Complex Regional Pain Syndrome

Contradictory as it may seem, the primary aim of a pain management team is not the curing of pain, as we have to accept that this may not be possible, but the restoration of function.  Therefore the first thing that has to be considered in the treatment of CRPS is ensuring that the problem does not get worse through disuse, and therefore physiotherapy is the first line of attack.  Specialist physiotherapists are not only well trained in the management of musculoskeletal disease, but are also able to help in the management of some of the other symptoms associated with CRPS, in particular the hypersensitivity of the skin, which is managed with desensitising measures.

However, the use of drugs is essential, especially in the early stages to facilitate the activity that is required through physiotherapy.  It is essential to remember that physiotherapy is something you do, not something you get.  Therefore it has to be an active process not a passive one.  Thus if there is already a degree of pain present, the client will often be afraid that things will get worse with activity.  We acknowledge that this may well be so, and therefore would advise using whatever strength of analgesia is necessary to support the physiotherapeutic input.  Also there is evidence that the more effective early pain management is, there is a reduced risk of developing chronicity.

Pain is not a simple sensory modality, but is a combination of different types of pain, which can be subdivided into three types, pain due to inflammation, pain from activation of pain receptors (nociception) and pain due to nerve damage (neurogenic).  No single drug will treat all types of pain, so a combination of drugs is necessary.

Inflammatory pain is treated by the use of anti-inflammatory medication.  This will include paracetamol, but the largest group of drugs in this class are the non-steroidal anti-inflammatory drugs (NSAIDs), which encompasses a large number of drugs, the most commonly used of which would be Ibuprofen.  There are also the Coxibs, which are similar to NSAIDs but are associated with fewer gastro-intestinal side-effects (stomach bleeding in particular), although they have been associated with an increase in heart attacks.  The evidence for this continues to be controversial.

Nociceptive pain is what most of us would consider to be normal pain, in that this is the type of pain which responds to opioid analgesics.  The opioid analgesics include drugs that would be considered to be weak acting opioids such as Dihydrocodeine, as well as medium strength drugs (such as Tramadol) and strong opioids such as Morphine.  The pain from CRPS may be strong enough to require the use of strong opioids, which may be of concern to some.  For further information on this I would refer to the excellent publication by the British Pain society “Recommendations for the appropriate use of opioids in persistent non-cancer pain” which can be accessed on-line through http://www.britishpainsociety.org/opioids_doc_2004.pdf   .

Finally neurogenic pain.  This is, many consider, to be the main component of the pain in CRPS, particularly in CRPS2 where there is known nerve damage.  Because of the pathology of the pain it tends to respond to drugs not normally associated with analgesics, namely anti-depressants and anti-convulsants.  None of these drugs are guaranteed to be effective, and with a greater understanding of the pathology we realise that it may be necessary for two or more of these drugs to be used in combination.  Unfortunately these drugs do tend to have a large range of side effects, which may render them intolerable to clients.

There are some very high-tec treatments for pain, which come under the umbrella of implantation technology.  Here devices are implanted into the body so that either drugs or electrical stimuli can be delivered directly to the central nervous system.  These are only put in in a few units in the country, and we use far fewer than other countries.  This is partly because of cost, as each unit will cost in the region of £10,000, as well as the need for careful monitoring and follow up which is only available in specialised units.  Another issue is the overall effectiveness, as one recent audit from a specialist unit has demonstrated that spinal stimulation for patients with CRPS gives 50% benefit in only about 50% of patients. 

The one form of treatment that has been shown to be of greatest benefit in managing pain from CRPS is that of the Pain Management Programme (PMP).  A PMP provides a multidisciplinary input to help clients manage their pain.  This continues the precept outlined at the start of this article, namely that the aim of treatment is to restore function, and not necessarily to cure pain.  The majority of clients referred to a PMP will have undergone extensive medical therapy before being considered for this type of treatment. 

The PMP provides significant psychological input, in particular using cognitive behavioural therapy, to teach people about pain and how it can be modified by using various psychological techniques.  There is also a strong physiotherapy input to teach about the use of exercise in managing pain.  There are inputs from other healthcare professionals to assist in the management of medicines, and other techniques to help deal with pain.   As long as the client is able to accept this type of treatment, and a formal assessment has to be made of each person prior to acceptance onto a PMP, there is generally a very good outcome in terms of improvement in function.

This is a very brief introduction into the management of CRPS.  I hope that this and the preceding articles have given you an insight into the problems associated with the management of what is a very challenging problem from the perspective of diagnosis, prognosis, and management.

Dr George R Harrison

Consultant in Pain Management

University Hospital Birmingham

corgigas@blueyonder.co.uk