Complex regional pain syndrome (CRPS), formerly reflex sympathetic dystrophy (RSD) or reflex neurovascular dystrophy (RND), is an amplified musculoskeletal pain syndrome (AMPS). CRPS is associated with dysregulation of the central nervous system and autonomic nervous system resulting in multiple functional loss, impairment, and/or disability. CRPS may initially affect an arm or leg and spread throughout the body. Signs and symptoms include changes in color and temperature of the affected body part and may be accompanied with intense burning pain, sensitivity to touch, sweating, and/or swelling. CRPS is typically caused by tissue injury.


Treatments for complex regional pain syndrome can include lumbar sympathetic blocks and stellate ganglion/sympathetic blocks.