Section: CME Category: Pain Management

Chronic Regional Pain Syndrome (CRPS)

Ryan Fitzgerald,

Ryan Fitzgerald, DPM reviews the essential features of Chronic Regional Pain Syndrome and the history, pathophysiology, susceptibility, symptoms and different types of the disease. Dr Fitzgerald describes the diagnostic criteria, diagnostic testing and different stages of CRPS. He also outlines treatment modalities for CRPS and illustrates various prognostic potentialities following treatment.

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Goals and Objectives
  1. Identify the essential features of Chronic Regional Pain Syndrome
  2. Understand the pathophysiology, susceptibility, symptoms and recognize the different types of the disease
  3. Describe the diagnostic criteria, diagnostic testing as well as distinguish between different stages of CRPS
  4. Propose appropriate treatment modalities for CRPS patients and evaluate prognostic potentialities
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  • Ryan Fitzgerald,

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    Ryan Fitzgerald none

  • Lecture Transcript
  • Male Speaker 1: Other talk that we’re going to this morning, a little bit heavier, but again very, very simple. We’re going to make up some time on both of these to get on Dr. Williams [Phonetic] up here. Chronic regional pain syndrome or CRPS. So, chronic regional pain syndrome is a pain syndrome that is characterized by pain out of proportion that is relentless. It’s about 1.2 million Americans, more or less. This is from the data on the reflex simplex dystrophy website. They have a society, sort of, coping mechanism society. But, I think that reality is that there are certainly a lot of people. You know, 200,000 to 1.2 million seems like a fairly broad spectrum. But certainly, a lot of people can get this. I actually see a fair amount of it in the practice, more than I would have expected when I was a resident, but you do see it. Historically, it was first described in the Civil War. A guy named Silas Mitchell described it, although he called it causalgia. He wasn’t the first person who came up with the name, but that was where he started to describe it. It was taken from the Greek word for pain and temperature in the context that these patients have increased red, swollen, painful extremities commonly associated with amputations in the Civil War. In the ‘40s, they started calling it reflex simplex dystrophy, RSD, because they started to recognize that there was a hyperactivity of the sympathetic nervous system. That was the belief that it had to do with that. Ultimately now, in the ‘90s, they progressed on towards the complex regional pain syndrome, which is sort of a catch-all. They made two subtypes and we’re going to talk about those. But essentially, one subtype is RSD and the other subtype is causalgia. Basically, they just subdivided into the same treatment terms. In terms of pathophysiology, it is hypothesized that it’s a problem with the central nervous system and a sensitization of the central nervous system, either due to neurotransmitters or trauma-related cytokine release. The key though is it’s not really fully understood. So, there will come a time when we very much understand what is happening. But for now, it is certainly through that. It’s in the context of some traumatic injury, something happens to the nerves. And essentially, you have a CNS sensitization with this short circuit, essentially, the nervous system. So, they are these pain reflex arcs that start going. And that’s ultimately why they have pain. In terms of susceptibility, it can happen at any age ultimately, but the mean average according to the data is about 42. So you think about your weekend warriors, people who were modestly active, having small injuries, ankle sprains, things like that. Interestingly enough, you can see a lot of pediatric patients too, more so girls than boys. But an increasing high number, the numbers of pediatric patients are increasing. So, that’s kind of interesting as you review the literature. More common in women than men, three to one, generally speaking. There’s a very high incidence of cigarette smoking in patients who develop CRPS. So when you’re thinking, a 42-year-old woman who is a smoker with an ankle sprain that comes in the pain out of proportion, that’s going to be a slam dunk. There is a genetic predisposition, it seems. Patients who have a history or a family history of CRPS have the tendency to progress towards CRPS themselves. And so, that is interesting sort of side note as well. About 5% of actual nerve injuries can progress to CRPS. As we all know, the reality is that larger, more traumatic wounds have the tendency not to progress towards CRPS. So, there’s something about the slight wound, the innocuous wound that starts this reflex are processing. So that’s important to think about, you know, having the clinical mindset when you’re looking at these patients, that they come in, they seem to be a little off in terms of why they’re experiencing pain. Symptoms, obviously, pain out of proportion, cigarette burning pain, traditionally, although it can also be described as a gnawing pain, a breaking pain. I had a patient who told me that she felt like her bones were melting, which was kind of an odd way to describe it. But that was how it felt to her. There are pathological changes in the skin and bone and these are things that you can see. Excessive sweating, so there you have a pseudomotor disorder as a consequence of the sympathetic nervous system being out of whack. Then, also, soft tissue swelling early on ultimately to sort of atrophy at the end. But there’s also hypersensitivity attached, not necessarily pain but they’re hypersensitive that progresses on towards pain syndromes. In terms of the types of CRPS, I mentioned before, there’s essentially two types, type one and type two. Type one is formally known as RSD. The way to remember this is type one is that one that isn’t really involved with a specific nerve. It’s a multifactorial, multinerve distribution. The whole extremity is involved. In contrast, type two is known as causalgia, and it’s more associated with an actual nerve injury, patients who’ve had a nerve laceration, even in the context of tarsal tunnel syndrome where they have a specific nerve that is involved, there are series of nerves that’s involved. If they have RSD symptoms or CRPS symptoms along with the course of that nerve and then sort of expanding out from there, that would be considered a type two or causalgia. In terms of making the diagnosis, again, because they don’t really know formally why people get this, it’s hard to say that there is a series of tests to do.


    But, essentially, the International Association for the Study of Pain came up with sort of guidelines for how you would go about describing a type one versus a type two CRPS. For type one CRPS, you do have to have an initiating event, something that is causing immobilization or usually it’s a non-noxious, so let’s say, a minor trauma, not a compression fracture or something, you know, really significant but something small. That then progresses towards continuing pain and an increasing sensation pain from a non-painful stimulus, so again, this pain out of proportion. And ultimately, the diagnosis is excluded if you have another reason for pain. So it’s pain that shouldn’t be there. Pain that is more than and ought to be, and in context, beyond that location. If they get hurt, they sprain their ankle but then they have pain all the way up to their knee, clearly, that there’s something else going on. If they have a knee pain and a knee problem, then that makes sense. In contrast, for type two CRPS, it’s all of those things for type one but it’s also the context of the nerve injury. So when you think of the subtypes, type one nerve injury, type two nerve injury. In terms of diagnosing, testing, there are a variety of things you can do. Bone scan for the medicine is very, very helpful in this context. But even plain from radiographs will show you the beginnings of this atrophy. And we’ve all heard this is a Sudeck’s atrophy where you get the sort of washed out appearance to the bones. It’s again something to do with the autonomic nervous system, the dysregulation of the vasculature, and the subsequent osteoporosis as a consequence of that. Thermography is something that’s becoming very useful in this context, if you have it available. Essentially, what you’re doing is you’re taking the skin temperatures. And in patients with pseudomotor disorders, these kind of temperatures are elevated, and there is a ratio of how much elevation is necessary to be an indicative of this kind of problem. Sweat testing is kind of an interesting and fun test that you can do. Essentially, you’re quantifying the degree of sweat that is excreted over the course of a certain amount of time. And in patients with a pseudomotor disorder, that would be more ultimately for that context. EMG studies and never conduction studies are used to distinguish between type one and type two CRPS. If there’s a nerve problem, specific nerve injury, they’re going to have aberrations in their nerve testing. If they have the pain out of proportion but the nerve testing comes back normal, then you can kind of assume that it’s a type one CRPS. Then also, the radiography as I spoke about, the Sudeck’s atrophy, it’s also helpful to get a series of x-rays over the course of time to see how it’s progressing, better or worse. In terms of staging, CRPS is staged into three groupings. The first stage is the acute stage. It’s in the days to weeks category. This is right after the event. They’re characterized by severe burning pain, increased swelling, redness, heat, all of the classic symptoms of CRPS. That progresses towards a dystrophic state in stage two, which is in the three to six-month category. You haven’t lost the fight at this point but you’re progressing. The longer this goes, the harder it is to treat and the less successful your outcomes are likely to be. Stage two is categorized more by this intense pain and swelling. The swelling and hair growth, these are having the pseudomotor changes that are more fixed and primary. Then ultimately progressing towards stage three, deformity, where atrophic, the swelling goes down. This is something more than about six months. These are arbitrarily designed. But in a review of all of the CRPS cases, they found that this was basically the timeframe. So, obviously, for these patients, you want to get them in their stage one ideally or at least to stage two. So you have to really be thinking in terms of CPRS when you have the patient that comes in with a pain that doesn’t fit, particularly after a small injury or, you know, hammertoe surgery, some smaller kind of thing. In terms of treatments, there are a variety of things. A neurology consult is key. I’ve also found that a psych consult is actually interesting. You have to present it in a way that doesn’t offend the patient, but there is definitely a correlation between patients with CRPS that have other things going on. I had a patient once who had been in a terrible car accident and she had type two CRPS as a consequence of a nerve injury in her back. She also had posttraumatic stress from the car accident. She’d been seen by a variety of other providers, including one of the local foot and ankle guys who wouldn’t do surgery on her. She had claw toes because of her neuromuscular disorder. She’s wanted her toes to be straight so she could fit into a shoe. They wouldn’t operate on her because she had CRPS. We talked about it. I mean, we talked about the reality that when you operate on these patients, that it’s very likely to ramp up their problem to give them more pain, and that was going to be something to deal with. But I told her that I was willing to go that route with her if she wanted to do it, understanding that there would be potential consequences. But prior to surgery, we had her queued up with pain management. We had her see a psychologist as well to kind of get all the other factors in order. She did great. She was like the model patient. She had some pain but it was so much easier than some of these other patients that come through. So it was an interesting learning process for me. But I think a lot of that had to do with the psychiatric consult. So, pain management as well. Physical therapy is key. You want to break this reflex arc, and so you have to keep them moving. You have to kind of get them through the idea of, that they can move it without it hurting.


    There are some interesting things that they can do with physical therapy. And the research for this lecture I found, they have something called mirror therapy where they actually put up mirrors to their other extremities so it looks like they have two good legs that they can move so that they can train their brain to see what they think is, let’s say, their left foot moving without pain. So that they can believe that they can move it without pain, and then they then move it without pain. It’s very, very interesting. Systemic steroids to a degree can be helpful. There are some research out there that talk about these beta blockers and the management of this. It’s still kind of in the early stages, but if you do a PubMed search, you could find it. TENS units, analgesics, epidural block, things like this can help. Ultimately, if you can’t break it with therapy and other less aggressive modalities, you progress towards sympathetic and these are chemical or surgical. Ultimately, you’re trying to break that sympathetic nerve arc. Also, spinal cord stimulation is something that’s coming up in the literature now. It’s something very, very good. Essentially, you’re shortcircuiting the brain’s idea of pain to kind of filter out the static. Ultimately, if that doesn’t work, patients will want an amputation because the pain becomes so severe, they just want it to go away. In terms of prognosis, it can be good but it depends on how the long the patient has had the problem. Certainly, as you get into the late stages, stage two and stage three, the prognosis becomes decreasingly likely that it’s going to be a good outcome. It does not burn itself out and you’re not cured from it. It will go into the background. You can deal with it. But once you’ve had CRPS, it’s a diagnosis that you carry, and it’s something that it could be ramped up against. So think of it like shingles or something. It’s always there in the background and they could flare up. And it’s important to have patients know that so that when they’re going on in the rest of their life, even if they’re not going to see you ever again, that they can tell the next guys, “Hey, I had this CRPS thing back in, you know, 2002.” That can help that provider know kind of how to proceed accordingly. There’s a study at a Hopkins that we talk about 77% of cases that there is a spread, that you can have CRPS in one part of your extremity and then ultimately you can have a recurrence somewhere else. So again, it doesn’t burn itself out. It doesn’t go away completely. You’re never cured. You can manage it and you can get to where you’re pain free but it’s always in the background. So the key is early and aggressive treatment management. Are there any questions?

    Male Speaker 2: Is there [indecipherable] [12:13] that will help you stage CRPS for some degree of pain of fibromyalgias or [indecipherable] [12:23].

    Male Speaker 1: To some degrees, diagnosis of exclusion, for fibromyalgia, there’s a very specific criteria for how that is diagnosed. So if you had a patient that you were trying to rule out between the two, largely what I would do is I’d refer to pain management and let them figure it out. But they would work that up. I think there are 13 points for fibromyalgia. So, if they fit those categories, then a lot of times, it’s going to be fibromyalgia. Also, the context of the injury, if patients with fibromyalgia just hurt and they don’t have the reason to hurt, they didn’t have a history of trauma in some context, my clinical threshold is any patient that comes in that seems a little off in terms of their pain, and it doesn’t have to be a ridiculous amounts of pain, but just enough that it kind of raises the eyebrow a bit. You can see it. Even at later cases, stage two cases, I had a patient that was referred to me for swelling. The concern was that the patient was swelling. I took an x-ray and the midfoot was just all out of whack. She had this twisting injury. She actually had a Lisfranc’s fracture that had been undiagnosed and had ultimately healed, sort of. But when we were working her up for that, she was having some pain. It wasn’t dramatic but it was some and this sort of residual doughy swelling. So we got the bone scan and she came back positive for CRPS. So we treated her with therapy and she’s been better. We had to get her on a bone stem to get the Lisfranc’s to heal completely. But, ultimately, the history of trauma plus that, I would say, if you think you have it, presume that you have it until you prove otherwise because it costs you relatively little to be treating it and it not be CRPS. But if you’re not treating it and it is, that’s a problem.

    Male Speaker 2: But you refer pain management for CRPS or not.

    Male Speaker 1: It depends on what we’re going to do. Early on, if it’s very, very early on, I get them into physical therapy. If that doesn’t seem to be working, I tell them right away that, you know, we’re going to give it a very, very narrow window of time. If it doesn’t start getting better quickly, we’re going to refer you out pretty quickly. In the town that I practice, there is a guy who is a pain management specialist. He’s actually a PMR physician who does the spinal cord stimulation and all those other stuff. So, he likes doing that kind of stuff, so we assume that we have a good flow. A lot of times, I’ll send it over too if I’m suspicious for CRPS but it’s not absolute just to get another set of eyes and then have him look at it as well. Any other questions? Yes, sir?

    Male Speaker 3: [indecipherable] [14:53].

    Male Speaker 1: No, no. I talk to them about antidepressants but I don’t want to manage it. So, I let that happen somewhere else. Yeah. Questions? Okay.