Complex Regional Pain Syndrome (CRPS)

What is Complex Regional Pain Syndrome?

Complex regional pain syndrome (CRPS) is a rare disorder leading to chronic pain in an arm or leg, rarely other parts of the body. Usually it follows injury but may occur after surgery, stroke or a heart attack.The pain is out of proportion to the initial injury and persists for a very long time. Other names for this condition include reflex sympathetic dystrophy or causalgia. The reasons for this condition are not clear. Many cases improve with time especially if treatment is initiated earlier on. In some cases however, the patient experiences persistent pain for several years.

It is a rare condition with a reported incidence of 26 per 100,000 in Europe. The incidence rises with increasing age with a peak incidence around 40 years, and is more common in women. The arm is affected more often than the leg. It is rare in the older age group. It is uncommon in children with peak incidence during adolescence and is more often reported in the lower limb. Again the incidence is much higher in girls than in boys.

What are the Causes and Risk Factors of Complex Regional Pain Syndrome

The cause of complex regional pain syndrome is unclear but is believed to be due to damage or injury to the nervous system leading to inappropriate and abnormal pain response. As stated previously, it mostly follows traumatic injury such as

• Fractures
• Sprains or muscle pulls
• Amputation
• Minor cuts and bruises
• Crush injury
• Surgery
• Minor injury such as needle pricks

Risk Factors of CRPS

• Immobilization of the affected limb
• Having a sibling with young age at onset of CRPS
• History of migraine or asthma
• Ingestion of angiotensin converting enzyme (ACE) inhibitors at the time of injury