Ep 255 – Referred Pain: “I Have a Client Who . . .” Pathology Conversations with Ruth Werner

0:00:01.2 Ruth Werner: Hey I Have a Client Who listeners, did you know I have a growing library of NCB approved one-hour online self-paced continuing education courses that you can do any time, anywhere? Well, now you know, current classes include what's next COVID-19 updates from massage therapists and A Massage Therapist's Introduction to Pharmacology part one, and brand new, a Massage Therapist's Introduction to Pharmacology part two, classes are $20 each, and they confer one hour of continuing education credit. Wanna know more? Visit my website at ruthwerner.com and check it out. Be sure to sign up for my mailing list so you'll never miss a new class.

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0:01:33.9 RW: Hi, and welcome to I Have a Client Who pathology conversations with Ruth Werner, the podcast where I will discuss your real life stories about clients with conditions that are perplexing or confusing. I'm Ruth Werner, author of a Massage Therapist's Guide to Pathology, and I have spent decades studying, writing about and teaching about where massage therapy intersects with diseases and conditions that might limit our client's health. We almost always have something good to offer even with our most challenged clients, but we need to figure out a way to do that safely, effectively and within our scope of practice, and sometimes as we have all learned... That is harder than it looks.

0:02:20.5 RW: Today's episode is a tender story that has elements of the heart disease and aneurysm issues that we've been talking about lately in this podcast, and then it takes an unexpected turn into things we've never talked about, and I'm always eager to carve out new pathways there, plus which I think you'll probably find some new food for thought, and it starts like this, "Hi Ruth regarding... I Have a Client Who ideas, my mom had chronic pain, there was obviously a lot of trauma and various things her body was dealing with, but she wound up in her later years developing cardiovascular issues, this accumulated in her having three aortic aneurysms and an attempted full aortic replacement as well as two arterial replacements. She didn't survive. Today is the three-year anniversary of losing her, so she's on my mind. What I'm thinking of specifically though, is that after she died, her surgeon told us that some of her chronic upper back pain could have been referrals from her aorta over the years. I feel like internal referral pain is more complicated than most massage therapists realize, and it's certainly not something most of us can easily recognize. I haven't listened through all of your podcasts, so maybe you've done these types of referral pain examples before, but if not, would it be a good topic besides the obvious one, in doubt, refer out, maybe you could help us with a few other symptoms or things to check on and monitor."

0:03:58.5 RW: I wanna thank our contributor for sharing this sensitive story with an interesting follow-up question, I've done some looking around and found a couple of things of interest, but this is a surprisingly unstudied field and our talk could go in several directions, but first, let's put some definitions on the terms pain and referred pain. If I were to ask you to define referred pain, you would probably come up with something like pain that is felt somewhere other than the origin of the tissue damage, and that's a pretty good starting place. However, before we go any further, I need to make a couple of clarifications both about pain and to delineate between referred pain and radiating pain.

0:04:47.1 RW: Firstly, as I hope you're aware, pain isn't exactly a sensation, it's a response to an incoming message, usually from nociceptors about real or potential damage, that message enters the central nervous system, and after a couple of few synapses, the cortex assigns a location to that information and decides how severe or how important it is, and that is what we experience as pain, when those incoming signals come from the skin, which is loaded with nociceptors, of course, as a protective mechanism, well, then the brain is usually good at mapping the source correctly. When we get a wasp sting on our left knee, we feel pain on the left knee, but sometimes the brain is less accurate about where those messages come from, and this can happen for several reasons, and that's a topic for another day, but as we talk about referred pain please, I'd like you to bear in mind, bear in mind that the brain sometimes makes mistakes about where damage is, or even if there's any damage at all, and also we can grow changes in the way the central nervous system processes incoming messages and responds to them.

0:06:05.9 RW: We can grow more of certain kinds of receptors and we can secrete more or less of certain kinds of neurotransmitters, and this can influence the strength of those messages, and of course, all of this adds to the confusion. Now about referred and radiating pain, with radiating pain, we will see pain that is experienced somewhere distal to nerve irritation, for instance, a bulging disc in the lumbar spine can cause pain in the buttocks and in the leg, and this is indeed pain that is not at the site of the tissue damage, but it is related to a nerve compression rather than to the brain having a hard time assigning an accurate receptive field for incoming information. Another common example of radiating pain is when people get hand pain and they assume it's carpal tunnel syndrome from the wrist, but in fact, it might be related to compression of the median nerve at the pronator teres or maybe in the thoracic outlet. These examples of radiating pain are not the type of pain signalling that I wanna talk about today, we could also talk about referred pain from activated trigger points or hyper-irritable muscular nodules, if you prefer that verbiage, and I will return to this concept in a bit.

0:07:28.3 RW: But again, it's not quite the type of referred pain that I wanna focus on right in this moment, instead, our contributor is asking about pain from our organs that our brain interprets as coming from somewhere else, like the skin or musculature. In this case, she's asking about pain that might refer from the aorta to the upper back, and that's a new one on me, but we are probably familiar with a couple of other examples of this where injury or irritation or damage to internal organs causes pain, the person experiences as musculoskeletal or even skin level sensation for instance, during a heart attack, it's very common to feel crushing chest pressure along with pain in the left shoulder and down the left arm.

0:08:15.0 RW: Interestingly, women are more likely to feel pain in their left neck and jaw between the scapula and to have nausea rather than crushing chest pain, we have no idea why that is true. Similarly, when a person has liver or gall bladder issues, it's very common for the brain to interpret that sensation as coming from the right mid-back, and I can speak from experience, when I say that the most gifted massage in the world to the musculature between the shoulder blades will not clear up an infected gall bladder. Spleen injuries refer to the left shoulder and arm, and this is typically related to some kind of significant trauma, and it's serious enough that in emergency departments, it has a name, it's called [0:08:58.4] ____. Maybe the most common version of referred pain from viscera, is menstrual cramps.

0:09:06.1 RW: Many, many, many, many, many, many people with uteruses experience menstrual cramps as pain in their sacrum, their buttocks and the groin... In fact, these are all referrals from the uterus, which is inflamed and in spasm, but why do these patterns happen, what is the mechanism behind referred pain from the viscera and how can we use that information maybe to make our work more effective or safer? To talk about this, we need to invest about 30 seconds in Embryology, and here we go very, very, very early in the development of a fetus, we develop structures called somites, these are paired blocks of mesoderm on either side of the embryos neural tube, and these somites eventually develop into skin tissues, organ tissues and musculoskeletal tissues that includes muscles and bones and tendons and ligaments and other connective tissues.

0:10:04.8 RW: And as the embryo grows the sensory neurons that supply these somite tissues feed into the areas that become the spinal cord, and this is the origin of our dermatomes. The areas of the skin that are supplied by specific neurons, and also our sclerotomes, the areas of musculoskeletal tissues that are supplied by specific sensory neurons, and also our visceratomes, the organs and blood vessels that are supplied by specific sensory neurons, and the sensory neurons that are feeding into their level of the spinal cord are running side by side and entering at the same spot, so that the visceratomes and the dermatomes and the sclerotomes for specific spinal nerve roots are all coming in together.

0:10:52.1 RW: Well, way back when I was in massage school, my teacher offered the leading theory about referred pain from that time, which is this, we get messages about tissue damage from our skin and our musculoskeletal tissues all the time, right? And much less often from our guts or heart or lungs, since the sensory neurons for certain areas of the skin, the dermatomes and areas of our organs, the visceratomes feed into the same sensory nerve roots, it would make sense that our brain would assume incoming... No secession, those signals about potential harm would be coming from the skin or the superficial musculoskeletal tissues, several newer theories about the mechanisms behind visceral referred pain have emerged.

0:11:37.9 RW: One of my favorite resources for information like this is Physiopedia, a website from the UK that serves physiotherapists, and I'm gonna include a quote from their page on this topic. And of course, the link will be in the show notes. So Physiopedia says several neuro-anatomic and physiologic theories state that nociceptive dorsal horn and brainstem Neurons receive converging inputs from various tissues. Ruth here, that means all those incoming sensations converge together back to Physiopedia as a result, higher centers cannot correctly identify the actual input source. Ruth again, in other words, the brain cannot accurately assign the receptive field and it defaults to the skin or nearby muscles and bones, back to Physiopedia, recent theories have suggested models in which plasticity of dorsal horn or brainstem neurons play a central role.

0:12:39.0 RW: During the past decade, a systematic attempt to chart referred musculoskeletal pain areas in humans has been made. In other words, when organs or visceral referred pain, that pain tends to be perceived in the skin or musculoskeletal structures. And this paper from Physiopedia also states that this perception of pain comes with a diffuse kind of achy quality rather than being sharp or cutting or easy to locate, but we have also found that the nervous system adapts, that's neuro plasticity, so the way the brain maps out our perception of pain may change, which makes it much harder to predict or use for our client's benefit. The Physiopedia article also provides a chart of visceral referral sites, so it's worth a visit. Sadly, I didn't see that they mapped out any referred pain sites for the aorta... Sorry, contributor. Before we wrap this up, I wanna offer one more small tangential take on referred pain, and this has to do with pelvic pain in men and women, both.

0:13:47.3 RW: So far, we've talked about internal organs referring pain to superficial tissues, right? But can this ever go the other way, let's think about idiopathic chronic pelvic pain. There's a pretty well-accepted theory that one contributor to idiopathic pelvic pain that is pain without any infection or injury or other lesions could be related to trigger points in the pelvic floor that refer inwardly to organs. This pelvic pain is both common and really difficult to treat, it tends not to respond well to most medications, and it can seriously interfere with a person's quality of life. Trigger points in the perennial muscles are outside our scope of practice, I hope that's obvious, but we could make referrals to pelvic floor physical therapists if that seems necessary, and this type of work does have some effectiveness for chronic pelvic pain, although it is not a quick fix.

0:14:52.8 RW: But what makes this phenomenon especially intriguing to me is the direction of the referral from the superficial perineal muscles to the internal organs of the pelvis, and this makes me wonder if this happens anywhere else, say for people with chronic gut pain or maybe for people with a chronic cough. And that's what I've got for you on referred pain from internal organs and to internal organs, it doesn't have immediate applicability for massage therapists except for to open our eyes a little bit when our clients are not responding to our musculoskeletal work the way we think that they might, and maybe it will give you some new things to think about. I wanna thank our contributor for their story and the chance to take a close look at yet another way our nervous system just boggles the mind.

0:15:49.2 RW: Hey everybody, thanks for listening to I Have a Client Who pathology conversations with Ruth Werner. Remember, you can send me your... I have a client who stories to ihaveaclientwho@abmp.com that's ihaveaclientwho all one word, all lower case @abmp.com. I can't wait to see what you send me and I'll see you next time.

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