| Frostbite is an injury to the skin and underlying tissues as a result of severe environmental cold exposure or direct contact with a very cold object. The tissue injury in frostbite results from both freezing temperatures and compromised circulation. The circulation ceases and tiny clots (thrombi) form in the blood vessels. The parts of the body most often affected by frostbite are the hands, feet, nose, and ears.
Frostbite starts with a mild form of cold injury called frostnip. Frostnip represents reversible damage. There is discomfort, blanching, and numbness of the skin that is relieved by rewarming. Superficial frostbite is limited to the skin and subcutaneous tissues. Severe frostbite involves the muscles, nerves, and deeper blood vessels and may result in tissue death (necrosis) and decay (gangrene), and loss of digits.
Mountain frostbite is a variation seen among mountain climbers and others exposed to extremely cold temperatures at high altitude. It combines tissue freezing with lack of oxygen (hypoxia) and general body dehydration.
Most cases of frostbite are seen in workers and soldiers, those who work outdoors in the cold, and among winter outdoor enthusiasts.Risk: There are several predisposing factors that increase the risk of frostbite. These are classified as physiologic, mechanical, psychologic, environmental, and cardiovascular. Physiologic risk factors include poor physical conditioning, dehydration, overexertion, and malnutrition. Mechanical factors include constricting or wet clothing, tight shoes or boots, and immobility. Psychologic factors include fatigue, mental impairment, and use of alcohol. Environmental factors include humidity, duration of exposure, and wind chill factor. Cardiovascular factors include vascular diseases, anemia, and diabetes. Children and the elderly are at increased risk for frostbite. Previous cold injury also increases the risk for frostbite. Finally, people from tropical climates who are not acclimatized to cold weather are at increased risk for frostbite. Most cases of frostbite occur in those stranded in cold weather, those who work in cold environments, winter athletes, and the homeless. Incidence and Prevalence: Because of inconsistent reporting systems and data, the prevalence and incidence of frostbite are unknown. Frostbite is uncommon in North America, occurring primarily in northern continental states, Alaska, and in Canada. The majority of frostbite victims are male, probably due to increased outdoor activity rather than sexual predisposition. |
Source: Medical Disability Advisor
| History: All affected individuals will report recent exposure to extreme cold or a prolonged exposure to cold. Numbness is the most commonly reported symptom, occurring in 75% of affected individuals. The individual may also complain of pain, prickling, itching, and pins and needles (paresthesias). Although the hands and feet are most often affected, individuals may also have symptoms affecting the shins, cheeks, nose, ears, and eyes. Following warming, the individual often describes tenderness or burning pain. Physical exam: An early sign of frostbite is white, waxy skin with decreased sensitivity. After thawing, the skin is reddened with superficial blisters and swelling. If frostbite has affected deeper tissue, gangrene and necrosis may occur. Tests: Lab studies are not important in the initial diagnosis and management of frostbite. They may be helpful, however, in identifying delayed systemic complications such as wound infection or underlying hypothermia. A complete blood count (CBC) and chemistry panel are commonly ordered. A radioisotope scan called Tc-99m (technetium 99) pertechnetate scintigraphy is useful in detecting tissue injury if performed within 48 hours after injury. |
Source: Medical Disability Advisor
| Treatment is first directed at managing life-threatening conditions. Administration of warm, intravenous fluids may be used as a warming measure to enhance blood flow especially in individuals with mountain frostbite or hypothermia. Frostbitten areas are treated with slow rewarming in cool water that is raised gradually over an hour to a maximum temperature of 104° F (40° C).
Tissue damage increases with trauma to the involved areas or with warming and refreezing therefore affected areas should not be massaged or rewarmed if the areas are still exposed to the cold environment. It is important not to walk, bear weight, or put pressure on affected areas. Bed rest, elevation of the affected area, tetanus toxoid administration, and administration of antibiotics is necessary if infection is present. Analgesics or narcotics are used for pain. In the case of necrosis or gangrene, resection of the dead tissue or amputation is performed. Except in minor cases, most individuals should be hospitalized for 24 to 48 hours to determine the extent of injury. |
Source: Medical Disability Advisor
| If treated early, frostbite is reversible by simple warming. Recovery is most often complete if not complicated by infection or gangrene. Early return of sensation and healthy skin color are signs of a favorable outcome. On the other hand, persistent blue discoloration (cyanosis) and blood blisters (hemorrhagic blebs) are signs of necrosis and a less favorable outcome.
Long-term effects include altered sensation of affected area, damage to sweat glands, cracking skin and loss of nails, abnormal color changes of area, cold sensitivity, joint stiffness, tremor, and osteoporosis. Muscle weakness and phantom pain may occur in amputated extremities. |
Source: Medical Disability Advisor
| Superficial frostbite (involving the skin only) does not need advanced therapeutic intervention. However, for deep frostbite (involving the skin and underlying tissue) therapy is initiated immediately after rewarming.
With diminished pain and swelling, the individual begins a routine of active range of motion exercises. Active range of motion is the movement of the limb that the individual can perform him or herself. For example, for the hand, an individual starts with the hand in full extension, and then the four fingers without the thumb are bent to form a tabletop. With the feet, active range of motion may be for the individual to point and flex their foot or move their toes. Active range of motion exercises are performed to the best ability of the individual 10 to 15 minutes each hour. Passive range of motion where the therapist assists the individual beyond the active range is prohibited as the tissue is too weak and may cause further tissue damage.
During weeks 2 and 3 post injury, the individual may be assessed for vascular status of the affected area with an angiogram (technique to find the size and shape of blood vessels) and bone scintigram (technique to determine the function of tissues). These tests may determine if amputation is necessary. Therapeutic protocol is adjusted if the decision is to amputate. How the program is modified depends on the affected extremity (e.g., foot versus hand) and extent of removal (e.g., finger versus whole hand). Final decisions to amputate are usually delayed 1 to 2 months post exposure. Rehabilitation protocol may also be altered if a fasciotomy is performed due to the development of severe contracture. However, if the individual shows signs of proper capillary filling (finger tips show color when engaging in exercise), sensation, movement, and clear fluid blistering, gradual return to function without surgical intervention is hopeful.
For hand treatment, splinting may be necessary for up to six months post exposure. An intense program to regain proper hand function is initiated once the skin and underlying tissue are able to tolerate force without risk of further damage. Gripping exercises such as squeezing a tennis ball or putty and more functional exercises such a picking up objects are gradually added to the routine. As therapy progresses, exercises should be reflective of the work environment. The individual should be reintroduced to tools associated with their occupation such as a hammer. In the final phase of therapy, around weeks 8 to 12, the individual must work to improve hand endurance. The work environment of the individual must be re-assessed in preparation for the individual's return to work. Changes in job environment may include wearing a splint while performing tasks that require continuous wrist motion or rotating tasks that may induce repetitive strain to the thumb. Protective clothing must continually be worn if the individual works in an outdoor environment.
Lower extremity therapy may initially include bracing the foot or feet. The individual may be required to use crutches or a wheel chair to ambulate. One major concern after prolonged immobilization is mobilizing the ankle and foot joints to ensure proper flexibility and biomechanics. Once the tissue can tolerate applied force, the therapist may assist by manually mobilizing joints through techniques such as talocrural joint traction, where the therapist applies a caudal (away from the head) force to slightly pull the foot from the lower limb in order to create more joint space while gently gliding the foot into dorsiflexion and plantar flexion. Progressive active flexibility activities such as towel stretches where the seated individual places a towel around the foot, and while holding the ends of the towel performs dorsiflexion, plantar flexion, eversion, and inversion movements for 3 sets of 10 to 15 repetitions in each position are initiated. These active stretch exercises are eventually replaced by isometric exercises that use the same movements. These exercises are geared to restore full toe and foot biomechanics that are necessary for proper walking.
Prior to full weight bearing, the individual may engage in functional balance or proprioceptive training using either a simple balance board that moves laterally or Biomechanical Ankle Platform System (BAPS) that moves in multiple directions. The seated individual places the involved foot on the board, which is set at an angle. The object of the task is to bring the board to a level position by adjusting the foot without lifting the foot up. Progressively, the individual works up to balancing on the board in a standing position. By the end of the twelfth week, the individual may have regained full function of the limb; however, nerve or muscular damage may prolong therapy.
In some severe cases of frostbite (e.g., requiring amputation), vocational rehabilitation as well as psychological services may be necessary. Care in these cases may be prolonged and financially as well psychologically devastating. Long-term effects of frostbite may include cold sensitivity, tingling or numbness, muscle contracture, and arthritis. These conditions may pose ongoing detriment to job performance and health. |
Source: Medical Disability Advisor
| Thawing and refreezing of the affected areas and trauma to the frozen area increase tissue damage. Other complications include hypothermia, infection, and gangrene. |
Source: Medical Disability Advisor
| With complete recovery, restrictions or accommodations are not necessary. Personal protective equipment should be considered for individuals who work outdoors. Any amputation of the digits may require a change in individual's work duties. |
Source: Medical Disability Advisor
| If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case. Regarding diagnosis:
- Does individual have a history of exposure to extreme cold or a prolonged exposure to cold?
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Are the symptoms and physical exam findings consistent with the diagnosis of frostbite such as pain, prickling and itching, pins and needles (paresthesias), or numbness particularly in the hands and feet? After warming was there tenderness or burning pain?
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On exam, is skin white and waxy with decreased sensitivity?
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Were other conditions with similar symptoms ruled out?
Regarding treatment:
- Was treatment of any life-threatening conditions such as hypothermia necessary?
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Were frostbitten areas rewarmed slowly?
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Were the affected areas protected from pressure or rubbing to prevent further damage?
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Did individual receive other appropriate interventions such as tetanus toxoid administration?
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Was dead tissue thoroughly resected?
Regarding prognosis:
- Was treatment prompt and appropriate?
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Did individual experience any complications such as gangrene that may impact recovery?
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Did individual experience any long-term effects such as altered sensation of affected area, damage to sweat glands, cold sensitivity, joint stiffness, tremor, or osteoporosis that may impact prognosis?
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Does individual have any comorbid conditions such as atherosclerosis, peripheral vascular disease, diabetes, thyroid dysfunction, arthritis, or nicotine use that would impact recovery?
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Source: Medical Disability Advisor
| Danzl, D. F. "Frostbite." Rosen's Emergency Medicine. Ed. J. A. Marx. 5th ed. St. Louis: Mosby, Inc., 2002. 1972-1979. |
Source: Medical Disability Advisor
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