Fourth Degree Burns

Generality

Fourth-degree burns are lesions that involve full-thickness skin and underlying structures (such as muscles, bones, and fatty tissue). The resulting damage is extremely serious and can put the patient's life at risk.

Fourth degree burns frequently result from excess heat applied to tissues (eg direct exposure to open flames), but can also be caused by electricity, aggressive chemicals and radiation.

In fourth-degree burns, the skin is typically charred and covered with blackish eschar .

The involvement of deeper tissues determines the need for surgical interventions to avoid functional losses and potentially fatal complications (compartment syndrome, septicemia, etc.). In any case, the course of these injuries is very complex and involves regular medication, physiotherapy and long reconstructive surgery treatments.

What are

The fourth degree burns are traumatic lesions in which there is the carbonization of the tissues, involving all the layers of the skin (epidermis, dermis and hypodermis) and subcutaneous structures, up to the bones.

In many cases, damage to the skin and underlying structures is irreversible. The fourth degree burns determine, in fact, the complete destruction of the tissues and the combustion of organic material.

To remember

Injuries resulting from fourth-degree burns and associated complications can lead to patient death.

Healing is not spontaneous: in addition to the necrosis of the intradermal epithelial structures that have the ability to regenerate the skin, the damage to the subcutaneous tissues causes a significant functional impairment of the affected area.

Therefore, the course of fourth-degree burns is characterized by different surgical reconstruction interventions or, if the damages are irreversible, involves the amputation of the part. Whenever possible, re-epithelialization is assisted by the implantation of synthetic skin grafts (temporary solution) or transplantation of epidermal tissue (permanent).

Causes

Fourth degree burns are injuries due to the transfer of thermal energy to the skin, caused by:

Thermal agents (direct contact or exposure to exposure to flames, vapors, hot liquids or other incandescent bodies);
Chemicals (contact with acids, alkalis or molten metals);
High voltage electricity ;
Radiation .

The factors that affect the severity of a fourth degree burn are:

Percentage of body surface area involved;
Burn depth (degree of involvement of the skin and underlying layers);
Anatomical site of the lesions.

The effects of third degree burn also depend on the characteristics of the causal agent:

Temperature of heat sources or incandescent bodies (the higher the heat transferred, the greater the damage);
Exposure time (the burn is deeper, the longer the contact with the heat source lasts);
Specific heat and physical state of the burning agent (liquid burns are more extensive, while those from solids tend to be localized, but deeper; electricity is dangerous for the whole organism).

Warning! Fourth-degree burns involving delicate parts of the body (such as the face, hands, abdomen, feet and airways) are very serious. In these cases, therefore, it is necessary to accompany the injured person to the emergency room or to call 118 with extreme urgency.

Symptoms and Complications

The fourth degree burns are the most invasive, as they extend over the entire thickness of the skin and involve the subcutaneous tissues, such as muscles, fat, tendons and bones.

These lesions are characterized by:

Carbonization : manifested by the blackening of the part, associated with the formation of deep eschars. To the touch, the burned area has a rigid and dry consistency. The skin that limits the charred area is wrinkled and forms folds.
Absence of pain : even in this type of burn, as in the third degree, the destruction of intradermal nerve receptors makes the injured part insensitive to stimuli.

A fourth degree burn generally requires an autograft of epidermis and heals in many months, leaving a significant functional limitation.

In the most serious cases, this lesion can lead to amputation and, sometimes, to the death of the patient.

Risks and possible consequences

The circumferential fourth-degree burns affecting the neck, thorax and limbs are very dangerous. In fact, these lesions cause a constriction of the affected site, which can lead to a reduced vascularization of the downstream tissues with damage, sometimes irreversible. If the eschar completely surrounds an arm, for example, the local ischemia or the resulting compartment syndrome can threaten the vitality of the limb itself. To avoid possible complications, it is necessary to urgently remove carbonized tissues ( escarotomy ) or surgical decompression of the affected muscle compartments ( fasciotomy ).
Fourth-degree burns can predispose to exposed tissue infections. In severe cases, the passage of bacteria into the blood ( septic state ) may occur.
In the hours following the accident, a systemic syndrome called " burn shock " may occur. This state of general suffering affects organs such as the brain, digestive system and kidneys. Hypovolemic shock is another life-threatening event for a burn patient.
In people trapped indoors during a fire, in addition to fourth-degree burns, inhalation injuries are common. These depend on the direct effects of heat on the mouth and on the upper airways or from exposure to toxic components in the smoke. Inhalation of gas can also cause airway obstruction and pneumonia .

Diagnosis

In the emergency room, the doctor assisting the victim must first check the vital functions (heart and respiratory frequency, blood pressure, oxygen saturation, etc.).

With regards to fourth-degree burns, on the other hand, the evaluation includes an analysis of the patient's clinical history, an objective examination and the collection of information relating to the accident.

In order to determine the severity of the clinical picture, in particular, it is necessary to consider the following parameters:

Burn depth, percentage of body surface area involved and anatomical site of lesions;
Type of causal agent;
Possible injuries associated with the burn and possible presence of internal injuries from inhalation of hot or toxic fumes;
Readiness and efficacy of therapy, especially in the restoration of fluids and electrolytes;
Age and pre-existence of diseases that can worsen the patient's general condition (note: the prognosis is worse when the patient is an elderly person, a carrier of chronic diseases, such as diabetes, or a child under 3 years of age).

In hospitalized patients, various blood chemistry parameters should be monitored (hemoglobin, hematocrit, serum electrolytes, azotemia, creatinine, albumin, protein, phosphate and ionized calcium). In addition, ECG, urinalysis to assess myoglobinuria (suggestive of haemolysis or rhabdomyolysis) and chest radiography (chest X-ray) are required. These tests are repeated as needed.

Therapy

Treatment of fourth-degree burns is very complex and depends, in general, on the severity of the accident and the extent of the body surface involved. In any case, it is advisable to contact the emergency room immediately, as fourth-degree burns must be managed as soon as possible by specialized medical personnel.

Once the critical phase is over, the treatment involves numerous reconstructive surgery operations. Often, fourth degree burn is related to deformations and functional losses of the parts involved.

First intervention

Given the seriousness of the accident, the management of fourth-degree burns is solely of medical relevance. Therefore, the subject must be immediately accompanied to the emergency room or transported to the hospital with an ambulance.

Pending the intervention of the doctor and / or hospitalization, the main precautions to pay attention to are:

Remove the injured person from the heat source or from the burner : lay the subject wrapped in flames and throw water or a blanket over him, extinguish the fire in case of fire, cut clothes in case of burns from boiling liquids or chemicals, remove electrical current from the skin, etc.
Move the victim from the closed environment to avoid the appearance of lesions to the respiratory tract from boiling fumes and vapors (inhaling these elements produces thermal and chemical damage); during a fire, the victim is exposed to carbon monoxide and cyanide poisoning.
Check for signs and symptoms of shock. If the subject is conscious and does not have the urge to vomit, help him drink water at room temperature to avoid dehydration and hypovolemia.
Cool the burn area and the apparently healthy area with fresh running water (at about 15 ° C) for about 5-10 minutes. Even when the injured part has been removed from the heat source, in fact, the damage to the skin continues. The cold is able to interrupt this destructive process, as well as having a pain-relieving effect. In the case of contact with chemical substances (eg quicklime), on the other hand, contact with water is absolutely to be avoided, as it could cause greater damage.
Protect the injured areas with sterile gauze or clean cotton towels wet with saline or clean water to avoid external contamination, being careful not to compress the burned part.

What to pay attention to :

In the case of a very large fourth degree burn, cooling should not last more than five minutes. The risk is to cause a dangerous drop in body temperature (hypothermia). In the same way, the application of ice directly on the area must be absolutely avoided, as it could cause further injury.
Do not try to remove the clothes that cover the injured area, if they are tenaciously attached to the skin: this operation can only be carried out by medical specialists;
Eliminate any object that can tighten (eg rings, bracelets, watches ...);
Do not apply products of any kind on the burn: oils and other substances do not cool the tissues and can infect the lesions, in addition to preventing a precise evaluation.

During hospitalization, the fourth degree burn is regularly checked, cleaned and medicated with specific gauze and ointments. Supportive treatment may include the use of drugs to be taken orally and / or applied locally, in order to reduce pain and prevent infective complications.

Fourth-degree burns may require other measures, such as intravenous fluid administration or intubation.

Surgical therapy

After initial medical therapy, fourth-degree burns must be treated with full-thickness surgical excision of the charred areas ( escarotomy ). This intervention allows to remove the devitalized tissues, to avoid sepsis below the eschar, to prevent the compartmental syndromes and to facilitate an early grafting, which shortens the recovery and improves the functional result.

After excision, the lesion bed requires coverage using the patient's skin ( autograft ) or, if the quantity of autologous material to be used is deemed insufficient, a synthetic epidermal tissue. As temporary grafts, allografts can also be used (deceased donor vital skin) or xenotransplantation (eg pig skin); these options are generally rejected within 10 to 14 days. Often, in order to limit the functional loss of the part and minimize the scars and retractions, intensive physiotherapy and rehabilitation is associated with reconstructive interventions, consisting of a series of mobilization exercises and use of splints.

If the affected areas are irreversibly damaged, a fourth degree burn may require an amputation .