Classification of frostbite

1. Depth of damage:

degree 1 - blood circulatory disorders and the development of reactive inflammations;

degree 2 - damage to the epithelia up till the germinal layer which is intact (fig. 83, a, colour inset);

degree 3 - complete skin necrosis and partial necrosis of the subcutaneous layer (see fig. 83, b, colour inset);

degree 4 - skin necrosis and necrosis of deep lying tissues.

2. According to the disease period (period of frostbite):

• latent (pre-reactive) period;

• reactive period.

Under the influence of very cold temperatures there can be local frost bite and general frostbite.

Local damage by extreme cold to the skin and deep lying tissues occurs due to disorders of blood circulation rather than as a result of the direct cold: spasm, and in the reactive period, vascular (capillary and minor arterial) paresis, the decrease in blood flow, stasis of blood cells and thrombus formation. Later morphological changes in the vascular walls are usually as follows: swelling of the endothelium, plasmatic infiltration of endothelial structures, formation of necrosis followed by connective tissue formation and vascular obliteration.

Thus, tissue necrosis in frostbite has the secondary character and continues into the reactive phase of frostbite. The changes that occur in the vascular walls after frostbite provide favourable conditions for the development of obliterating vascular diseases and the development of trophic disorders.

Most commonly (in 95% of cases) it is the extremities that get frostbitten since blood circulation in the limbs is rather vulnerable.

The latent period, or hypothermia, continues from several hours to a day up to the beginning of the period of warming and restoration of blood circulation.

The reactive period starts from warming the affected organ and restoration of blood circulation. It is divided into early and late reactive periods. Early reactive period lasts for 12 hours from the beginning of warming and is characterised by the disorders in blood circulation, changes in the vascular walls, hypercoagulation and clotting. The late reactive period follows the early one and is characterised by necrotic changes and infectious complications. It is normally associated with intoxication, anaemia and hypoproteinaemia.

Degrees 1 and 2 are superficial, while degrees 3 and 4 are deep.

In first degree frostbite there is blood circulation disorders without necrotic changes in the tissues. Full recovery is usually evident on days 5-7. In second degree burns the superficial layers of skin are damaged, the germinal layer is intact. Skin damage is fully healed within 1-2 weeks.

In the third degree frostbite, skin regeneration is impossible, and after the eschar has fallen off a skin defect forms, which is covered by granulation tissue and unless skin grafting is done to cover the defect, the wound heals with the formation of a scar.

In fourth degree frostbite, a dry or wet gangrene of the affected organ, usually of the limb, occurs.

Evaluation should include complaints and history. It is required that the patient be questioned as to the circumstances under which the frostbite occurred (air temperature, humidity, wind, long periods in the cold, the character and contents of the first aid given).

It is worthwhile to reveal all the factors that may reduce the body's general resistance to cold (e.g. cachexia, fatigue, blood loss, shock, vitamin deficiency and drunkenness), as well as local tissue resistance (obliterating vascular conditions, disorders of innervation, trophic skin and tissue disorders and previous one episodes of frostbite)

During the latent (pre-reactive) phase, the patient may experience paraesthesia in the frozen areas, which is later joined by a feeling of numbness. Pain is not always present. Skin in those areas is pale, rarely cyanosed, cold to touch, sensory function is reduced or absent. It is not possible to determine the extent of frostbite in this period; it can only be estimated that the absence of sensation indicates severe frostbite.

During warming the limb, as the blood circulation improves, frostbite moves into the reactive period. Tingling, burning sensations, itching and pain (in deep frostbite pains do not increase) occur in the frozen area and the limb warms up. Examination reveals reddened skin, and in deep frostbite -cyanotic with marble coloration or very hyperaemic. As the patient warms up tissue oedema, which is more pronounced in cases of deep freezing sets in.

It may be possible to ascertain the spread and depth of damage only after all the signs have manifested themselves, i.e. after several days.

Patients with first-degree frostbite complain of pain occasionally burning and unbearable during the warming period. As the patient warms, skin pallor turns into hyperaemia and becomes warm to touch, tissue oedema is minimal, limited to the damaged areas and do not progress. All types of sensation and movement in the hand and foot joints are intact.

Patients with second degree frostbite complain of itching, burning sensation, tension in the tissues, which persist for several days. Blister formation, which commonly appears in the first days, occasionally on the second day, and rarely on the third-fifth day, is a characteristic sign. Blisters are filled with transparent contents, when there are opened a red or pink papilla layer of the skin that is occasionally covered with fibrin shows. When the bare layer at the base of the blister is touched the patient experiences severe pain. Skin oedema spreads beyond the damaged area.

In third degree frostbite, pain is more severe and long lasting; there is a history of staying in the cold for long. The skin in the reactive period is violet bluish and cold to touch. If blisters form (which is rarely the case), they are usually filled with haemorrhagic contents. During the first days or even hours, pronounced oedema that extends beyond the affected skin areas occurs. All types of sensation are lost. When the blisters are opened violet-bluish surface of the blister base that is not sensitive to skin prick or irritation by gauze swabs soaked with alcohol is found. Subsequently dry or wet skin necrosis sets in; and when they peel off granulation tissue forms.

During the first few hours or even days, the fourth degree frostbite is unlikely to be distinguished from that of the third degree. The damaged skin looks pale or bluish. All types of sensation are lost; the limb is cold to touch. Blisters can appear in the first hours and are friable, filled with haemorrhagic dark contents. Limb oedema develops very fast - 12 or a few hours after warming. Oedema occupies much larger areas than the necrotic area: hence, in frozen fingers the whole forearm becomes oedematous, the foot - the whole leg. Subsequently dry or wet gangrene develops. After a week, oedema subsides and the demarcation line appears - a line that separates the intact side from the necrotic areas.

Because of long repeated frostbite (interchanging with warming) at 0... + 10 °C and high humidity a particular type of localised frost bite «trench foot» develops. Frostbite commonly persists for several days after which dull pains and burning sensations as well as a wooden type of limb is felt.

Examination reveals a pale, oedematous foot, which is cold to touch. All types of sensation are lost. Blisters with haemorrhagic content are then formed, their bases being part of the necrotic papilla layer. Intoxication is pronounced: high body temperature, tachycardia and general malaise. Sepsis commonly sets in.

First aid. Fast warming of the affected area is the main element of treatment since that leads to a quick restoration of the blood circulation. Warming can be done through any means but best results are achieved when heating is fast.

The injured has to be taken to a room. Since it is normally the limbs that are frozen they are put in warm baths with the temperature of water at 18-20 °C and within a period of 20-30 min the temperature is raised to 39-40 °C while at the same time massaging the limb carefully from the periphery to the centre, manually or with soaped sponge. After 30-40 minutes of massage and heating, the skin gets warm and pink. The limb is taken out of the water, dried with a clean towel and treated with 70% alcohol after which an aseptic dressing is applied; a thick layer of cotton wool is used to cover the first dressing and bandaged. The patient is placed in bed keeping the limbs raised, hot drinks and a little alcohol is given.

When the external ear, nose and cheeks are frozen, they can be rubbed with warm hands or some soft material until they become red. They are then treated with 70% alcohol and sterile Vaseline oil. They should never be rubbed with snow, since that can freeze the skin more and the snow crystals can cause mechanical damage to the skin creating the conditions for infection and the development of erysipelas inflammations.

When it is impossible to actively heat the affected part, heat insulation dressing that prevents heat loss and further cooling is used. Sterile dressing is put on the affected part on top of which only cotton wool is placed and bandaged. Woollen blankets and fur materials can be used for the heat insulation purpose. Using heat insulation materials to warm the affected part takes 5-6 hours whilst active warming takes just 40-60 min.

Heating under field conditions is done with such heat sources as burning fire, or hot water bottles. The affected limb can be placed in the armpit, on the stomach, in between the thighs of either the injured or the one giving the first aid. In all instances it has to be made sure that the rate of heat production is greater and the rate of heat loss is reduced by covering the injured with warm clothing, hot tea and injections of spasmolytics.

When the adequate first aid is given in the latent period the development of primary tissue necrosis is avoided.

Treatment. This is primarily directed to restoration of blood circulation, treatment of local damage, prevention and treatment of infectious complications. Treatment is either conservative or surgical.

Infusion therapy is the most important measure in the conservative therapy. The choice of the solution for transfusion varies with the period of injury.

In the pre-reactive period, when vascular spasm, increased blood viscosity and aggregation of blood cells persist, preparations that improve metabolism are given either intra-arterially or intravenously: rheopolyglucin, rheogluman (10% dextran and 5% mannit in 0, 9% normal saline); spasmolytics: 2% solution of papaverin - 2 ml mixed with 1% nicotinic acid - 2 ml in of the mixture with 10 ml of 0, 25% novocain (intra-arterially). Prevention of thrombosis is achieved by giving 20, 000-30, 000 IU of heparin. This therapy is continued in the early reactive period in the first 12 hours after the limb has been heated.

At the early stages of intoxication blood substitutes with detoxication properties (haemodes), crystalloids are added to the drug infused. Apart from intravenous and intra-arterial modes of administration, heparin can also be given subcutaneosly every 6 hours at the dose of 5, 000 IU.

In the late reactive period in view of infections, intoxication and necrosis that develop, the following preparations are commonly used: detoxication drugs, blood components, immune stimulators, and preparations for parenteral nutrition. Antibacterial therapy is achieved with antibiotics, bacteriophages, and chemical antiseptics.

Surgical treatment for frostbite is aimed at excising the necrotic tissue and closure of tissue defect by autodermaplasty. These can be achieved by the following methods: necrotomy - incision of necrotic tissue within the first 3 days; necrectomy - early (i.e. within the first day) in gangrene and impending sepsis and delayed, 15-30 days after trauma; limb amputation - amputation of the damaged segment proximal from the demarcation line; plastic and reconstruction surgeries - skin transplant on the granulated wound, modification of stump and improvement of stump functions, restoration of cosmetic defects.

Local treatment of frostbite starts from primary wound toileting. The wound is opened, surrounding skin cleaned with alcohol solution and some ointment with antiseptic property (e.g. synthomycin emulsion) is used for the dressing.

In first and second degree frostbites, treatment is conservative, which involves the change of dressing every 2-3 days. Blisters that form in second-degree frostbite can be opened slightly at the base, and when they are infected, the contents have to be evacuated with the dead epidermis. After the blisters have been opened, they have to be dressed with antiseptic bandage.

In third degree frostbite, treatment is conservative and includes of the change of dressing and using antiseptic dressing, and proteolytic enzymes. After the wound has been cleaned of all the necrotic tissue in case of minor wounds, ointments that enhance wound healing can be used for the dressing. Extensive wounds need skin grafting.

In fourth degree frostbite, conservative treatment (the use of antiseptics for the prevention of wound infection) is a means of preoperative preparation.

Local treatment of fourth degree frostbite is step-wise: necrotomy - necrectomy - amputation. Necrotomy is done towards the end of the first week: necrotic tissues are incised up to the bone. Anaesthesia is not necessary, since there is normally no sensation in this part of the body. The resulting wound is treated according to the general principles of treating septic wounds: using antiseptics and proteolytic enzymes. After necrotomy the patient's condition normally improves - intoxication, adjacent tissue oedema and skin hyperaemia reduce, the demarcation line becomes more distinct. Necrectomy is done 7-10 days after necrotomy and involves excision of the necrotic tissue until intact tissue up to 1-2 cm distal from the demarcation line. Amputation is accomplished 2-3 weeks after the necrectomy and it is done taking into account the most functionally advantageous position of the involved limb.

General hypothermia. This is a serious condition, in which the body temperature drops to below 34 °C, and rectal temperature is below 35 °C. It is blood circulatory and metabolic disorders, hypoxia and the like that underlie the changes within the body.

Three degrees or forms of general hypothermia are as follows: mild (adynamic form) when the body temperature reduces to 35-34 °C; average (stupor form) when the body temperature reduces to 33-29 °C; and severe (convulsive form) when the body temperature falls to below 29 °C. A fall in the body temperature to as low as 25-22 °C leads to death.

The mild form of hypothermia (adynamic) is characterised by general fatigue, malaise and somnolence. Movement is stiff, speech is distorted, pulse is slow - 60-66 beats per min and the blood pressure is moderately increased (up to 140/100 mm Hg). The patient complains of thirst and rigors. Skin is pale or cyanotic with marble colour (alternating pale and cyanotic spots), «goose pimples» appear all over the skin, and rectal temperature is within 35-33 °C.

In moderate hypothermia, or stupor, the patient is stuporous (semiconscious), joints movements are very stiff, rare and shallow breath movements (8-12 per minute), bradycardia (34-56 beats per minute), weak pulse, blood pressure is moderately reduced. Skin is pale, cyanotic and cold to touch.

The patient with the severe form of frostbite (convulsive type) is unconscious, pupils are constricted, reaction to light is very weak or absent. Tonic spasms of the limbs are difficult to cope with. The chewing muscles and those of the abdominal press are contracted and stiff. Skin is pale, cyanotic and cold to touch. Breath movements are rare (4-6 per minute), shallow and intermittent, weak and rare pulse (34-30 beats per minute), blood pressure markedly falls.

First aid is aimed at warming the affected person as fast as possible. He/she is placed in a bath with the water temperature of 36 °C, and is increased to 38-40 °C within 15-20 minutes. Warming is continued for about 1¹/₂-2 hours until the body temperature has increased to as low as 35 °C. The patient is simultaneously given hot drinks: tea, coffee; 50-70 ml of 40% glucose solution, 5-10 ml of 10% calcium chloride, 200 ml of 5% sodium bicarbonate are given intravenously, cardiac preparations, vascular drug (corglucon, caffeine), antihistamine agents and analgesics are also given.

After warming in the reactive period, prevention of possible complications or treatment of pre-existing ones (bronchitis, pneumonia, pulmonary oedema, cerebral oedema, neuritis, paresis, paralysis etc.) should be started.

TESTS

Chapter X. TRAUMA

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