Mechanism-based treatment in complex regional pain syndromes.

Complex regional pain syndromes (CRPS) are multifactorial disorders with complex aetiology and pathogenesis. Management of CRPS is challenging, partly because of a lack of clinical data regarding the efficacy of the various therapies, and partly because successful treatment of CRPS requires a multidisciplinary, patient-tailored approach. The pain in CRPS is often described as typical 'burning' neuropathic pain, and is accompanied by a variety of sensory, motor and autonomic signs and symptoms. Because research into therapies specifically in CRPS has been scarce, treatment for these syndromes has been largely based on therapeutic strategies adapted from neuropathic pain states; however, increased understanding of the pathogenesis of CRPS has provided the opportunity to develop mechanism-based treatments. The interactions between the multiple pathophysiological mechanisms that contribute to the development, progression and maintenance of CRPS remain poorly understood. This Review describes the challenges in linking the current theories and knowledge of pathophysiological mechanisms to the mode of actions of the different treatment approaches. We discuss the current treatment strategies for CRPS, including pharmacotherapy, sympathetic ganglion block interventions, psychological support, physiotherapy and occupational therapy, and establish the concept of mechanism-based treatment for CRPS.