Chronic Pain Syndromes

Chronic pain persists for three months or longer, often after the original injury should have healed. It is not simply acute pain that has lasted too long. Repeated nociceptive input can change how the nervous system detects, amplifies, and inhibits danger signals. Central sensitization is one contributor. Dorsal horn neurons become more excitable, descending inhibitory pathways become less effective, and the nervous system may begin to interpret ordinarily non-threatening input as painful. A light touch may hurt, movement may feel disproportionately threatening, and pain can spread beyond the original injury site. The pain is real even when imaging is normal or tissue damage no longer explains its intensity. Pain is best understood as a protective output of the nervous system, not a direct measuring device for tissue damage. A smoke alarm may keep sounding after the fire is out because its circuitry has become overly sensitive. Chronic pain does not mean that a new problem cannot occur, however. New symptoms must never be dismissed as “just the chronic pain.” Chronic low back pain, fibromyalgia, chronic headache disorders, complex regional pain...