Definition

There are approximately 450,000 burn injuries requiring medical treatment and 45,000 burn hospitalizations, including 25,000 at burn centers, in the United States each year [1]. Adult burn injury patients are most likely to be young (average age at injury for adults is 42 years) and male (70%-75%) [1,2]. Most burns in adults result from fire or flame injuries (44%-61%) [1,2]. Other causes of burns that are also commonly reported include scald, contact, grease, electrical, and chemical injuries [1,2]. Burns usually happen in the home (68%) but also occur in the workplace (10%) or as a result of motor vehicle accidents (7%) [1]. For children, scald injuries are the most common cause and occur more frequently in children younger than 5 years. However, there are disproportionally more scald and inhalation injuries in minority populations [3].

Although there are 3500 estimated deaths from fire and burns annually in the United States [1], the incidence of burns has decreased dramatically in the past 50 years as a result of public education as well as home and work safety efforts. In addition, mortality from burn injury has declined by approximately 50% during the same period [4]. Advances in medical care and the development of comprehensive burn centers (Table 121.1) have contributed to this improved mortality rate. Survival of patients admitted to burn centers is estimated to be 96% [1]. Currently, once survival is ensured, medical management and treatment of burn injury are focused on wound healing, management of complications, and rehabilitation.

Symptoms

The symptoms of burn injury are directly related to the depth, size, and location of the injury. As expected, nociceptive pain is a major symptom of burn injury. Involvement of nerve endings in the dermal layer may also result in impaired or altered sensations causing neuropathic pain. Pruritus is common in the acute period and is linked to both the chronic inflammatory state and altered pain pathways of burns. Furthermore, postburn pain and pruritus may persist for years after injury, and regular monitoring with use of standardized measures is recommended. The visual analog scale, numeric pain rating scale, and 5-D scale for itching [5] are useful in assessing symptoms and treatment response.

Deep partial-thickness and full-thickness burns interrupt the function of skin appendages. Damaged skin appendages may include the apocrine sweat glands, resulting in dry, friable skin that does not heal well and is susceptible to infection. In larger burns, the loss of sweat glands may also impair body temperature regulation. The overall poor skin condition after burn injury may lead to chronic wounds.

Scar tissue develops weeks to months after closure of deep partial-thickness and full-thickness burns. Hypertrophic scars and contractures may result. This can be painful, cause deformity, and interfere with joint function. Contractures may lead to subluxation of hand or feet joints and dislocation of hips or shoulders. Scoliosis and kyphosis can result from burn scar contracture and postural changes.

Other symptoms are related to the multitude of other burn complications (see section on potential disease complications), some of which arise from the complex and prolonged intensive care and hospital course. Severe deep injury of extremities can require amputations of nonviable limbs. Formation of osteophytes and heterotopic ossification occur in burns and are associated with long-term immobilization [6]. Chronic infections from skin wounds and immune compromise are significant concerns. Other issues include complications from inhalation injury resulting in chronic pulmonary symptoms, hormone imbalances, deconditioning and malnutrition, and loss of bone and muscle mass [7]. Last, premorbid psychiatric disorders and psychiatric complications from the burn itself are prevalent and include sleep disturbances, depression, anxiety, substance abuse, and post-traumatic stress.

Physical Examination

A thorough physical examination is necessary to assess the burn itself as well as resulting complications. The evaluation should begin with an examination of the skin for burn location and depth, sensation, and signs of infection. Determination of burn depth allows categorization of wound severity.

The current burn classification system groups burns into four categories of varying depth: superficial, superficial and deep partial thickness, and full thickness. Superficial injuries, traditionally known as first-degree burns, solely affect the epidermal layer. The category of second-degree burns is divided into superficial and deep partial-thickness burns. Superficial partial-thickness burns interrupt the epidermis and superficial (papillary) dermis. These often have good vascular supply and are painful with a pink or red and sometimes blistered appearance [8]. Deep partial-thickness burns extend into the deep (reticular) dermis and damage skin appendages, which affects some degree of sensory and apocrine function. Full-thickness burns, also called third-degree burns, affect the entire epidermal and dermal layers and result in complete loss of skin appendages. Deep partial-thickness and full-thickness burns usually have poor blood flow and can be painless and appear less red [8]. Severe injuries also may penetrate to the muscle, tendon, and bone. Such deep injuries, classified as fourth-degree burns, are not part of the newer anatomic classification system (Fig. 121.1 and Table 121.2).

The depth of burn is an important factor in determining acute management of wounds. Burn surgeons often classify burns as superficial wounds, which heal by conservative management, or deep wounds, which require surgical intervention. Clinical assessment is the most widely used technique to evaluate burn wound depth and severity. Unfortunately, the clinical evaluation is accurate only about 64% to 76% of the time, and other techniques, briefly discussed in diagnostic studies, may also be used to evaluate wound depth [9,10]. Because of the evolving nature of burn wounds in the first few days after injury, monitoring the progression of the wound over time allows one to best assess its ultimate anatomic classification and management plan.

Postoperative burn wounds should also be closely watched in the rehabilitation setting. Postoperative wound evaluation includes inspection of grafts for hematoma, seroma, infections, and areas of graft loss [8]. After skin grafting, and as the skin matures, one should monitor for signs of hypertrophic scarring, which initially appears as erythematous, raised, and hardened skin.

A complete neurologic examination including an assessment of motor and sensory function, reflexes, and cognition should also be performed. Immediately after injury or surgery, the sensory examination is primarily limited to light touch modality because of pain. However, after wound closure, the sensory examination enables one to evaluate for small- and large-fiber neuropathies. Deep burn wounds may involve the vascular supply and affect wound healing. A pertinent vascular examination includes assessment of peripheral pulses of the involved extremities. The musculoskeletal examination should assess not only strength but also joint range of motion and deformities. The motor examination of joints crossed by a deep partial-thickness or full-thickness burn should not be performed until after skin graft “take” is ensured, usually within a week after grafting. Note that burn patients may have significant weakness from deconditioning and lean muscle loss. A complete cardiac and pulmonary examination should be performed with particular attention to signs of respiratory complications and hypermetabolic state. Psychiatric examination should include a thorough screening for signs of sleep disturbance, depression, anxiety, substance abuse, and post-traumatic stress. Patients who exhibit symptoms of a major psychiatric disorder should receive a complete psychiatric evaluation.

Functional Limitations

Functional limitations are directly related to the severity and location of the burn and related complications. Those with burns to the upper extremities may experience impairments in activities of daily living, fine motor tasks, and occupational activities. Burns to the lower extremities may result in impairments in mobility and higher level exercise and sport activities. Small burns to sensitive areas such as the face, including the eyes, ears, nose, or mouth, and genitals may result in significant impairments in specific functions.

Another effect is impaired psychological function. Psychological impairments are common and significant, leading to difficulty with community and social integration [11,12]. Factors associated with delayed return to work include increased hospital length of stay, electrical etiology, injury at work, and the need for inpatient rehabilitation. After hospitalization, barriers for returning to work include pain, neurologic issues, and impaired mobility [13].

Diagnostic Studies

Many different diagnostic tests are useful in the initial assessment of the burn patient. These may include tests to assess wound depth. The “gold standard” of burn depth analysis is biopsy with histologic assessment, but this is not standard practice [14]. Techniques using laser Doppler imaging, thermography, vital dyes, ultrasonography, and confocal laser scanning microscopes have been suggested for wound depth assessment, but these methods are not routinely used clinically. Bronchoscopic evaluation of the airway is performed for inhalation injury along with serum carboxyhemoglobin level.