VIEWS & REVIEWS
Complex regional pain syndrome medicalises limb pain
BMJ 2014; 348 doi: http://dx.doi.org/10.1136/bmj.g2631 (Published 28 April 2014)
Psychosocial factors may be more important than biomedical ones in type 1 disorder, writes Christopher Bass...
I am a psychiatrist who has worked in general hospitals and pain clinics since the 1970s and have assessed many patients given a diagnosis of type 1 complex regional pain syndrome (CRPS). The syndrome is often diagnosed by inexperienced junior doctors when confronted by patients with unexplained symptoms, especially pain in the hands and feet. CRPS was once called algodystrophy, then reflex sympathetic dystrophy, but by 1994 the sympathetic component was abandoned and the current term was introduced.1 CRPS is part of a larger problem in chronic pain and reflects our lack of knowledge of causal mechanisms.
It has been my impression that increasing numbers of patients are being diagnosed with this disorder, and that incidence rates are increasing (estimates in 2007 of 50 000 new cases annually in USA).2 In my opinion excessive reliance on this so called biomedical diagnosis for these patients is misguided. How has this occurred?
Several new diagnostic criteria have been proposed,3 but they are not sufficiently objective or reliable.4 For example, criteria such as “continuing pain that is disproportionate to …
Janet T Holly, Physiotherapist Clinical Specialist in Pain Sciences;
It was with great interest that I read Dr. Bass’s viewpoint in BMJ. I am a physiotherapist who is a Clinical Specialist in Pain Sciences working in Canada and long have been frustrated by the impact of clinician language and behaviour on many rehabilitation diagnoses. I have 23 years working with pain patients and 5 to 6 years working with Complex Regional Pain Patients as a critical mass. I too have felt at times labels can be harmful for patients receiving adequate comprehensive care. Unlike Dr Bass however, I find the label chronic pain or non-specific pain can be just as harmful as patients are frequently told, “there is nothing I can do” or “get over it”. Both responses are inappropriate but aid to highlight that changing the label does not change the problem that Dr. Bass is trying to address. Non-specific pain does not immediately lead to proper assessment and treatment of psychosocial flags.
He is correct that there is some cause for criticism of the Budapest Criteria and those involved in the world of research of complex regional pain are striving to improve upon these. However, The Budapest Criteria do have a specificity of 0.68 and a sensitivity of 0.99. In the world of clinical diagnostic testing, there are certainly worst tests for sensitivity and specificity. Continuing pain, which is disproportionate to the inciting event, is not the sole diagnostic criteria but rather they must report both one symptom in three or more categories and one sign in two or more categories at the time of the assessment. 1
The studies he alluded to re brief immobilisation and prolonged casting of a limb producing signs and symptoms mimicking CRPS drew no definitive conclusions re causation or potential future treatment. 2,3 Rather they were an insight as to where researchers may want to direct their efforts further. It is far too early in the game to be taking two studies and drawing conclusions re causation when the neurophysiology and immunology behind CRPS is complex and still being determined.
CRPS can cause profound disability in some but not all patients. The reference he used to support psychosocial factors being a potential causative factor is for general chronic pain.
Beerthuizen et al, 2011 actually did not find psychosocial factors pre-disposed individuals to CRPS. 4 This also is only one study and as such too early to make a judgment.
There are some distinct differences in those with chronic pain versus those with CRPS and the literature should not be intertwined. One of the main principles of applying best practice principles to a population is the literature has to match the context of the population. 5 Patients with chronic low back pain do not get spontaneous swelling, cooling or heating of a body area, loss of motor initiation, trophic changes, extensive loss of sensation etc…. the two groups cannot be compared. In addition, there is a subgroup of CRPS that have pain but the biggest disabling features are the temperature changes, trophic changes and swelling, not pain. As such, the term arm ache or leg ache or non-specific arm pain does not describe the population well at all. In addition, there are treatment techniques such as graded motor imagery that have some clinical level of success for CRPS but are not so useful for chronic non-specific low back and neck pain. 6 Lumping all pain diagnoses together will limit the usefulness of matching treatments that have positive effects on the subgroups where they are successful.
I agree screening for psychosocial factors is necessary to manage any condition, not just pain conditions. The tools he mentions are good ones for depression and pain and easy to use by all clinicians in busy practices. I would add screening for sleep dysfunction as this too has a large impact on healing and pain control. Screening for depression, anxiety and sleep dysfunction was recommended by Rakesh, 2012 at the International Association for the Study of Pain Congress in Milan based on published literature. 7,8
Dr Bass makes a good point in his title that CRPS should not be medicalised. However, this holds true for any condition in medicine from pain to cardiac issues. The key to health in any domain is self-reflection and self-management with occasional interventional procedures from physicians or allied health professionals. True health is a work in progress and takes time. If we add medicalization and the usual resultant fear to any diagnosis, we disempower patients from managing their own care. Iatrogenic harm happens in all medical diagnostic groups not just pain patients. We, the entire medical community, do not cure patients. We teach them to manage the changes that aging, trauma and exposure to illnesses cause. The problem Dr. Bass wants to tackle is not the label we put on our patients but rather the lack of evidenced based knowledge of health professionals and ability at identification of psychosocial flags early on (optimally before CRPS even occurs by their general practitioner) and management of these flags. We must practice holistically not just in our areas of specialization. We also must start and continue to train incoming practitioners about the power of language, excessive diagnostic procedures and the need to be truly present with all diagnostic groups of patients. We need to let patients tell their narrative so that belief systems/fears etc... can be expressed and addressed immediately in every day non-threatening language. No one is too busy for this as we spend the time later down the line managing beliefs once they are ingrained. We also need to teach our clinicians about knowledge translation to patients, styles of learning, readiness to change and barriers to learning. Without practicing with all these tools in place we cannot demedicalise any diagnosis nor empower our patients to manage it. Changing the label only pushes the problem to a new label.
Write on, Janet T Holly, Physiotherapist Clinical Specialist in Pain Sciences and Clinical Researcher at The Ottawa Hospital Rehabilitation Centre, undoubted star of the Clinical Epidemiology Program... and, apparently, skier extraordinaire.