Burns: Nursing pathophysiology

Burns are injuries that occur when the skin and underlying tissues are damaged from exposure to heat chemicals, electricity or radiation burns can cause localized damage or have widespread effects that can impact multiple organs in the body.

Ok. The skin is the largest organ in the body and provides important body functions like helping regulate body temperature, preventing loss of body fluids and protecting against microorganisms, radiation and mechanical stress.

Now, the skin is comprised of two main layers, the epidermis and dermis that rest upon the hypodermis, that's sometimes considered a third layer of skin.

The epidermis or the outermost layer is composed of multiple layers of keratinocytes that synthesize keratin a protein that forms a tough waterproof barrier to shield underlying structures from mechanical stress.

The epidermis also contains melanocytes which produce melanin a pigment that helps protect the skin from ultraviolet radiation.

The next layer is the dermis which contains structures like hair follicles, nerves, sensory receptors and sweat glands. This layer also contains macrophages and mast cells that aid in immune function.

Lastly, the hypodermis is the subcutaneous layer made up of fat and connective tissue that insulates deeper tissues and anchors the skin to the underlying muscle.

Now, burn injuries can be classified as thermal or non thermal thermal burns result from direct contact with a hot object, open flame, hot liquid or steam.

Other causes of thermal burns include electrical shock and friction. On.

The other hand, nonthermal burns come from a source other than heat. For example, chemical burns occur from exposure to strong acids, alkalis or solvents, either by direct contact with the skin inhalation into the respiratory tract or ingestion into the gi tract.

Nonthermal burns can also be caused by ultraviolet light and radioactive sources. Most burns occur in the home and individuals at highest risk for burn injuries include biological males, those who are younger than age four or older than age 65 and individuals who are economically challenged or live in substandard housing.

Local effects of a burn injury can be described in three zones. First, the zone of necrosis is the central zone where the heat transfer is greatest resulting in coagulative necrosis and irreversible cell death surrounding.

This is the zone of stasis where damage to the microcirculation results in sluggish circulation. This zone is potentially salvageable with appropriate treatment.

Lastly, the outermost area is the zone of hyperemia characterized by vasodilation, increased blood flow and limited cellular damage that can heal on its own.

As far as systemic effects of burn injuries go. Cellular damage causes the release of inflammatory mediators and the resulting inflammatory response causes increased capillary permeability and vasodilation.

As capillary permeability increases. Third spacing occurs as plasma proteins move out into the interstitial space, pulling fluid with them.

This leads to an accumulation of fluid within the interstitial space and a decreased intravascular volume. This together with lost fluid through evaporation from the burnt surface, further decreases circulating volume, resulting in hypotension to make matters worse.

Vasodilation accentuates hypotension, precipitating a fall in cardiac output which then culminates in a type of shock called burn shock.

And the resulting decreased tissue perfusion can result in metabolic acidosis. At the same time, increased sympathetic activity and release of stress hormones like catecholamines and cortisol produce a hypermetabolic state leading to accelerated protein and fat metabolism, increased glucose levels as well as increased oxygen demand.

Finally, as the systemic inflammatory response continues, multiple organ dysfunction syndrome or MDS can develop all right.

The signs and symptoms of burns depend on the depth of the burn injury. Superficial burns also known as first degree burns involve just the epidermal layer of the skin.

The burn is red, dry and painful usually without blisters and it blanches with pressure. Next are superficial and deep partial thickness.

Burns that are also known as second degree burns, superficial partial thickness. Burns involve the epidermis in the top layer of the dermis, producing a moist, painful pinkish red wound with clear fluid filled blisters.

The wound blanches with pressure, deep partial thickness burns affect most of the dermis. The wound can look moist or waxy and dry with variable colors and blanching is either prolonged or absent.

These wounds are usually less painful because the pain sensors are damaged. Full thickness burns or third degree burns extend through all layers of the skin and affect the subcutaneous tissue.

These burns are often painless and the skin can have a dry leathery appearance with absent blanching. Finally, if the injury extends to the underlying tissue, like muscle tendons or bones, the full thickness burns are referred to as fourth degree burns.

These burns appear black leathery and contain a layer of necrotic tissue called sar, there's extensive nerve damage. So this type of burn will also be painless if burn shock occurs, massive fluid shifts and shock will manifest as hypotension, tachycardia and tachypnea, hypoperfusion of organs and hypoxemia can present as decreased levels of consciousness, decreased urine output and hypoactive bowel sounds as well as metabolic acidosis.

All right, as a quick recap burns or injuries that occur when the skin and underlying tissues are damaged from exposure to heat, chemicals, electricity or radiation and are classified as superficial, superficial partial thickness, deep, partial thickness and full thickness based on the depth of injury.

Burns can cause localized damage or have widespread effects that can impact multiple organs in the body.