Clinical features and pathophysiology of complex regional pain syndrome.

A complex regional pain syndrome (CRPS)--multiple system dysfunction, severe and often chronic pain, and disability--can be triggered by a minor injury, a fact that has fascinated scientists and perplexed clinicians for decades. However, substantial advances across several medical disciplines have recently improved our understanding of CRPS. Compelling evidence implicates biological pathways that underlie aberrant inflammation, vasomotor dysfunction, and maladaptive neuroplasticity in the clinical features of CRPS. Collectively, the evidence points to CRPS being a multifactorial disorder that is associated with an aberrant host response to tissue injury. Variation in susceptibility to perturbed regulation of any of the underlying biological pathways probably accounts for the clinical heterogeneity of CRPS.