pain

pain unpleasant or hurtful sensation resulting from stimulation of nerve endings. The stimulus is carried by nerve fibers to the spinal cord and then to the brain, where the nerve impulse is interpreted as pain. The excessive stimulation of nerve endings during pain is attributed to tissue damage, and in this sense pain has protective value, serving as a danger signal of disease and often facilitating diagnosis. Unlike other sensory experiences, e.g., response to touch or cold, pain may be modified by sedatives and nonsteroidal anti-inflammatory drugs or, if unusually severe, by opioid narcotics. Recently, patient-controlled analgesic techniques have been introduced, in which patients have the option of injecting small quantities of narcotic type analgesics to control their own pain. Microprocessor-controlled injections may be made through intravenous catheters, or through a catheter into the epidural (covering of the spinal cord) area. If such treatments do not suffice and if the cause of the pain cannot be removed or treated, severing a nerve in the pain pathway may bring relief.

Pain is occasionally felt not only at the site of stimulation but in other parts of the body supplied by nerves in the same sensory path; for example, the pain of angina pectoris or coronary thrombosis may extend to the left arm. This phenomenon is known as referred pain. Subjective or hysterical pain originates in the sensory centers of the brain without stimulation of the nerves at the site of the pain.

Progress has been made in the management of chronic pain and in the education of patients and physicians in such techniques as biofeedback, acupuncture, and meditation and the appropriate use of narcotics and other medications. Using advanced medical-imaging technology, researchers have now located multiple pain centers in the cerebral cortex of the brain, offering promise of possible improvements in measuring and managing pain.

Bibliography: See F. T. Vertosick, Jr., Why We Hurt: The Natural History of Pain (2000).

pain Unpleasant sensation signalling actual or threatened tissue damage as a result of illness or injury; it can be acute (severe but short-lived) or chronic (persisting for a long time). Pain is felt when specific nerve endings are stimulated. Pain is treated in a number of ways, most commonly by drugs known as analgesics.

pain (payn) n. an unpleasant sensation ranging from mild discomfort to agonized distress, associated with real or potential tissue damage. Pain is a subjective response to impulses from the peripheral nerves in damaged tissue, which pass to nerves in the spinal cord, where they are subjected to a gate control. This gate modifies the subsequent passage of the impulses in accordance with descending controls from the brain. Because attention is a crucial component of pain, distraction can act as a basis for pain therapy. On the other hand, anxiety and depression focus the attention and exaggerate the pain. If the nerve pathways are damaged, the brain can increase the amplification in the pathway, maintaining the sensation as a protective mechanism.