Complex regional pain syndrome

Last reviewed: 28 Oct 2022

Last updated: 17 Dec 2019

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.

The affected extremity is often held immobile, and this can be associated with dystonia, focal weakness, and contractures.

Diagnosis is clinical. No specific tests are diagnostic; investigations may be useful to support the diagnosis or rule out alternative pathology.

The treatment goal is functional restoration of a limb by using adequate pain management techniques, with patient education, physiotherapies, pharmacotherapy, and appropriate psychological techniques tailored to the individual patient.

Definition

Complex regional pain syndrome (CRPS) is defined as continuing (spontaneous and/or evoked) regional pain that is 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
body scheme changes
oedema
trophic skin and nail changes
erythema or bluish appearance
local sweating changes or sweating asymmetry
muscle weakness

More key diagnostic factors

Other diagnostic factors

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

Other diagnostic factors

Risk factors

trauma
immobilisation
female sex
other inciting event

More risk factors

Diagnostic investigations

1st investigations to order

no test required: diagnosis is clinical

More 1st investigations to order

Investigations to consider

electromyogram
nerve conduction studies with surface electrodes
punch skin biopsy
radiograph of affected limb
bone scintigraphy with technetium 99m
dual-energy x-ray absorptiometry (DXA)
quantitative CT scan
MRI testing
vascular studies
sympathetic nerve blocks
intravenous regional anaesthetic blocks

More investigations to consider

Emerging tests

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

Treatment algorithm

ONGOING

early CRPS (within 6 months of onset)

chronic CRPS (>6 months since onset)

Contributors

Authors

Nicholas Shenker, BM BCh, MA, PhD, FRCP

Consultant in Rheumatology

Cambridge University Hospitals NHS Foundation Trust

Addenbrooke's Hospital

Cambridge

Disclosures

NS is medical adviser to Cambridge Nutraceuticals with stock options. He has received consultancy fees from Roche to provide unrestricted sponsored educational meetings, and grants from Versus Arthritis, the National Institute for Health Research Clinical Research Network, and the Medical Research Council. NS is an author of references cited in this topic.

Gaurav Chhabra, MBBS, FRCA, FFPMRCA

Consultant in Pain Medicine and Anaesthesia

North Bristol NHS Trust

Bristol

Disclosures

GC has been sponsored by Medtronic, Boston Scientific, Abbott, Nevro, Stimwave, and Polar Medical for attending various conferences and cadaveric workshops relevant to pain medicine and neuromodulation. GC is an associate examiner for the European Society of Regional Anaesthesia & Pain Therapy European Diploma of Pain Medicine exam and is also the regional advisor for pain medicine for the South West Severn deanery.

Acknowledgements

Dr Nicholas Shenker and Dr Gaurav Chhabra would like to gratefully acknowledge Dr Steven H. Horowitz, a previous contributor to this topic.

Disclosures

SHH declares that he has no competing interests.

Peer reviewers

Andre Tomasino, MD

Department of Neurological Surgery

Weill Cornell Medical College

New York-Presbyterian Hospital

New York

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

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

Disclosures

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

Differentials
- Infection
- Arterial compromise
- Bone pathology
More Differentials
Guidelines
- Neuropathic pain in adults: pharmacological management in non-specialist settings
- Standards for the diagnosis and management of complex regional pain syndrome
More Guidelines
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Complex regional pain syndrome

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

1st investigations to order

Investigations to consider

Emerging tests

Treatment algorithm

early CRPS (within 6 months of onset)

chronic CRPS (>6 months since onset)

Contributors

Authors

Nicholas Shenker, BM BCh, MA, PhD, FRCP

Disclosures

Gaurav Chhabra, MBBS, FRCA, FFPMRCA

Disclosures

Acknowledgements

Disclosures

Peer reviewers

Andre Tomasino, MD

Disclosures

Ari Weinreb, MD, PhD

Disclosures

Jonathan Berman, MBBS

Disclosures

Differentials

Guidelines

Log in or subscribe to access all of BMJ Best Practice

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