It’s the billion-dollar question: who is most likely to develop Complex Regional Pain Syndrome? Are there risk factors that can be identified? If so, are any of these risks ones that we can control? Are there any identified patterns to this disease at all, or is it just a mix of contradictions and uncertainties?
Everyone who has CRPS knows that it is hard to treat, and often, hard to diagnose, with one doctor telling me the average time between onset of symptoms and clinical diagnosis is 12 years. Everywhere you turn there seems to be uncertainty; no-one knows exactly what causes it, how the disease is maintained and definitely not, as yet, how to treat it effectively.
I wanted to know if there were any discernible trends amongst those who do develop CRPS. Are there any specific elements that put us particularly at risk? Can I find commonalities between the people I know with the condition? I undertook two lines of research. Firstly, I read everything I could about risk factors for CRPS, and secondly, I reached out to the CRPS sufferers of Facebook support groups with a simple questionnaire to ask them about their illness. It was a fascinating undertaking.
CRPS is more common in women
The first correlation I found is that researchers believe CRPS is far more likely to occur in women. My own informal research certainly bore this out, with 97% of my respondents being female. There’s disagreement on how much more likely women are to contract the illness, with the ratio going from as high as 4:1 women to men, to as low as 56% women versus 44% men, depending on the study you read.
CRPS is more common if you’re older
There also seems to be a correlation with age, with several studies suggesting post-menopausal women are the most likely candidates. However, that doesn’t mean you can’t develop it at a younger age; my own CRPS started at the age of 34, and I’d already had it (and recovered) as a child aged 11. In my own questionnaire, there was a huge difference in the age of onset, with sufferers reporting symptoms starting at ages ranging from 10 to 59. There was a slight skewing towards onset around the age of 40 and older, but it certainly made it very clear that CRPS can start at any time in your life.
There’s likely to be a precipitating injury
Whilst CRPS can develop spontaneously, most cases are a result of some kind of trauma. Clinical research says this is most likely to be a wrist fracture, with rates of onset after this injury ranging in different studies from 1 to 37%. Other injuries that seem especially likely to trigger CRPS include ankle dislocation and bone fractures where the break passes into the surface of a joint, causing cartilage damage. In my own research, patients reported a huge range of issues causing their CRPS, including surgery, sprains, fractures, chemical burns and frostbite.
It is also undoubtedly true that CRPS can develop without any clear initiating event. 12% of those who answered my questions simply ‘woke up with the pain’; this chimes with clinical studies, that tend to suggest around 10% of CRPS cases lack any precipitating trauma.
It’s more likely to start in an upper limb
Clinical studies suggest that CRPS is most likely to occur in one of the upper limbs. I find this interesting because my knowledge of my friends with CRPS suggested it was the other way round, and certainly the responses to my questions bore that out, with 44% of my respondents stating their CRPS started in their foot or feet. The next highest location of onset was the ankle, with 26%. The hand came next with 21%, and the wrist and lower leg are tied at 18% each.
Those who get CRPS tend to report higher pain in the first few days after an injury
I find this very interesting, because it certainly tallies with my own experience. My injury was misdiagnosed for a fortnight, which meant I was trying to walk on an ankle that should have either gone straight to surgery or into plaster. For me, this was one of the key factors that distinguished this injury, where I did develop CRPS, from several other, possibly more serious injuries, where I didn’t.
Research doesn’t go so far as to suggest a causal link here, merely reporting that those who went on to develop CRPS complained of higher than average pain levels early on. This feels like it could be an interesting area for doctors to explore; why is that higher pain being felt and what effect does it have? Could CRPS actually start to develop very early on after an injury, causing pain levels to almost immediately climb? Or could it be that inappropriate treatment after an injury, causing high pain levels, could contribute to CRPS developing?
Most people who get CRPS have had other injuries before
I couldn’t find any clinical research on this, but I am interested in this question from a personal view; I’ve had several similar injuries prior to the accident that triggered my CRPS, but I’ve recovered from all of them perfectly well. So is CRPS simply waiting for us all along, ready to strike after our first significant injury, or could there be something different about the triggering injury that causes the condition to develop specifically in this situation? If other sufferers had experienced other serious injuries without CRPS developing, then it would suggest that was the case and my questions bore it out: 76% of those who replied to me had gone through other problems of a similar severity without CRPS developing. Clearly, something different is happening with these injuries where CRPS occurs.
So what do we know?
There’s not a vast range of hugely helpful information out there about how to avoid getting CRPS. Most of the (very few) recognised risk factors are unavoidable; you can’t help being female or getting older (if only we could – or possibly that’s just the fact I turn 40 this week talking!).
There are some factors that potentially are linked; for example, there’s some research that suggests CRPS is more likely to occur in those who’ve suffered menstrual problems, migraines or autoimmune disorders. Again, there’s not a lot you can do to avoid having those problems, but it’s possible that the recognition of a link could lead to some kind of scientific breakthrough in understanding what really causes CRPS and therefore, hopefully, how to cure it.
In nearly six years of living with and learning about CRPS, I’ve only come across one thing that is clinically suggested to inhibit its development: vitamin C. Research says that taking 0.5g of vitamin C daily after trauma will greatly diminish the likelihood of CRPS developing. It may not be much, but at least we have something we can do to decrease the likelihood of its onset. I can only hope that in the years to come, the different pieces of evidence science is compiling will eventually come together into an effective cure for this life-destroying disease.