Complex regional pain syndrome – Mechanisms, diagnosis, and management

Abstract

Complex regional pain syndrome (CRPS) is a chronic neurological disorder characterized by regional disabling pain, increased sensitivity to tactile stimuli, swelling, vasomotor and sudomotor abnormality, and impairment of motor function. The disorder usually develops after minor trauma (contusions, sprains, and fractures) or surgery. No specific diagnostic test is available; hence, diagnosis is based mainly on history, clinical examination, and supportive laboratory findings. Evidence suggests that this interaction between peripheral and central systems arises from a number of sources including sympathetic–afferent coupling, re-organization of the central autonomic control, and changes in the somatomotor system and peripheral inflammation. Oral, topical, and intravenous medications targeting alpha-adrenergic receptors (clonidine) and the sympathetic nervous system have not been proven effective by Randomised Controlled Trials. The most commonly used agents, such as anticonvulsants, antidepressants, and opioids, have been found to be useful for other neuropathic pain conditions in large-scale trials but have not been adequately studied in CRPS. This article explores an interdisciplinary setting with comprehensive approach (pharmacological, interventional, and psychological in conjunction with rehabilitation pathway) as the protocol for the practical management of CRPS. Insight in predisposing factors may facilitate early diagnosis and elucidate underlying mechanisms that could provide targets for pharmacotherapy.