No Responses to “Complex regional pain syndrome This condition is also known as reflex sympathetic dystrophy. The symptoms can worsen over time and spread through the body as they are reinforced in the cycle shown here. The sympathetic response (green) from the brain (upper right) to the pain impulses (blue) cause vessel spasms (lower right) that increase the pain. In this case, the pain and swelling are in the hand, but other areas of the body can also be affected. It is severely painful and treatment is difficult, involving drugs, electrical stimulation, and psychological and neurological forms of therapy.”