Complex regional pain syndrome

Abstract

As suggested by this article, considerable advances in clinical management and research have taken place during the past 20 years. Although mechanisms underlying the pain syndrome CRPS I and CRPS II remain far from one's understanding, glimpses of the pathophysiology are beginning to take shape. There is now strong evidence that these syndromes exemplify a complex neurologic disease involving the brain at several integrated levels. The changes that occur in CRPS I patients involve somatosensory, sympathetic, and somatomotor systems. The diagnostic criteria have helped to focus on aspects of these foregoing systems and whereas there is no specific laboratory test for CRPS, enough is now known about the pathophysiology to use the following tests: quantitative sensory testing (QST), autonomic testing that include quantitative sudomotor axon reflex test (QSART) for sweating abnormalities, the cold pressor test in conjunction with thermographic imaging to observe the vasoconstrictor response, and laser Doppler flowmetry to monitor background vasomotor control. Recognition of a motor disorder requires accurate documentation and may be a component of the diagnostic criteria in the future. Until a better understanding of mechanistic overtones that would help to put in place mechanism-based therapeutic strategies, current management is built around a rehabilitation model. For this to be successful, as described in the foregoing pages, different non-interventional and interventional modalities are applied in a time-restricted manner to facilitate those modalities that favor progress in the treatment algorithm. As has been described, it is important when using physiotherapeutic maneuvers to minimize joint movement in the affected region to reduce the mechanorecpetor barrage and its increase in perceived pain to encourage and maintain a patient's compliance with their rehabilitation. Finally, of greater significance is the understanding that sympatholysis per se is not a "diagnostic" test for CRPS, but rather a useful procedure that may facilitate treatment for pain that is sympathetically maintained.