Complex regional pain syndrome (CRPS) refers to a chronic condition that affects the nerves and blood vessels of one or more limbs.

There are two types of CRPS:

  • CRPS 1, also called reflex sympathetic dystrophy or RSD, has no observable nerve damage.
  • CRPS 2, also called causalgia, produces similar symptoms after a verified nerve injury has occurred.

Complex Regional Pain Syndrome
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The cause of CRPS is not known. The condition likely results from several factors. It may involve overactivity of the sympathetic nervous system. This directs automatic body functions that a person cannot control. Inflammation may also play a role in the disorder.