Pain Management Health Center

Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS), also called reflex sympathetic dystrophy syndrome, is a chronic pain condition in which high levels of nerve impulses are sent to an affected site. Experts believe that CRPS occurs as a result of dysfunction in the central or peripheral nervous systems.

CRPS is most common in people aged 20-35. The syndrome also can occur in children; it affects women more often than men.

There is no cure for CRPS.

What Causes Complex Regional Pain Syndrome?

CRPS most likely does not have a single cause; rather, it results from multiple causes that produce similar symptoms. Some theories suggest that pain receptors in the affected part of the body become responsive to catecholamines, a group of nervous system messengers. In cases of injury-related CRPS, the syndrome may be caused by a triggering of the immune response which may lead to the inflammatory symptoms of redness, warmth, and swelling in the affected area. For this reason, it is believed that CRPS may represent a disruption of the healing process.

What Are the Symptoms of Complex Regional Pain Syndrome?

The symptoms of CRPS vary in their severity and length. One symptom of CRPS is continuous, intense pain that gets worse rather than better over time. If CRPS occurs after an injury, it may seem out of proportion to the severity of the injury. Even in cases involving an injury only to a finger or toe, pain can spread to include the entire arm or leg. In some cases, pain can even travel to the opposite extremity. Other symptoms of CRPS include:

• "Burning" pain
• Swelling and stiffness in affected joints
• Motor disability, with decreased ability to move the affected body part
• Changes in nail and hair growth patterns: There may be rapid hair growth or no hair growth.
• Skin changes: CRPS can involve changes in skin temperature -- skin on one extremity can feel warmer or cooler compared to the opposite extremity. Skin color may become blotchy, pale, purple or red. The texture of skin also can change, becoming shiny and thin. People with CRPS may have skin that sometimes is excessively sweaty.

CRPS may be heightened by emotional stress.

How Is Complex Regional Pain Syndrome Diagnosed?

There is no specific diagnostic test for CRPS, but some testing can rule out other conditions. Triple-phase bone scans can be used to identify changes in the bone and in blood circulation. Some health care providers may apply a stimulus (for example, heat, touch, cold) to determine whether there is pain in a specific area.

Making a firm diagnosis of CRPS may be difficult early in the course of the disorder when symptoms are few or mild. CRPS is diagnosed primarily through observation of the following symptoms:

• The presence of an initial injury
• A higher-than-expected amount of pain from an injury
• A change in appearance of an affected area
• No other cause of pain or altered appearance