Frostbite

Depending upon the depth of tissue damage, frostbite has been classified into various categories, each of which has its own characteristic clinical manifestations. These include:

First-degree frostbite

Commonly known as “frost nip”. Involves only the superficial part of skin. Presents as:

• Itching
• Painful sensations like pins and needles followed by numbness
• Red or white patches on the skin

Second-degree frostbite

It is also called “superficial frost bite”. The skin freezes without the involvement of deeper soft tissues. It manifests as:

• Hardening of skin
• Blistering
• Yellowish, waxy appearance of skin
• Blackening of the skin
• Swelling
• Burning
• Edema
• Erythema

Third- and fourth-degree frostbite

All the layers of the skin are involved at this stage. Permanent and irreversible tissue damage occurs. Deeper tissues like muscles, tendons, nerves get involved at this point. If left untreated, gangrene might set in, which is a major indication for amputation of the affected organs. It presents as:

• Loss of sensations as a result of destruction of nerve endings
• Purplish blisters formation
• Formation of a black eschar after about 2 weeks

The diagnosis of frostbite is made with through the following elements [4].

• Physical examination
• Tissue biopsy
• Complete blood count (CBC)
• Blood urea nitrogen (BUN)
• Blood electrolytes
• Serum creatinine levels
• Blood glucose levels
• Liver function tests (LFTs)
• Urinalysis
• Gram staining of cultures obtained from the tissues
• Radiography
• Angiography
• Technetium-99m (99m Tc) scintigraphy
• Bone scans
• Laser Doppler flowmetry
• Magnetic resonance imaging

The management of frostbite consists of the following [5].

Field care

• Immediate removal of the patient from the cold environment.
• Removal of wet, soaked clothing.
• Airway, breathing and circulation of the patient must be checked.
• Thawing for about 20 to 40 minutes for superficial frost bite and for almost an hour in case of deep tissue involvement [6].
• Splinting or wrapping of the affected part to avoid movements and damage caused by ice crystals
• Heating and rewarming by using circulating water at 40° to 42° C. Rewarming may be passive or active.

Medical treatment

• Analgesics such as non-steroidal antiinflammatory drugs (NSAIDs) are administered to treat the pain of rewarming and to reduce inflammation.
• Intra-venous alpha blockers (eg. reserpine) can be given for pain relief and edema formation
• Tetanus toxoid is given as prophylaxis to prevent infection with Clostridium tetani.
• Antibiotics are given to prevent secondary infections.
• Low molecular weight heparin is given to prevent venous thrombosis [7].
• Vasodilators may also be given to improve peripheral blood flow.
• Thrombolytic agents such as streptokinase are used to reduce the risk of the formation of thrombi.

Surgical interventions

• Excision of the areas affected by wet gangrene should be done.
• Surgical amputation of the parts affected by necrosis and gangrene is essential. However, prompt amputation is not recommended.
• Needle aspiration of blisters can also be done.
• Escharotomy may be needed to lessen the pull of the affected part on the surrounding tissues.
• Routine hydrotherapy for 30 to 45 min at 40° C is done as a rehabilitative measure.
• Skin grafting may be needed.

Long-term therapy

• Physiotherapy is recommended to enable proper use of the affected limb.
• Psychotherapy is recommended for the patients who undergo amputation of the limb.
• Cosmetic reconstruction of nose, ears, toes that have been amputated may also be done according to the patients’ demands.

Irreversible tissue damage is common after frostbite. The mortality rate related with frost bite is about 11%.

Inadequate blood supply to the extremities when exposed to hypothermic environmental conditions as a result of vasoconstriction leading to inadequate tissue perfusion is the basic cause of frostbite.

Various risk factors associated with frostbite are:

• Smoking
• Alcohol use
• Use of certain drugs like beta blockers
• Diabetes mellitus
• Peripheral neuropathy

Frostbite is common at the altitudes of 11,000-22,000 feet above sea level. It is common in military personnel, mountaineers and in people who engage in activities like high altitude camping. Any racial, gender or age association has not been established as yet.

Body responds to hypothermia by directing the flow of blood from extremities towards the core organs like heart and lungs in an effort to maintain body’s homeostasis. This is done by peripheral vasoconstriction. The body parts likely to be exposed are affected the worst. These include earlobes, tip of nose, chin, fingers, knuckles and toes. Decrease in the flow of blood in the peripheral parts decreases the already falling temperature even further.

If exposure to the cold continues, cellular changes start taking place. Ice crystal formation occurs around the cell membrane [2]. Dehydration of cells causes them to shrink and they begin to die as a result of loss of cellular architecture [3]. Capillary endothelium is also affected which causes leakage of blood out of the blood vessels into the tissue spaces. Blood also begins to clot inside the small vessels, initiating the recruitment of the mediators of inflammation which cause further tissue damage.

Frostbite can be prevented by the following measures [8] [9] [10].

• The affected part of the body should not be excessively moved as the ice crystals that have formed around the cells can cause further damage.
• The affected part should not be rubbed or massaged for the purpose of warming.
• Education of soldiers who are more susceptible to frostbite.
• While going to high altitudes, appropriate warm clothing must be chosen.
• Clothing should be protected from getting wet.
• Position should be changed every few minutes or so in extremely cold conditions to maintain the circulation.
• Skin should be examined every 20 minutes or so for signs of frost bite.
• Smoking and drinking for the purpose of keeping warm should be avoided in cold weather as it slows the circulation and aggravates the condition.

Frostbite refers to the damage to the tissues caused by prolonged exposure to cold environment [1]. Exposure to minus 10 °C for even a few minutes is enough to cause frostbite. The parts of the body that are normally exposed to the external environment are likely to be affected the most.

The condition goes unnoticed at first as numbness sets in almost immediately. A form of frostbite, the “trench foot”, is common in soldiers. It is however, a preventable condition that can be avoided with proper precautionary measures.

Freezing of the body tissues when exposed to cold environmental conditions for prolonged time period is known as frost bite. It commonly occurs in hands, feet, toes, earlobes and tip of nose.

Initially, it is limited to the superficial layer of skin only but later on, it proceeds to deeper tissues. Tingling is followed by numbness. Skin becomes initially red, then white and yellow, ultimately becoming black. Infection of the affected tissues may lead to the need for amputation. That is why frost bite should be given prompt medical attention.

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• Severe frostbite and liver problems
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