Burn (injury)
Encyclopedia
A burn is a type of injury
to flesh
caused by heat
, electricity
, chemicals, light
, radiation
or friction
. Most burns affect only the skin (epidermal tissue and dermis
). Rarely, deeper tissues, such as muscle
, bone
, and blood vessel
s can also be injured. Burns may be treated with first aid
, in an out-of-hospital setting, or may require more specialised treatment
such as those available at specialised burn center
s.
Managing burn injuries properly is important because they are common, painful and can result in disfiguring and disabling scarring, amputation
of affected parts or death in severe cases. Complications such as shock, infection
, multiple organ dysfunction syndrome
, electrolyte imbalance and respiratory distress
may occur. The treatment of burns may include the removal of dead tissue (debridement
), applying dressings to the wound, fluid resuscitation, administering antibiotic
s and skin grafting
.
While large burns can be fatal, modern treatments developed in the last 60 years have significantly improved the prognosis
of such burns, especially in children and young adults. In the United States, approximately 4 out of every 100 people with injuries from burns will succumb to their injuries. The majority of these fatalities occur either at the scene or enroute to hospital.
and remains in use today.
It is often difficult to accurately determine the depth of a burn. This is especially so in the case of second degree burns, which can continue to evolve over time. As such, a second-degree partial-thickness burn can progress to a third-degree burn over time even after initial treatment. Distinguishing between the superficial-thickness burn and the partial-thickness burn is important, as the former may heal spontaneously, whereas the latter often requires surgical excision and skin grafting
.
The following tables describe degrees of burn injury under this system as well as provide pictorial examples.
These burns typically require referral to a specialised burn treatment center.
Persons suffering these burns often need to be hospitalised for burn care.
These burns usually do not require hospitalization.
The size of a person's hand print (palm and fingers) is approximately 1% of their TBSA. The actual mean surface area is 0.8% so using 1% will slightly overestimate the size.
Burns of 10% in children or 15% in adults (or greater) are potentially life threatening injuries (because of the risk of hypovolaemic shock) and should have formal fluid resuscitation and monitoring in a burns unit. Burns units will use surface area to predict severity and mortality, using a methodology such as the Baux score
.
s are strong acid
s or bases
. Chemical burns can be caused by caustic
chemical compounds such as sodium hydroxide or silver nitrate
, and acids such as sulfuric acid
. Hydrofluoric acid
can cause damage down to the bone and its burns are sometimes not immediately evident.
or an uncontrolled short circuit
(A burn from a hot, electrified heating element
is not considered an electrical burn). Common occurrences of electrical burns include workplace injuries
, or being defibrillated or cardioverted
without a conductive gel. Lightning
is also a rare cause of electrical burns.
Since normal physiology
involves a vast number of applications of electrical forces, ranging from neuromuscular signaling to coordination of wound healing, biological systems are very vulnerable to application of supraphysiologic electric fields. Some electrocution
s produce no external burns at all, as very little current
is required to cause fibrillation
of the heart
muscle
. Therefore, even when the injury does not involve any visible tissue damage, electrical shock survivors may experience significant internal injury. The internal injuries sustained may be disproportionate to the size of the burns seen (if any), and the extent of the damage is not always obvious. Such injuries may lead to cardiac arrhythmias, cardiac arrest
, and unexpected falls with resultant fractures or dislocations.
The true incidence of electrical burn injury is unknown. In one study of 220 deaths due to electrical injury, 40% of those associated with low-voltage (<500 AC volts) injury demonstrated no skin burns or marks whatsoever. Most household electrical burns occur at 110 AC volts. This is sufficient to cause cardiac arrest
and ventricular fibrillation
but generates relatively low heat energy deposit into skin, thus producing few or no burn marks at all.
(in people undergoing cancer
therapy), sunlamps, radioactive fallout, and X-rays. By far the most common burn associated with radiation is sun exposure, specifically two wavelengths of light UVA
, and UVB, the latter being more dangerous. Tanning booths also emit these wavelengths and may cause similar damage to the skin such as irritation, redness, swelling, and inflammation
. More severe cases of sun burn result in what is known as sun poisoning or "heatstroke". Microwave burn
s are caused by the thermal effects of microwave
radiation
.
in baths or showers or spilled hot drinks. A so called immersion scald is created when an extremity is held under the surface of hot water, and is a common form of burn seen in child abuse
. A blister is a "bubble" in the skin filled with serous fluid
as part of the body's reaction to the heat and the subsequent inflammatory reaction. The blister "roof" is dead and the blister fluid contains toxic inflammatory mediators. Scald burns are more common in children, especially "spill scalds" from hot drinks and bath water scalds.
that occurs from fluid volume shifts. Initially cardiac output
decreases. At approximately 24 hours after burn injuries, cardiac output
returns to normal if adequate fluid resuscitation has been given. Following this, cardiac output increases to meet the hypermetabolic needs of the body.
The effects of high temperature on tissue include speeding chemical reactions and unfolding (denaturing) proteins.
Early cooling reduces burn depth and pain, but care must be taken as uncontrolled cooling can result in hypothermia.
formula. This formula calculates the amount of Ringer's lactate required to be administered over the first 24 hours post-burn.
Parkland formula: 4mL x (percentage of total body-surface-area sustaining non-superficial burns) x (person's weight in kgs).
Half of this total volume should be administered over the first eight hours, with the remainder given over the following 16 hours. It is important to note that this time frame is calculated from the time at which the burn is sustained, and not the time at which fluid resuscitation is begun. Children also require the addition of maintenance fluid volume. Such injuries can disturb a person's osmotic balance. Inhalation injuries in conjunction with thermal burns initially require up to 40–50% more fluid.
The formula is a guide only and infusions must be tailored to the urine
output and central venous pressure
. Inadequate fluid resuscitation may cause renal failure
and death
, but over-resuscitation also causes morbidity.
cleaning and then dressings are important aspects of wound care. The wound should then be regularly re-evaluated until it is healed. In the management of first and second degree burns little quality evidence exists to determine which type of dressing should be used. Silver sulfadiazine (Flamazine) is not recommended as it potentially prolongs healing time while biosynthetic dressings may speed healing.
may help in managing pain of minor first-degree and second-degree burns.
) to prevent problems with distal circulation or ventilation.
is a major complication of burns. Infection is linked to impaired resistance from disruption of the skin's mechanical integrity and generalized immune suppression. The skin barrier is replaced by eschar
. This moist, protein rich avascular environment encourages microbial growth. Migration of immune cells is hampered, and there is a release of intermediaries that impede the immune response. Eschar
also restricts distribution of systemically administered antibiotics because of its avascularity.
Risk factors of burn wound infection include:
Burn wounds are prone to tetanus
. A tetanus booster shot is required if individual has not been immunized within the last 5 years.
Circumferential burns of extremities may compromise circulation. Elevation of limb may help to prevent dependent edema. An Escharotomy
may be required.
Acute Tubular Necrosis of the kidneys can be caused by myoglobin
and hemoglobin
released from damaged muscles and red blood cells. This is common in electrical burns or crush injuries where adequate fluid resuscitation has not been achieved.
is determined by adding the size of the burn (% TBSA) to the age of the patient. In most burn units a score of 140 or greater is a non-survivable injury, and comfort care should be offered. In children all burn injuries less than 100% TBSA should be considered a survivable injury.
The 2009 National Burn Repository reports the most common cause of burns as direct fire/flame (43%) followed by scalds (30%). Scald injuries were the predominant cause in children under the age of 5. Burns sustained at home accounted for 65.5% of all burn injuries in the United States that year, and had a mortality rate of 4% overall. This mortality rate was directly associated with advancing age, burn size, the presence of inhalational injury and the female sex. It is estimated that approximately 75% of deaths from burns and fires in the United States occur either at the scene of the incident or enroute to medical facilities.
Demographically, people sustaining burns in the United States tended to be male (70%) and to have suffered their injuries in a residential setting (43%). The highest incidence of burns occurs in the 18-35yr old age group, while the highest incidence of scalds occurs in children 1-5yrs old and adults over 65.
In India about 700,000 people a year are admitted to hospital, though very few are looked after in specialist burn units.
About 90% of burns occur in the developing world and 70% of these are in children. Survival of injuries greater than 40% total body surface area is rare in the developing world.
Injury
-By cause:*Traumatic injury, a body wound or shock produced by sudden physical injury, as from violence or accident*Other injuries from external physical causes, such as radiation injury, burn injury or frostbite*Injury from infection...
to flesh
Flesh
In vertebrate animals, flesh is the colloquial for biological tissue which consists of skeletal muscles and fat as opposed to bones, viscera and integuments. Flesh may be used as food, in which case it is called meat....
caused by heat
Heat
In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
, electricity
Electricity
Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...
, chemicals, light
Light
Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...
, radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...
or friction
Friction
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and/or material elements sliding against each other. There are several types of friction:...
. Most burns affect only the skin (epidermal tissue and dermis
Dermis
The dermis is a layer of skin between the epidermis and subcutaneous tissues, and is composed of two layers, the papillary and reticular dermis...
). Rarely, deeper tissues, such as muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
, bone
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
, and blood vessel
Blood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...
s can also be injured. Burns may be treated with first aid
First aid
First aid is the provision of initial care for an illness or injury. It is usually performed by non-expert, but trained personnel to a sick or injured person until definitive medical treatment can be accessed. Certain self-limiting illnesses or minor injuries may not require further medical care...
, in an out-of-hospital setting, or may require more specialised treatment
Treatment
Treatment may refer to:* Treatment, therapy used to remedy a health problem* Treatment, a process or intervention in the design of experiments* Treatment group, a collection of items or individuals given the same treatment in an experiment* Water treatment...
such as those available at specialised burn center
Burn center
A Burn center or Burns unit is a hospital specializing in the treatment of burns. Burn centers are often used for the treatment and recovery of patients with more severe burns....
s.
Managing burn injuries properly is important because they are common, painful and can result in disfiguring and disabling scarring, amputation
Amputation
Amputation is the removal of a body extremity by trauma, prolonged constriction, or surgery. As a surgical measure, it is used to control pain or a disease process in the affected limb, such as malignancy or gangrene. In some cases, it is carried out on individuals as a preventative surgery for...
of affected parts or death in severe cases. Complications such as shock, infection
Infection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
, multiple organ dysfunction syndrome
Multiple organ dysfunction syndrome
Multiple organ dysfunction syndrome ', previously known as multiple organ failure or multisystem organ failure , is altered organ function in an acutely ill patient requiring medical intervention to achieve homeostasis...
, electrolyte imbalance and respiratory distress
Respiratory distress
Respiratory distress may refer to either/both:* Labored breathing, the physical presentation of respiratory distress*Shortness of breath or dyspnea - a sensation of respiratory distress-See also:*List of terms of lung size and activity...
may occur. The treatment of burns may include the removal of dead tissue (debridement
Debridement
Debridement is the medical removal of a patient's dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue...
), applying dressings to the wound, fluid resuscitation, administering antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
s and skin grafting
Skin grafting
Skin grafting is a type of graft surgery involving the transplantation of skin. The transplanted tissue is called a skin graft.Skin grafting is often used to treat:*Extensive wounding or trauma*Burns...
.
While large burns can be fatal, modern treatments developed in the last 60 years have significantly improved the prognosis
Prognosis
Prognosis is a medical term to describe the likely outcome of an illness.When applied to large statistical populations, prognostic estimates can be very accurate: for example the statement "45% of patients with severe septic shock will die within 28 days" can be made with some confidence, because...
of such burns, especially in children and young adults. In the United States, approximately 4 out of every 100 people with injuries from burns will succumb to their injuries. The majority of these fatalities occur either at the scene or enroute to hospital.
Classification
Burns can be classified by mechanism of injury, depth, extent and associated injuries and comorbidities.By depth
Currently, burns are described according to the depth of injury to the dermis and are loosely classified into first, second, third and fourth degrees. This system was devised by the French barber-surgeon Ambroise PareAmbroise Paré
Ambroise Paré was a French surgeon. He was the great official royal surgeon for kings Henry II, Francis II, Charles IX and Henry III and is considered as one of the fathers of surgery and modern forensic pathology. He was a leader in surgical techniques and battlefield medicine, especially the...
and remains in use today.
It is often difficult to accurately determine the depth of a burn. This is especially so in the case of second degree burns, which can continue to evolve over time. As such, a second-degree partial-thickness burn can progress to a third-degree burn over time even after initial treatment. Distinguishing between the superficial-thickness burn and the partial-thickness burn is important, as the former may heal spontaneously, whereas the latter often requires surgical excision and skin grafting
Skin grafting
Skin grafting is a type of graft surgery involving the transplantation of skin. The transplanted tissue is called a skin graft.Skin grafting is often used to treat:*Extensive wounding or trauma*Burns...
.
The following tables describe degrees of burn injury under this system as well as provide pictorial examples.
| Nomenclature | Layer involved | Appearance | Texture | Sensation | Time to healing | Complications | Example |
|---|---|---|---|---|---|---|---|
| First degree | Epidermis | Redness (erythema Erythema Erythema is redness of the skin, caused by hyperemia of the capillaries in the lower layers of the skin. It occurs with any skin injury, infection, or inflammation... ) |
Dry | Pain Pain Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."... ful |
1wk or less | None |  |
| Second degree (superficial partial thickness) | Extends into superficial (papillary) dermis Dermis The dermis is a layer of skin between the epidermis and subcutaneous tissues, and is composed of two layers, the papillary and reticular dermis... |
Red with clear blister Blister A blister is a small pocket of fluid within the upper layers of the skin, typically caused by forceful rubbing , burning, freezing, chemical exposure or infection. Most blisters are filled with a clear fluid called serum or plasma... . Blanches with pressure |
Moist | Painful | 2-3wks | Local infection/cellulitis Cellulitis Cellulitis is a diffuse inflammation of connective tissue with severe inflammation of dermal and subcutaneous layers of the skin. Cellulitis can be caused by normal skin flora or by exogenous bacteria, and often occurs where the skin has previously been broken: cracks in the skin, cuts, blisters,... |
|
| Second degree (deep partial thickness) | Extends into deep (reticular) dermis | Red-and-white with bloody blisters. Less blanching. | Moist | Painful | Weeks - may progress to third degree | Scarring, contractures (may require excision and skin grafting Skin grafting Skin grafting is a type of graft surgery involving the transplantation of skin. The transplanted tissue is called a skin graft.Skin grafting is often used to treat:*Extensive wounding or trauma*Burns... ) |
|
| Third degree (full thickness) | Extends through entire dermis | Stiff and white/brown | Dry, leathery | Painless | Requires excision | Scarring, contractures, amputation | |
| Fourth degree | Extends through skin, subcutaneous tissue Subcutaneous tissue The hypodermis, also called the hypoderm, subcutaneous tissue, or superficial fascia is the lowermost layer of the integumentary system in vertebrates. Types of cells that are found in the hypodermis are fibroblasts, adipose cells, and macrophages... and into underlying muscle and bone |
Black; charred with eschar Eschar An eschar is a slough or piece of dead tissue that is cast off from the surface of the skin, particularly after a burn injury, but also seen in gangrene, ulcer, fungal infections, necrotizing spider bite wounds, and exposure to cutaneous anthrax.... |
Dry | Painless | Requires excision | Amputation, significant functional impairment |
By severity
In order to determine the need for referral to a specialised burn unit, the American Burn Association devised a classification system to aid in the decision-making process. 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 (TBSA) burnt, the involvement of specific anatomical zones, age of the person and associated injuries.Major
Major burns are defined as:- Age 10-50yrs: partial thickness burns >25% of total body surface area
- Age <10 or >50: partial thickness burns >20% of total body surface area
- Full thickness burns >10%
- Burns involving the hands, face, feet or perineum
- Burns that cross major joints
- Circumferential burns to any extremity
- Any burn associated with inhalational injury
- Electrical burns
- Burns associated with fractureFractureA fracture is the separation of an object or material into two, or more, pieces under the action of stress.The word fracture is often applied to bones of living creatures , or to crystals or crystalline materials, such as gemstones or metal...
s or other trauma - Burns in infants and the elderly
- Burns in persons at high-risk of developing complications
These burns typically require referral to a specialised burn treatment center.
Moderate
Moderate burns are defined as:- Age 10-50yrs: partial thickness burns involving 15-25% of total body surface area
- Age <10 or >50: partial thickness burns involving 10-20% of total body surface area
- Full thickness burns involving 2-10% of total body surface area
Persons suffering these burns often need to be hospitalised for burn care.
Minor
Minor burns are:- Age 10-50yrs: partial thickness burns <15% of total body surface area
- Age <10 or >50: partial thickness burns involving <10% of total body surface area
- Full thickness burns <2% of total body surface area, without associated injuries
These burns usually do not require hospitalization.
By surface area
Burns can also be assessed in terms of total body surface area (TBSA), which is the percentage affected by partial thickness or full thickness burns. First degree (erythema only, no blisters) burns are not included in this estimation. The rule of nines is used as a quick and useful way to estimate the affected TBSA. More accurate estimation can be made using Lund & Browder charts which take into account the different proportions of body parts in adults and children.The size of a person's hand print (palm and fingers) is approximately 1% of their TBSA. The actual mean surface area is 0.8% so using 1% will slightly overestimate the size.
Burns of 10% in children or 15% in adults (or greater) are potentially life threatening injuries (because of the risk of hypovolaemic shock) and should have formal fluid resuscitation and monitoring in a burns unit. Burns units will use surface area to predict severity and mortality, using a methodology such as the Baux score
Baux score
The Baux score is a system used by medical professionals to predict the chance of mortality due to a patient suffering severe burns. The score is an index which takes in to account the correlative and causal relationship between mortality and factors including advancing age, burn size, the...
.
Cause
Burns are caused by a wide variety of substances and external sources such as exposure to chemicals, friction, electricity, radiation, and heat.Chemical
Most chemicals that cause chemical burnChemical burn
A chemical burn occurs when living tissue is exposed to a corrosive substance such as a strong acid or base. Chemical burns follow standard burn classification and may cause extensive tissue damage. The main types of irritant and/or corrosive products are: acids, bases, oxidizers, solvents,...
s are strong acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...
s or bases
Base (chemistry)
For the term in genetics, see base A base in chemistry is a substance that can accept hydrogen ions or more generally, donate electron pairs. A soluble base is referred to as an alkali if it contains and releases hydroxide ions quantitatively...
. Chemical burns can be caused by caustic
Corrosive
A corrosive substance is one that will destroy or irreversibly damage another surface or substance with which it comes into contact. The main hazards to people include damage to the eyes, the skin, and the tissue under the skin; inhalation or ingestion of a corrosive substance can damage the...
chemical compounds such as sodium hydroxide or silver nitrate
Silver nitrate
Silver nitrate is an inorganic compound with chemical formula . This compound is a versatile precursor to many other silver compounds, such as those used in photography. It is far less sensitive to light than the halides...
, and acids such as sulfuric acid
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...
. Hydrofluoric acid
Hydrofluoric acid
Hydrofluoric acid is a solution of hydrogen fluoride in water. It is a valued source of fluorine and is the precursor to numerous pharmaceuticals such as fluoxetine and diverse materials such as PTFE ....
can cause damage down to the bone and its burns are sometimes not immediately evident.
Electrical
Electrical burns are caused by either an electric shockElectric shock
Electric Shock of a body with any source of electricity that causes a sufficient current through the skin, muscles or hair. Typically, the expression is used to denote an unwanted exposure to electricity, hence the effects are considered undesirable....
or an uncontrolled short circuit
Short circuit
A short circuit in an electrical circuit that allows a current to travel along an unintended path, often where essentially no electrical impedance is encountered....
(A burn from a hot, electrified heating element
Heating element
A heating element converts electricity into heat through the process of Joule heating. Electric current through the element encounters resistance, resulting in heating of the element....
is not considered an electrical burn). Common occurrences of electrical burns include workplace injuries
Occupational safety and health
Occupational safety and health is a cross-disciplinary area concerned with protecting the safety, health and welfare of people engaged in work or employment. The goal of all occupational safety and health programs is to foster a safe work environment...
, or being defibrillated or cardioverted
Defibrillation
Defibrillation is a common treatment for life-threatening cardiac arrhythmias, ventricular fibrillation and pulseless ventricular tachycardia. Defibrillation consists of delivering a therapeutic dose of electrical energy to the affected heart with a device called a defibrillator...
without a conductive gel. Lightning
Lightning
Lightning is an atmospheric electrostatic discharge accompanied by thunder, which typically occurs during thunderstorms, and sometimes during volcanic eruptions or dust storms...
is also a rare cause of electrical burns.
Since normal physiology
Physiology
Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...
involves a vast number of applications of electrical forces, ranging from neuromuscular signaling to coordination of wound healing, biological systems are very vulnerable to application of supraphysiologic electric fields. Some electrocution
Electrocution
Electrocution is a type of electric shock that, as determined by a stopped heart, can end life. Electrocution is frequently used to refer to any electric shock received but is technically incorrect; the choice of definition varies from dictionary to dictionary...
s produce no external burns at all, as very little current
Electric current
Electric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
is required to cause fibrillation
Fibrillation
Fibrillation is the rapid, irregular, and unsynchronized contraction of muscle fibers. An important occurrence is with regards to the heart.-Cardiology:There are two major classes of cardiac fibrillation: atrial fibrillation and ventricular fibrillation....
of the heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
. Therefore, even when the injury does not involve any visible tissue damage, electrical shock survivors may experience significant internal injury. The internal injuries sustained may be disproportionate to the size of the burns seen (if any), and the extent of the damage is not always obvious. Such injuries may lead to cardiac arrhythmias, cardiac arrest
Cardiac arrest
Cardiac arrest, is the cessation of normal circulation of the blood due to failure of the heart to contract effectively...
, and unexpected falls with resultant fractures or dislocations.
The true incidence of electrical burn injury is unknown. In one study of 220 deaths due to electrical injury, 40% of those associated with low-voltage (<500 AC volts) injury demonstrated no skin burns or marks whatsoever. Most household electrical burns occur at 110 AC volts. This is sufficient to cause cardiac arrest
Cardiac arrest
Cardiac arrest, is the cessation of normal circulation of the blood due to failure of the heart to contract effectively...
and ventricular fibrillation
Ventricular fibrillation
Ventricular fibrillation is a condition in which there is uncoordinated contraction of the cardiac muscle of the ventricles in the heart, making them quiver rather than contract properly. Ventricular fibrillation is a medical emergency and most commonly identified arrythmia in cardiac arrest...
but generates relatively low heat energy deposit into skin, thus producing few or no burn marks at all.
Radiation
Radiation burns are caused by protracted exposure to UV light (as from the sun), tanning booths, radiation therapyRadiation therapy
Radiation therapy , radiation oncology, or radiotherapy , sometimes abbreviated to XRT or DXT, is the medical use of ionizing radiation, generally as part of cancer treatment to control malignant cells.Radiation therapy is commonly applied to the cancerous tumor because of its ability to control...
(in people undergoing cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
therapy), sunlamps, radioactive fallout, and X-rays. By far the most common burn associated with radiation is sun exposure, specifically two wavelengths of light UVA
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
, and UVB, the latter being more dangerous. Tanning booths also emit these wavelengths and may cause similar damage to the skin such as irritation, redness, swelling, and inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
. More severe cases of sun burn result in what is known as sun poisoning or "heatstroke". Microwave burn
Microwave burn
Microwave burns are burn injuries caused by thermal effects of microwave radiation absorbed in a living organism.In comparison with radiation burns caused by ionizing radiation, where the dominant mechanism of tissue damage is internal cell damage caused by free radicals, the primary damage...
s are caused by the thermal effects of microwave
Microwave
Microwaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...
radiation
Electromagnetic radiation
Electromagnetic radiation is a form of energy that exhibits wave-like behavior as it travels through space...
.
Scalding
Scalding (from the Latin word calidus, meaning hot) is caused by hot liquids (water or oil) or gases (steam), most commonly occurring from exposure to high temperature tap waterTap water
Tap water is a principal component of "indoor plumbing", which became available in urban areas of the developed world during the last quarter of the 19th century, and common during the mid-20th century...
in baths or showers or spilled hot drinks. A so called immersion scald is created when an extremity is held under the surface of hot water, and is a common form of burn seen in child abuse
Child abuse
Child abuse is the physical, sexual, emotional mistreatment, or neglect of a child. In the United States, the Centers for Disease Control and Prevention and the Department of Children And Families define child maltreatment as any act or series of acts of commission or omission by a parent or...
. A blister is a "bubble" in the skin filled with serous fluid
Serous fluid
In physiology, the term serous fluid is used for various bodily fluids that are typically pale yellow and transparent, and of a benign nature, that fill the inside of body cavities. Serous fluid originates from serous glands, with secretions enriched with proteins and water. Serous fluid may also...
as part of the body's reaction to the heat and the subsequent inflammatory reaction. The blister "roof" is dead and the blister fluid contains toxic inflammatory mediators. Scald burns are more common in children, especially "spill scalds" from hot drinks and bath water scalds.
Pathophysiology
Following a major burn injury, heart rate and peripheral vascular resistance increase. This is due to the release of catecholamines from injured tissues, and the relative hypovolemiaHypovolemia
In physiology and medicine, hypovolemia is a state of decreased blood volume; more specifically, decrease in volume of blood plasma...
that occurs from fluid volume shifts. Initially cardiac output
Cardiac output
Cardiac output is the volume of blood being pumped by the heart, in particular by a left or right ventricle in the time interval of one minute. CO may be measured in many ways, for example dm3/min...
decreases. At approximately 24 hours after burn injuries, cardiac output
Cardiac output
Cardiac output is the volume of blood being pumped by the heart, in particular by a left or right ventricle in the time interval of one minute. CO may be measured in many ways, for example dm3/min...
returns to normal if adequate fluid resuscitation has been given. Following this, cardiac output increases to meet the hypermetabolic needs of the body.
The effects of high temperature on tissue include speeding chemical reactions and unfolding (denaturing) proteins.
Management
The resuscitation and stabilization phase begins with the reassessment of the injured person's airway, breathing and circulatory state. Appropriate interventions should be initiated to stabilize these. This may involve aggressive fluid resuscitation and, if inhalation injury is suspected, intubation. Once the injured person is stabilized, attention is turned to the care of the burn wound itself. Until then, it is advisable to cover the burn wound with a clean and dry sheet or dressing.Early cooling reduces burn depth and pain, but care must be taken as uncontrolled cooling can result in hypothermia.
Intravenous fluids
Children with >10% total body surface area burns, and adults with >15% total body surface area burns need formal fluid resuscitation and monitoring (blood pressure, pulse rate, temperature and urine output). Once the burning process has been stopped, the injured person should be volume resuscitated according to the ParklandParkland Memorial Hospital
Parkland Memorial Hospital is a hospital located at 5201 Harry Hines Boulevard, just west of Oak Lawn in Dallas, Texas . It is the main hospital of the Dallas County Hospital District and serves as Dallas County's public hospital.- History :The original hospital opened in 1894 in a wooden...
formula. This formula calculates the amount of Ringer's lactate required to be administered over the first 24 hours post-burn.
Parkland formula: 4mL x (percentage of total body-surface-area sustaining non-superficial burns) x (person's weight in kgs).
Half of this total volume should be administered over the first eight hours, with the remainder given over the following 16 hours. It is important to note that this time frame is calculated from the time at which the burn is sustained, and not the time at which fluid resuscitation is begun. Children also require the addition of maintenance fluid volume. Such injuries can disturb a person's osmotic balance. Inhalation injuries in conjunction with thermal burns initially require up to 40–50% more fluid.
The formula is a guide only and infusions must be tailored to the urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...
output and central venous pressure
Central venous pressure
Central venous pressure describes the pressure of blood in the thoracic vena cava, near the right atrium of the heart...
. Inadequate fluid resuscitation may cause renal failure
Renal failure
Renal failure or kidney failure describes a medical condition in which the kidneys fail to adequately filter toxins and waste products from the blood...
and death
Death
Death is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....
, but over-resuscitation also causes morbidity.
Wound care
DebridementDebridement
Debridement is the medical removal of a patient's dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue...
cleaning and then dressings are important aspects of wound care. The wound should then be regularly re-evaluated until it is healed. In the management of first and second degree burns little quality evidence exists to determine which type of dressing should be used. Silver sulfadiazine (Flamazine) is not recommended as it potentially prolongs healing time while biosynthetic dressings may speed healing.
Antibiotics
Intravenous antibiotics may improve survival in those with large and severe burns. However due to the poor quality of the evidence, routine use is not currently recommended.Analgesics
A number of different options are used for pain management. These include simple analgesics (such as ibuprofen and acetaminophen) and narcotics. A local anestheticLocal anesthetic
A local anesthetic is a drug that causes reversible local anesthesia, generally for the aim of having local analgesic effect, that is, inducing absence of pain sensation, although other local senses are often affected as well...
may help in managing pain of minor first-degree and second-degree burns.
Surgery
Wounds requiring surgical closure with skin grafts or flaps should be dealt with as early as possible. Circumferential burns of digits, limbs or the chest may need urgent surgical release of the burnt skin (escharotomyEscharotomy
An escharotomy is a surgical procedure used to treat full thickness circumferential burns. Since full thickness burns are characterized by tough, leathery eschar, an escharotomy is used primarily to combat compartment syndrome...
) to prevent problems with distal circulation or ventilation.
Alternative treatments
Hyperbaric oxygenation has not been shown to be a useful adjunct to traditional treatments. Honey has been used since ancient times to aid wound healing and may be beneficial in first and second degree burns, but may cause infection.Complications
InfectionInfection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
is a major complication of burns. Infection is linked to impaired resistance from disruption of the skin's mechanical integrity and generalized immune suppression. The skin barrier is replaced by eschar
Eschar
An eschar is a slough or piece of dead tissue that is cast off from the surface of the skin, particularly after a burn injury, but also seen in gangrene, ulcer, fungal infections, necrotizing spider bite wounds, and exposure to cutaneous anthrax....
. This moist, protein rich avascular environment encourages microbial growth. Migration of immune cells is hampered, and there is a release of intermediaries that impede the immune response. Eschar
Eschar
An eschar is a slough or piece of dead tissue that is cast off from the surface of the skin, particularly after a burn injury, but also seen in gangrene, ulcer, fungal infections, necrotizing spider bite wounds, and exposure to cutaneous anthrax....
also restricts distribution of systemically administered antibiotics because of its avascularity.
Risk factors of burn wound infection include:
- Burn > 30% BSA
- Full-thickness burn
- Extremes in age (very young, very old)
- Preexisting disease e.g. diabetes
- Virulence and antibiotic resistance of colonizing organism
- Failed skin graft
- Improper initial burn wound care
- Prolonged open burn wound
Burn wounds are prone to tetanus
Tetanus
Tetanus is a medical condition characterized by a prolonged contraction of skeletal muscle fibers. The primary symptoms are caused by tetanospasmin, a neurotoxin produced by the Gram-positive, rod-shaped, obligate anaerobic bacterium Clostridium tetani...
. A tetanus booster shot is required if individual has not been immunized within the last 5 years.
Circumferential burns of extremities may compromise circulation. Elevation of limb may help to prevent dependent edema. An Escharotomy
Escharotomy
An escharotomy is a surgical procedure used to treat full thickness circumferential burns. Since full thickness burns are characterized by tough, leathery eschar, an escharotomy is used primarily to combat compartment syndrome...
may be required.
Acute Tubular Necrosis of the kidneys can be caused by myoglobin
Myoglobin
Myoglobin is an iron- and oxygen-binding protein found in the muscle tissue of vertebrates in general and in almost all mammals. It is related to hemoglobin, which is the iron- and oxygen-binding protein in blood, specifically in the red blood cells. The only time myoglobin is found in the...
and hemoglobin
Hemoglobin
Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates...
released from damaged muscles and red blood cells. This is common in electrical burns or crush injuries where adequate fluid resuscitation has not been achieved.
Prognosis
The outcome of any injury or disease depends on three things: the nature of the injury, the nature of the injured or ill person and the treatment available. In terms of injury factors in burns, the prognosis depends primarily on total body surface area percentage and the age of the person. The presence of smoke inhalation injury, other significant injuries such as long bone fractures and serious co-morbidities (heart disease, diabetes, psychiatric illness, suicidal intent etc.) will also adversely influence prognosis. Advances in resuscitation, surgical management, intensive care, control of infection, control of the hyper-metabolic response and rehabilitation have resulted in dramatic improvements in burn mortality and morbidity in the last 60 years. The modified Baux score determines the futility point for major burn injury. The Baux scoreBaux score
The Baux score is a system used by medical professionals to predict the chance of mortality due to a patient suffering severe burns. The score is an index which takes in to account the correlative and causal relationship between mortality and factors including advancing age, burn size, the...
is determined by adding the size of the burn (% TBSA) to the age of the patient. In most burn units a score of 140 or greater is a non-survivable injury, and comfort care should be offered. In children all burn injuries less than 100% TBSA should be considered a survivable injury.
Epidemiology
According to the American Burn Association, an estimated 500,000 burn injuries receive medical treatment yearly in the United States.The 2009 National Burn Repository reports the most common cause of burns as direct fire/flame (43%) followed by scalds (30%). Scald injuries were the predominant cause in children under the age of 5. Burns sustained at home accounted for 65.5% of all burn injuries in the United States that year, and had a mortality rate of 4% overall. This mortality rate was directly associated with advancing age, burn size, the presence of inhalational injury and the female sex. It is estimated that approximately 75% of deaths from burns and fires in the United States occur either at the scene of the incident or enroute to medical facilities.
Demographically, people sustaining burns in the United States tended to be male (70%) and to have suffered their injuries in a residential setting (43%). The highest incidence of burns occurs in the 18-35yr old age group, while the highest incidence of scalds occurs in children 1-5yrs old and adults over 65.
In India about 700,000 people a year are admitted to hospital, though very few are looked after in specialist burn units.
About 90% of burns occur in the developing world and 70% of these are in children. Survival of injuries greater than 40% total body surface area is rare in the developing world.
Further reading
External links
- NHS Choices - Burns and Scalds
- British Burn Association
- American Burn Association
- European Burn Association
- The UK National Burn Care Government Review
- Cochrane Injuries Group, systematic reviews on the prevention, treatment and rehabilitation of traumatic injury