Complex Regional Pain Syndrome, Causalgia, and Reflex Sympathetic Dystrophy

Complex regional pain syndrome (CRPS) has become the preferred term for a syndrome of pain that is usually out of proportion to the physical findings but still accompanied by evidence of extremity swelling, joint stiffness, vasomotor instability, and skeletal demineralization. The active component is often slow to resolve, in occasional cases taking as long as 2 years, and often residual joint stiffness is left in its wake. CRPS was formerly known as reflex sympathetic dystrophy (RSD). Causalgia is a related and similar phenomenon that is a result of trauma to a peripheral nerve, rather than the still unclear nervous system origin for CRPS. With this information as background, the following cautions are appropriate for the physician undertaking examination of a patient with a pain syndrome:

Be familiar with the discussion of pain in Chapter 5.
Physical findings should corroborate evidence of chronic pain (i.e., guarding, muscle atrophy, skin changes).
The condition should have existed long enough that the examiner is convinced that it has reached its terminal point, (i.e., maximal medical improvement) and will not be significantly improved by the natural course of the condition (CRPS) or by treatment.
Impairment ratings in the higher classes are quite extreme, and the evaluator should have evidence of the home, work, or social situation to substantiate the rating.