Current Trends in the Diagnosis and Treatment of Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS) is a painful and debilitating disorder affecting mainly one or more extremities. The key features are spontaneous pain, hyperalgesia, allodynia, edema, temperature change, abnormal vasomotor and sudomotor activity, trophic changes, and motor dysfunction (see Appendix). CRPS has two types, and the International Association for the Study of Pain (IASP) has established diagnostic criteria for both. The criteria required to diagnose CRPS type I include: (1) the presence of an initiating noxious event or a cause of immobilization; (2) continuing pain, allodynia, or hyperalgesia with pain disproportionate to the inciting event; (3) evidence at some time of edema, changes in skin blood flow, or abnormal sudomotor activity in the region of the pain; and (4) the exclusion of medical conditions that would otherwise account for the degree of pain and dysfunction. CRPS type II requires: (1) the presence of continuing pain, allodynia, or hyperalgesia after a nerve injury, not necessarily limited to the distribution of the injured nerve; (2) evidence at some time of edema, changes in skin blood flow, or abnormal sudomotor activity in the region of the pain; and (3) the exclusion of any medical condition that would otherwise account for the degree of pain and dysfunction (Table 1).