Complex regional pain syndrome workshop at Cardiff: editorial.

Complex regional pain syndrome (CRPS) is the current taxonomic label for a syndrome previously known by many names (reflex sympathetic dystrophy, causalgia, Sudeck’s atrophy, shoulder-hand syndrome, neuroalgodystrophy, reflex neurovascular dystrophy, etc). It is an inflammatory and neuropathic pain disorder, often involving both peripheral and central sensitization, but principally characterized by regional dysfunction of the autonomic nervous system. It involves a full measure of bio-psychosocial features and it can be significantly disabling. CRPS remains one of the most enigmatic and difficult to treat of all pain conditions probably in large part due to the fact that the pathophysiology remains poorly characterized. In fact, there is increasing consensus that CRPS is unlikely to be caused by a single, simple pathophysiological mechanism. Rather, it is likely to be the result of multiple interacting systems throughout the neuroaxis, with varying relative contributions of these various mechanisms across different patients at different times.