Complex regional pain syndrome
Evidence: Unconfirmed
Names
Amplified musculoskeletal pain syndrome
Causalgia
Complex Regional Pain Syndrome
Reflex Sympathetic Dystrophy
Description
Complex regional pain syndrome (CRPS) and amplified musculoskeletal pain syndromes (AMPS) are chronic pain conditions lasting at least 6 months. CRPS is often triggered by an injury followed by immobilization, and is marked by pain that does not diminish in a manner typical for the injury. Patients experience unreasonably intense pain in the arms, legs, hands, or feet, both in response to painful and non-painful triggers. Pain can include burning, tingling, or squeezing sensations. Redness and swelling are often present in the affected area.
There are two types of CRPS. Patients with CRPS-I/Reflex Sympathetic Dystrophy do not have a confirmed nerve injury, whereas patients with CRPS-II/Causalgia do have an associated, confirmed nerve injury. CRPS usually occurs after an injury that caused damage to the nervous system.
The cause is unknown but there are correlations with immune processes that result in swelling surrounding injury. Treatments are available to manage symptoms, which help some patients, but not all. Younger patients are more likely to recover than older patients, whose pain may persist and lead to disability.
There is no known cause, and autoimmunity is suspected, but no evidence of autoimmunity has been definitively linked to CRPS.
Patient Groups
Prevalence
US Cases: 65,000 [Sandroni 2003]
Typical Age of onset
50-70 years of age
Source: Guthmiller and Varacallo (2019)
Symptoms
Chronic pain in the limbs
Initial redness and swelling of the affected area followed by coolness and blue coloring
Thin, shiny skin over the affected area
Changes in nail and hair growth patterns on the affected limb
Stiffness in the affected joints/limbs
Decreased mobility or coordination in affected limb
Tremors or involuntary spasms (dystonia)
