Fig. 63.—Cicatricial Contraction following Severe Burn.
The distinction between a burn which results from the action of dry heat on the tissues of the body and a scald which results from the action of moist heat, has no clinical significance.
In young and debilitated subjects hot poultices may produce injuries of the nature of burns. In old people with enfeebled circulation mere exposure to a strong fire may cause severe degrees of burning, the clothes covering the part being uninjured. This may also occur about the feet, legs, or knees of persons while intoxicated who have fallen asleep before the fire.
The damage done to the tissues by strong caustics, such as fuming nitric acid, sulphuric acid, caustic potash, nitrate of silver, or arsenical paste, presents pathological and clinical features almost identical with those resulting from heat. Electricity and the Röntgen rays also produce lesions of the nature of burns.
Pathology of Burns.—Much discussion has taken place regarding the explanation of the rapidly fatal issue in extensive superficial burns. On post-mortem examination the lesions found in these cases are: (1) general hyperæmia of all the organs of the abdominal, thoracic, and cerebro-spinal cavities; (2) marked leucocytosis, with destruction of red corpuscles, setting free hæmoglobin which lodges in the epithelial cells of the tubules of the kidneys; (3) minute thrombi and extravasations throughout the tissues of the body; (4) degeneration of the ganglion cells of the solar plexus; (5) œdema and degeneration of the lymphoid tissue throughout the body; (6) cloudy swelling of the liver and kidneys, and softening and enlargement of the spleen. Bardeen suggests that these morbid phenomena correspond so closely to those met with where the presence of a toxin is known to produce them, that in all probability death is similarly due to the action of some poison produced by the action of heat on the skin and on the proteins of the blood.
Clinical Features—Local Phenomena.—The most generally accepted classification of burns is that of Dupuytren, which is based upon the depth of the lesion. Six degrees are thus, recognised: (1) hyperæmia or erythema; (2) vesication; (3) partial destruction of the true skin; (4) total destruction of the true skin; (5) charring of muscles; (6) charring of bones.
It must be observed, however, that burns met with at the bedside always illustrate more than one of these degrees, the deeper forms always being associated with those less deep, and the clinical picture is made up of the combined characters of all. A burn is classified in terms of its most severe portion. It is also to be remarked that the extent and severity of a burn usually prove to be greater than at first sight appears.
Burns of the first degree are associated with erythema of the skin, due to hyperæmia of its blood vessels, and result from scorching by flame, from contact with solids or fluids below 212° F., or from exposure to the sun's rays. They are characterised clinically by acute pain, redness, transitory swelling from œdema, and subsequent desquamation of the surface layers of the epidermis. A special form of pigmentation of the skin is seen on the front of the legs of women from exposure to the heat of the fire.
Burns of Second Degree—Vesication of the Skin.—These are characterised by the occurrence of vesicles or blisters which are scattered over the hyperæmic area, and contain a clear yellowish or brownish fluid. On removing the raised epidermis, the congested and highly sensitive papillæ of the skin are exposed. Unna has found that pyogenic bacteria are invariably present in these blisters. Burns of the second degree leave no scar but frequently a persistent discoloration. In rare instances the burned area becomes the seat of a peculiar overgrowth of fibrous tissue of the nature of keloid (p 401).
Burns of Third Degree—Partial Destruction of the Skin.—The epidermis and papillæ are destroyed in patches, leaving hard, dry, and insensitive sloughs of a yellow or black colour. The pain in these burns is intense, but passes off during the first or second day, to return again, however, when, about the end of a week, the sloughs separate and expose the nerve filaments of the underlying skin. Granulations spring up to fill the gap, and are rapidly covered by epithelium, derived partly from the margins and partly from the remains of skin glands which have not been completely destroyed. These latter appear on the surface of the granulations as small bluish islets which gradually increase in size, become of a greyish-white colour, and ultimately blend with one another and with the edges. The resulting cicatrix may be slightly depressed, but otherwise exhibits little tendency to contract and cause deformity.
Burns of Fourth Degree—Total Destruction of the Skin.—These follow the more prolonged action of any form of intense heat. Large, black, dry eschars are formed, surrounded by a zone of intense congestion. Pain is less severe, and is referred to the parts that have been burned to a less degree. Infection is liable to occur and to lead to wide destruction of the surrounding skin. The amount of granulation tissue necessary to fill the gap is therefore great; and as the epithelial covering can only be derived from the margins—the skin glands being completely destroyed—the healing process is slow. The resulting scars are irregular, deep and puckered, and show a great tendency to contract. Keloid frequently develops in such cicatrices. When situated in the region of the face, neck, or flexures of joints, much deformity and impairment of function may result (Fig. 63).
In burns of the fifth degree the lesion extends through the subcutaneous tissue and involves the muscles; while in those of the sixth degree it passes still more deeply and implicates the bones. These burns are comparatively limited in area, as they are usually produced by prolonged contact with hot metal or caustics. Burns of the fifth and sixth degrees are met with in epileptics or intoxicated persons who fall into the fire. Large blood vessels, nerve-trunks, joints, or serous cavities may be implicated.
General Phenomena.—It is customary to divide the clinical history of a severe burn into three periods; but it is to be observed that the features characteristic of the periods have been greatly modified since burns have been treated on the same lines as other wounds.
The first period lasts for from thirty-six to forty-eight hours, during which time the patient remains in a more or less profound state of shock, and there is a remarkable absence of pain. When shock is absent or little marked, however, the amount of suffering may be great. When the injury proves fatal during this period, death is due to shock, probably aggravated by the absorption of poisonous substances produced in the burned tissues. In fatal cases there is often evidence of cerebral congestion and œdema.
The second period begins when the shock passes off, and lasts till the sloughs separate. The outstanding feature of this period is toxæmia, manifested by fever, the temperature rising to 102°, 103°, or 104° F., and congestive or inflammatory conditions of internal organs, giving rise to such clinical complications as bronchitis, broncho-pneumonia, or pleurisy—especially in burns of the thorax; or meningitis and cerebritis, when the neck or head is the seat of the burn. Intestinal catarrh associated with diarrhœa is not uncommon; and ulceration of the duodenum leading to perforation has been met with in a few cases. These phenomena are much more prominent when bacterial infection has taken place, and it seems probable that they are to be attributed chiefly to the infection, as they have become less frequent and less severe since burns have been treated like other breaches of the surface. Albuminuria is a fairly constant symptom in severe burns, and is associated with congestion of the kidneys. In burns implicating the face, neck, mouth, or pharynx, œdema of the glottis is a dangerous complication, entailing as it does the risk of suffocation.
The third period begins when the sloughs separate, usually between the seventh and fourteenth days, and lasts till the wound heals, its duration depending upon the size, depth, and asepticity of the raw area. The chief causes of death during this period are toxin absorption in any of its forms; waxy disease of the liver, kidneys, or intestine; less commonly erysipelas, tetanus, or other diseases due to infection by specific organisms. We have seen nothing to substantiate the belief that duodenal ulcers are liable to perforate during the third period.
The prognosis in burns depends on (1) the superficial extent, and, to a much less degree, the depth of the injury. When more than one-third of the entire surface of the body is involved, even in a mild degree, the prognosis is grave. (2) The situation of the burn is important. Burns over the serous cavities—abdomen, thorax, or skull—are, other things being equal, much more dangerous than burns of the limbs. The risk of œdema of the glottis in burns about the neck and mouth has already been referred to. (3) Children are more liable to succumb to shock during the early period, but withstand prolonged suppuration better than adults. (4) When the patient survives the shock, the presence or absence of infection is the all-important factor in prognosis.
Treatment.—The general treatment consists in combating the shock. When pain is severe, morphin must be injected.
Local Treatment.—The local treatment must be carried out on antiseptic lines, a general anæsthetic being administered, if necessary, to enable the purification to be carried out thoroughly. After carefully removing the clothing, the whole of the burned area is gently, but thoroughly, cleansed with peroxide of hydrogen or warm boracic lotion, followed by sterilised saline solution. As pyogenic bacteria are invariably found in the blisters of burns, these must be opened and the raised epithelium removed.
The dressings subsequently applied should meet the following indications: the relief of pain; the prevention of sepsis; and the promotion of cicatrisation.
An application which satisfactorily fulfils these requirements is picric acid. Pads of lint or gauze are lightly wrung out of a solution made up of picric acid, 1½ drams; absolute alcohol, 3 ounces; distilled water, 40 ounces, and applied over the whole of the reddened area. These are covered with antiseptic wool, without any waterproof covering, and retained in position by a many-tailed bandage. The dressing should be changed once or twice a week, under the guidance of the temperature chart, any portion of the original dressing which remains perfectly dry being left undisturbed. The value of a general anæsthetic in dressing extensive burns, especially in children, can scarcely be overestimated.
Picric acid yields its best results in superficial burns, and it is useful as a primary dressing in all. As soon as the sloughs separate and a granulating surface forms, the ordinary treatment for a healing sore is instituted. Any slough under which pus has collected should be cut away with scissors to permit of free drainage.
An occlusive dressing of melted paraffin has also been employed. A useful preparation consists of: Paraffin molle 25 per cent., paraffin durum 67 per cent., olive oil 5 per cent., oil of eucalyptus 2 per cent., and beta-naphthol ¼ per cent. It has a melting point of 48° C. It is also known as Ambrine and Burnol. After the burned area has been cleansed and thoroughly dried, it is sponged or painted with the melted paraffin, and before solidification takes place a layer of sterilised gauze is applied and covered with a second coating of paraffin. Further coats of paraffin are applied every other day to prevent the gauze sticking to the skin.
An alternative method of treating extensive burns is by immersing the part, or even the whole body when the trunk is affected, in a bath of boracic lotion kept at the body temperature, the lotion being frequently renewed.
If a burn is already infected when first seen, it is to be treated on the same principles as govern the treatment of other infected wounds.
All moist or greasy applications, such as Carron oil, carbolic oil and ointments, and all substances like collodion and dry powders, which retain discharges, entirely fail to meet the indications for the rational treatment of burns, and should be abandoned.
Skin-grafting is of great value in hastening healing after extensive burns, and in preventing cicatricial contraction. The deformities which are so liable to develop from contraction of the cicatrices are treated on general principles. In the region of the face, neck, and flexures of joints (Fig. 63), where they are most marked, the contracted bands may be divided and the parts stretched, the raw surface left being covered by Thiersch grafts or by flaps of skin raised from adjacent surfaces or from other parts of the body (Fig. 1).