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Complex Regional Pain Syndrome

Complex Regional Pain Syndrome is a topic covered in the 5-Minute Clinical Consult.

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  • 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

Risk Factors

  • Minor or severe trauma (upper extremity fracture noted in 44%)
  • Surgery (particularly carpal tunnel release)
  • Lacerations
  • Burns
  • Frostbite
  • Casting/immobilization after extremity injury
  • Penetrating injury
  • Polymyalgia rheumatica
  • Myocardial infarction (MI)
  • Cerebral vascular accident

General Prevention

  • 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.

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Stephens, Mark B., et al., editors. "Complex Regional Pain Syndrome." 5-Minute Clinical Consult, 27th ed., Wolters Kluwer, 2019. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116940/all/Complex_Regional_Pain_Syndrome.
Complex Regional Pain Syndrome. In: Stephens MB, Golding J, Baldor RA, et al, eds. 5-Minute Clinical Consult. 27th ed. Wolters Kluwer; 2019. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116940/all/Complex_Regional_Pain_Syndrome. Accessed April 24, 2019.
Complex Regional Pain Syndrome. (2019). In Stephens, M. B., Golding, J., Baldor, R. A., & Domino, F. J. (Eds.), 5-Minute Clinical Consult. Available from https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116940/all/Complex_Regional_Pain_Syndrome
Complex Regional Pain Syndrome [Internet]. In: Stephens MB, Golding J, Baldor RA, Domino FJ, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2019. [cited 2019 April 24]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116940/all/Complex_Regional_Pain_Syndrome.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Complex Regional Pain Syndrome ID - 116940 ED - Stephens,Mark B, ED - Golding,Jeremy, ED - Baldor,Robert A, ED - Domino,Frank J, BT - 5-Minute Clinical Consult, Updating UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116940/all/Complex_Regional_Pain_Syndrome PB - Wolters Kluwer ET - 27 DB - Medicine Central DP - Unbound Medicine ER -