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Complex Regional Pain Syndrome

By John Markman, MD, Sri Kamesh Narasimhan, PhD

Complex regional pain syndrome is characterized by persistent burning or aching pain plus certain abnormalities that occur in the same area as the pain. Abnormalities include increased or decreased sweating, swelling, changes in skin color, damage to the skin, hair loss, cracked or thickened nails, muscle wasting and weakness, and bone loss.

The pain often causes people to limit their use of the affected part. As a result, muscles may become stiff and shortened (called a contracture), and people may be unable to move a joint normally, through its normal range of motion.

This syndrome typically occurs after an injury. There are two types:

  • Type 1, which used to be called reflex sympathetic dystrophy, results from injury to tissues other than nerve tissue, as when bone is crushed in an accident or when heart tissue is damaged in a heart attack.

  • Type 2, which used to be called causalgia, results from injury to nerve tissue.

Sometimes complex regional pain syndrome is made worse by activity of the sympathetic nervous system, which normally prepares the body for stressful or emergency situations—for fight or flight. For this reason, doctors may suggest treatment with a sympathetic nerve block.


  • Physical and/or occupational therapy

  • Stimulation of nerves or the spinal cord

  • Pain relievers (analgesics and adjuvant analgesics)

  • Psychologic therapy

Usually, a combination of treatments is used to treat complex regional pain syndrome.

Physical therapy can help in the following ways:

  • Making sure that people move the painful part to prevent muscles from wasting away

  • Maintaining and/or increasing range of motion and helping prevent scar tissue from forming around unused joints

  • Making the affected area less sensitive to the pain (desensitization)

  • Enabling people to function better

Nerves or the spinal cord can be stimulated to reduce the pain's intensity.

Spinal cord stimulation involves surgically placing a spinal cord stimulator (a device that generates electrical impulses) under the skin, usually in a buttock or abdomen. Small wires (leads) from the device are placed in the space around the spinal cord (epidural space). These impulses change the way pain signals are sent to the brain and thus change how unpleasant symptoms are perceived.

Transcutaneous electrical nerve stimulation (TENS) can also be used, but there is far less evidence for its effectiveness than there is for spinal cord stimulation. TENS involves placing electrodes on the skin. The electrodes produce a low current that causes tingling but does not cause muscles to contract.

Analgesics and adjuvant analgesics (such as antidepressants and anticonvulsants) may be used to relieve the pain.

Psychologic therapy may also be used.

* This is the Consumer Version. *