Introduction and classification
Since man has learned to "domesticate" fire, small burns and burns have become one of the most common injuries suffered in the home, at work and in recreation.
A burn is, by definition, a more or less extensive lesion of the skin, and sometimes of the underlying tissues, caused by a thermal, physical or chemical agent. The possible causes are therefore numerous and heterogeneous, as is the extent of the damage they cause.
In relation to the causative agent, burns can be distinguished into:
- HEAT BURNS: flames, liquids, objects or gases at high temperatures alter the structure and functionality of surface tissues, to the point of causing cell death, protein coagulation or tissue carbonization. Even excessively rigid temperatures can cause serious injury.
- BURNS FROM CHEMICALS: strong acids or bases generally cause serious alterations which, although limited to the contact area, are rather deep.
- ELECTRICITY BURNS: they can be attributed to the heat generated by the electric current during its passage in the body, between the entry point and the exit point; these are generally apparently limited burns but which, in the most serious cases (high voltage), can cause a rather extensive deep necrosis.
- BURNS FROM RADIANT AGENTS: the sun and any other source of UVA (including tanning lamps) or ionizing radiation can cause burns of varying degrees.
In relation to the aforementioned etiological agents, the severity of the burn depends on the degree of heat reached, the duration of the contact and the anatomical area involved.
- We speak of first degree burn when the pathological process affects only the most superficial layer of the skin (called epidermis); this category includes minor burns that occur with a slight redness, associated with local swelling, pain and burning. The "barrier" function of the skin is not compromised, as is the patient's general health; healing occurs within a few days, usually without scarring and often with extensive scaling. Injuries from excessive sun exposure or those caused by contact with liquids at a moderately high temperature, such as coffee or tea that are still too hot, are a typical example of first-degree burns.
- In second-degree burns the lesion is deeper, affects the dermis (the second of the three skin layers) and is accompanied by filittene (vesicles filled with a clear liquid); intense pain is also characteristic. The second degree burns are further divided into simple and deep. The first ones, similar to the first grade, heal spontaneously and with a favorable outcome, even if they require longer times (10-20 days) and may have minor complications; for this reason it is advisable to subject them to a medical check. The deeper burns, as well as those of the third degree, do not tend to heal or repair very slowly (within 3-4 weeks) and with often serious scars. For this reason, timely surgical treatment is often necessary, with the aim of removing necrotic tissues and applying skin grafts (dermo-epidermal).
- The maximum severity of the damaging process is reached with third-degree burns, where the physical or chemical thermal insult causes injury to the deep layers of the skin (it can affect the adipose and muscular tissue, up to, in the most serious cases, to the underlying bones). When the burn is caused by flame or red-hot objects, skin necrosis leads to the formation of dry and black scabs, whereas when the etiological agent is a boiling liquid the skin appears fluffy and whitish. Due to the carbonization of nerve endings, pain can be paradoxically scarce or even absent. Surgery is always necessary.
See also: Symptoms Burns
Along with depth, the severity of burns is also determined by the extent of the injured area; both this is greater and the more insidious the danger of life of the burned.
For a quick calculation of the body surface involved, the so-called "rule of nine" is used: the body surface is divided into zones and a percentage is assigned to each one (in this case nine, a multiple or a fraction thereof is used) ). The sum of these numbers provides a simple and immediate assessment of the severity of the burn. This formula is inaccurate when applied to children, due to the proportionately larger head and proportionally smaller limbs than adults.
Thirdly, the severity of a burn depends on the body area involved (areas covered with hair and a skin layer more often protect better than hairless areas with thin skin, such as flexor surfaces and joint folds), but also from the conditions general of the injured: age (the youngest and the elderly are most at risk), physical conditions and concomitant injuries (factors aggravating the burn are the simultaneous presence of cranial traumas, fractures, body dehydration) and pre-existing diseases (it is more dangerous in the presence of cardiomyopathies, bronchopneumopathies, diabetes and liver or kidney diseases).
Burns and health hazards
The skin is the largest organ of the body and constitutes, by itself, about 15% of body weight; real interface with the external environment, it is opposed, first of all, to an excessive dispersion of organic liquids. For this reason, when it is damaged by a burn, water losses can become dramatic, up to compromising the survival of the individual. The situation is further complicated by the massive release of inflammation mediators in the circulation, which facilitate the passage of fluids from the blood to the interstitial spaces. Dehydration, associated with a reduction in the volume of circulating blood, can lead to hypotension and hypovolemic shock. It is precisely the loss of the serum that oozes from the dermal surfaces to give rise, in second-degree burns, to the characteristic blisters or flittene.
Another and very important function of the skin, which is less in the case of burns, is the protective effect against bacterial agents which, in its absence, can penetrate deeply taking advantage, among other things, of the decrease in the immune defenses due to severe organic suffering. For this reason, at hospital level there are specialized departments for severe burn victims, built and managed in order to minimize the risk of infections.
In severe burns, the body's metabolism undergoes a sharp surge, doubling up in the most desperate situations. The protein and fat catabolism is high, the weight loss rather rapid; preventing the malnourished state of the serious burned person is therefore essential to increase the chances of survival.
All those burns that are considered SERIOUS:
- they are complicated by respiratory tract injuries, other soft tissue injuries and bone injuries.
- Burns extended to the face, hands, feet, anal-genital and major joints, respiratory tract or digestive tract.
- Burns with inhalation, explosion, electrical and chemical burns.
- III grade burns involving more than 10% of the body surface.
- Grade II burns involving more than 25-30% of body surface area or 18-20% in children.
- When the extension exceeds 40% the chances of survival are significantly reduced.
