CRPS stands for Complex Regional Pain Syndrome. This syndrome can be caused by trauma or injury to a part of the body, resulting in nerve and other chronic pain. It’s an interesting syndrome in that there are people without a documented injury to the affected part of the body that are diagnosed. CRPS can affect the immune system, blood vessels and flow, and other parts of the nervous system.
Other symptoms include allodynia, changes to the skin surrounding the affected area, stiffness, and tremors.
Since some of these symptoms mirror rheumatic diseases, there is a lot of exclusionary testing with this diagnosis.
Treatment varies significantly from case to case. Steroids and NSAIDs can help, or nerve medications like Lyrica may need to be used. There are more severe methods of treating this disease as well including surgery, nerve blocks, and more.
Sources:
http://www.ninds.nih.gov/disorders/reflex_sympathetic_dystrophy/detail_reflex_sympathetic_dystrophy.htm