Complex regional pain syndrome: yes, it’s complex

Complex regional pain sydrome or “CRPS” (pronounced CRIPS) is an enigma. It’s complex. It involves different body systems. It’s very, very painful, and it can be incredibly disabling. It has had lots of different names over the years – in 1982 when I trained it was called “causalgia” or “Sudeck’s atrophy”, but in 1993 the International Association for the Study of Pain developed guidelines for diagnosing and managing this complex pain problem.

Since then we’ve heard a lot about CRPS, at least those of us working in the pain management field have. I am not so sure that the general public, or even healthcare professionals who don’t deal primarily in pain will have heard nearly so much.

What is it?

CRPS is a pain problem that may develop spontaneously (roughly 10%), but more often develops after what seems to be a trivial kind of injury. I’ve seen people develop CRPS after a cat bite, an abrasion to an ankle, an undisplaced metatarsal fracture, and a rose bush scratch. It can also develop when a limb is immobilised (for example after a fracture or sprain), after surgery, and stroke. What people will experience is very high pain intensity (more than normally expected with a minor injury), changes in skin colour (either pale, blue, or red or mottled), swelling, hyperalgesia (increased pain with usually painful stimulus), allodynia (pain with usually nonpainful stimulus), and changes to movement. Pain doesn’t conform to a dermatomal or myotomal pattern, but might be like a glove, or a sock, it may spread far from the original insult, can even go to the other side of the body, and can lead to skin ulceration and tissue breakdown.

That’s in the worst case, of course. Many CRPS begin with fairly vague symptoms that can quickly become severe, while others will begin with very severe symptoms but rapidly resolve. It usually begins, however, with a burning, tingling, electric shock type of pain (neuropathic type pain).

It’s hard to identify the number of people who develop CRPS partly because it can resolve very quickly in some people, and partly because it’s a complex problem to diagnose – not the least because it can occur in acute treatment settings where perhaps clinicians are not fully aware of the potential for a chronic pain problem to develop. The open source paper I’ve cited indicates that two studies show an incidence of 5.4 – 26 per 100,000 people, and a prevalence of 20.57 in 100,000, with a female:male ratio of 3.4-4.0:1. Two more recent studies found 3.8% of 1549 people with wrist fracture developed CRPS within four months, while another 7% of 596 people with wrist, scaphoid, ankle, or metatarsal fracture.

What this means is there are a lot of people who experience CRPS after what usually looks like a simple fracture. And of course, many of these cases resolves spontaneously, and it’s not yet known why some fail to resolve and can turn particularly nasty.

What are the mechanisms?

Here the contenders: ” disturbances involving abnormal response to tissue injury, peripheral and central pain sensitisation processes, neurogenic inflammation, endothelial dysfunction, disturbed sympathetic-afferent coupling, hyperalgesic priming, somatosensory cortical reorganisation, genetic predisposition, and even some degree of autoimmunity”.

That’s quite a few! No wonder it’s called “complex”!

What do we do about it?

Unfortunately, even though there have been many studies looking at ways to treat CRPS in a recent Cochrane review the conclusion was that most approaches are not very strongly indicated. In other words, the field is wide open.

Moseley and associates in Adelaide have certainly made waves about using “brain training” to address cortical reorganisation with CRPS, but an overview of recent meta-analysis found that graded motor imagery (asking an individual to imagine progressively more complex movements of their affected limb), laterality training (asking an individual to identify left or right hands/feet or other body parts amongst more and more complex settings) and mirror training (using a mirror to reflect the unaffected limb, to “fool” the brain into seeing it as the affected limb but not experiencing pain), were somewhat useful when compared with “usual care” (whatever that is!), that bisphosphonates, calcitonin or a daily course of intravenous ketamine may be effective for pain when compared with placebo, and low quality evidence that physiotherapy and occupational therapy have positive effects but after one year, have limited effect when compared with social work support (O’Connell, Wand, McAuley, Martson & Moseley, 2013).

What does this mean? Well, we don’t have very much to go on.

Here’s my take on managing CRPS based on my clinical experience and reading this literature.

All treatment is a balance of risks and benefits. The risks associated with having substances put into a body are well-known, and the findings from O’Connell’s review suggest that there are adverse affects with all of the pharmaceutical approaches, along with some benefits. The studies weren’t methodologically strong on the whole, and many of them didn’t use patient-oriented outcomes, particularly quality of life measures (remember this!). I think if I had CRPS I’d be happy to try some of the infusions – but I’d want to have an end-point in mind. If it didn’t change my pain so I could engage in using my body part I’d be likely to stop within a month.

Because graded motor imagery, laterality and mirror therapy are all non-invasive, I’d be happy to try these. I would need to be prepared for some weird effects – having put my hand into a mirror box already and experiencing some odd perceptual effects I’d be prepared for these to be far greater if I had CRPS. I’m also pretty slow at laterality identification. Once again I’d be keen on establishing, from the outset, a time frame for response – but these approaches appear relatively safe. I have to say that patients I’ve worked with have reported increased pain at times, and “feeling weird” or slightly disoriented.

I would also be ready to try a treatment that wasn’t included in this review – and I think it didn’t feature because it was a very, very small sample size, a repeated measures “N = 1” trial using single subject experimental design. This was a graded exposure in vivo (not graded imagery) following Vlaeyen’s fear-avoidance approach. In contrast with GMI and mirror therapy, this approach addresses avoidance rather than pain intensity (deJong, Vlaeyen, Onghena, Cuypers, den Hollander & Ruijgrok, 2005) .  In the study, people were asked to develop a hierarchy of feared and avoided tasks, and were introduced to those tasks beginning with the least feared. The aim wasn’t to reduce pain but instead to reduce avoidance and increase use of the affected limb.

Why would I try this? Because the thing I’m most worried about is being confident about doing things. Pain is often not able to be reduced – it happens in many chronic pain conditions. Pretty much all the other interventions are aimed at reducing pain, and my experience with working with people who have pain reduction as the focus is that this can (not always) lead to a delay in “getting on with life as it is now”. Instead, people invest a lot of energy and time into trying to “get back to normal”.

Of course it’s a personal question: how long do you wait before deciding it’s more useful to get on with life as it is, or stay looking for a chance to go back to “normal”. I can’t answer that for anyone else except myself – but I wonder if people are given a fair chance to think about the possibility that a person CAN live well with their pain?

 

de Jong, Jeroen R, Vlaeyen, Johan WS, Onghena, Patrick, Cuypers, Corine, Hollander, Marlies den, & Ruijgrok, Joop. (2005). Reduction of pain-related fear in complex regional pain syndrome type I: the application of graded exposure in vivo. Pain, 116(3), 264-275.

Fukushima, F.B., Bezerra, D.M., Villas Boas, P.J.F., Valle, A.P., & Vidal, E.I.O. (2014). Complex regional pain syndrome BMJ, 348 (g3683 )

O’Connell Neil, E., Wand Benedict, M., McAuley, James, Marston, Louise, & Moseley, G. Lorimer. (2013). Interventions for treating pain and disability in adults with complex regional pain syndrome- an overview of systematic reviews. Cochrane Database of Systematic Reviews, (4). http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD009416.pub2/abstract doi:10.1002/14651858.CD009416.pub2