Complex regional pain syndrome

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Last reviewed: January 2019

Last updated: March 2018

Summary

Prolonged pain, disproportionate to the initiating event, most frequently following minor trauma and most commonly affecting the distal aspect of an extremity.

Pain often described as spontaneous, burning, lancinating, sharp, shooting, or electric. Characteristically develops dull, boring, and aching qualities with chronicity. Allodynia and hyperalgesia are almost always present.

Local oedema, erythema, sweating abnormalities, and trophic skin and nail changes are often, but not always, present.

Affected extremity is often held immobile, resulting in dystonia, focal weakness, and contractures, probably due to disuse.

Diagnosis is clinical. No specific tests are diagnostic for this condition.

The main focus of treatment is adequate analgesia and improvement of mobility and function.

Definition

Complex regional pain syndrome (CRPS) is defined as continuing (spontaneous and/or evoked) regional pain out of proportion to the severity of the inciting event and beyond the normal time frame expected following the event. The pain is usually regional (not in a specific nerve territory or dermatome) and has a distal predominance of abnormal sensory, motor, sudomotor, vasomotor, and/or trophic findings with variable progression over time.

History and exam

Key diagnostic factors

presence of risk factors
chronic pain
limb pain with radiation
allodynia and hyperalgesia
oedema
trophic skin and nail changes
erythema or bluish appearance
local sweating changes or sweating asymmetry
muscle weakness

Full details

Other diagnostic factors

tremors
dystonic posturing
contractures
sensory loss in glove and stocking distribution
local changes in hair growth
skin bullae

Full details

Risk factors

trauma
immobilisation
female gender
other inciting event

Full details

Diagnostic investigations

1st investigations to order

no test required: diagnosis is clinical

Full details

Investigations to consider

nerve conduction studies with surface electrodes
EMG
punch skin biopsy
radiograph of affected limb
bone scintigraphy with technetium 99m
DXA
sympathetic nerve blocks
intravenous regional anaesthetic blocks

Full details

Emerging tests

quantitative sensory testing
thermography
laser Doppler flowmetry
sweat (sudomotor) tests

Full details

Treatment algorithm

ONGOING

early CRPS (within 6 months of onset)

chronic CRPS (>6 months since onset)

Contributors

Authors VIEW ALL 

Steven H. Horowitz, MD

Adjunct Clinical Professor

Department of Neurology

Tufts University School of Medicine

Boston

MA

Disclosures

SHH declares that he has no competing interests.

Peer reviewers VIEW ALL 

Andre Tomasino, MD

Department of Neurological Surgery

Weill Cornell Medical College

New York-Presbyterian Hospital

New York

NY

Disclosures

AT declares that he has no competing interests.

Ari Weinreb, MD, PhD

Associate Chief of Rheumatology

VA Greater Los Angeles Healthcare System

Associate Professor of Medicine

David Geffen School of Medicine

UCLA

Los Angeles

CA

Disclosures

AW declares that he has no competing interests.

Jonathan Berman, MBBS

Consultant in Pain Management and Anaesthesia

Pain Management Department

Royal National Orthopaedic Hospital NHS Trust

Middlesex

UK

Disclosures

JB has been reimbursed by Pfizer for a number of lectures given at Pfizer-sponsored meetings and courses.

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