Class I.—The skin in cases such as may occur from a brief contact with a hot body or water near the boiling-point shows a slight redness or scorching with no enduring mark. Pain is considerable.
Class II.—In the mildest cases the cutis is destroyed in its whole thickness, and the parts injured are occupied by eschars of a yellowish-gray or brownish color. The surrounding skin is reddened, and the formation of blisters occurs either immediately or after an interval of a few hours. In these cases a shining cicatrix remains after the healing, without contraction of surrounding parts. In the severer cases the subcutaneous cellular tissue and underlying muscles and nerves are destroyed. The blackish eschars formed are insensible and separate by suppurative process, leaving a granulating surface below. Extensive redness of surrounding tissues, with more or less vesication, is usually noted. The resulting cicatrices, together with the skin and adjoining structures, are prone to contraction, resulting in considerable deformity, according to location and extent. So great is the deformity in injuries of the extremities, or even some parts of the head and trunk, that extensive surgical operations become necessary to relieve it.
Class III.—Burns of this class are so severe that an immediately fatal issue is usually the result. Such instances involve a prolonged exposure to flame or to a source of intense heat. The appearances described as belonging to the preceding class are in part found here with the addition of charring or carbonizing the parts destroyed.
EFFECTS OF BURNS.
The effects of burns may be considered as I., Local, and II., Constitutional.
Local Effects.—In different instances the effects vary in accordance with the extent and severity of the burn. Redness, blisters, destruction of the cuticle and of the subcutaneous cellular tissue, blackening of the skin, scorching of the hair, and roasting of portions of the body are met with in varying degrees. In some severe cases all these are found upon a single body. The redness produced varies in intensity and extent, according to the nature of the agent producing the burn, its form, and the length of time the part was exposed.
Very soon after the infliction of the burn a special line of redness appears between the burned parts and the uninjured skin. This red line of demarcation is formed by intensely injected vessels and becomes a very important medico-legal sign in some cases. The vesication may be single or multiple, consisting of one or two large and full blisters or a number of large and small ones, scattered over the portions burned, some unbroken and still holding their contents, others broken and denuded of cuticle or with breaks from which their serum has escaped upon the surrounding parts. In some cases of burning cracks or fissures in the skin occur, due to the effect of the heat, making it dry and brittle and causing it to rupture by the movements of the patient (Case 8). These fissures are most frequently noted in proximity to the joints.[704] They resemble wounds, and it occurs occasionally that it is important to accurately distinguish their character. In some cases the skin only is fissured; in others the subjacent tissues are also involved. This difference depends upon the depth of the burn. In the first condition the skin splits, leaving the subcutaneous fat exposed, which in some instances is partially melted by the heat and flows out over the edge of the crack upon the surrounding skin (Cases 8, 13). The blood-vessels in such cases usually are not burned and, owing to their elasticity, remain stretching across the fissure (Case 14). The smaller may be seen by careful examination with a lens: they should always be looked for. In the second class of injuries the vessels are involved in the burn and break with the cracking of the skin. The importance of careful observation of these fissures is emphasized in cases of apparent wounds associated with burning. It may be necessary to decide whether the wounds are the result of the action of heat as above described or were caused by some sharp instrument or weapon. Careful inspection of the edges of the wounds will show whether they are ragged, as the result of fissure, or clean-cut by some sharp instrument. The absence of evidences indicating hemorrhage upon the surrounding parts and the detection of uncut blood-vessels extending across the fissure will establish the differential diagnosis. Wounds of the above character resulting from the action of fire may exist on the same body with wounds of actual violence. It is important, therefore, in all cases to examine each wound with special care and record its position, shape, depth, and other characteristics.
Constitutional Effects.—As in all sudden and violent injuries, the effect of a severe burn upon the nervous system is very marked. This is manifest in the symptoms of “shock,” with pallor and coldness of the surface of the body, a feeble pulse, chills or shivering, and a tendency to collapse. In other cases, proving immediately fatal, these symptoms are followed by obstructed respiration with death from coma succeeding. In other cases convulsions precede death, while in such as are not immediately fatal a reaction more or less imperfect ensues upon the first constitutional symptoms.
Death from cerebral congestion or effusion may result before any definite evidence of reaction appears. In some instances pulmonary congestion or œdema occurs, with or without pleural effusion, terminating in death before reaction. This period usually covers the first two days. In some cases immediate death results from the depression produced by the severity of the pain. During the subsequent two weeks a period of inflammatory reaction succeeds, when inflammations of the thoracic and abdominal viscera, with ulcerative processes in some organs, are developed and induce a fatal termination (Cases 10, 11, 16).