Burns




Key Points



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  • Pursue early endotracheal intubation in patients with significant inhalation injuries.



  • Emergency escharotomy may be a life- or limb-saving procedure in patients with evidence of respiratory compromise or limb ischemia.



  • Consider concurrent carbon monoxide andcyanide poisoning in all fire victims.



  • Never overlook the possibility of concomitant multisystem trauma, and always consider the possibility of abuse or neglect in burned children or the elderly.





Introduction



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Burn injuries can occur from thermal, chemical, or electrical mechanisms. Of the 3, thermal burns are the most common and occur with either scalding or flame injuries. Chemical burns occur secondary to exposures to strong acids or alkali and account for 5–10% of all burn admissions. Electrical burns result from the flow of current through susceptible tissue and are frequently much more severe than initially visible.



The prevalence of burns is highest in patients between 18 and 35 years of age. Scald burns from hot liquids are most common in children under the age of 5 and the elderly, and approximately 20% of pediatric burns are attributable to either abuse or neglect. The American Burn Association estimates that burns account for more than 450,000 emergency department (ED) visits, 45,000 hospitalizations, and 3,500 deaths annually in the United States. There are currently 125 specialized burn centers in the United States that account for more than half of these admissions.



Burned skin classically undergoes a coagulative necrosis by which denatured skin proteins constrict to form a firm and potentially constricting eschar. A subsequent cascade of inflammatory reactions leads to the development of significant localized edema and the potential for further tissue loss. This inflammatory response becomes systemic when more than 30% of the patient’s total body surface area is involved, resulting in multisystem organ injury.



Burns can be clinically classified as first, second, or third degree. First-degree burns are limited to the superficial epidermis and heal within 7 days without any long-term sequelae (eg, sunburn). Second-degree burns are partial-thickness injuries that extend into the dermis. They are further subdivided into superficial and deep partial thickness injuries. Deep partial thickness burns result in destruction of the deeper dermal structures including the hair follicles and sweat and sebaceous glands, whereas these tissues are spared with superficial partial thickness injuries. Superficial partial thickness burns tend to heal within a period of 2–3 weeks with minimal long-term scarring, whereas their deep counterparts often necessitate skin grafting for definitive care. Third-degree burns extend deep into the subcutaneous tissues and represent full-thickness injuries of the skin. All dermal structures including the capillary networks and neuronal tissues are destroyed, leaving behind an avascular and insensate skin. Skin grafting is invariably required.



From a physiologic standpoint, the skin functions to reduce evaporative water loss, in addition to creating a barrier to infection and controlling body temperature. Hypovolemic shock is common with severe burns as a result of a combination of increased peripheral blood flow with evaporative fluid losses and excessive capillary leak with circulating volume third-spacing. The decreased cardiac output that frequently complicates the systemic reaction to significant burns further exacerbates the circulatory insufficiency.



Inhalational injuries are common in fire victims who are found in enclosed spaces. They can be divided anatomically into supraglottic and infraglottic injuries. Supraglottic burns represent direct thermal injury to the face and pharyngeal tissues. They develop very rapidly, within minutes of exposure, and often necessitate emergent endotracheal intubation. Infraglottic burns represent chemically mediated injury to the bronchioles and alveoli. They develop much more slowly over the course of several hours and clinically mimic acute respiratory distress syndrome (ARDS).




Clinical Presentation



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History



Details concerning the nature of the injury are extremely important. Identify the mechanism of injury, as this may provide a clue its severity. For example, scald injuries usually result in partial-thickness burns, whereas flash and flame exposures more commonly produce full-thickness injuries. Deeper injuries should be suspected in patients with electrical or chemical burns, especially those with high voltage or strong alkali exposures, respectively. Identify all victims of closed space fires, as they have an increased potential for inhalational injuries, carbon monoxide (CO) poisoning, and cyanide (CN) toxicity. Cyanide is formed by the combustion of nitrogen-containing compounds (eg, wool, silk, polyurethane, vinyl), and toxicity is not uncommon in victims of industrial fires. Obtain a very detailed history in all pediatric burn victims to uncover any possibility for abuse or neglect.

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Jan 3, 2019 | Posted by in EMERGENCY MEDICINE | Comments Off on Burns

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