Frostbite - cold injury, causing superficial or deep tissue damage. Frostbite can arise not only when the temperature is below zero, and at a temperature of +4oC, +8 degrees and even higher (see Trench foot). Among the factors contributing to the development of frostbite include: wind, long lasting effect of cold, humidity, wet clothes, wet and tight shoes, gloves, impeding blood circulation, a condition of alcoholic intoxication, the weakening of the body (old age, disease, hemorrhage), limb injury, etc.
Frostbite most often exposed fingers of hands and feet, face and ear. Frostbite large areas of the body (buttocks, abdomen etc) are very rare. Frostbite limb above the ankle and wrist joints are also observed rarely and usually end fatally. This is because such frostbite can be almost as a rule, during freezing, (see).
For frostbite distinguish two periods: the period of local tissue hypothermia (see), or reaktivny (warming up), and the period reactive (after warming). In the period up to warming amazed feel cold, tingling and burning in the area frostbite, then comes complete loss of sensitivity. The affected area has a characteristic appearance: the skin is pale or bluish, the extremity is not capable of active movements, gives the impression of petrified. In this period it is impossible to determine the extent and prevalence of tissue damage, as they have no signs of inflammation and they seem to be viable. In the second period, after warming, in the field of frostbite develops rapidly swelling, and then gradually revealing inflammatory or necrotic changes, so that the true weight of frostbite can be determined only in 10-15 days.

Fig. 4. Frostbite foot, II and III degrees and fingers of the IV degree. Fig. 5. Frostbite of the first toe of the III degree. Fig. 6. Total frostbite foot of the IV degree. Fig. 7. Stage of mummification and the exclusion of necrotic tissue when frostbite foot of the IV degree.

On the gravity of the defeat there are four degrees of frostbite. If frostbite 1, the easiest, degree are marked bluish coloration of the skin and its swelling. Frostbite 2 degrees accompanied by destruction of the surface layers of the skin. For this degree is characterized by the appearance of bubbles (Fig. 4)filled with clear content. In the outcome of the observed recovery of the normal structure of the skin, scars are formed. If frostbite 3 degrees (Fig. 5) there comes a necrosis of the skin and subcutaneous tissue. Generated bubbles contain bloody exudate. In Exodus dead skin cells rejected, develop granulation and after healing scars. Frostbite 4 degree is characterized by the death of skin, soft tissues, bones and joints, limbs (Fig. 6), the cartilage of the ear, etc. of the Dead tissue modifitsiruyutsya (Fig. 7)that remained in this state for a long time (2-3 months. and more). In these terms is delimitation (demarcation) dead tissue from the living along the line of demarcation is developing granulation shaft, favors rejection off of dead skin soft tissues and bones (mutilate).
Severe frostbite often accompanied complications such as pneumonia, acute tonsillitis, may develop tetanus, anaerobic infection and other Parts of the body exposed to frostbite, are particularly sensitive to cold, so frostbite them easily occur again.

Frostbite (congelatio)-cold injury, local effects which manifest themselves inflammatory and necrotic changes in the tissues.
In peacetime severe frostbite is very rare, mainly during natural disasters, far from settlements, in the mountains, in the desert and the sea, outside dwellings and for loss of or damage to shoes and clothes. Under normal conditions, the Acting is more likely to occur in people who are in a condition of alcoholic intoxication. In the war's Acting can be massive.
In most cases, O. flow easily, but can be severe cases, often combined with freezing (see), which are accompanied by relatively high fatality.
Frostbite can occur not only in winter when the negative external temperature, but also in autumn or spring by prolonged exposure positive temperature of the external environment, which is much lower than the temperature of the body (4th, 8th and above). If even a moderate cooling continues for a long time, the body is unable forces of the natural mechanisms of thermoregulation to maintain the normal temperature of peripheral tissues of the body. Gradually slowed, and later stops circulation, lost the pain and sensitivity, the conductivity of the nerve trunks, and there are conditions for the development of cold ossification tissue. Its mechanism to date not fully installed because even glaciation of cells and tissues may cause of their death. It is known, for example, that glaciation able to endure not only the simplest, Noah more complexly organized living beings (some insects and fish). Decisive in Acting has circulatory disorders of tissue caused by prolonged spasm of the blood vessels under the influence of cooling.
Among the factors contributing to the development O., is primarily hydration of the skin. So, wet shoes and long stay soldiers in trenches in the cold season, in the conditions excluding or hindering the movement of the body, were the cause of mass Acting in the first world war in the armies of the warring countries. These O. called "trench foot". Usually affects both feet. A form of frostbite - perniosis (see) is developing with moderate, but long, and most importantly multiple cooling (for example, when working in cold rooms with bare hands). Proceeds perniosis, as dermatitis, with the formation of the swelling, cracks, sometimes ulcers. It is characterized by relatively easy clinical course, localization on the hands, face, prone to relapses. Victims of osnaline complain of itching and pain in the place of damage to the skin. Oznamenie mostly affects young people, especially women, which suggests a part in the pathogenesis of this disease of the endocrine system. Once again postponed Acting provokes many perniosis in spring and autumn.
Very low external temperature, as well as touching the very chilled subjects can cause instant O. similar period of occurrence with burns. In the polar climate are observed primary lesion cold respiratory tract and lungs. These lesions only conditionally can be caused by O.
Frostbite is possible only with the exception of fatal General hypothermia. Therefore, when disasters at sea (for example, the shipwrecks in the cold season in the dead of the total cooling signs of Acting is not observed, and for those who survive in these conditions always develop severe O.
O. most often exposed to the fingers and toes (90-95% of the total number of all About.). O. face and ear is less common, and O. other areas of the body (buttocks, abdomen, genitals, neck)- only rarely (for example, childbirth out of dwellings in the snow, inappropriate laying bags with ice on his stomach).
Frostbite affects the skin, muscles, bones, joints and tendons to the fingers and hands and feet. Deep Acting lower leg and arm are rare and in many cases are fatal, especially if the Acting was deadened all the lower leg and foot. Proximal knee and elbow joints total of mortification if frostbite in the period after warming is not observed; this is probably due to the fact that frostbite, not having reached such degrees, ended in death. For the same reason, never affected the initially cold internal organs.
Area of mortification when Acting wedge-shaped with a forked base facing the center of the body (Fig. 1). Later the wedge shape of dead tissue is aligned.
Often there is About. only one arm or leg. In these cases, the cause of O. there are damage, loss or hydration of clothing and shoes, pressure on the foot and hand, which facilitates the fall of the tissue temperature.
Pathological anatomy. If frostbite develops dry or moist gangrene (see). Death usually results from septicaemia.
Clinical course and classification. In the clinical course of O. there are two periods: the period of local tissue hypothermia, or hidden (doreaktivnyh), and the period after warming (reactive). In the period of local tissue hypothermia patients initially feel a sense of cold, tingling and burning in the area of destruction, then gradually comes complete loss of sensitivity. Victims from Acting in many cases to hear about it from others, noticing typical white or bluish skin color frostbitten body part. For Acting characterized by a sense of rigor Mortis affected areas of the extremities. In the period of local tissue hypothermia it is impossible to objectively determine the depth and spread of ossification tissue. The gravity Acting directly proportional to the spread clenched skin and the duration of the period of local tissue hypothermia.
In the USSR adopted the classification applied to frostbite fingers and toes. O. divided into four degrees (Fig. 2). For classification characteristics Acting to figure characterizing the degree added their name (for example, O. IV degree toes and tarsal or Acting III degree field of patella).
Frostbite I degree. The period of local tissue hypothermia in the shortest time, and the rate of decline tissue temperature least. The skin of the affected area bluish, sometimes there is a characteristic marble colouring of the coat. Very rarely has a skin ulceration. Bubbles not. Microscopically necrosis not defined.

Frostbite II degree (Fig. 3). The period of local tissue hypothermia increases, there is the mortification of the surface layers of the epidermis, the papillary layer of the skin is saved completely or partially. Characteristic bubbles, a variety of shapes and sizes, filled with clear fluid, and the folds of fibrin. Fibrin and covered the bottom of the bubbles is very sensitive to chemical and mechanical irritation.
Because O. II degree is not damaged germ layer, in Exodus it always has been complete restoration of normal structure of the skin grows back down the nails, granulation and scars are not developing.
In doubtful cases for the differential diagnosis between About. II and III extent use the so-called alcohol-test - touch to the bottom of the bubble, which cleared the epidermis, small gauze ball dipped in water alcohol. If the touching is painful, it is About. II degree; in these cases, you should immediately dry the area of O. dry bulb.
Frostbite III degree (Fig. 4). The duration of the local fabric of hypothermia increase. Border ossification takes place in the lower layers of the dermis or subcutaneous fat. Bubbles contain hemorrhagic fluid. The bottom of their crimson, neither insensitive to applications alcohol (negative alcohol test)nor to mechanical irritation. The death of the entire thickness of the skin and therefore all its epithelial cells is the cause of development of granulations and scars. Descended again nails don't grow, and in their place is also developing scars.
Frostbite IV degree (Fig. 4). Depending on the boundaries of Acting the duration of the local fabric of hypothermia and the decrease of tissue temperature varies greatly, but in any case both are most pronounced. The border of the ossification was held at the level of the phalanges, metacarpal, metatarsal bones and the bones of the wrist or of Tarsus, lower third of the leg or distal sections of the bones of the forearm. Very rarely there is a partial or total O. IV degree field of the patella. Dead soft tissue modifitsiruyutsya (Fig. 5), and remained in this state for a long term (2-3 months. and more). At the same time at the border demarcation of the dead and living tissues gradually develops granulation shaft, favors rejection off of dead skin bones (mutilate). If the demarcation is on the level of the joints of the hand or foot, rejection dead tissue may occur within 3-4 weeks. In these cases limb looks after Mytischi quite common (Fig. 6). Of leather, covering the soft tissue of the face of the foot, are dead head metacarpal bones. The most unfavorable in terms of keeping the support ability O. IV degree forefoot and heel bone. Prognostic doubtful flows O. IV degree whole foot, in particular the "trench foot".
In the period after warming start to develop necrosis and reactive inflammation. The depth O. and its distribution on the surface, you can determine more or less exactly no earlier than 5-7 days, although in this period the possible errors in one direction or another. So, O. IV degree may be accepted for Acting II and III degree, in other cases lighter O. taken for Acting III and IV degree. Only 10-15 days you can precisely define the degree of O. When Acting auricular diagnosis O. IV degree is in case of the death of her cartilage.
Severe frostbite often accompanied by various diseases and complications, pneumonia, acute tonsillitis. Sometimes aggravated chronic colitis, tuberculosis, dysentery. To About. can join septicaemia and anaerobic infection. Very often when Acting observed acute reactive lymphadenitis and lymphangitis, sometimes phlegmon. When deep Acting stop and, in particular, when Acting IV level of calcaneus observed faltering deep ulcers, which contribute fungi, vegetating in human skin. It is very likely that in the etiology and pathogenesis of some forms of obliterating endarteritis and chronic neuritis limbs plays the role of a previous Acting or systematic and long-term cooling of the feet, for example, fishermen, irrigators rice fields and people skills relate to the constant and prolonged soaking shoes.

Fig. 1. Scheme of zones of pathological processes if frostbite: 1 - zone of total necrosis; 2 - irreversible degenerative processes; 3 - reversible degenerative processes; 4 - the ascending of pathological processes.
Fig. 2. Classification scheme frostbite. Border frostbite is held with frostbite II degree above the germinal layer of the skin, if frostbite III degree below it, if frostbite IV degree - through the bones of the skeleton. If frostbite I degree tissue necrosis is not defined.
Fig. 3. Frostbite II degree I toe.
Fig. 4. Frostbite fingers III and IV degree.
Fig. 5. Mummification if frostbite IV degree.
Fig. 6. Mutilate fingers if frostbite IV degree.
Fig. 7. The appearance of the rear (1) and bottom (2) of the foot after necrotomy.