ABSTRACT
The complex regional pain syndromes (CRPS) comprise a variety of clinical presentations in which severe pain is associated with vasomotor changes and dysfunction in response to injury. Previously known as reflex sympathetic dystrophy and causalgia, the latter being a description of the presentation following specific nerve injury, they were reclassified in 1994 in an attempt to distance the syndromes from the implication that the sympathetic nervous system was always involved in the pathophysiology. However, the new taxonomy is by no means universally accepted, and references to the old taxonomy are regularly found in the literature. The syndromes also include conditions known as ‘shoulder-hand syndrome’, ‘Sudek’s atrophy’ and ‘algodystrophy’. The complex regional pain syndromes are neuropathic pain syndromes (type 2 is defined by the presence of nerve injury as the primary mechanism).
