Complex Regional Pain Syndrome (CRPS) is a chronic progressive disease characterized by severe pain, swelling and changes in the skin. The International Association for the Study of Pain [1] has divided CRPS into two types based on the presence of nerve lesion following the injury.

• Type I, also known as Reflex Sympathetic Dystrophy (RSD), Sudeck's atrophy, Reflex Neurovascular Dystrophy (RND) or Algoneurodystrophy, does not have demonstrable nerve lesions.
• Type II, also known as Causalgia, has evidence of obvious nerve damage.

The cause of this syndrome is currently unknown. Precipitating factors include illness, injury and surgery, although there are documented cases that have no documentable injury to the original site.