Frostbite

Frostbite is an open tissue injury caused by local exposure to low temperatures. The effect of low temperatures on the entire body is called hypothermia. Human tissues are very resistant to the effects of cold (except for general hypothermia), the outcome depends not only on the temperature, duration of exposure to cold, but also on the qualifications of the assistance provided to the victim. Only with a local decrease in temperature below 25 degrees does irreversible damage to nerves and blood vessels develop in the form of vasculitis and thrombosis with impaired tissue trophism. Therefore, in case of frostbite, the main principles are the timeliness and correctness of first aid and subsequent treatment. It is necessary to remember that rapid restoration of blood flow can provide reversibility of the developed process.

[ 1 ]

Clinic of the pre-reactive period

The clinical picture and complaints are the same for any degree of frostbite. Pain, loss of sensitivity, movement, and sense of support are troubling.

On examination: the limb is pale, with a marbled tint. On palpation, it is cold to the touch, dense to the point of "woodiness", loss of tactile sensitivity and dysfunction are determined.

[ 2 ], [ 3 ], [ 4 ]

Jet Period Clinic

Depends on the degree of frostbite and the tissue's ability to regenerate, which is largely determined by the correctness of the care provided in the pre-reactive period. It is possible to fully determine the degree of frostbite only by the end of the second week.

• 1st degree frostbite. After thawing, during the first day the following develop: bursting pain, moderate swelling, manifestations of cold dermatitis (skin tension due to swelling, cyanosis, cyanosis of the skin), from the second day: increased skin sensitivity (hyperesthesia), tingling, crawling ants (paresthesia), the skin turns red, a feeling of support appears.

The swelling and pain disappear by the 5th-7th day, and the skin begins to peel profusely. Recovery occurs by the 7th-10th day. Hyperpigmentation of the skin, chilliness, and increased sensitivity to cold persist for a long time. The vessels remain labile, prone to the development of angiopathies.

• 2nd degree frostbite. The pain is significant, there is a feeling of distension and heaviness. On the 2nd-3rd day, blisters with serous contents (in the form of jelly) form. Tissue edema is significant, covering large areas. By the end of the week, the blisters open. Epithelialization of the surface is insular for 2-3 weeks. No scars are formed. Persistent hyperpigmentation of the skin and increased sensitivity to cold persist for years. Changes in the vessels are persistent, there is a pronounced tendency to angiospasm, up to the development of obliterating endarteritis. Sometimes Besnier's disease develops - persistent, symmetrical infiltrated foci of a bluish color appear on the nose, cheeks, auricles, fingers.
• 3rd degree frostbite. The pain is constant, sharp, and radiates throughout the entire limb. There is a long-term loss of tactile sensitivity. The swelling of the limb is pronounced, with compression of the vessels, which determines a decrease in pulsation in the peripheral arteries.

On the second day, blisters with jelly-like hemorrhagic contents are formed. On the 3rd-5th day, they open. At this time, preliminary differential tests can be carried out to determine the depth of frostbite. Unlike the 2nd degree of frostbite, with the third: pricking with a needle (Bilroth method), applying alcohol applications (Mikulich method) are painless. When thermometry of the skin, a persistent decrease in temperature is noted, which is not typical for the second degree of frostbite.

By the end of the week, the swelling decreases and demarcation zones appear, which are clearly defined (demarcation) with the formation of a dense black scab. Granulations develop under it, epithelialization occurs from the edges, very slowly. Healing occurs with the formation of a scar.

• 4th degree frostbite. The pain is sharp, throughout the limb, but there is no tactile sensitivity. The swelling is huge, throughout the limb, with compression of the vessels and nerve trunks. There may be no blisters, or they form with hemorrhagic contents, but quickly open. The fingers and distal areas turn black within a week, the nails are rejected} they dry out (mummify). By the end of the second week, the frostbite zone is clearly delimited by a demarcation line. If the segment is not removed surgically, then after 3-4 weeks it is naturally rejected along the demarcation lines. After this, there is very slow granulation of the surface and epithelialization from the edges (sometimes for years), with the formation of a rough scar. The stump in these cases is incapable of supporting. Moreover, causalgia (burning, phantom pain in the stump) often develops due to the club-shaped deformation of the nerves. Perhaps the only way out of the situation is to perform early amputation within healthy tissues with the formation of a supporting stump.

[ 5 ], [ 6 ], [ 7 ]

Frostbite classification

According to the characteristics of occurrence, frostbite is divided into 3 types:

• from prolonged exposure to cold, even at temperatures above 0 degrees, the so-called trench foot develops in peacetime among fishermen and timber raftsmen, etc.;
• from: exposure to temperatures below 0 degrees in cases of local tissue freezing;
• from contact with a cooled object (for example, if you lick a frozen piece of metal).

Depending on the depth, 4 degrees of frostbite are formed:

1. Only the epidermis of the skin is affected.
2. The lesion deepens to the basal layer.
3. The entire thickness of the skin and subcutaneous tissue is affected.
4. Bones and soft tissues are affected.

Due to the high regenerative capacity of tissues to recover after exposure to cold, as well as the possibilities of providing assistance and the quality of the treatment, the final decision on the depth of frostbite can be made only 2 weeks after the injury.

According to the course of the process, 3 periods are distinguished.

• Pre-reactive - from the moment of freezing to thawing of a limb segment.
• Reactive - from the moment of thawing until the restoration of the skin.
• The recovery period is until full recovery of working capacity or disability.

[ 8 ], [ 9 ], [ 10 ]

Complications of frostbite

• The addition of infection with the development of: purulent dermatitis, streptostaphyloderma, wet gangrene, sepsis, etc.
• Development of complications from the veins: thrombophlebitis, phlebitis, phlebothrombosis, up to the development of trophic ulcers.
• Formation: muscle atrophy, arthritis, contracture changes in joints with stiffness, up to ankylosis.
• Development of Raynaud's disease and obliterating endarteritis due to damage to nerve trunks and arteries.
• Formation of cold: neurovasculitis, neurodermatitis, dermatitis of the extremities.
• Involvement of the lymphatic vessels of the extremities in the process: lymphadenitis, lymphangitis, lymphedema, etc.

[ 11 ], [ 12 ]