strains. Compare chilblain, immersion foot.

observations Manifestations for superficial frostbite present as a white, waxy, soft, and numb appearance of the injured area while it is still cold. As thawing occurs, the area becomes flushed, edematous, and painful, and may become mottled and purple. Within 24 hours, large blisters form and remain for about 2 weeks before turning into a hardened eschar, which separates in about a month. As the eschar separates, it leaves painful, sensitive new skin that often sweats excessively. In deep frostbite, the injured part remains hard, cold, mottled, and blue-gray after thawing; edema forms in entire limb and may remain for months. Blisters may or may not form weeks after the injury. After several weeks, dead tissue blackens and sloughs off and a line demarcates dead from live tissue. Diagnosis is made by clinical evaluation plus a history of exposure to cold. Loss of digits, ears, nose, and extremities is possible, as is secondary infection and long-term residual symptoms, such as neuropathic pain, sensory deficits, hyperhidrosis, hair and nail deformities, and arthritis.

interventions Acute treatment centers around rapid rewarming by immersion in water (40° C to 42° C) for 15 to 30 minutes. Intravenous analgesics are used for pain. Immunologic agents (tetanus) and antiinfective drugs are given for prophylaxis. Fluid and electrolytes are replaced. After the affected area has thawed, plasma expanders are used to reduce sludge and thrombus formation. Whirlpool hydrotherapy is used 20 to 30 minutes three to four times a day. Physical therapy is used to increase function after edema resolves. In deep and severe cases, escharotomy may be performed with debridement after retraction of viable tissue. Amputation is done for nonviable extremities. Sympathectomy may be performed for severe vasospasm.

nursing considerations Immediately after injury, constrictive and wet clothing should be removed and the affected area should be insulated and immobilized. The area should never be massaged or rubbed or subjected to dry heat. Associated hypothermia must be stabilized with heated saline; warming blankets; and warmed, humidified oxygen. Long-term precautions should be taken with injured area to prevent dislodgement of eschar and further damage. An exercise program may be needed to prevent joint restriction. Counseling may be needed for altered body image from loss of digits or limbs. Education is needed about adequate protection when exposed to cold temperatures and use of preventive measures, such as carrying extra clothing, coats, blankets, fluids, high carbohydrate foods, cell phone, and hazard markers in the car when traveling in cold weather.

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frostbite,

n skin and subcutaneous tissue damage caused by prolonged exposure to extreme cold. Characterized by cessation of blood circulation, frostbite results in a number of signs and symptoms including edema, pain, vesiculation, anoxia, and necrosis.

Frostbite.

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frostbite

injury to tissues due to exposure to extreme cold. Not a common occurrence in free-living animals in the wild but is observed in poorly housed captive animals and birds. May cause whole-body freezing or gangrene of extremities including deer antlers. Deer forms are probably the most susceptible animals. Gangrene of the extremities, especially in pigs, and of the comb in chickens does occur in the domestic species but only if they are in poor condition and are caught outside in a storm.

Ear necrosis from frostbite. By permission from Blowey RW, Weaver AD, Diseases and Disorders of Cattle, Mosby, 1997

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frostbite

Tissue damage or destruction induced by temperatures below 0ºC, which is divided into superficial–frostnip and deep forms; in deep frostbite, subcutaneous tissue, muscle, and bone are involved Clinical Numbness, prickling, itching, if severe paresthesia, stiffness, bullae formation, necrosis, gangrene Treatment-immediate Rewarm in water 40-42ºC/104ºF-107.6ºF, never warmer Treatment-post emergent Debride blister, topical aloe vera gel, tetanus prophylaxis, analgesia, NSAIDs, penicillin, hydrotherapy, physical therapy

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Patient discussion about frostbite.

Q. What are the visual distinctions between thermal burns and frostbite? Is it possible to definitively distinguish the two from each other in all cases, or do they present identically in many cases? In other words, are frostbite injuries-for all intents and purposes, actual burns and if they are not, in what ways do they differ?

A. Early frostbite and minor burns may resemble one another visually (by whitened, blanched looking skin, and blister formation). However, last stage frostbite and thermal (heat) burns are very different.
In late stage frostbite, the ice crystals in the cells melt and the ruptured cells pour out their contents, then blisters may form. Since the affected area has basically lost circulation, gangrene sets in rather quickly and the tissue turns black and dry.
Deep (full thickness) heat related burns are surrounded by areas of erythema (reddened skin) and skin with less degrees of burning. Also, eschar is obviously charred skin tissue forming a scab like structure, and looks nothing like gangrene. The wound bed in a burn leaks plasma constantly. Blistering is pretty immediate with heat related burns of a sufficient degree.