Burn

This is about various forms of bodily injury; for other senses, see Burn (disambiguation).

In medicine, a burn may be an injury caused by heat, cold, electricity, chemicals, friction or radiation (e.g. a sunburn).

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Traditional Classification

• First-degree burns are usually limited to redness (erythema), a white plaque, and minor pain at the site of injury. These burns usually extend only into the epidermis.
• Second-degree burns additionally fill with clear fluid, have superficial blistering of the skin, and can involve more or less pain depending on the level of nerve involvement. Second-degree burns involve the superficial (papillary) dermis and may also involve the deep (reticular) dermis layer.
• Third-degree burns additionally have charring of the skin, and produce hard, leather-like eschars. An eschar is a scab that has separated from the unaffected part of the body. Frequently, there is also purple fluid^{[citation needed]}. These types of burns are often considered painless, because nerve endings have been destroyed in the burned areas. However, there is in reality a significant amount of pain involved in a third degree burn. Hair follicles and sweat glands may also be lost. Third degree burns result in scarring although surgery and elastic banding of the skin can smooth the scarred skin.Goodpaster (talk) 00:15, 4 January 2008 (UTC)
• Fourth-degree burns are burns in which much or all of the dermis is lost often exposing and burning the muscle and possibly bone underneath. These burns usually present irreversible damage to the skin and there is no sensation in the burn area as a result. These type of burns will definitely require hospitalization. While skin grafting is usually needed to close up the areas, amputation of the extremity may be required. Often, fourth degree burns can be fatal.
• Fifth-degree burns additionally have charring or burning away of the muscle. These types of burn may leave bone exposed, thoroughly roast surviving muscle tissue to the point of immobility, and burn the bone.
• Sixth-degree burns are burn types in which all muscle tissue in the area is burned away leaving nothing but charred bone. In some instances the bone tissue may be partially or completely burned away as well though this would require extreme conditions. Sixth degree burns are the highest burn category.

Current Classification

A newer classification of "Superficial Thickness", "Partial Thickness" (which is divided into superficial and deep categories) and "Full Thickness" relates more precisely to the epidermis, dermis and subcutaneous layers of skin and is used to guide treatment and predict outcome.

Table 1. A description of the traditional and current classifications of burns.

Serious burns, especially if they cover large areas of the body, can cause death; any hint of burn injury to the lungs (e.g. through smoke inhalation) is a medical emergency.

Chemical burns are usually caused by chemical compounds, such as sodium hydroxide (lye), silver nitrate, and more serious compounds (such as sulfuric acid). Most chemicals (but not all) that can cause moderate to severe chemical burns are strong acids or bases. Nitric acid, as an oxidizer, is possibly one of the worst burn-causing chemicals. Hydrofluoric acid can eat down to the bone and its burns are often not immediately evident. Most chemicals that can cause moderate to severe chemical burns are called caustic.

Electrical burns are generally symptoms of electric shock, being struck by lightning, being defibrillated or cardioverted without conductive gel, etc. The internal injuries sustained may be disproportionate to the size of the "burns" seen - as these are only the entry and exit wounds of the electrical current.

Survival and outcome (scars, contractures, complications) of severe burn injuries is remarkably improved if the patient is treated in a specialized burn center/unit rather than a hospital.

Scald

    Scalding is a specific type of burning that is caused by hot fluids (i.e. liquids or gases). Examples of common liquids that cause scalds are water and cooking oil. Steam is a common gas that causes scalds. The injury is usually regional and usually does not cause death. More damage can be caused if hot liquids enter an orifice. However, deaths have occurred in more unusual circumstances, such as when people have accidentally broken a steam pipe. Young children, with their delicate skin, can suffer a serious burn in a much shorter time of exposure than the average adult. Also, their small body surface area means even a small amount of hot/burning liquid can cause severe burns over a large area of the body.

Table 2. Scald Time (Hot Water)

Cold burn

A cold burn (see frostbite) is a kind of burn which arises when the skin is in contact with a low-temperature body. They can be caused by prolonged contact with moderately cold bodies (snow and cold air for instance) or brief contact with very cold bodies such as dry ice, liquid helium, liquid nitrogen, or canned air, all of which can be used in the process of wart removal. In such a case, the heat transfers from the skin and organs to the external cold body (as opposed to most other situations where the body causing the burn is hotter, and transfers the heat into the skin and organs). The effects are very similar to a "regular" burn. The remedy is also the same as for any burn: for a small wound keep the injured organ under a flow of comfortably temperatured water; the heat will then transfer slowly from the water to the organs and help the wound. Further treatment or treatments of a more extended wound also are usual.

Assessing burns

Main article: Total body surface area

Burns are assessed in terms of total body surface area (TBSA), which is the percentage affected by partial thickness or full thickness burns (superficial thickness burns are not counted). The rule of nines is used as a quick and useful way to estimate the affected TBSA.

Management

The first step in managing a person with a burn is to stop the burning process. With dry powder burns, the powder should be brushed off first. With other burns, the affected area should be rinsed with a large amount of clean water to remove foreign bodies and help stop the burning process. Cold water should never be applied to any person with extensive burns, as it may severely compromise the burn victim's temperature status.

At this stage of management, it is also critical to assess the airway status. If the patient was involved in a fire, then it must be assumed that he or she has sustained inhalation injury until proven otherwise, and treatment should be managed accordingly.

Once the burning process has been stopped, and airway status is ensured, the patient should be volume resuscitated according to the Parkland formula. This formula dictates that the amount of Lactated Ringer's solution to deliver in the first twenty four hours after time of injury is:

Fluid = 4cc x %TBSA x weight in kg

%TBSA excludes any first degree burn

Half of this fluid should be given in the first eight hours post injury and the rest in the subsequent sixteen hours. The formula is a guide only and infusions must be tailored to urine output and central venous pressure. Inadequate fluid resuscitation causes renal failure and death.

Severe edema in full thickness burns may be treated by escharotomy.

Treatment of low-grade burns

A local anesthetic is usually sufficient in managing pain of smaller first-degree and second-degree burns. Lidocaine can be administered to the spot of injury and will generally negate most pain.

See also

• Sunburn
• Radiation burn
• Bruise
• Branding iron
• Friction burn
• Chemical burn

References

• St. John Ambulance (2000). First aid: First on the Scene: Activity Book, Chapter 19. ISBN 1-894070-20-8. 

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