Giới thiệu
Burns are injuries that result from exposure to the skin to heat sources, including flames, flash burns, hot objects, grease, and scalding liquids, as well as chemical agents and electrical currents.
Dịch tễ học
Burn injuries are commonly encountered in emergency departments around the world. According to the World Health Organization, approximately 11 million people sustain burn injuries each year and account for at least 265,000 deaths annually. The highest incidence of severe burn injuries occurs in Africa and Southeast Asia, with mortality rates disproportionately higher in developing countries. Adult men are at higher risk of occupational burns, while women are more commonly affected by domestic burns, particularly in the kitchen.
Sinh lý bệnh
Locally, burns involve three zones: Coagulation (irreversible tissue death), stasis (potentially salvageable tissue), and hyperemia (inflamed tissue). Without timely fluid resuscitation and wound care, injury may worsen due to ischemia and infection. Burns involving >25% TBSA can trigger a systemic inflammatory response, leading to burn shock followed by a prolonged hypermetabolic state.
Yếu tố nguy cơ
Risk factors for burn injuries include low socioeconomic status, overcrowded living conditions, unsafe cooking practices, poor health, and inadequate safety measures. Burn injuries are also more common among children, older adults, individuals with psychiatric disorders or substance use, and those living in disadvantaged environments.
Phân loại
Types of Burn Injury
Thermal Burns
Thermal burns are due to external heat sources that raise skin and tissue temperature, causing tissue cell death or charring. Flame is the most common type of burn. Inhalational injury is found in 30% of victims of major flame burns. In thermal burns, there is a history of flame burns or burns in an enclosed space; full-thickness or deep dermal burns to the face, neck, or upper torso; singed nasal hair; carbonaceous sputum or carbon particles in the oropharynx; charred lips or carbonaceous secretions; posterior pharyngeal edema; and hoarseness, cough, or wheezing. A scald or contact burn is usually found in the skin that comes in contact with hot objects.
Chemical Burns
Chemical burns are due to strong acids, alkalis, detergents, or solvents coming into contact with the skin. Tissues are damaged by protein coagulation or liquefaction rather than hyperthermic activity.
Electrical Burns
Electric burns are due to electrical current or lightning coming in contact with the body. The extent of injury correlates with the voltage of the electric shock, and although not initially apparent, it is often extensive, involving skeletal muscles and other tissues.
Radiation Burns
Radiation burns are skin or tissue injuries caused by ultraviolet exposure, radiation therapy, or more rarely, nuclear emissions, with their severity determined by the radiation type, energy, penetration and ionization capacity, total dose, fractionation, and overall exposure time. The resulting damage can range from erythema to dry or moist desquamation, necrosis, ulceration, and even death.
Depths of Burns
Burns - Initial Management_Disease BackgroundFirst-Degree Burns or Superficial Burns
The appearance of superficial burns is similar to sunburn, which is painful, dry, swollen, and erythematous without blisters. This involves only the epidermis. This is not included in estimates for fluid resuscitations and hospitalization is not required. Pain resolves in 48-72 hours and peels off without residual scarring in 2-5 days.
Second-Degree Burns or Partial-Thickness Burns
The appearance of partial-thickness burns are moist blebs, the formation of vesicles, and blisters. The underlying tissue is mottled pink and white with good capillary refill, which may bleed. This involves the entire epidermis and a variable portion of the dermis (papillary and reticular layer). These are considered significant burns and are counted in burn size estimates. Subclassification includes the following:
Superficial
Extreme pain is attributed to a large number of remaining viable nerve endings exposed. This re-epithelializes 7-21 days in the absence of infection.
Deep
There are damaged hair follicles and glandular tissue. Pain is less because fewer nerve endings remain viable; fluid losses and metabolic effects are similar to those of third-degree burn. This heals in 21-35 days if without infection, which may convert to full-thickness burns if there is a wound infection and may require grafting.
Third-Degree Burns or Full-Thickness Burns
The appearance of a full-thickness burn is dry, leathery eschar mixed with white waxy, khaki, mahogany, and soot-stained without blanching or bleeding. This involves the entire epidermis and dermis, leaving no residual epidermis cells; it may include fat, subcutaneous tissue, fascia, muscle, and bone. There are no pain sensation and capillary filling due to loss of nerves and capillary elements. The wound cannot epithelialize and heals only by wound contracture or skin grafting.
The difference in the growth rate of the head and extremities throughout childhood makes it necessary to use surface area charts. The “rule of nines” used in adults is applicable only to children >14 years old or as a rough estimate to initiate therapy before transfer to a burn unit. In small burns (<10% of body surface area [BSA]), the “rule of palm” (area from the wrist crease to finger crease in the child) may be used. This equals 1% of the child’s BSA. Calculation of the fluid for resuscitation depends on the total BSA involved in the burn injury.