Complex regional pain syndrome (CRPS) is a chronic neurological syndrome characterized by: severe burning pain, pathological changes in bone and skin, excessive sweating, tissue swelling and extreme sensitivity to touch. It is best described in terms of an injury to a nerve or soft tissue (e.g. broken bone) that does not follow the normal healing path CRPS development does not appear to depend on the magnitude of the injury. The sympathetic nervous system seems to assume an abnormal function after an injury.
This syndrome occurs after 1 to 2 % of various fractures, after 2 to 5% of peripheral nerve injuries, and 7 to 35% of prospective studies of Colles fracture of the wrist (distal radius). In the USA, surveys of veterans suggest that the incidence of causalgia following injury to a peripheral nerve is 1-5%. The likelihood of developing CRPS/RSD is higher if the lesion is distal or if the sciatic nerve is affected. The diagnosis is often not made early and some of the very mild cases may resolve with no treatment and others may progress through the stages and become chronic, and often debilitating.
The highest incidence of the disease appears to be in adults aged 40-49 years; it appears frequently in almost every age group except children. RSD/CRPS type 1 has been described in children, but the incidence is much lower than in adults. RSD affects all races; no racial predilection is observed. A female predominance exists; female-to-male ratio is 2:1.