Pain associated with burn injury is widely reported as being the worst pain imaginable. Tissue damage from burns causes the release of sensitizing substances and inflammatory mediators (e.g., prostaglandins, bradykinin, serotonin, histamine) that activate A delta and C fiber nociceptors (i.e., free nerve endings that are widely distributed in skin and deep tissues that function as receptors for painful stimuli), which transmit pain signals to the central nervous system (CNS). Pain may be felt at the time of injury, throughout the healing and rehabilitative phases of burn recovery, and for years following the initial injury. In addition to the local response to injury, systemic changes in sensory function occur, including sensitization of nociceptive fibers and changes in peripheral cutaneous nerves, which may play a role in the development of chronic pain after burns.
Burn pain is highly variable and is a challenge to treat effectively because the degree of pain may not be related to the severity of the burn injury. In an effort to quantify pain, hospitals and burn centers use standardized assessment tools. A variety of ordinal and ratio scales exist for pain; some attribute numeric values to pain intensity, with 0 indicating absence of pain and 10 being the worst pain imaginable, and others present a range of words that describe pain in increasing intensity from “extremely weak” to “extremely intense.” Picture scales may be appropriate for younger children and other patients who cannot utilize numeric or descriptive systems. Pain assessment is particularly difficult in preverbal and nonverbal patients, including infants, individuals with profound cognitive or developmental disabilities, and ventilated patients. In such instances, healthcare clinicians should assess pain based on observable signs such as facial grimacing and crying, and on physiologic indicators such as tachycardia and tachypnea.
Treatment for burn pain is primarily pharmacologic, but adjunctive therapies such as distraction, hypnosis, and relaxation techniques may be incorporated into the treatment plan. Opioid analgesics, usually morphine, are the mainstay of medical treatment. Analgesics are most effective when administered on a fixed schedule as prevention rather than as needed when pain becomes severe. Anxiolytics are often prescribed to reduce anxiety associated with pain. Frequent assessment of pain is important for evaluating the effectiveness of current strategies and for justifying the use of alternative approaches to pain management. Effective pain management is important for the prevention of debilitating psychological conditions, including depression, stress disorders (e.g., posttraumatic stress disorder [PTSD]) and suicidal ideation.