1.3.1 Thermal Injury

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Burns and scalds belong to the most frequent accidents in the environment of household and leisure. People of all ages are susceptible to minor burn injury. The highest incidence occurs during the first few years of life and in persons aged 20-29 years. The mechanism of minor burn injury varies considerably with the age of the victim. Minor burns in children younger than 4 years are caused primarily by contact with hot surfaces and by liquid scalds, with scalds accounting for approximately 75% of burns in children under age 5 years.

Thermal injury induces a direct tissue damage on the site of energy (> 65 `C) delivered from exogenous thermal energy of different origin (UVB, fire, gas explosion, hot water and other fluids, hot dump, hot metals, electric energy). The thermal injury is followed by denaturation of proteins and finally coagulation necrosis. Depending on the degree and depth of injury, capillaries are destroyed and plasma and electrolytes move to the interstitial tissue. The more tissue damage, the more the risk of hypovolemic shock (1 square meter body surface around 3 liters loss of volume/day) exist. Furthermore, within the following 72 hrs, the damage can continue and, therefore, has to be stopped as quickly as possible.

Thermal injury induces a cascade of symptoms which are characterized by erythema, blistering and necrosis depending on the degree of energy delivered to the skin and deeper tissues.

In general, the area of exposure is the hot spot of energy delivered to the tissue with a decrease of damage moving away from the side of highest exposure.

Burns (combustio) and scalding (ambustio) show a characteristic feature of the thermal injuries. The tissue damage is divided into three degrees:

• The 1st degree is characterised by: erythema and pain.

• The 2nd degree is characterised by: grade 2 a: superficial destruction with epidermal and dermal blistering, and 2 b: deep destruction with dermal blistering and destruction of hair and other skin adnexae.

• The 3rd degree is characterised by: involvement of all layers of the skin and all adnexae and with extension to the subcutis and muscles.

If burning and scalding have reached grade 2b and grade 3 constant monitoring of electrolyte and protein balance is necessary. Supervision at an intensive care unit is essential.

History of event and clinical features makes the diagnosis quite easy. The exact estimation of degree of burning /scalding, however, is essential for management decisions.

Usually the case history, the place and environment where the thermal energy has been delivered will enable a clear diagnosis. Unconscious patients, however, can show differential diagnoses of generalized or localized erythema caused by drugs, spider bites, jellyfish toxic fluids and other causes of erythroderma.

Therapy must be initiated as soon as possible, adjusted to the extent and severity of the thermal energy delivered. Minor burns should be cooled by local corticoid emulsions. Systemic NSAID plus LTB4 inhibitors can reduce initial prostaglandin and leukotriene release. Therapeutic prevention of superinfection depends on the amount of involvement of body surface.

With more severe burns, temperature control is a problem. The management involves in general wound care, electrolyte and protein replacement, pain control and systemic antibiotics and referral to a regional burn centre the injury is of grade IIB and III. Skin transplantation can be considered at a later stage. Preservation of normal skin for in vitro growth / cell culture is done in specific burn centers providing the appropriate equipment.

The critical body surface involvement >10% children and >20% adults make hospital admission necessary and care by specialists.