Burns: Classification and Community Management

Abstract

Every year, 250 000 people experience burns in the UK, 175 000 will attend an emergency department and 13 000 will require admission to hospital. Burns are usually accidents, often due to carelessness or inattention, but they may also be associated with alcohol or drug abuse or related to a pre-existing medical condition. The key role of the GP is to oversee patient care from initial first aid provision to rehabilitation and to be aware of when it is appropriate to refer to secondary care, including specialist burns units.

The GP curriculum and burns

Burns are listed as an important condition in Clinical example 3.20: Care of People with Musculoskeletal Problems. In particular, GPs should be able to:

Initiate management of the patient who has been burnt

Be aware of the safety of the patient and medical staff at the scene of the incident

Be aware of how to summon help in an emergency

Be competent in reducing pain with the use of analgesia or other methods

Recognize referrals requiring emergency action to save life or prevent serious long-term sequelae

Understand the roles of allied health professionals (nursing, physiotherapy, occupational therapy, counselling and psychological services)

Consider chronic disease management including systems of care, multidisciplinary teamwork and shared-care arrangements

Almost all adults will have personal experience of a burn at some point. The majority of these burns are minor and can be managed with prompt first aid in the community, but up to 50% will suffer some restriction of daily activity as a result of being burned (British Burns Association, 2001). The home is the most common location where adults and children are likely to be burnt. The kitchen and bathroom are most frequently associated with scalds, while the laundry and garden shed may contain corrosive substances, which can cause chemical burns or flammable liquids which may cause thermal burns.

Causes

Burns can be divided into four broad aetiological categories: thermal, inhalation, electrical and chemical. Thermal injury is most common. Table 1 summarizes the aetiology and associated features of each type of burn and management strategies for chemical and electrical burns.

Table 1.

Aetiology of burns, associated features and management

Thermal
Flame	Common (up to 50% of adult burns) Example: house/vehicle fire Associated with inhalation injury Any depth, usually deep dermal or full thickness
Contact	Often in children with small burns to extremities or face, intoxicated adults or the elderly following a fall or seizure Examples: iron, radiator, glass in front of gas fire Deep dermal or full thickness burns
Flash	Ignition of volatile substance, unexpected ball of fire Example: pouring petrol over a barbeque
Scalds	Common (up to 70% of burns in children) Examples: hot water from kettle, bath, drinks Usually superficial dermal
Inhalation
Airway injury	Inhalation of hot gases, flame or steam Larynx closes quickly, injury frequently limited to supraglottic airway Rapid respiratory obstruction over a few hours
Lung injury	Inhalation of products of combustion inhaled beyond the glottis, dissolved in fluid lining bronchial tree Examples: burning home, decorating materials Delayed onset of symptoms
Systemic intoxication	Alveolar absorption of combustion products Example: fires in enclosed spaces, carbon monoxide and cyanide Cherry red skin Mental status changes Persistent acidosis
Chemical
Acid	Usually painful Examples: hydrofluoric, sulphuric and hydrochloric acid pH testing with litmus paper Manage with copious irrigation
Alkali	May lead to deeper burns Delayed onset of pain Examples: household cleaning agents, bleaches, cement pH testing with litmus paper Manage with copious irrigation. For hydrofluoric acid burns, use calcium gluconate gel
Organic hydrocarbons	Bitumen (tarmac burns) Manage with copious irrigation to cool wound Removal of bitumen (e.g. using sunflower oil) Avoid chemical debridement with, e.g. kerosene or alcohol, as it can cause irritation
Electrical
Low voltage	Less than 1000 V Example: domestic electrical supplies (up to 240 V) Small deep burns at entry and exit sites Perform electrocardiogram (ECG) to identify possible arrhythmias (may require hospital admission for monitoring)
High voltage	Greater than 1000 V Examples: power cables, industrial accidents, lightning strikes Risk of systemic injuries Extensive tissue damage, occasionally limb loss Admit to hospital to rule out musculoskeletal, renal and cardiac damage

Pathophysiology

A burn can be described by three pathological zones as first proposed by Jackson in 1953 (Fig. 1).

Figure 1.

Jackson's burn zones and the effects of adequate and inadequate resuscitation.

Zone of coagulative necrosis

The zone of coagulative necrosis is the point of maximum damage where the heat cannot be conducted away. Irreversible tissue death occurs due to coagulation of constituent proteins.

Zone of stasis

The burn injury in the zone of stasis causes damage to the microcirculation and resultant decreased tissue perfusion. Tissue in this zone may progress to necrosis due to release of inflammatory cytokines but is potentially salvageable with early resuscitation. Prolonged hypotension, oedema or infection may cause this zone to progress to an area of complete tissue loss.

Zone of hyperaemia

The zone of hyperaemia is the outermost area affected. It represents increased tissue perfusion in response to injury with inflammation, cytokine release and increased blood flow. In smaller burns, the tissue in this zone will return to normal after the hyperdynamic vascular response has resolved. In burns over 20% total body surface area (TBSA), this zone may include the whole body.

Depth

Burns are usually classified as superficial or deep according to the depth of tissue damage; however, there may be a combination of both within the wound. Fig. 2 illustrates the layers and structures, which are present in normal skin.

Figure 2.

Skin histology diagram.

Superficial burns

Superficial burns have the ability to heal spontaneously by epithelization. They can be sub divided into epidermal burns and superficial dermal burns.

Epidermal burns only affect the epidermal layer. The stratified layers are burned and complete healing occurs from regeneration of the basal layer. The skin is classically erythematous due to inflammatory mediators producing hyperaemia, but no blisters are present. These burns are initially painful but the pain typically ceases after 48–72 hours. They usually heal within 7 days, leaving no scar. Pure erythema is not included in percentage TBSA calculations.

Superficial dermal burns extend through the epidermis into the superficial part of the dermis. They are characterized by pink erythematous blisters as shown in Fig. 3. The skin covering the blister is no longer viable and is separated from its living base by inflammatory oedema. Sensory nerve endings are exposed and therefore, the burn is extremely painful. Superficial dermal burns usually heal spontaneously within 14 days, leaving a colour match defect but no long-term scarring.

Figure 3.

Sperficial dermal burn of a patient's neck and back, showing pink skin with erythematous blisters.

Deep burns

Deep burns are more severe. They are less likely to heal spontaneously or by epithelization and may heal after a prolonged period with significant scarring. They can be sub divided into deep dermal burns and full-thickness burns.

Deep dermal burns may have some blistering but are blotchy red in colour, due to extravasation of haemoglobin from destroyed red cells leaking from ruptured vessels as shown in Fig. 4. The burn destroys the dermal vascular plexus and surrounding nerve endings and so sensation will be dull or absent.

Figure 4.

Deep dermal burn of a patient's arm and torso shows areas of pale insensate skin with surrounding erythema.

Full-thickness burns destroy both epidermis and dermal layers. Deep underlying structures may also be affected.

There are no blisters, they are leathery dense white or possibly charred black (known as an eschar). Blood vessels and sensory nerve endings are completely destroyed. Sensation and capillary return are absent.

Management

History and examination

It is essential to take a history of the incident with particular attention to mechanism (blast or explosions may lead to co existing injuries), time course and location (enclosed spaces suggest possible inhalation injury). If known, the causative agent will give an indication of whether the burn is likely to be superficial or deep. If inconsistencies are noted between the appearance of injury and history, be suspicious of non-accidental injury and refer to a burns unit for further investigation.

The burn should be carefully examined and appearance recorded. Note:

The colour

Area involved

Presence or absence of blistering

Capillary return

Level of pain

Any exudate and its nature

Presence or absence of surrounding inflammation suggesting sepsis

Burn area

Burn severity is determined by the area and depth of a burn. The likelihood of mortality is calculated using the patient's age and %TBSA burnt.

The %TBSA affected by a burn can be easily estimated using the' Wallace rule of nines'. The body is divided into areas of 9% and the total burn area can be calculated as shown in Fig. 5. This has been modified for children as they have proportionally smaller hips and legs and larger shoulders and heads than adults. Smaller burns can be estimated using the surface area of the patient's palm (from wrist to fingertips), which equates to approximately 1% of TBSA. It is important to remember that erythema is not included in these estimations.

Figure 5.

Wallace's rule of nines.

Alternatively, Lund and Browder charts can be used which are more accurate than the rule of nines. They are useful across all age groups, particularly in children as they take into consideration the patient's age and body proportions. Charts are required, however, to make these calculations.

Small partial thickness burns less than 10% TBSA are compatible with out-patient management. This may be in the GP setting or in conjunction with an out-patient clinic at the local hospital. Intravenous fluid resuscitation is required in children with greater than 10% TBSA and adults with greater than 15% TBSA burns and therefore requires referral to a burns unit.

First aid

The principles of first aid are to remove the burning source, stop the burning process and to cool the burn wound (Hudspith and Rayatt, 2004). Stopping the burning process reduces tissue damage. Cooling the surface of the burn is extremely effective analgesia, reduces the inflammatory reaction and can prevent further necrosis in the zone of stasis.

Hot charred clothing should be removed as quickly as possible. Similarly, with scalds, wet clothing should be removed as soon as possible as it can act as a reservoir for heat. If clothing is tightly stuck to the patient, cut it away from the edge of the burn leaving the remaining adherent fabric in place.

Cool the burned surface with cold running water for 20 minutes, ideally at 15°C (8–25°C is acceptable). Sponging the wound is quite effective if running water is not available. Wet towels are less efficient as they heat up, and if used, they must be changed frequently (Yuan et al., 2007). Do not use ice or iced water; this increases vasoconstriction and experiments have suggested that it may deepen the injury (Sawadal et al., 1997). It also leads to a greater risk of hypothermia. Small children are at particular risk of becoming hypothermic due to their increased surface area to body mass ratio. It is very important to keep the rest of the child (or adult) wrapped up warm and if required, raise the ambient room temperature. If more than 3 hours have elapsed since the time of injury, there is no benefit to applying cold water.

With chemical burns, it is important to be aware not to injure the patient further. Wearing thick rubber gloves and cutting off contaminated clothing prevents spread. Follow this by washing with copious amounts of water. With electrical burns, try to isolate the power source; if this is not possible, use an electrically insulated tool to move the patient away from the current source.

Covering the burn, preferably with a clean cotton sheet (sterile if available) or preferably polyvinyl chloride film (cling-film) helps limit evaporation and hence heat loss. A transparent covering enables the wound to be reviewed and it can be easily removed as it is non-adhesive. Ensure dressings are not circumferentially constrictive as this may compromise circulation to the wound. Do not apply any topical creams or agents such as silver sulfadiazine as these can alter the initial assessment of burn depth. If a limb is affected by the burn, elevate where possible to help limit swelling.

Considerations in primary care

Analgesia

When appropriately dressed, small burns can usually be managed with oral analgesia titrated in a step-wise fashion according to the patient's needs. If pain is not well controlled and narcotics are required, consider admission to hospital for interim treatment. Pain is usually most severe during dressing changes and physiotherapy. Consider oral opioid analgesia 30–45 minutes before these activities are undertaken. Dressings of burns in children can cause considerable distress. A familiar face to provide distraction with toys during a dressing change can be helpful.

Wound care

Manage burns with the same principles as any wound, taking care to avoid further tissue damage. Aseptic technique minimizes the risk of contamination. Wash the burn with soap and water and then remove any loose skin with sterile scissors. Small blisters can be left intact. If blisters are greater than 1 cm across, consider bursting and de-roofing with scissors as the skin will be dead and insensate; this procedure will prevent re-accumulation of fluid which is a possible medium for bacteria (Hudspith and Rayatt, 2004).

Once the area has been cleaned and debrided, it is essential to re-examine the wound as the depth can change with time. Always be alert for evidence of surrounding inflammation suggestive of infection. Antibiotics are not routinely required but it is important to make sure tetanus immunizations are up to date.

Dressings

There is little evidence about the best dressing to use in the management of burns. However, it is generally accepted that keeping the wound environment moist is a key feature in optimal wound healing; therefore, plain gauze is not widely used (Hudspith and Rayatt, 2004). Advice should be provided by the hospital if a specialist opinion has been requested. For epidermal and superficial dermal wounds managed solely in the community, simple non-adhesive dressings such as silicone [Mepitel® (Mölnlycke)] followed by padded gauze are most effective. Other non-adhesive dressings such as dressing gauze impregnated with paraffin [Jelonet® (Smith and Nephew)] are a suitable alternative but are more prone to drying.

Hydro-colloids [Comfeel® (Coloplast), DuoDERM® (ConvaTec)] are suitable for superficial dermal or small areas of deep dermal burns and particularly useful in difficult areas such as elbows, heels and digits. Semi-permeable plastic films [Opsite® (Smith and Nephew), Tegaderm® (3M)] are suitable for superficial or superficial dermal burns with minimum exudate. Advantageously, they allow for visual checks and may be left in place for 2–3 days but should not be used for infected or heavily exuding burns.

Silver sulfadiazine hydrophilic creams [Flamazine® (Smith and Nephew)] are widely used as topical agents. The silver ions act as a broad-spectrum antimicrobial agent, with the additional benefit of keeping the wound well hydrated. They should not be used in early treatment of superficial burns as they make burn depth assessment very difficult due to staining of the wound. They should be reserved for deep dermal burns. When in use, silver sulfadiazine creams should be changed on alternate days until any eschar has lifted and there is evidence of epithelization.

Further layers of gauze padding, wool, and crepe in a' figure of eight' fashion, secured by tape will help prevent movement and shearing forces of the dressing layers below. Examine the burns 48 hours after initial dressing and reassess the depth of wound. They can then be reviewed every 3–5 days providing there was no prior soakage of dressings, evidence of infection or malodour and the patient is relatively pain free.

When applying bandages, care must be taken to ensure that they are not applied too tightly. It is important to ensure fingers and toes are left exposed so sensation and circulation of limbs can be assessed at regular intervals. Limbs should be elevated in a sling or on pillows to encourage resolution of dependent oedema.

Referral guidelines

The British Burn Association has identified a list of injuries that are known to predict a complex clinical course (Box 1). All patients with these injuries should have early consultation with a burns unit.

Surgery

A circumferential full-thickness burn can compromise circulation by acting like a tourniquet. It may therefore become necessary to surgically release the constriction by surgically incising down to subcutaneous fat with cutting diathermy or scalpel. This procedure is known as an escharotomy. Light dressings are required to cover the area once the incision is performed. Split-thickness skin grafting may be required for deep dermal or full-thickness burns. The department where these procedures are performed should arrange follow-up in their out-patient/dressing clinic.

Box 1:

National burn injury referral guidelines

A burn is more likely to be complex if it is associated with the following criteria:
Age	Under 5 or older than 60 years
Site	Face or hands or perineum or feet or Any flexure, particularly the neck or axilla or Any circumferential dermal or full-thickness burn of the limbs, torso or neck
Inhalation injury*	Any significant inhalation injury excluding pure carbon monoxide poisonong
Mechanism of injury	Chemical burns (greater than 5% TBSA) Hydrofluoric acid burns (greater than 1% TBSA) Exposure to ionizing radiation High pressure steam injury High tension electrical injury Suspected non-accidental burn injury**
A complex burn injury is also suggested by one involving:
Size of skin injury (dermal or full thickness loss)	Paediatric greater than 5% TBSA or Adult (aged 16 years or older) greater than 1% TBSA
A burn injury may also be deemed complex if it occurs alongside:
Co-existing conditions	Cardiac limitation and/or myocardial infarction within 5 years Respiratory limitation of exercise Pregnancy Diabetes Immunosuppression for any reason Hepatic impairment, cirrhosis
Associated injuries	Crush injuries Fractures Head injury Penetrating injuries
Associated injuries, such as those listed, complicate any burn injury and make it complex. However, the range of presenting problems must be carefully considered and the most compelling injury dealt with first, according to clinical need. This may, in some circumstances, delay any referral for the burn injury to be dealt with. In such instances, advice as regards burn management should always be sought.
A complex burn would include:
Inhalation injury	Any significant such injury with no cutaneous harm, excluding pure carbon monoxide poisoning
Vesicullobullous disorders (e.g. any over 5% TBSA)	Epidermolysis bullosa Staphylococcal scalded skin syndrome (Ritter's) Stevens-Johnson syndrome Toxic epidermal necrolysis (Lyell's)
* Suspect inhalation injury if: Burns occurred in enclosed space (e.g. a house fire) Smoke during incident Blast, explosion and detonation Patient is unconscious Facial burns or singed hairs Soot in airway, hoarseness of voice or stridor Tachypnoea Decreased Glasgow Coma Scale rating	**Suspect non-accidental injury in a vulnerable patient (child or adult) if: Presentation is delayed Unusual pattern of injury Inconsistent history Discrepancy between history and clinical findings Multiple injuries with or without old scare in unusual anatomical locations

Multi disciplinary approach

Minor burns to anatomical areas such as hands, wrists, elbows, axilla and neck are prone to hypertrophic scarring and contractures. These patients should be referred to physiotherapists and occupational therapists as soon as possible. Exercises, pressure garments, adhesive tape and silicone therapy can help to minimize functional limitation. Those patients with persistent contracture and skin shortage may require referral for secondary surgical treatment.

Considerable cosmetic disability can occur after burns have healed. Colour match defects and irregular wound contours post skin grafting can lead to disturbance in body image. The availability of a psychiatrist specializing in body image disorders is limited outside major burns centres and the third sector is often the main source of support. Camouflage makeup preparations like Derma Blend can provide excellent results and there are many centres throughout the UK, being run by charitable organizations like The British Red Cross, which have trained volunteers to teach its application. The charity Changing Faces also provides support for those with facial disfigurement. The GP is the cornerstone of a multi disciplinary team approach to promote confidence and independence for these patients and their families post-burn injury.

Key points

There are 250 000 burns/year in the UK; the majority are avoidable

Many minor burns can be adequately treated in the community with initiation of prompt first aid

Appropriate dressings changed in a timely manner facilitate normal healing and help prevent complications

Referral to a burns unit may be required to prevent long-term sequelae

Secondary referral of healed minor burns may be required for physiotherapy, psychotherapy, scar management and surgical reconstruction

References

British Burn Association. (2001) Standards and strategy for burn care. A review of care in the British Isles. National burn care review London. Retrieved from www.britishburnassociation.org/downloads/NBCR2001.pdf.

British Burn Association (2004). Emergency management of severe burns course manual, UK version. 8th edition.

British Red Cross. Retrieved from www.redcross.org.uk/What-we-do/Health-and-social-care/Social-support-in-the-UK/Skin-camouflage.

Changing Faces. Retrieved from www.changingfaces.org.uk.

Hudspith

Rayatt

(2004) First aid and treatment of minor burns. British Medical Journal 328: 1487–9. doi:10.1136/bmj.328.7454.1487.

Jackson

(1953) The diagnosis of the depth of burning. British Journal of Surgery 40: 588–96.

Lund

Browder

(1944) The estimation of areas of burns. Surgery, Gynecology & Obstetrics 79: 352–8.

RCGP Clinical example 3.20: Care of People with Musculoskeletal Problems. Retrieved from www.rcgp-curriculum.org.uk/pdf/RCGP-Curriculum-3.20-Musculoskeletal-Problems.pdf.

Sawadal

Urushidate

Yotsuyanagil

Ishita

(1997) Is prolonged and excessive cooling of a scalded wound effective? Burns 23: 55–8.

10.

Wallace

(1951) The exposure and treatment of burns. Lancet 1 (6653): 501–4.

11.

Yuan

Holland

Harvey

Martin

La Hei

Godfrey

(2007) Assessment of cooling on an acute scald burn injury in a porcine model. Journal of Burn Care & Research 28: 514–20.