|Chronic pain generally refers to persistent, non-acute, sometimes disabling pain in the extremities or other areas of the body. The pain can be associated with a known cause such as a major or minor injury, or it can be a symptom of a painful chronic condition such as fibromyalgia. It can just as often be of unknown origin. Considerable controversy continues to surround the cause (etiology), definition, diagnosis, and treatment of chronic pain.|
The term "chronic pain" is not used consistently. The term can refer to pain that has been present for an arbitrarily defined period, for example, longer than 6 months. Alternatively, the term "chronic pain" is often used as a synonym for the term "chronic pain syndrome," a descriptive term used to indicate persistent pain, subjective symptoms in excess of objective findings, associated dysfunctional pain behaviors, and self limitation in activities of daily living. Chronic pain syndrome is the presentation of combined physical and psychological changes due to chronic pain. It is not to be confused with “Complex regional pain syndrome” (CRPS), also called reflex sympathy dystrophy, which also involves chronic pain but is defined and diagnosed using an established set of clinical criteria.
Chronic pain syndrome is not the same as acute pain or recurrent acute pain. Acute pain is due to actual or pending tissue damage. Its duration is short and its psychosocial consequences are minimal. A person's perception of acute pain and behavior following the onset of acute pain are commensurate with the inciting event. Acute pain resolves as healing occurs. Acute pain is common, occurring for example with fractured bones, skin lacerations, sprains and other similar events. Recurrent, acute pain refers to episodic pain associated with chronic conditions such as trigeminal neuralgia or cluster migraine headaches.
Although chronic pain differs from acute pain, the current understanding of neurophysiologic mechanisms involved in the development and persistence of pain recognizes that transmission of pain (nociceptive signals) from peripheral sites results in changes at all levels of the central nervous system (CNS). Genetic and environmental factors along with increases in innate (endogenous) CNS excitatory controls and decreases in inhibitory controls are also believed to contribute to the evolution of chronic pain (Marchand). Evidence-based research suggests that when acute pain does not resolve within a few months, continued activation of nerves that transmit pain (nociceptors) may result in changes in the spinal cord and brain (CNS changes) that can eventually lead to the development of chronic pain (Apkarian; Jayson). This knowledge of CNS changes due to prolonged pain may help to explain the disproportionate and non-dermatomal presentation of chronic pain and may help in the diagnosis and treatment of the individual.
Chronic pain syndrome refers to persistent pain that usually has no identifiable source and is associated with abnormal illness behaviors, including expressions of pain (moaning, groaning, gasping, or grimacing) that are grossly disproportional to any underlying cause, substance abuse involving prescription drugs, non-prescription drugs and alcohol; self-imposed prolonged excessive disuse; self-limitation of social and recreational activities; and a self-perception of total occupational disability.
Chronic pain syndrome is complex and involves multiple factors, but should be considered if a person does not respond to appropriate medical care within a reasonable time frame or if the person's pain behavior greatly exceeds the usual response to a specific disorder.
Risk: Chronic pain is reported more frequently in women than men. There is no racial predilection for chronic pain. Risk for chronic pain syndrome is increased in individuals with psychological problems such as major depression, somatization disorder, or hypochondriasis.
Incidence and Prevalence: It is estimated that about 35% of the American population has some degree of chronic pain, and up to 50 million Americans are partially or totally disabled due to chronic pain (Singh). Pain is the most frequent complaint leading individuals to seek medical care. Because pain is considered a symptom rather than a diagnosis, there are no valid incidence figures available for chronic pain itself.
Source: Medical Disability Advisor