Introduction[edit | edit source]A burn is an injury to the skin or other organic tissue primarily caused by exposure to heat or other causative agents (radiation, electricity, chemicals)[1][2]. According to WHO, it is a global public health problem, accounting for an estimated 180,000 deaths annually. It is among the leading causes of disability in low and middle-income countries and almost two-thirds occur in the WHO African and South-East Asia regions. Burns do not only affect the skin, they can have other effects on the tissue, organ and system networks such as smoke inhalation, as well as psychological effects. Burns affect all genders although females have slightly higher rates of death from burns compared to males. They also affect all age groups and are the fifth most common cause of non-fatal childhood injuries[2]. Show
Types of Burns[edit | edit source]Electrical Burn[edit | edit source]Electrical burn injury is caused by heat that is generated when the electrical energy passes through the body causing deep tissue injury. The magnitude of the injury depends on the pathway of the current, the resistance of the current flow through the tissues, the strength, and the duration of the current flow. The different types of current causes various degrees of injury. For example, an alternating current is more dangerous than a direct current and it is often associated with cardiac arrest, ventricular fibrillation, and tetanic muscle contractions.[1][3] Thermal Burn[edit | edit source]Thermal burn injuries are caused by external heat sources (hot or cold), scalds (hot liquids), as a result of energy transfer, hot solid objects, steam and cold objects. The types of thermal burns are:
Chemical Burn[edit | edit source]A chemical burn injury is caused by tissue contact with chemical agents such as strong acids, alkaline, or organic compounds. Chemical agents depending on the duration of exposure and the nature of the agent have different effects on the skin. For example, contact with acid causes coagulation necrosis of the tissue (whereby the architecture of the dead tissue can be preserved), while alkaline burns generate liquefaction necrosis (whereby the tissue is transformed into a liquid, viscous mass). Systemic absorption of some chemicals is life-threatening, and local damage can include the full thickness of skin and underlying tissues[1]. Radiation Burn[edit | edit source]Radiation burn is damage to the skin or other biological tissue and organs due to prolonged exposure to radiation. It is the least common burn injury and the most common type of radiation burn is the sunburn caused by prolonged exposure to Ultraviolet rays (UV). Other causes are associated with the use of ionising radiation in industry, high exposure to radiotherapy e.g. X-ray, and nuclear energy. Radiation burns are often associated with cancer due to the ability of ionising radiation to interact with and damage DNA[1]. Classifications of Burns[edit | edit source]Burns can be classified according to their severity, depth,[1] and size of the burn. Classification by Depth[edit | edit source]Superficial-thickness or first-degree burns - Superficial thickness burns are burns that affect the epidermis only and are characterised by redness, pain, dryness, and with no blisters. Mild sunburn is an example of a superficial thickness burn. Partial-thickness or second-degree burns - These burns involve the epidermis and a portion of the dermis. Partial-thickness burns are often broken down into two types, superficial partial-thickness burns and deep partial-thickness burns. Superficial partial-thickness burns - Partial-thickness burns involve the epidermis and part for the dermis layer of the skin. Superficial partial-thickness burns extend through the epidermis down into the papillary, or superficial, a layer of the dermis. The injured site become erythematous because the dermal tissue has become inflamed. When pressure is applied to the reddened area. The area will blanch, but will demonstrate rapid capillary refill upon release of the pressure. Deep partial-thickness burns- These burns extend deeper into the dermis and cause damage to the hair follicle and glandular tissue. They are painful to pressure, form blisters, are wet, waxy, or dry, and may appear ivory or pearly white. Full-thickness or third-degree burns - These burns extend through the full dermis and often affect the underlying subcutaneous tissue. Skin appearance can vary from waxy white to leathery grey to charred and black. The skin is dry and inelastic and does not blanch to pressure, it is not typically painful due to the damage to the nerve endings. The dead and the denatured skin (eschar) are removed to aid healing and scarring is usually severe. Full-thickness burns cannot heal without surgery. Subdermal or fourth-degree burns - These involve injury to the deeper tissues, such as muscle or bone. They are often blackened and it frequently leads to loss of the burned part. Classification by Size[edit | edit source]Burn size is determined by one of the three techniques: The Rule of Nine, The Lund-Browder Method, The Palmar Surface. The Rule of Nine- This method is also known as the Wallace Rule of Nines because it is named after Dr Alexander Wallace the surgeon who first publish the method. The Rule of Nine is used to estimate the total body surface area (TBSA) involved in burn patients and also used to estimate fluid resuscitation required by a burns patient. The body surface estimation is by assigning percentages to different body areas[6].
Lund-Browder Method - This method is used instead of the rule of nine method for assessing the total surface area affected in children[7]. Different percentages are used because the ratio of the combined surface area of the head and neck compared to the surface area of the limbs is typically larger in children than in adults. Palmar Surface Method - The palmar surface can be used to estimate relatively small burns or large burns. But for medium size burns, it is inaccurate. The surface area of a patient’s palm including the fingers is used to calculate the TBSA. Pathophysiology of Burns[edit | edit source]A burns injury depending on the severity of the injury can result in both local and debilitating systemic effects on all other organs and systems distant to the burn area. Local Effect[edit | edit source]This occurs immediately after the injury and the burn wound can be divided into three zones[8][4].
[9] Systemic Response[edit | edit source]In severe burn injury, >30% TBSA complex reaction occurs both from the burn area and in the area distant to the burn. Cytokines, chemokines and other inflammatory mediators are released in excess resulting in extensive inflammatory reactions within a few hours of injury[10]. The initial response depending on the size of the burn injury is similar to the inflammation that is triggered after tissue destruction such as trauma or major surgery[11]. Different factors contribute to the magnitude of the host response, they include: burn severity (percentage TBSA and burn depth), burn cause, inhalation injury, exposure to toxins, other traumatic injuries, and patient-related factors such as age, pre-existing chronic medical conditions, drug or alcohol intoxication, and timing of presentation to medical aid[1]. This inflammatory response leads to rapid oedema formation which is caused by increased microvascular permeability, increased hydrostatic microvascular pressure, vasodilation, and increased extravascular osmotic activity. These reactions are due to the direct heat effect on the microvasculature and to the chemical mediators of inflammation. Vasodilation and increased venous permeability at the early stage of the injury are caused by the release of histamine. Also, prostaglandin is released by damage to the cell membranes which causes the release of oxygen-free radicals released from polymorphonuclear leucocytes which activate the enzymes catalyzing the hydrolysis of prostaglandin precursor. These hemodynamic changes lead to continuous loss of fluid from the blood circulation causing increased haematocrit levels and a rapid fall in plasma volume, leading to a decrease in cardiac output and hypoperfusion on the cellular level. Burn shock occurs if fluid loss is not adequately restored[12]. Besides burn shock, the burn injury can result in other types of injury which include inhalation injury. Inhalation injury is caused by heat or inhalation of smoke or chemical products of combustion leading to various degrees of damage. Usually, it is present in conjunction with the burn and can range from a minor injury to a severe injury. Inhalation injury can be divided into three types: systemic toxicity due to products of combustion (carbon monoxide (CO) and cyanide poisoning); upper airway thermal injury; and lower (bronchi and distal) airway chemical injury. Patients can sustain all of these in a closed-space fire. CO poisoning, more accurately categorised as a systemic intoxication, is easily diagnosed from the serum carboxyhaemoglobin level determined as part of the arterial blood gas measurement at hospital admission[1]. In addition to the effects above, a severe burn injury has an effect on different organs and systems in the body. The effects include: Effect on the Cardiovascular System[edit | edit source]The initial response to a severe burn injury is characterised by hypovolemia and reduced venous return. This concomitantly leads to a decrease in cardiac output, increased heart rate, and peripheral resistance. In addition to the cardiac dysfunction, pulmonary resistance increases causing an increase in right and left-ventricular work-load[13][14]. Effect on the Respiratory System[edit | edit source]Following smoke inhalation, inflammatory mediators are released in the lungs leading to bronchoconstriction and adult respiratory distress syndrome[4]. Effect on the Renal System[edit | edit source]The renal system is affected following alterations in the cardiovascular system. Renal blood flow and glomerular filtration rate are reduced secondary to hypovolemia, diminished cardiac output, and the effects of angiotensin, vasopressin and aldosterone. These alterations are usually translated in the form of oliguria as an early sign of renal compromise. Failure to promptly and adequately manage these cases may lead to acute tubular necrosis, renal failure, and mortality. Effect on the Liver[edit | edit source]There is substantial depletion of the hepatic proteins, alterations in serum levels of triglycerides and free fatty acids are highlighted, both of which are significantly increased secondary to a decrease in fat transporter proteins rendering the liver susceptible for fatty infiltration and hepatomegaly with resultant increased risk of sepsis and burn mortality. Effects on Gastrointestinal System/Metabolism[edit | edit source]The basal metabolic rate increases up to three times its original rate. This coupled with splanchnic hypoperfusion, necessitates early and aggressive enteral feeding to decrease catabolism and maintain gut integrity. It causes mucosal atrophy, reduced absorptive capacity, and increased surface permeability. Effect on the Endocrine System[edit | edit source]The stress hormones i.e. catecholamine, glucagon and cortisol among other hormones are actively involved at the onset of burns injuries. These hormones display an exponential increase in their levels; sometimes reaching 10 fold their normal values. The significance of such an upsurge resides in its influence on the cardiovascular system and the resultant fluid shifts that follow these changes. The stress hormones are thereby considered as the initiators of the hypermetabolic-catabolic and proteolytic-response. Burn Prevention[edit | edit source]Recommendations from the World Health Organization for individuals, communities and public health officials on how to reduce burn risk[15].
Conclusion[edit | edit source]Burns injuries have physical, socio-economic, and psychological effects especially in cases of severe burns injuries. They impact not only the affected part of the body, but also the organs and systems of the body. They require an early and prompt response to reduce the effect of an injury. Besides this, they require an interdisciplinary approach to prevent the adverse effects of the injury. References[edit | edit source]
Which type of burn injury occurs on the layers of subcutaneous fat muscle or deeper structures?Full-thickness burn definition
With this type of burn, all layers of the skin — epidermis and dermis — are destroyed, and the damage may even penetrate the layer of fat beneath the skin.
Which type of burn injury would the nurse identify as occurring on the layers of subcutaneous fat?Third-degree burns damage every layer of the skin, the epidermis, dermis, and subcutaneous tissue layer as well as the hair follicles. Third-degree burns have a dry, white, leathery appearance.
What is a subcutaneous burn?Third-degree (full thickness) burns.
Third-degree burns destroy the epidermis and dermis. They may go into the innermost layer of skin, the subcutaneous tissue. The burn site may look white or blackened and charred.
Which depth of burns goes down to the subcutaneous layer?For a comparison of the two classification systems, see the table below. When the epidermis and dermis are both destroyed and the burn extends down into the subcutaneous tissue, including fat, muscles and even bones, this is referred to as a full-thickness burn (third- and fourth degree burn).
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