Complex Regional Pain Syndrome

Abstract

Complex regional pain syndrome (CRPS) is a neuropathic disorder marked by pain, autonomic and vasomotor instability, and sensory abnormalities. Typically, the syndrome presents after surgery or trauma and is characterized by continuing pain which is disproportionate to the inciting event. Although some cases will resolve within the first year of presentation, many patients progress to a chronic form of the disease. CRPS type I (formerly known as reflex sympathetic dystrophy, or RSD) and CRPS II (formerly known as causalgia) are distinguished by the latter being associated with damage to a specific peripheral nerve. The diagnosis of CRPS is based mainly on history and physical examination. Multiple treatment options have been discussed in the literature, and some as discussed below show potential benefit. However, there is still no clear consensus regarding diagnosis and therapeutic algorithms.

What are the main symptoms of CRPS?	Swelling, pain, hyperesthesia/allodynia, sensory abnormalities, skin changes
What are the modalities available for diagnosis of CRPS other than history and physical examination?	Radiography (showing demineralization of the limb), triple phase bone scan, quantitative sweat test versus the contralateral limb, thermography, and diagnostic sympathetic nerve block
What changes occur in the transition to the chronic form of CRPS?	There is a transition from “warm CRPS,” which is dominated by inflammatory symptoms, to “cold CRPS,” characterized by autonomic dysfunction, atrophy, contractures, dystonia, hair/nail changes
What has been shown in some studies to decrease rates of CRPS following distal radius fracture?	Vitamin C
What are other available treatment options for CRPS?	Bisphosphonates, calcitonin, occupational therapy (graded motor imagery and mirror therapy), oral steroids, acupuncture, spinal cord stimulation, sympathectomy, and in some severe cases, amputation