CRPS may develop following an injury or surgery. The exact cause is not clear, but multiple mechanisms may be involved. Research published in 2005 lists the likely mechanisms as:
__trauma-related release of cytokines, substances produced by the immune system
__exaggerated inflammation in the nervous system
__changes to the nervous system that cause the pain to continue
Some people may have an existing abnormality in the peripheral nerves that make them more sensitive if damage occurs. If the individual experiences an injury, they may react to it in a different way than most people do.
Some theories propose that inflammation and changes in the brain and sympathetic, peripheral, and spinal nervous systems, aggravated by immobility, may contribute.
CPRS does not always result from an obvious injury. It may happen because of damage that has occurred internally, such as a blood vessel problem.
If CPRS occurs in members of the same family, it may be more severe, suggesting that genetic factors may play a role or make some people more susceptible.