Complex Regional Pain Syndrome

This syndrome was previously known as reflex sympathetic dystrophy, algodystrophy, causalgia, Sudeck atrophy, transient osteoporosis, and acute atrophy of bone. Usually occurring after an injury, CRPS presents with pain out of proportion to the injury, temperature change, edema, and abnormal skin color. Type I CRPS (90% of CRPS cases) occurs without a definable nerve lesion, while type II occurs with a definable nerve lesion. The pathogenesis is likely due to an injury causing increased sensitivity to sympathetic nerves, an abnormal response to and sensation of pain, and increased neuropeptide release causing burning pain to light touch (allodynia).