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 edema, 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, physical therapies, pharmacotherapy, and appropriate psychological techniques tailored to the individual patient.
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
- history of trauma
- history of immobilization
- female sex
- chronic pain
- limb pain with radiation
- allodynia and hyperalgesia
- body scheme changes
- trophic skin and nail changes
- erythema or bluish appearance
- local sweating changes or sweating asymmetry
- muscle weakness
Other diagnostic factors
- dystonic posturing
- sensory loss in glove and stocking distribution
- local changes in hair growth
- skin bullae
- female sex
- other inciting event
1st investigations to order
- no test required: diagnosis is clinical
Investigations to consider
- 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 anesthetic blocks
- quantitative sensory testing
- laser Doppler flowmetry
- sweat (sudomotor) tests
early CRPS (within 6 months of onset)
chronic CRPS (>6 months since onset)
Nicholas Shenker, BM BCh, MA, PhD, FRCP
Consultant in Rheumatology
Cambridge University Hospitals NHS Foundation Trust
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
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.
Dr Nicholas Shenker and Dr Gaurav Chhabra would like to gratefully acknowledge Dr Steven H. Horowitz, a previous contributor to this topic.
SHH declares that he has no competing interests.
Andre Tomasino, MD
Department of Neurological Surgery
Weill Cornell Medical College
New York-Presbyterian Hospital
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
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
JB has been reimbursed by Pfizer for lectures given at Pfizer-sponsored meetings and courses.
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