Causes and Symptoms Burns are injuries to tissues caused by contact with dry heat (fire), moist heat (steam or a hot liquid, also called scalds), chemicals, electricity, lightning, or radiation. The word “burn” comes from the Middle English brinnen or brennen (to burn) and from the Old English byrnan (to be on fire) combined with baernan (to set afire). As of 2014, the American Burn Association reported that nearly a half million people recieve medical attention for burns each year, with over thirty thousand hospitalized in burn centers. According to the World Health Organization in 2015, globally, an estimated 265,000 deaths occur annually due to fires; fire-related deaths alone rank among the fifteen leading causes of death among individuals aged five to twenty-nine years (these figures do not include burns from scalding, electricity, chemicals, or radiation). Burns are most common in children and older people and in low-income countries; many burns are caused by accidents in the home that are preventable.
The depth of the injury is proportional to the intensity of the heat of the causative agent and the duration of exposure. Burns can be classified according to the agent causing the damage. Some examples of burns according to this classification are brush burns, caused by friction of a rapidly moving object against the skin or ground into the skin; chemical burns, caused by exposure to a caustic chemical; flash burns, caused by very brief exposure to intense radiant heat (the typical burn of an atomic explosion); radiation burns, caused by exposure to radium, x-rays, or atomic energy; and respiratory burns, caused by inhalation of steam or explosive gases.
Burns can also be classified as major or severe (involving more than 20 percent of the body and any deep burn of the hands, face, feet, or perineum), moderate (a burn that requires hospitalization but not specialized care, as with burns covering 5 to 20 percent of the body but without deep burns of hands, face, feet, or perineum), or minor (a superficial burn involving less than 5 percent of the body that can be treated without hospitalization).
While many domestic burns are minor and insignificant, more severe burns and scalds can prove to be dangerous. The main danger for a burn patient is the shock that arises as a result of loss of fluid from the circulating blood at the site of the burn. This loss of fluid leads to a fall in the volume of the circulating blood in the area. The maintenance of an adequate blood volume is essential to life, and the body attempts to compensate for this temporary loss by withdrawing fluid from the uninjured areas of the body into the circulation. In the first forty-eight hours after a severe burn is received, fluid from the blood vessels, salt, and protein pass into the burned area, causing swelling, blisters, low blood pressure, and very low urine output. The body loses fluids, proteins, and salt, and the potassium level is raised. Such low fluid levels are followed by a shift of fluid in the opposite direction, resulting in excess urine, high blood volume, and low concentration of blood electrolytes. If carried too far, this condition begins to affect the viability of the body cells. As a result, essential body cells such as those of the liver and kidneys begin to suffer, eventually causing the liver and kidneys to cease proper function. Liver and renal failure are revealed by the development of jaundice and the appearance of albumin in the urine. In addition, the circulation begins to fail, with a resultant lack of oxygen in the tissues. The victim becomes cyanosed, restless, and collapsed, and in some cases death ensues. Other possible problems related to burns include collapse of the circulatory system, shutdown of the digestive and excretory systems, shock, pneumonia, and stress ulcers.
In addition, particularly with severe burns, there is a strong risk of infection. Severe burns can leave a large area of raw skin surface exposed and extremely vulnerable to any microorganisms. The infection of extensive burns may cause fatal complications if effective antibiotic treatment is not given. The combination of shock and infection can often be life-threatening unless expert treatment is immediately available.
The immediate outcome of a burn is more determined by its extent (amount of body area affected) than by its depth (layers of skin affected). The “rule of nines” is used to assess the extent of a burn in relation to the surface of a body. The head and each of the arms cover 9 percent of the body surface; the front of the body, the back, and each leg cover 18 percent; and the crotch accounts for the remaining 1 percent. The greater the extent of a burn, the more seriously ill the victim will become from loss of fluid. The depth of the burn (unless it is very great) is mainly of importance when the question arises as to how much surgical treatment, including skin grafting, will be required. An improvement over the rule of nines in the evaluation of the seriousness of burns is the Berkow formula, which takes into account the age of the patient.
A burn caused by chemicals differs from a burn caused by fire only in that the outcome of the chemical burn is usually more favorable, since the chemical destroys the bacteria on the affected part and reduces the chance of infection. Severe burns can also be caused by contact with electric wires. As current meets the resistance in the skin, high temperatures are reached and burning of the victim takes place. Exposure to 220 volts burns only the skin, but higher voltage can cause severe underlying damage to any tissue in its path. Electrical burns normally cause minimal external skin damage, but they can cause serious heart damage and require evaluation by a physician. Explosions and the action of acids and other chemicals also cause burns. Severe and extensive fire burns are most frequently produced by the clothes catching fire.
Treatment and Therapy General treatment of a burn injury includes pain relief, the control of infection, the maintenance of the balance of fluids and electrolytes in the system, and a good diet. A high-protein diet with supplemental vitamins is prescribed to aid in the repair of damaged tissue. The specific treatment depends on the severity of the burn. Major burns should be treated in a specialized treatment facility, while minor burns can be treated without hospitalization. A moderate burn normally requires hospitalization but not specialized care.
In the case of minor burns or scalds, all that may be necessary is to hold the body part in cool water until the pain is relieved, as cooling is one of the most effective ways of relieving the pain of a burn. However, the application of ice to a burn may cause more harm to the skin, as ice will restrict blood flow to the affected area and slow the healing process. If the burn involves the distal part of a limb—for example, the hand and forearm—one of the most effective ways of relieving the pain is to immerse the burned part in lukewarm water and add cold water until the pain disappears. If the pain does not return when the water warms up, the burn can be dressed in the usual way (a piece of sterile gauze covered by cotton with a bandage on top). The part should be kept at rest and the dressing dry and clean until healing takes place. Blisters can be pierced with a sterile needle, but the skin should not be cut away. No ointment or oil should be applied, and an antiseptic is not always necessary. Even minor burns can be serious if it covers as much as two-thirds of the body area. On a child, such burns are dangerous on an even smaller area of the skin, and special attention should be given to the patient.
In the case of moderate burns or scalds, it is advisable to use antiseptics (such as chlorhexidine, bacitracin, and neomycin), and the patient should be taken to a doctor. Treatment may consist of applying a dressing with a suitable antibiotic or an antiseptic or pain-relieving cream and covering the burn with a dressing sealed at the end. This dressing is left on for four to five days and removed if there is evidence of infection or if pain occurs.
For severe burns and scalds, the patient must go to the hospital. Unless there is a need for resuscitation, or attention to other injuries, nothing should be done on the spot except to make sure that the patient is comfortable and to cover the burn with a sterile cloth. Clothing should be removed from the burned area only if this does not traumatize the skin further. Burned clothing should be sent to the burn center, as it may help determine the chemicals and other substances that either caused or entered the wound. Once the victim is in the hospital, the first thing to check is the extent of the burn and whether a transfusion is necessary. If the burn covers more than 9 percent of the body surface, a transfusion is required. It is essential to prevent infection or to bring it under control. A high-protein diet with ample fluids is needed to compensate for the protein that has been lost along with the fluid from the circulation. The process of healing is slow and tedious, including careful nursing, physiotherapy, and occupational therapy. The length of hospital stay can vary from a few days in some cases to many weeks in the case of severe and extensive burns.
In some cases, depending on the extent of the burn, it will be necessary to consider skin grafting, in which a graft of skin from one part of the body (or from another individual) is implanted over another part. Skin grafting is done soon after the initial injury. The donor skin is best taken from the patient, but when this is not possible, the skin of a matched donor can be used. Prior to grafting, or in some cases as a substitute for it, the burn may be covered with either cadaver or pig skin to keep it moist and free from exogenous bacterial infection. Artificial skin holds great promise for treating severe burns.
In the case of chemical burns, treatment can be specific and depends on the chemical causing the burn. For example, phenol or lysol can be washed off promptly, while acid or alkali burns should be neutralized by washing with sodium bicarbonate or acetic acid, respectively, or with a buffer solution for either one. In many cases, flushing with water to remove the chemical is the first method of action.
Victims who have inhaled smoke may develop swelling and inflammation of the lungs, and they may need special care for burns of the eyes. People who have suffered an electrical burn may suffer from shock and may require artificial respiration, which should begin as soon as contact with the current has been broken.
Perspective and Prospects Burns have been traditionally classified according to degree. The French surgeon Guillaume Dupuytren divided burns into six degrees, according to their depth. A first-degree burn is one in which there is simply redness; it may be painful for a day or two. This level of burn is normally seen in cases of extended exposure to sunlight or x-rays. A second-degree burn affects the first and second layers of skin. There is great redness, and the surface is raised up in blisters accompanied by much pain. Healing normally occurs without a scar. A third-degree burn affects all skin layers. The epidermis is entirely peeled off, and the true skin below is destroyed in part, so as to expose the endings of the sensory nerves. This is a very painful form of burn, and a scar follows on healing. With a fourth-degree burn, the entire skin of an area is destroyed with its nerves, so that there is less pain than with a third-degree burn. A scar forms and later contracts, and it may produce great deformity in the affected area. A fifth-degree burn will burn the muscles as well, and still greater deformity follows. In a sixth-degree burn, a whole limb is charred, and it separates as in gangrene.
In current practice, burns are referred to as superficial (or partial thickness), in which there is sufficient skin tissue left to ensure regrowth of skin over the burned site, and deep (or full thickness), in which the skin is totally destroyed and grafting will be necessary. It is difficult to determine the depth of a wound at first glance, but any burn involving more than 15 percent of the body surface is considered serious. As far as the ultimate outcome is concerned, the main factor is the extent of the burn—the greater the extent, the worse the outlook.
Unfortunately, burns are most common in children and older people, those for whom the outcome is usually the worst. Many burns are caused by accidents in the home, which are usually preventable. In fact, among the primary causes of deaths by burns, house fires account for the majority of the incidents. Safety measures in the home and on the job are extremely important in the prevention of burns. Severe and extensive burns most frequently occur when the clothes catch fire. This rule applies especially to cotton garments, which burn quickly. Particular care should always be exercised with electric fires and kettles or pots of boiling water in houses where small children or elderly people are present.
In the United States, most severely burned patients are given emergency care in a local hospital and are then transferred to a large burn center for intensive long-term care. The kind of environment provided in special burn units in large medical centers varies, but all have as their main objective avoiding contamination of the wound, as the major cause of death in burn victims is infection. Some special units use isolation techniques and elaborate laminar air-flow systems to maintain an environment that is as free of microorganisms as possible.
The patient who has suffered some disfigurement from burns will have additional emotional problems in adjusting to a new body image. Burn therapy can be long and tedious for the patient and for family members. They will need emotional and psychological support as they work their way through the many problems created by the physical and emotional trauma of a major wound.
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