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NINDS Disorders is an index of neurological conditions provided by the National Institute of Neurological Disorders and Stroke. This valuable tool offers detailed descriptions, facts on treatment and prognosis, and patient organization contact information for over 500 identified neurological disorders.

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Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS) is a chronic pain condition.  The key symptom of CRPS is continuous, intense pain out of proportion to the severity of the injury, which gets worse rather than better over time. CRPS most often affects one of the arms, legs, hands, or feet.  Often the pain spreads to include the entire arm or leg.  Typical features include dramatic changes in the color and temperature of the skin over the affected limb or body part, accompanied by intense burning pain, skin sensitivity, sweating, and swelling.  Doctors aren’t sure what causes CRPS.  In some cases the sympathetic nervous system plays an important role in sustaining the pain.  Another theory is that CRPS is caused by a triggering of the immune response, which leads to the characteristic inflammatory symptoms of redness, warmth, and swelling in the affected area.


Because there is no cure for CRPS, treatment is aimed at relieving painful symptoms.  Doctors may prescribe topical analgesics, antidepressants, corticosteroids, and opioids to relieve pain.  However, no single drug or combination of drugs has produced consistent long-lasting improvement in symptoms.  Other treatments may include physical therapy, sympathetic nerve block, spinal cord stimulation, and intrathecal drug pumps to deliver opioids and local anesthetic agents via the spinal cord.


The prognosis for CRPS varies from person to person. Spontaneous remission from symptoms occurs in certain individuals.  Others can have unremitting pain and crippling, irreversible changes in spite of treatment.


The National Institute of Neurological Disorders and Stroke (NINDS) and other institutes of the National Institutes of Health (NIH) conduct research relating to CRPS and also support additional research through grants to major medical institutions across the country.  NINDS-supported scientists are studying new approaches to treat CRPS and intervene more aggressively after traumatic injury to lower the chances of developing the disorder.  Researchers hope to identify specific cellular and molecular changes in sensory neurons following peripheral nerve injury to better understand the processes that underlie neuroplasticity (the brain’s ability to reorganize or form new nerve connections and pathways following injury or death of nerve cells). Identifying these mechanisms could provide targets for new drug therapies that could improve recovery following regeneration.  Other researchers hope to better understand how CRPS develops by studying immune system activation and peripheral nerve signaling using an animal model of the disorder.

View a list of studies currently seeking patients.

View more studies on this condition.

Read additional information from Medline Plus.


Reflex Sympathetic Dystrophy Syndrome Association (RSDSA)

National not-for-profit organization that promotes greater public and professional awareness of RSD, a painful neurological syndrome. Raises funds for research and educates patients, their families and friends, insurance and healthcare providers, professionals, and the public.

P.O. Box 502
99 Cherry Street
Milford, CT 06460
Tel: 203-877-3790 877-662-7737
Fax: 203-882-8362

American RSDHope Organization

National nonprofit organization for patients, families, medical professionals, and others concerned with RSDS/CRPS. Offers medical information and emotional support and works to raise national awareness and funding for research.

P.O. Box 875
Harrison, ME 04040-0875
Tel: 207-583-4589

International Research Foundation for RSD/CRPS

Not-for-profit organization dedicated to education and research on RSD/CRPS. Works to establish an international research network to help educate medical professionals and support research worldwide.

1910 East Busch Boulevard
Tampa, FL 33612
Tel: 813-907-2312
Fax: 813-830-7446

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