Complex Regional Pain Syndrome (CRPS) is a chronic condition that is ranked on the McGill Pain Index as one of the most extreme manifestations of pain. CRPS is also referred to as Reflex Sympathetic Dystrophy Syndrome (RSDS) or Causalgia.

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. The condition 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.

CRPS is poorly understood by patients, their families, and health care professionals. In some cases, the condition is mild, in some it is moderate, and in others it is severe. In rare instances, pain is not a symptom which further complicates diagnosis for this mysterious condition.

A recent comprehensive literature review found that there is a critical lack of high quality effectiveness of most therapies for CRPS.

CRPS is not a psychological syndrome, but the Reflex Sympathetic Dystrophy Syndrome Association (RSDSA) states that people may develop psychological problems when physicians, family, friends, and co-workers do not believe their complaints of pain.

Several observations suggest that genetic determinants play a role in the predisposition to develop CRPS: 1) familial cases of CRPS have been reported; 2) these patients often experience severe disease marked by early disease onset, disease recurrences, spreading of the disease to multiple sites, and/or dystonia; and 3) in some instances, affected siblings show identical profiles of a key protein marker. However, a clear pattern of inheritance cannot be determined.

A recent study used MRI to compare differences in brain volume between patients with right upper extremity CRPS and matched controls. The CRPS group showed decreased gray matter volume in several pain-affected regions. Greater gray matter volume in CRPS patients was seen in the bilateral dorsal putamen and right hypothalamus. Pain duration was associated with decreased gray matter in the left dorsolateral prefrontal cortex.

Pain intensity was positively correlated with volume in the left posterior hippocampus and left amygdala, and negatively correlated with the bilateral dorsolateral prefrontal cortex. These findings demonstrate that CRPS is associated with abnormal brain system morphology, particularly pain-related sensory, affect, motor, and autonomic systems.

CRPS is a chronic pain syndrome most often characterized as constant and extremely intense pain. CRPS is thought to be a malfunction of part of the nervous system. Nerve misfire, sending constant pain signals to the brain. It develops in response to an event the body regards as traumatic, such as an accident or a medical procedure.

CRPS may follow 5% of all nerve injuries.

  • The RSDSA states that people with CRPS report seeing an average of five physicians before being accurately diagnosed.
  • CRPS is two to three times more frequent in females than males.
  • The mean age at diagnosis of CRPS is 42 years. However, health care providers are seeing more injuries among young girls. Children as young as three-years old can get CRPS.
  • One web-based survey found that CRPS frequently interfered with work (62% disability rate), sleep (96%), mobility (86%), and self-care (57%). Remissions and relapses were both common.
  • A study of 190 patients with mostly long-standing CRPS found that 21 patients (11%) had co-existing widespread pain. These patients considered their widespread pains as important in reducing their quality of life, and in most cases as equally severely as their CRPS pains. Additional patients reported have concomitant regional pains, most frequently headaches/migraines, lower back pain, and irritable bowel syndrome.
  • One study found the incidence of CRPS in the 4 months after wrist fracture was 3.8%. A prediction model based on four clinical assessments (pain, reaction time, dysynchiria (associated pain), and swelling) discriminated well between patients who would and would not subsequently develop CRPS. A simple assessment of pain intensity provided nearly the same level of discrimination. The study found that a pain score of five or greater in the first week after fracture should be considered a “red flag.”


American RSDHope Organization

For Grace

National Organization for Rare Disorders

Reflex Sympathetic Dystrophy Syndrome Association of America