Burn injury

Burns are of four main types which are thermal burns,radiant heat burns,chemical burns & microwave burns.Burns involving large surface area of body and especially serious burns i.e third degree or higher burns can be fatal.If not fatal,they may cause long term phyical & emotional disability to the survivor.

We get thermal burns by dry heat e.g from flash,flame,friction and contact to any source of heat.And burns by hot liquid or steam e.g immersion burns,splash/spill burns & steam burns. An open flame is the leading cause of burn injury for adults, while scalding is the leading cause of burn injury for children.

Severity of burn injuries depends on source of burn injury,bodily region,degree of burn injury and burn injury surface area.

Dry heat burns: Burn injuries acquired by dry heat are comparatively less severe than steam injuries or scalds.

Flame burns If a part of our body comes in actual contact with flame accidentally or intentionally,we get flame burns that result in singering of the body hair,scorching of the skin leading to the charring of the body.

Radiant heat burnsThey are due to heat waves a type of electromagnetic waves.Radiation burns are caused by exposure to ultraviolet radiations of sun for a long time(sunburns) , X-ray or radiation therapy or anyother source.These burn injuries differ from others as there is no contact between the body and the flame or with the hot surface. The skin normally appears crythematous and blistered with areas of slippery pieces. With prolonged exposure to low heat,the skin will become light brown and leather like. If the radiant heat continues for long time,there willbe charring of the body. With most radiant heat burns,the hair are intact in every case.

Chemical burns In chemical burns the amount of tissue damage depend upon nature of the agent,strength & concentration,quantity,duration of contact and extent of penetration to body.We get chemical burns coming in conact with acids,alkalis or detergents.

Microwave burns Microwave create heat throuh molecular agitation.The greater the water contents of particular tissue,the greater is the heat produced so that the muscles which contain more fat tend to be more heated with the routine heat,the maximum energy is on the external surface of the body while with the microwaves,the oposite may occur.

Classification of burns:

Third degree burns: The most serious type of burns.Here all layers of skin are destroyed,extremely painful if the nerves are not damaged.Skin appears brown and charred with the loss of skin hair and sweat glands.Usually take a long time to heal depending on the severity of burn.

Mostly burns are first degree,second degree or third degree but there couldbe higher degree burns( fourth degree,fifth degree & sixthn degree burns) resutling from deeply exposed tissues effecting muscle tissues,superficial fascia and bones respectively.

Superficial burns and deep burns: Burns are also grouped on the basis of degree of penetration.If the dermis and epidermis(upper two layers of skin) are burnt,these are the superficial burns while in deep burns there is extreme destruction of subcutaneous tissue & muscles with charring of deeper tissues.Charring is the incomplete combustion of tissues removing hydrogen and oxygen finally reducing it to carbon(char).

The death of a person due to passage of electric current through the body is known as electrocution.In electric burns there maybe small entry and exit points visible of electric current Fatal electrocution is divided into:

Domestic electrocution low voltage(220-240V)

Indutrial electrocution high voltage(400,00-11,00,000V)

Lightening very high voltage in thunder storms

Domestic electrocution will cause electric shock with or without burning whereas in industrial electrocution burns maybe caused even when there is no physical contact with the live conductor,all that is necessary is to come with the arcing distance of the conduction. Arcing lesion:In high voltage wires,there is an area of passage of electric current,round the wire,AC is more lethal than DC current where the current flows constantly in the same direction.

Mode of death due to electrocution: (1)Ventricular fibrillation (2)Respiratory muscle paralysis (3)Paralysis of respiratory centre

Factors influencing the outcome of electric shock:

1)Duration of passage of current:With high voltage persom may thrown clear of the source by the violent muscular contration

With low voltage the current may indicate the spasm of the muscles causing the victim to grip the conduction so that the current passes for more time.

2)Earthing:The better contact between the person and the earth,the more dangerous willbe its effects.

3)Resistance of the body: Dry intact skin is a good insulator,blood is avery good conductor.The most vascular area offers the least resistance to current conduction while sweating and moisture furthermore reduce this resistance.

Lightning burns

When high current voltage passes through the body it causes burns on the body.And at the site of lightning,the blast effect of rapidly expanding air will tear the clothing.The specifications of lightning burns are:1)There is an exit wound present on the body which is the point of dicharge of electric current from the body2)Primary burn is usually on the head & maybe diffused.3)The metallic objects in the victim may have been diffused or magnetized.

Wallace's rule of nine is the method to estimate the extent of burning in living individuals where the extent of burn is indicated as the percentage of total surface area involved by the thermal injury.The total body surface area (or TBSA) refers to the percentage of the body that received the burn injury. Each area of the body is assigned a different percentage (see table).