Complex Regional Pain Syndrome
Medicine Central™ is a quick-consult mobile and web resource that includes diagnosis, treatment, medications, and follow-up information on over 700 diseases and disorders, providing fast answers—anytime, anywhere. Explore these free sample topics:
-- The first section of this topic is shown below --
- Complex regional pain syndrome (CRPS) is a pain syndrome that can be chronic and debilitating. It is divided into two subtypes and can have significant physical and psychosocial short- and long-term disability. Most cases are a result of a physical insult to an extremity such as trauma or surgery.
- Type I: no nerve injury (reflex sympathetic dystrophy [RSD])
- Type II: associated with a demonstrable nerve injury (causalgia)
- Synonym(s): traumatic erythromelalgia; Weir Mitchell causalgia; causalgia; RSD; posttraumatic neuralgia; sympathetically maintained pain
- Incidence of 5.46/100,000 for type I and 0.82/100,000 for type II in United States (1)
- Peak age 50 to 70 years
- Predominant gender: female > male (3:1, 60–81%), favoring postmenopausal
- Recent studies found 3.8% occurrence after wrist fracture and 7% occurrence after intra-articular ankle fracture—both independent strong risk for CRPS (2)[B].
- More prevalent in patients that report higher than usual expected pain in early phases of trauma (2)
Etiology and Pathophysiology
- Poorly understood activation of abnormal sympathetic reflex that lowers pain threshold
- Increased excitability of nociceptive neurons in the spinal cord; “central sensitization”
- Exaggerated responses to normally nonpainful stimuli (hyperalgesia, allodynia)
- Other than known nerve injury (type II or causalgia), no known definitive pathogenesis
No known genetic pattern
- Minor or severe trauma (upper extremity fracture noted in 44%)
- Surgery (particularly carpal tunnel release)
- Casting/immobilization after extremity injury
- Penetrating injury
- Polymyalgia rheumatica
- Myocardial infarction (MI)
- Cerebral vascular accident
- Early mobilization after fracture, stroke, and MI has proven benefit in reducing incidence of CRPS.
- One study of wrist fractures found that addition of 500 mg/day of vitamin C lowered rates of CRPS.
- There is evidence that limiting use of tourniquets, liberal regional anesthetic use, and ensuring adequate perioperative analgesia can reduce the incidence of CRPS-I.
Commonly Associated Conditions
- Serious injury to bone and soft tissue
- Herpes zoster
- Postherpetic neuralgia results from partial or complete damage to afferent nerve pathways.
- Pain occurs in dermatomes as a sequela of herpes zoster.