Burn

In the United States, fire and hot liquids are the most common causes of burns.[4] Of house fires that result in death, smoking causes 25% and heating devices cause 22%.[5] Almost half of injuries are due to efforts to fight a fire.[5] Scalding is caused by hot liquids or gases and most commonly occurs from exposure to hot drinks, high temperature tap water in baths or showers, hot cooking oil, or steam.[26] Scald injuries are most common in children under the age of five[2] and, in the United States and Australia, this population makes up about two-thirds of all burns.[4] Contact with hot objects is the cause of about 20–30% of burns in children.[4] Generally, scalds are first- or second-degree burns, but third-degree burns may also result, especially with prolonged contact.[27] Fireworks are a common cause of burns during holiday seasons in many countries.[28] This is a particular risk for adolescent males.[29] In the United States, for non-fatal burn injuries, white males, aged <6 comprise most cases.[30]  Thermal burns from grabbing/touching and spilling/splashing were the most common type of burn and mechanism, while the bodily areas most impacted were hands and fingers followed by head/neck.[30]

Chemical burns can be caused by over 25,000 substances,[2] most of which are either a strong base (55%) or a strong acid (26%).[31] Most chemical burn deaths are secondary to ingestion.[2] Common agents include: sulfuric acid as found in toilet cleaners, sodium hypochlorite as found in bleach, and halogenated hydrocarbons as found in paint remover, among others.[2] Hydrofluoric acid can cause particularly deep burns that may not become symptomatic until some time after exposure.[32] Formic acid may cause the breakdown of significant numbers of red blood cells.[16]

Electrical burns or injuries are classified as high voltage (greater than or equal to 1000 volts), low voltage (less than 1000 volts), or as flash burns secondary to an electric arc.[2] The most common causes of electrical burns in children are electrical cords (60%) followed by electrical outlets (14%).[4][33] Lightning may also result in electrical burns.[34] Risk factors for being struck include involvement in outdoor activities such as mountain climbing, golf and field sports, and working outside.[18] Mortality from a lightning strike is about 10%.[18]

While electrical injuries primarily result in burns, they may also cause fractures or dislocations secondary to blunt force trauma or muscle contractions.[18] In high voltage injuries, most damage may occur internally and thus the extent of the injury cannot be judged by examination of the skin alone.[18] Contact with either low voltage or high voltage may produce cardiac arrhythmias or cardiac arrest.[18]

Radiation burns may be caused by protracted exposure to ultraviolet light (such as from the sun, tanning booths or arc welding) or from ionizing radiation (such as from radiation therapy, X-rays or radioactive fallout).[35] Sun exposure is the most common cause of radiation burns and the most common cause of superficial burns overall.[36] There is significant variation in how easily people sunburn based on their skin type.[37] Skin effects from ionizing radiation depend on the amount of exposure to the area, with hair loss seen after 3 Gy, redness seen after 10 Gy, wet skin peeling after 20 Gy, and necrosis after 30 Gy.[38] Redness, if it occurs, may not appear until some time after exposure.[38] Radiation burns are treated the same as other burns.[38] Microwave burns occur via thermal heating caused by the microwaves.[39] While exposures as short as two seconds may cause injury, overall this is an uncommon occurrence.[39]

In those hospitalized from scalds or fire burns, 3–10% are from assault.[40] Reasons include: child abuse, personal disputes, spousal abuse, elder abuse, and business disputes.[40] An immersion injury or immersion scald may indicate child abuse.[27] It is created when an extremity, or sometimes the buttocks are held under the surface of hot water.[27] It typically produces a sharp upper border and is often symmetrical,[27] known as "sock burns", "glove burns", or "zebra stripes" - where folds have prevented certain areas from burning.[41] Deliberate cigarette burns most often found on the face, or the back of the hands and feet.[41] Other high-risk signs of potential abuse include: circumferential burns, the absence of splash marks, a burn of uniform depth, and association with other signs of neglect or abuse.[42]

Bride burning, a form of domestic violence, occurs in some cultures, such as India where women have been burned in revenge for what the husband or his family consider an inadequate dowry.[43][44] In Pakistan, acid burns represent 13% of intentional burns, and are frequently related to domestic violence.[42] Self-immolation (setting oneself on fire) is also used as a form of protest in various parts of the world.[19]

Burn severity is determined through, among other things, the size of the skin affected. The image shows the makeup of different body parts, to help assess burn size.

The size of a burn is measured as a percentage of total body surface area (TBSA) affected by partial thickness or full thickness burns.[2] First-degree burns that are only red in color and are not blistering are not included in this estimation.[2] Most burns (70%) involve less than 10% of the TBSA.[4]

There are a number of methods to determine the TBSA, including the Wallace rule of nines, Lund and Browder chart, and estimations based on a person's palm size.[10] The rule of nines is easy to remember but only accurate in people over 16 years of age.[10] More accurate estimates can be made using Lund and Browder charts, which take into account the different proportions of body parts in adults and children.[10] The size of a person's handprint (including the palm and fingers) is approximately 1% of their TBSA.[10]

To determine the need for referral to a specialized burn unit, the American Burn Association devised a classification system. Under this system, burns can be classified as major, moderate, and minor. This is assessed based on a number of factors, including total body surface area affected, the involvement of specific anatomical zones, the age of the person, and associated injuries.[48] Minor burns can typically be managed at home, moderate burns are often managed in a hospital, and major burns are managed by a burn center.[48] Severe burn injury represents one of the most devastating forms of trauma.[49] Despite improvements in burn care, patients can be left to suffer for as many as three years post-injury.[50]

In those with poor tissue perfusion, boluses of isotonic crystalloid solution should be given.[10] In children with more than 10–20% TBSA (Total Body Surface Area) burns, and adults with more than 15% TBSA burns, formal fluid resuscitation and monitoring should follow.[10][56][57] This should be begun pre-hospital if possible in those with burns greater than 25% TBSA.[56] The Parkland formula can help determine the volume of intravenous fluids required over the first 24 hours. The formula is based on the affected individual's TBSA and weight. Half of the fluid is administered over the first 8 hours, and the remainder over the following 16 hours. The time is calculated from when the burn occurred, and not from the time that fluid resuscitation began. Children require additional maintenance fluid that includes glucose.[16] Additionally, those with inhalation injuries require more fluid.[58] While inadequate fluid resuscitation may cause problems, over-resuscitation can also be detrimental.[59] The formulas are only a guide, with infusions ideally tailored to a urinary output of >30 mL/h in adults or >1mL/kg in children and mean arterial pressure greater than 60 mmHg.[16]

While lactated Ringer's solution is often used, there is no evidence that it is superior to normal saline.[10] Crystalloid fluids appear just as good as colloid fluids, and as colloids are more expensive they are not recommended.[60][61] Blood transfusions are rarely required.[2] They are typically only recommended when the hemoglobin level falls below 60-80 g/L (6-8 g/dL)[62] due to the associated risk of complications.[16] Intravenous catheters may be placed through burned skin if needed or intraosseous infusions may be used.[16]

Early cooling (within 30 minutes of the burn) reduces burn depth and pain, but care must be taken as over-cooling can result in hypothermia.[2][10] It should be performed with cool water 10–25 °C (50.0–77.0 °F) and not ice water as the latter can cause further injury.[10][45] Chemical burns may require extensive irrigation.[2] Cleaning with soap and water, removal of dead tissue, and application of dressings are important aspects of wound care. If intact blisters are present, it is not clear what should be done with them. Some tentative evidence supports leaving them intact. Second-degree burns should be re-evaluated after two days.[45]

In the management of first and second-degree burns, little quality evidence exists to determine which dressing type to use.[63] It is reasonable to manage first-degree burns without dressings.[45] While topical antibiotics are often recommended, there is little evidence to support their use.[64][65] Silver sulfadiazine (a type of antibiotic) is not recommended as it potentially prolongs healing time.[63][66] There is insufficient evidence to support the use of dressings containing silver[67] or negative-pressure wound therapy.[68] Silver sulfadiazine does not appear to differ from silver containing foam dressings with respect to healing.[69]

Burns can be very painful and a number of different options may be used for pain management. These include simple analgesics (such as ibuprofen and acetaminophen) and opioids such as morphine. Benzodiazepines may be used in addition to analgesics to help with anxiety.[45] During the healing process, antihistamines, massage, or transcutaneous nerve stimulation may be used to aid with itching.[17] Antihistamines, however, are only effective for this purpose in 20% of people.[70] There is tentative evidence supporting the use of gabapentin[17] and its use may be reasonable in those who do not improve with antihistamines.[71] Intravenous lidocaine requires more study before it can be recommended for pain.[72]

Intravenous antibiotics are recommended before surgery for those with extensive burns (>60% TBSA).[73] As of 2008, guidelines do not recommend their general use due to concerns regarding antibiotic resistance[64] and the increased risk of fungal infections.[16] Tentative evidence, however, shows that they may improve survival rates in those with large and severe burns.[64] Erythropoietin has not been found effective to prevent or treat anemia in burn cases.[16] In burns caused by hydrofluoric acid, calcium gluconate is a specific antidote and may be used intravenously and/or topically.[32] Recombinant human growth hormone (rhGH) in those with burns that involve more than 40% of their body appears to speed healing without affecting the risk of death.[74] The use of steroids is of unclear evidence.[75]

Wounds requiring surgical closure with skin grafts or flaps (typically anything more than a small full thickness burn) should be dealt with as early as possible.[76] Circumferential burns of the limbs or chest may need urgent surgical release of the skin, known as an escharotomy.[77] This is done to treat or prevent problems with distal circulation, or ventilation.[77] It is uncertain if it is useful for neck or digit burns.[77] Fasciotomies may be required for electrical burns.[77]

Skin grafts can involve temporary skin substitutes, derived from animal (human donor or pig) skin or synthesized. They are used to cover the wound as a dressing, preventing infection and fluid loss, but will eventually need to be removed. Alternatively, human skin can be treated to be left on permanently without rejection.[78]

There is no evidence that the use of copper sulphate to visualise phosphorus particles for removal can help with wound healing due to phosphorus burns. Meanwhile, absorption of copper sulphate into the blood circulation can be harmful.[79]

Honey has been used since ancient times to aid wound healing and may be beneficial in first- and second-degree burns.[80] There is moderate evidence that honey helps heal partial thickness burns.[81][82] The evidence for aloe vera is of poor quality.[83] While it might be beneficial in reducing pain,[20] and a review from 2007 found tentative evidence of improved healing times,[84] a subsequent review from 2012 did not find improved healing over silver sulfadiazine.[83] There were only three randomized controlled trials for the use of plants for burns, two for aloe vera and one for oatmeal.[85]

There is little evidence that vitamin E helps with keloids or scarring.[86] Butter is not recommended.[87] In low income countries, burns are treated up to one-third of the time with traditional medicine, which may include applications of eggs, mud, leaves or cow dung.[24] Surgical management is limited in some cases due to insufficient financial resources and availability.[24] There are a number of other methods that may be used in addition to medications to reduce procedural pain and anxiety including: virtual reality therapy, hypnosis, and behavioral approaches such as distraction techniques.[71]

Burn patients require support and care – both physiological and psychological. Respiratory failure, sepsis, and multi-organ system failure are common in hospitalized burn patients. To prevent hypothermia and maintain normal body temperature, burn patients with over 20% of burn injuries should be kept in an environment with the temperature at or above 30 degree Celsius.[88]

Metabolism in burn patients proceeds at a higher than normal speed due to the whole-body process and rapid fatty acid substrate cycles, which can be countered with an adequate supply of energy, nutrients, and antioxidants. Enteral feeding a day after resuscitation is required to reduce risk of infection, recovery time, non-infectious complications, hospital stay, long-term damage, and mortality. Controlling blood glucose levels can have an impact on liver function and survival.

Risk of thromboembolism is high and acute respiratory distress syndrome (ARDS) that does not resolve with maximal ventilator use is also a common complication. Scars are long-term after-effects of a burn injury. Psychological support is required to cope with the aftermath of a fire accident, while to prevent scars and long-term damage to the skin and other body structures consulting with burn specialists, preventing infections, consuming nutritious foods, early and aggressive rehabilitation, and using compressive clothing are recommended.

A number of complications may occur, with infections being the most common.[4] In order of frequency, potential complications include: pneumonia, cellulitis, urinary tract infections and respiratory failure.[4] Risk factors for infection include: burns of more than 30% TBSA, full-thickness burns, extremes of age (young or old), or burns involving the legs or perineum.[90] Pneumonia occurs particularly commonly in those with inhalation injuries.[16]

Anemia secondary to full thickness burns of greater than 10% TBSA is common.[10] Electrical burns may lead to compartment syndrome or rhabdomyolysis due to muscle breakdown.[16] Blood clotting in the veins of the legs is estimated to occur in 6 to 25% of people.[16] The hypermetabolic state that may persist for years after a major burn can result in a decrease in bone density and a loss of muscle mass.[46] Keloids may form subsequent to a burn, particularly in those who are young and dark skinned.[86] Following a burn, children may have significant psychological trauma and experience post-traumatic stress disorder.[91] Scarring may also result in a disturbance in body image.[91] In the developing world, significant burns may result in social isolation, extreme poverty and child abandonment.[19]

An estimated 500,000 burn injuries receive medical treatment yearly in the United States.[45] They resulted in about 3,300 deaths in 2008.[5] Most burns (70%) and deaths from burns occur in males.[2][14] The highest incidence of fire burns occurs in those 18–35 years old, while the highest incidence of scalds occurs in children less than five years old and adults over 65.[2] Electrical burns result in about 1,000 deaths per year.[95] Lightning results in the death of about 60 people a year.[18] In Europe, intentional burns occur most commonly in middle aged men.[40]

In India, about 700,000 to 800,000 people per year sustain significant burns, though very few are looked after in specialist burn units.[96] The highest rates occur in women 16–35 years of age.[96] Part of this high rate is related to unsafe kitchens and loose-fitting clothing typical to India.[96] It is estimated that one-third of all burns in India are due to clothing catching fire from open flames.[97] Intentional burns are also a common cause and occur at high rates in young women, secondary to domestic violence and self-harm.[19][40]

• National Burn Repository (PDF). American Burn Association. 2012. Archived from the original (PDF) on 3 March 2016. Retrieved 20 April 2013.