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Complex regional pain syndrome medicalises limb pain

BMJ 2014; 348 doi: https://doi.org/10.1136/bmj.g2631 (Published 28 April 2014) Cite this as: BMJ 2014;348:g2631

Re: Complex regional pain syndrome medicalises limb pain

Sir,

We have read with interest the recent Personal View by Dr. Chris Bass on Complex Regional Pain Syndrome1.

For clarification, Complex Regional Pain Syndrome (CRPS) is an uncommon disorder affecting limbs, which in over 90% of cases arises after trauma. Comprehensive reviews on CRPS have been published 2 3, and the UK Royal College of Physicians has supported the development of the UK Guidance, which was recently published with the support of over 20 UK professional organisations and Royal Colleges, including the British Psychological Society4 5. A guidance chapter for the diagnosis and management of CRPS in psychiatric practice is currently being written by a multidisciplinary group, which includes representation from the Royal College of Psychiatrists; this will be available with the first revision of the UK CRPS Guidance in 2015. Dutch and US guidance is also available.

Dr. Bass makes four propositions (a-d), which need to be refuted, and additional suggestions (e-f), which should be addressed:

a) Dr. Bass asserts that CRPS can be diagnosed on the basis of sensory and motor signs. This is incorrect – the Budapest diagnostic criteria require the presence of additional symptoms. A synopsis of the CRPS diagnostic criteria can be found in appendix 4 of the referenced ‘long’ UK Guidance.

b) Dr. Bass indicates that CRPS, when diagnosed in GP practice should best be managed first by identifying possible yellow flags, then arranging referral for an (unspecified) ‘appropriate intervention’. This proposed management strategy conflicts with the Royal College of Physicians guidance for the management of CRPS in GP practice, which has been supported by the RCGP. The latter guidance proposes that GPs refer patients to Pain Medicine Specialists or (for complex multiple disabilities) to Rehabilitation Specialists (except in mild cases). Specific treatments and expertise are then available through these services.

c) ‘..abundant evidence shows that it is psychosocial, not biological factors, that are associated with a higher likelihood of developing chronic painful disorders…’ Here Dr. Bass abandons the discussion on CRPS altogether for a more general discussion on chronic pain. In CRPS research, the pre-existence of major psychological factors has now been soundly refuted6. Dr. Bass would do well do acknowledge such population-based research. In these same studies CRPS was associated with ACE inhibitor intake (but not with intake of other anti-hypertensives) 7, and asthma (but not COPD) 6, highlighting a likely contribution from neurogenic inflammation, which had earlier already been suggested in microdialysis studies 8. The prospective (but not population-based) study of patients after limb fracture by Berthuitzen et al., which Dr. Bass cites, again found no correlation between psychological factors and the development of CRPS; in contrast biological factors such as intra-articular fractures and fracture dislocations were correlated 9. Further research is indeed called for to assess the impact of psychological factors on variability after trauma, but until the results of such research are available, they should not be pre-empted.

d) Dr. Bass calls for appropriate education and training for clinicians working in pain clinics. We could not agree more. Dr. Bass should feel reassured by the rigorous training and examination programme which Pain Medicine Consultants now undertake to achieve the professional qualification of Fellowship of the Faculty of Pain Medicine of the Royal College of Anaesthetists (FFPMRCA). It is disappointing that this has not been acknowledged.

e) Dr. Bass calls for adequate psychological services in pain clinics. Such a call is in keeping with a modern understanding of Pain Medicine, and should be applauded (see http://www.britishpainsociety.org for details on UK initiatives to secure multidisciplinary provision of pain services). The primary goal is to treat patients in their biopsychosocial contexts. It is not to elucidate psychological causative factors (with selected exceptions where the input of psychiatrists is indeed important). The idea, that we should generally look for non-biological causative factors for CRPS in order to then help the patient by treating their psychology has been largely discredited 9-11, and has the potential to cause harm by suggesting their condition is psychological/psychiatric, when this is not the case.

f) We believe that Dr. Bass is right to point out the potential for causing iatrogenic damage by making an inappropriate diagnosis, which he says he has many times witnessed. We too have seen inappropriate diagnoses of CRPS, although these are normally relatively easily recognised and refuted by appropriately trained professionals. Of note, in medico-legal practice, the diagnosis of CRPS poses particular challenges, but a discussion around the judicial system is beyond the scope of this letter.

In summary, whilst we are mindful that this is a ‘personal view’, the viewpoint of Dr Bass leaves us somewhat underwhelmed as it lacks medical and diagnostic accuracy and makes only partial reference to the available literature. We are concerned that BMJ readers may have been misinformed or misguided. Full information and guidance on the management of CRPS are detailed in the UK CRPS Guidelines [6].

Dr. Andreas Goebel, Chair UK CRPS Guideline Group
Dr. William Campbell, President British Pain Society
Dr. Beverly Collett, Chair Chronic Pain Policy Commission
Dr. Martin Johnson, RCGP Lead for Chronic Pain
Dr. Kate Grady, Dean Faculty of Pain Medicine Royal College of Anaesthetists

Bibliography

1. Bass C. Complex regional pain syndrome medicalises limb pain. BMJ 2014;348:g2631.
2. Marinus J, Moseley GL, Birklein F, Baron R, Maihofner C, Kingery WS, et al. Clinical features and pathophysiology of complex regional pain syndrome. Lancet Neurol. 2011/7;10(7):637-48.
3. Goebel A. Complex regional pain syndrome in adults. Rheumatology (Oxford) 2011/10;50(10):1739-50.
4. Turner-Stokes L, Goebel A. Complex regional pain syndrome in adults: concise guidance. Clin Med 2011;11(6):596-600.
5. Goebel AB, Ch; Turner-Stokes, L; et al. Complex Regional Pain Syndrome in Adults. UK guidelines for diagnosis, referral and management in primary and secondary care. London: Royal College of Physicians, 2012.
6. de Mos M, Huygen FJ, Dieleman JP, Koopman JS, Stricker BH, Sturkenboom MC. Medical history and the onset of complex regional pain syndrome (CRPS). Pain 2008;139(2):458-66.
7. de MM, Huygen FJ, Stricker BH, Dieleman JP, Sturkenboom MC. The association between ACE inhibitors and the complex regional pain syndrome: Suggestions for a neuro-inflammatory pathogenesis of CRPS. Pain 2009/4;142(3):218-24.
8. Birklein F, Schmelz M, Schifter S, Weber M. The important role of neuropeptides in complex regional pain syndrome. Neurology 2001/12/26;57(12):2179-84.
9. Beerthuizen A, van 't SA, Huygen FJ, Klein J, de WR. Is there an association between psychological factors and the Complex Regional Pain Syndrome type 1 (CRPS1) in adults? A systematic review. Pain 2009/9;145(1-2):52-59.
10. Lohnberg JA, Altmaier EM. A review of psychosocial factors in complex regional pain syndrome. Journal of clinical psychology in medical settings 2013;20(2):247-54.
11. Feliu MH, Edwards CL. Psychologic factors in the development of complex regional pain syndrome: history, myth, and evidence. Clin J Pain 2010;26(3):258-63.

Competing interests: No competing interests

04 June 2014
Andreas Goebel
Consultant and Senior Lecturer in Pain Medicine
William Campbell, Beverly Collett, Martin Johnson, Kate Grady
The Walton Centre NHS Foundation Trust and University of Liverpool
Liverpool L9 7LJ