The Neurotransmitters: Clinical Neurology Education

Chief Concern Series: Diagnosing Neuropathy

Michael Kentris

Dr. Marcus Pinto joins us to break down how to evaluate new numbness, tingling, and foot pain with simple bedside tests that separate true neuropathy from common mimics. Practical steps, key red flags, and a high-yield lab strategy give primary care and non-neuro clinicians a clear path forward.

• distinguishing positive vs negative symptoms
• using location and constancy to sort causes
• recognizing stocking–glove vs focal patterns
• bedside “eyes closed” test for persistence
• neuropathic pain descriptors vs mechanical pain
• autonomic clues: gastroparesis and orthostatic hypotension
• gait, heel–toe walking, and reflex triage
• light touch, pinprick, temperature, and vibration methods
• when vibration beats proprioception
• ulcers as a marker of severity and healing issues
• chronicity clues: atrophy, high arches, hammered toes
• targeted labs: CBC, CMP, HbA1c, lipids, B12, B1, B6, copper, zinc
• when to order EMG and what to avoid
• metabolic health and neuropathy progression

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Michael Kentris:

Hello and welcome back to the neurotransmitters. Uh we are today continuing our chief concern series. So for all of our primary care and other non-neurology colleagues, uh hopefully this one goes out to you. I am joined as always by the relentless educator, uh, Dr. Galena Geigman. Thank you again for joining me on this adventure. And our special guest for today, Dr. Marcus Pinto, an adult neurologist and peripheral nerve and neuromuscular specialist at the Mayo Clinic in Rochester, Minnesota. Thank you so much for joining us today.

SPEAKER_01:

It's my honor. Thank you, Michael, and thank you, Galena, for inviting me.

Michael Kentris:

So, Galena, go ahead and kick us off. What are we starting up on today?

SPEAKER_00:

Yeah, well, thanks again, Michael, for letting me uh join as your co-conspirator in this uh special series. I'm super excited for today's topic, which is kind of the new the patient with the new sensory change. And um, we're actually gonna dive into I think the history and kind of how patients come in. But Marcus, I just wanted to start with um, I mean, I know you're a specialist, but you know, how often do you get this referral from primary care doctors? And I can't tell you enough that in my clinic, I often hear, you know, the referral is actually written neuropathy, and the patient comes in and they say, I'm here for my neuropathy. And, you know, they use this term. Um, so I'm curious how often are you seeing this? And and when you kind of actually drill down to what patients complain of, how is it, you know, what are the symptoms, I guess, in a way, that really bring people in for this for this chief concern?

SPEAKER_01:

Yeah, so yeah, that's a very common, I think. And also I do EMG. So it's a very common indication for EMG, the question of neuropathy, and you and I completely agree with you. I think a lot of times patients start to feel abnormal sensory changes in their body, and they always attribute to neuropathy right away, and they usually come to you saying they do have a neuropathy, and that's what Google tells them as well, right? If you type, I think new onset uh paresthesias or new onset numbers and chingling in the feet, you know, that Google will tell you. So I think the most important thing when someone is complaining to you about new numbness or new chingling, you know, so patients. So I usually tell my residents, you know, and my fellows to not because the definitions of numbness and tingling, you know, they're a little bit so the textbook definition would be that numbness is the kind of a novel cane type of sensation that you feel, like when you're a dentist, for example, kind of uh numbs you for anesthesia, and the tingling will be the tingling prickling sensation. But it's very hard for the patient to differentiate that and also differentiate numbness, which also by textbook definition, numbness and tingling are both positive symptoms, and the decreased sensation or lack of sensation, it's a negative symptom. You know, so usually patients do not complain much about that. When we also talk about kind of a specificity of symptoms, so the decreased sensation, the lack of sensation, and usually they will tell you that they can't feel the temperature in the soles of their feet when they walk in the beach, or they live in Minnesota, like I live, when they go outside, kind of a barefoot, you know, in the winter they can't feel that the floor is very cold or the snow. So, you know, whenever the patient tells you a negative symptom, that is much more specific of neuropathy and objective that they may be having in neuropathy. But that's not the most common. So then you know, life is complicated. So that numbers and tingling, as I told you, they're positive symptoms, and they they can happen from neuropathy, from venous insufficiency, from musculoskeletal issues, you know, just you staying on the same position for a long time. So there are so many other causes other than neuropathy, you know, that I think people should be aware of. And usually what is important to me is not only that they feel it, but where they feel and uh and is it constant or not? So and why where they feel. So it's because if you have any numbers or jingle or any sensory changes in your legs, but not in your feet, that's very unlikely to be a neuropathy. If you have sensory changes in your hands, that you wake up at night, you shake your hand, and it improves, which is most likely carpotonous syndrome. If you have, for example, sensory changes in your like lateral thigh, and you don't know, you have an abnormal BMI, you know, you have uh you're overweight, you're obese, or you do a lot of uh, for example, kind of you wear a lot of tight clothing, or you work in construction, you know, and then you have sensory changes in your lateral thigh, which might be myalgia parasthetica. So the location of the symptoms is so important. You have, for example, cervical spine disease, and then you have intermittent shooting, sensory changes to your arms. So the classic sensory changes of peripheral neuropathy, which is a process that you know is worse in the feet than in the legs and thighs, and also worse in the hands than in your shoulders and forearms. So you must have a distal, which means hand and feet symptoms. If they are constant or not, that's a very important question. Usually intermittent sensory changes are what you call benign, and benign means can be anything else, okay? Can be musculoskeletal, it can be vein, can be any other cause other than neuropathy. So neuropathy usually causes constant symptoms. So whenever someone tells you that they have constant numbers and chingling in their feet, that increases the likelihood. It's not diagnostic at all, okay, it's not that specific, like for example, the decreased sensation in your entire foot when you're walking the beach again, but that makes it more likely than if they're intermittent. And I just posted on X doing a little bit of also here of uh advertising out my X accounts. Then you guys can follow me there, and I post neuropathy stuff there. And usually these neuropathy posts come from the clinic. I don't have an agenda, I don't have like you guys very organized. You have like schedule and series of posts. I don't have that.

Michael Kentris:

Marcus, what's the what's your handle for folks to find you there?

SPEAKER_01:

Yeah, so it's Marcus M-A-R-C-U-S-V Pinto, like the Pinto bean. So P-I-N-T-O. Okay. Yeah, so Marcus V Pinto. You can find me there. So I even posted there because of the day in the clinic, I was teaching a fellow this and someone else heard. So, oh good, good, I never heard about it. Because I learned this from one of my uh faculty uh in my personal fellowship, which is so I always ask the patients if they come for sensory changes, I always ask them in the office to close their eyes and they close their eyes and make them close their eyes. If they don't close it, close, close, and then they close. And I say, okay, so now try to concentrate in your own body, okay? And I give them like two, three seconds. And then I say, okay, do you feel anything abnormal in your feet or your legs? I ask them that. Because why I say that? Because intermittent parest seasures can also be neuropathy. Because you know, you all know that our brain is very powerful. Our brain has a power to block any type of sensory kind of input. That's why people go to war, they lose a limb and they keep running, you know, they keep fighting. So, like if you, Michael, and I are you know, if you lose an arm at your office, I'm sure we're gonna pass out on the floor, gonna be a cold blue and all that. So, but no, but your brain is able to block signals, and that's why also that any kind of uh a patient that has a sensory complaint or pain or any sort of sensory change, if they go on vacation, the symptoms get better. But going back to the know, going back to the the question. So then I ask them to close their eyes constantly in the body and say, hey, do you feel anything abnormal in your feet? And if they usually say no, I've never studied this, okay? This is just kind of historic neurology education, okay? Uh it would be an interesting, I think, even someone will say, Oh, you should study this, but it's interesting to study this prospectively. But if you do that and they say no, that they don't feel anything abnormal in their feet, it's unlikely that they have a sense of neuropathy. Okay, so I always do that with everyone. And then people can do that in the primary care doctor office anywhere, you can just ask that. And if they say that when they close their eyes, they constant their body and they still they feel that they have abnormal sensation in their feet, so that increases again the likelihood they may have a neuropathy.

Michael Kentris:

Interesting. I'll also try that one out.

SPEAKER_01:

Yeah, yeah. Tell me what you think.

Michael Kentris:

Now that kind of raises a question, because we were talking about positive-negative symptoms. And, you know, one of the I think the most other than the typical ones, like balance problems, a lot of people are describing pain of some character or another. What role does pain have in your diagnostic assessment? Or does it factor in at all or comes in at the end when we talk about treatment?

SPEAKER_01:

Yeah, no, no, that that's a very good question. Because it's usually what the patient comes for, because usually the negative symptoms, the balance and the lack of sensation, they usually don't complain about it. So usually only when it gets more severe. Like, for example, you all know in urology, like you see a patient, for example, with negative motor symptoms, you know, if they don't have any positive sensory symptoms like pain or paresthesia, they may only show up to your office when they are significantly impaired and disabled because they just, you know, the symptoms, they are not like stroke-like, any kind of a chronic symptom, they come slowly progressive, and then it's very hard for the patient to know exactly when it started. But when that is pain, it's much easier because it's painful. They will always be reminded of that. So the pain, I also uh use positive sensory symptom, parasites and chingling, abdominals and chingling, and usually if the pain is constant, not constant, the same kind of pattern. The neuropathic pain can be described by the patient as essentially anything other than achy pain. So very rarely, true neuropathic pain is achy. Usually ache is musculoskeletal or any other kind, but very rarely is neuropathic, however, it's possible, you know. So be careful because patients, you know, we all know, and it's not easy to describe how you feel, you know. And for many people, many, many people. Like my wife, for example, she has migraines and she took like 10 years to tell me her migraine was throbbing. She couldn't describe to me the throbbing nature of her migraine. She's a physician, you know. So just because you know, life is much harder than what you read in the textbook. So I think keep an open-minded, but but usually description will be of a burning and a shocking, like a zynga. Some patients can describe as kind of a kind of a knife stabbing sometimes, but and and is usually will affect not only one location, that's an important thing. So where do you feel the pain? So usually gonna be of a of a kind of a stock, sock or glove distribution, you know, for the pain, or sometimes a distribution of a specific nerve, but uh very rarely will be at a focal spot. So if someone says, hey, I have a focal spot in my foot that hurts like hell, that's usually not neuropathy. Uh foot arthritis, for example, it's a kind of and I usually what I do also, we haven't talked about exam yet, but as a neuropathy doctor, patients always apologize to me about their feet. You say, Oh no, I'm a neuropathy doctor, you know, I see the ugliest feet in the world. Because I go to their feet and I palpate their feet, I press the balls of their foot, I press, you know, the kind of a because for example, the common thing and some people sometimes think is neuropathy, which is um uh whenever people have uh plantar fasciitis. So more common in runners, people who all are on their feet a lot, and there are two things important for plantar fasciitis. One, so you ask them when in the day your pain is the worst, because plantar fasciitis is when they step out of bed. And the other thing is to go to their foot and press the middle of their foot. Just go, you know, say, Hey, I'm gonna press your foot here, see if it then you go and you don't know, press the foot to see that it's tenderness there, you know, because it's if it's plantar fasciitis, they may have, but also arthritis of the metatasal joints and all that is the same thing. You have to palpate. Some people you see, some people have like, we don't know why, but some people have not neuropathic, but they have a very kind of a um small uh uh fat pad in their feet, and their feet like usually planus, you know, and also flat foot, and they have no protection of the bones, and they develop more commonly arthritis of the feet and all that. But again, usually the neuropathic pain will be usually worse at night, usually we also worse when they walk, worse when they keep standing. You know, if someone tells you, oh, I have pain in my feet, and then at night, and then I stand up and walk, and that makes it better. It's weird. So maybe, okay, think about sometimes rarely, but sometimes we see in the office people showing up with sensory changes and they have restless leg syndrome, you know, which we all know can be associated with neuropathy, but sometimes it's just RLS. So using, I think, you know, a good history and a good exam helps a lot seeing patients with neuropathy. Great points.

SPEAKER_00:

Yeah, I love the discussion about the how difficult it is to describe the symptoms. I feel like I'm keeping like a mental log of just the interesting things people say. Like they'll say, My feet are like cinder blocks, or I feel like I'm wearing socks all the time, or they'll say, Oh, don't put bed sheets on my feet, you know, don't touch my feet. And also the one I hear a lot, quite a lot, is like my legs are heavy or they're weak. And so I think as a neurologist, you have to take, you know, with a grain of salt the description and then verify with the exam. But I often hear people complain of weakness um when they really mean like a sensory taxi, for example, that makes it difficult to, you know, find grip things or to find the right place of um when they're walking. And we'll we'll definitely get to the exam. But I was wondering actually, Marcus, do you ask about autonomic symptoms? I feel like this is something I think about sometimes on the history, especially when I'm suspecting small fiber neuropathy. Um, and I want to maybe get a little bit more information because you know, as we know on exam, that that may not necessarily be so revealing. Could you talk a little bit about that? And if you would you ask that, and if so, how how do you ask about that?

SPEAKER_01:

Yeah, yeah, no, I always ask. Yeah. So the, you know, the the the the review of systems of neuropathy that I usually do, I always ask about autonomic symptoms, I always ask about bulbar symptoms, I always ask about fever, night sweats, and I always ask about weight loss. And I also I always ask about skin changes, you know, rashes. Yeah, I always ask about so all my fellows need to come with the neurologists' questions and so uh and I just questions ask it and and give me the answers when I staff them. So, but then going back to autonomic, so autonomic symptoms are tricky, okay? Why? Because they are sensitive, but they are not specific of true autonomic dysfunction. So, for example, someone can tell you that they have dry eyes and dry mouth, and that can be, you know, Jogrin syndrome, or can be if they take like duloxygen or they take something, I don't know. So, so I think I always ask, but I think the most significant ones, the most specific ones, uh gastroparesis. So when they never they tell you, say, hey doc, you know, especially when it's when they spontaneously tell you. I think I think also when they complain without you asking, always specificity, you know, I think is increased. Because a lot of times, like Galena, you probably see that as well, that patients, they are nice people and they want to be nice to their doctors. They usually they think that saying yes to our questions they're gonna satisfy us. Oh, and then and then they say yes. So, anyway, this is what I see a lot of times. People, the patients they try to be nice to their doctors and they don't know that you know they should really should be very thoughtful when answering the question. But but going back to the symptoms, so gastroparries. So whenever they tell you that they used to eat a normal full meal, now they can eat like only like 10% of it. They have a lot of you know, they they feel bloated all the time when they eat just a little bit, and usually ask them for examples, or whenever they can give you examples uh of things they have eaten. Hey, I ate like half an apple for lunch and I was completely full, or I ate like uh like a full meal at X restaurant and then I was throwing up, you know. So gas repairs is very specific with early society, what you're talking about, and also easy bloating. And I also uh think that orthostatic hypotension is very specific. And so whenever I ask, hey, do you feel lightheaded when you stand up? Like all of us, right? So if you go to the beach and then you stay there, you know, kind of uh for like uh five hours and you drink take no liquors and you stand up, you're gonna feel lightheaded, maybe even pass out. So it's always important for you to ask the patient what situation and how often that happens. Because when it's true autonomic dysfunction, they will tell you that I stand up, I have to hold myself. A lot of times I feel I'm gonna pass out, and then after like 30 seconds or so, I can go. And or some will have episodes of syncope, you know. So whenever you know uh uh it happens quite frequently, they have this near syncope sensation, or they have already syncopized. So that is very specific because if you do have a neuropathy and orthostatic hypotension, this will send you to a bucket of very few types of neuropathy that can cause orthostatic hypotension and that and will help you in your diagnostic workup and treating the patient, you know. But yes, again, I do believe that asking for autonomic symptoms is very important. But again, with a grain of thought, that for example, you can have patients with fibromyalgia, patients, you know, with um uh chronic fatigue syndrome, who will respond yes to a lot of your questions. And then it will be the frequency and also your exam and the testing that will help you out differentiating these disorders. Because very important, fibromyalgia is not a small fiber neuropathy. Okay, so that's a very important concept that unfortunately in the literature is uh confusing, and especially because of the European, we can badmouth them here. I hope they don't hear, but you know, they are the ones who create a lot of confusion regarding this.

Michael Kentris:

I thought, you know, to that point, that there were were they the ones who have done some studies that show that there's an increased incidence of small fibrone neuropathy in the fibromyalgia population?

SPEAKER_01:

Yes, yes, yes. Yeah, they don't want to be.

Michael Kentris:

So it's more like a comorbidity, not a causative kind of thing.

SPEAKER_01:

Yeah, we can talk more about the the point is that um uh as uh you brought it up, is that a lot of times it would be very hard for you to differentiate clinically if they have small fibromyalopathy or fibromyalgia. The most important thing we have talked about exam yet, but is the exam? Because you know it's a diagnostic criteria for small fibromyalpathy, for you to have an abnormal sensory exam and you must have um decreased sensation for pimplick or temperature, and or if you have hyperalgesia, you know, uh, which is you just touch someone with a pimprick, they ah, they scream out, you know. So and it's not like they just say, Oh, oh yeah, it's a little painful. No, it's like you you you stick that, not you just go test the pimprick sensation and they will scream out in pain or have a lot of pain. So that's it be true, you know, hyperalgesia. Or if they have allogenia, which is someone who has pain to non painful stimuli. So you just go with your finger, and then the point that you mentioned, Galina, it's uh it's a specific complaint usually if a patient. Patient complain to you that they cannot uh when they when they sleep, they cannot put any sheet on their feet, so they the bad sheet can't touch their feet, is usually a specific symptom of neuropathy, because usually they have either hyperesthesia, which is they feel the touch stimulus uh more prominently, or they have allogenia, which is they will feel pain with any touch of that region, you know, and uh but it usually when the allodenia is reproducible at the office, that is very specific that this is some kind of neuropathy going on.

Michael Kentris:

So let's talk. We've kind of been dancing around it a little bit, but let's talk about the physical exam a little bit. So, you know, a lot of people, both neurologists and non-neurologists, can sometimes get a little uncomfortable with aspects of the uh peripheral anatomy examination. So, what are the things that you think are the most important and that you see most often done incorrectly?

SPEAKER_01:

Okay, okay, yeah, that's yeah, yeah, you know, in special we know that you know uh the neurologic examination is not easy to do and and a lot of uh providers shy away from doing. So I think we could try to divide into motor reflexes and sensory uh phoneuropid and also gauge, you know. I think gauge is very important. So um and and and also as we are talking mostly to non-neurologists, you know, I think that asking your patient to walk in your office, you know, uh, or what else have the office in the in the corridor, uh I think will give you a lot of information and why. So if they walk and they think that they are walking normally, that's great. So then you know, if they're walking normally, so you can say that most likely they don't have significant motor impairment, they most likely don't have significant imbalance, even though they may be complaining, but you don't see it. They're walking with a narrow base, they are turning okay, they are not almost falling on you, you know. So you don't have to be a neurologist to say, oh, this is a stappage gate, oh, this is a sensory ataxia gate. No, you just walk, you know, you see people in the streets walking. We as neurologists are always looking at people, you know, walking in in the streets all the time and diagnosing them. But you know, but you don't have to be that, so just see them walk. If they walk normally, that shows you a lot that if the patient has a neuropathy, it's not a severe neuropathy. And also, you know, after the gate exam, I always uh I also have people walking on their heels and on their toes. That is more difficult for them, you know, it's difficult to interpret, but I usually hold their hands for balance because I want to do that mostly for the strength. Because also tiptoes and and heel walking, that is also balance into it, you know, the old people. So then I I ask them to I hold their hand and I see how they walk and they can give me a lot of information. So if they can go high on their heels, you know, uh and their feet off the ground and take a few steps. That's great. So the dorsiflexion of the ankles, you know, and the foot are completely normal. So again, this is not a civil neuropathy. If they can walk on their tiptoes, like you know, they don't have to be like a ballerina. I joke and say, oh, let's see, oh, say, well, good ballerina, bad ballerina, I joke with them. But I ask them to walk on their toes. And if they can do that, you know, kind of going high on their tiptoes and walk forward, this also means a lot to you. That's you know, there is no civil neuropathy going on. And I always also do tendon walking, uh, which again is also more difficult to interpret. But again, if you use the normal abnormal, it can help you a lot. So if you have someone, a 60-year-old person who should be walk normal, you know, who should be able to walk five, ten steps on tandem, on heel toe walking or tandem walking, that also means to you say, oh, the balance of this person is completely normal. Okay, if they can tendon walk and they do not kind of uh step aside or fall, that you can you as a primary care doc, you could use that as a normal abnormal testing, you know, and uh and don't have to put that much of an emphasis on oh, if they took one step or two steps, that still may be normal, but you know, but you can just use it as a specific evaluation to uh not having to refer someone, you know, for neurology. So I think that can be helpful. And then I always always ask them, you know, the stance exam, I ask them to put their feet together, looking forward. I I usually ask them to just lay uh their hands uh on their side, but you can also ask them to cross their hands on their chest and uh with the hands touching their shoulders and then close their eyes with myself close to them, looking for the Rhombeck sign. And uh and if they can stay with eyes closed for 20 seconds or so without stepping aside, you know, that's usually also a sign that they do not have significant large fiber sensation loss. Talk about gauge and stance, and then uh moving forward, the motor exam. So the motor exam, again, it's not easy to do, especially the way we do, and you know, to check. And but I think if you feel comfortable, so two very strong muscles. So the TBL is anterior, the muscle that lifts the foot off, that does dorsiflexion of the ankle, okay, or dorsiflexion of the foot, which is a kind of a complicated from anatomy to think about, but lift the foot off the ground, you know. So TBL is anterior in the interior leg, that muscle is very strong. So you should not be able to break anyone, even if it's an old person, without putting your weight on it. So I would I would recommend to people, for example, just come with your hand, like your finger. So you can even ask them with the sitting on the office couch or chair, and then you just come to their side, keep your heels on the ground, and then you put them, hey, put your foot off the ground. It should be able to do that. When they do that, you go with your hand and you push down. You can't put your weight on it, because otherwise you may be able to break them. But you then go to push down and see if you have received feel resistance, and and you should not be able to uh uh break anyone, and this is very important, and also uh the plantar flexion, you know, which is the tiptoe is best exam with doing the tiptoe walking because plantar flexion gastrocrine is a very strong muscle to test. But if you check the ankle dorsiflexion only for neuropathy, it's already a lot, you know. It's already we're gonna should give a lot of information because to test toe weakness, you need to be a neurologist, you know, because it's is it's uh you you need to test with your index and you go there and then you press. So, you know, it's so easy to break uh like a toe flexion or extension with anyone, you know. Of course, you again can use like, okay, if I cannot do that, this person is kind of very strong bodybuilder. But I would recommend you not to test to toe strength because it's much harder. But foot dorsiflexion, you know, and plunder flexion and the tiptoe walking, I think that can be give you a lot of information again, because if you do not have ankle dorsiflexion weakness, you do not have a severe neuropathy.

Michael Kentris:

As a quick aside, when we're kind of thinking about uh you know, like muscle bulk as it relates to your findings on your strength exam, how often do you find that people have diminished muscle bulk before they have like a functional change in their strength exam findings? Interesting question.

SPEAKER_01:

I think for neuropathy, you know, as the usual neuropathy will affect more the leg and the hand than the feet. Sorry, than the thighs. Because it's it's hard, you know, it's hard, I think, Michael, a lot of times for you to know like how they may tell you my legs usually to be much, much uh larger or my muscle book. But I think on examination, I think when you see atrophy, you know, I think atrophy will mean to you chronicity. And it will mean to you, for example, you see someone who shows up to your office complaining only of uh bilateral foot drop, and then you look at their legs, they have very high arches, they have very ugly feet because the toes get very hammered, you know. So uh, and then they have high arches, hammered toes. Uh, and they have thin legs, you know, and they tell you that, yeah, my legs were used to be much larger than this, and now they're so thin. So, and then the thighs are usually pseudo-normal size, so usually and they don't have pain, it'll be a motor predominant process, usually an inherited neuropathy, like a charcot maritou disease, you know. So I think looking for atrophy, hematose, and also high arches will help you with chronicity, and usually will suggest an inherited process. And usually it will be people who have neuropathy for many years, but they may show up to you saying the neuropathy started three months ago, right? That is a good story of the doctor Peter Jake, you know, who uh just passed away uh I think uh last month, how our who founded our neuropathy center here and everything. So a neighbor of his, he had noticed that for many years he had bilateral foot drop and had a stappage gate. So he already suspected the neighbor had charcot marie tooth disease. And then his neighbor shows up to his office a few years later telling him that the weakness started three months before. And they say, No, no, no, I know you're my neighbor. I've seen you walking for five, six years, you have just for a long time. So just to tell you that uh the patient perception of time also sometimes can be a little tricky, and that's why also we discuss it in the history that because it's offline actually, so the the best diagnostic tool for neuropathy will be time. So seeing your patient back will bring you so much information because if this patient shows up to you with a three-month um history of symptoms, you know, and you don't remember how he was doing, or he's a new patient to you, okay, because if of course it's a patient of yours and you know them for like 10 years and this is very different, okay, sure, let's go ahead and pull the trigger on an investigation or referral. But if there's anyone coming up to you that you don't know well with new symptoms, yeah, see them back in two, three months. Because if it's a kind of a rapidly progressive neuropathy, you see, or they will report to you like a few weeks later, a month later, say, hey doc, I think you need to be seeing me back again because this thing is worsening. Now I'm needing a K and I wasn't needing a K and now I'm needing a walker or so. So I think that time is a great diagnostic tool for neuropathy.

SPEAKER_00:

It's so helpful to hear you talk about the elements of the exam that you would do, the motor testing, the gates. I didn't hear sensory testing though. So uh let's put ourselves in the exam room of a PCP who granted may not have a tuning fork. I hear that all the time. So what what can they do, you know, without that? And uh let's say they have one, um, how would they use it? And and how helpful is that? Is it important to document that at the time when they're first seen? Uh you mean you you gave us a lot of information, how even just where the where the symptoms are, how the symptoms have come on the carnicity, that's very helpful diagnostically. Uh, they're almost the exam. I agree with you. I always do strength testing mostly to verify the severity and if there's a motor component. Um, but let's just talk a little bit about the sensory testing.

SPEAKER_01:

Yeah, I think I think the sensory testing is uh uh I think reflexes are also important. You know, if you feel skilled testing reflexes, I think if a patient of any type of age has a neuropathy and the ankle reflexes are present, you can also say they don't have a severe neuropathy, okay, of any age. So especially if they're older, because after 60, you can have absent ankle reflexes and it can be normal. But I know that ankle reflexes are not easy to test, you know. So then the reflexes, but again, you can again use the normal abnormal rule. And whenever it's you think it's normal and present, it also reassures you that you're not dealing with something severe and sinister. But going to the sensory exam, sensory exam is very subjective. So then you have to tell the patient, you know, I usually tell them to close their eyes and explain well what you're gonna do. So I think if you do not have a turning fork, I think that's kind of yeah, we all have it's okay. So you yeah, but using, I think, a cotton or a like a or a Kleenex, you know, can be helpful to you. And and also using either like a pin, a pinprick, you know, a pinprick can do any kind of pin. Do you just go to your office and say most of doctor offices have something you know they put there with a pin, get that pin and examine the patient, then you just card it, okay? Don't put it back. Don't put it back. That's not good practice. Yes, just card it, okay? Just card it after use. Then you ask the desk for more pins. But uh, but I think I think a pin, I also, but it just is the one is harder to find, but I I love uh temperature sensation. I think temperature is more specific than pin. But let's do one by one. Let's first use the the Kleenex, you know. So usually I tell the patient I go with my Kleenex very lightly, and I just touch their toes very lightly, and I say, Hey, oh, so now you tell me, so am I touching you? And I will touch with the Kleenex in the toe, in the big toe, usually only. And then they say, Yeah, and I say, Where? Say my toe. So if they can feel a very light Kleenex, you know, or a cotton, I usually lose more cotton, cotton ball. So if they can feel that, you can also again say, This patient does not have a severe neuropathy, okay? Because the light touch is either minimally affected or normal. Okay, so then if they do not feel the cotton, then I use my finger and then I touch them with my finger. If they also don't feel my finger, then I do pressure with my finger, okay, and see if they can feel. If they can't feel that, yeah, it's severe neuropathy, okay. If they they they should be able to feel your finger if they can't feel when you use, you know, uh kind of when you when you press with your finger. So that's a sign of uh usually a severe neuropathy. Uh, but that's a light touch. And light touch is usually not as sensitive as the other ones we're gonna talk about now, which are pimprick and the temperature. So the pimplick, so usually I go with the pin and then you know I touch them with the pin at at the the big toe, and I say, Hey, can you feel I'm touching you? Okay, and they can if they feel what I do is I do not ask normal or abnormal, I just say can you feel? They can, and then I go with my pin climbing up the foot, going up the foot, up to the leg, and then I ask them say, Hey, do you feel the same all the way up? Okay, I try to ask specific questions. I do not say, hey, I do say what you feel you think is normal, it's not normal. Oh, because for the patient is so hard. And and usually I also uh use specificity in my question. So I do not ask when I check, for example, the toe and the knee. I do not ask, do you feel less at the toe than the knee? Because they want to be nice to you to say, yes, I feel less at my toe than my knee. So I do the opposite, I use their niceness on you know on my behalf and their behalf as well. So I go and say, Okay, I touch the toe and the knee, and I say, Hey, do you feel the same on both sides? And you know, and they will say yes or no. Usually I give value when they say, and the toe should feel more than the knee, okay? That should be the normal because of how we were innervated and how we were we evoluted as a species. So because I have more skin receptors at the foot and at the hand, then at the thigh and at the shoulders, and the face is where you have you feel the most, okay. So, but then I I go with my uh pimpreck, and then if they say that it's abnormal at the toe compared to the knee, I say, okay, so if you think the knee is normal, I do if the knee is a hundred percent, how much you give me at the toe, okay? And then if they give me like 95%, that's normal, okay. And another good qu another good pro as well is if they ask you to repeat, it's because it's normal, okay? Whenever they ask you to repeat, it's because the difference is so small that they are having to ask you to do it again. So, anyway, I don't remember a case that I trusted that it was truly abnormal. Because it's just completely subjective. You know, you don't know what the patient is feeling, so you have to try to be specific when you do it. So that's the pinprick. And then I usually go up and neuropathy, the loss will be more at the feet than the leg. And I usually go up to where they feel normal. And I ask them, hey, where do you feel normal again? And then that's where, and usually it's gonna be symmetric on both sides, okay? If they don't have anything on top of it. And that's light touch. The pinprick, light touch, pinprick. And then, oh pimp prick also, if they say they don't feel at all at the big toe, what I usually do is usually the pins have a dull, kind of a head, or they have a dull part of it. So I usually do I ask them to tell me which one is the pin, which one is the dull part. And then and then I only say it's absent where they cannot differentiate both. And I feel that is helpful. Then temperature, I love temperature sensation because I think you know it's uh and I like more uh you know, I have this uh this privilege of the office I work, we have kind of a thermistor and we have a hot thing there, like uh that you can use and test uh like a hot sensation, heat sensation of the patient. But I think you can also use code, you can get like a like ice pack, you know. Everyone has an ice pack, and you can use an ice pack, and I usually test uh the dorsum of the foot and compare it to the knee, okay, or to the lateral leg. And uh, and then you see if they feel it's different, you know, the the cold, coldness or the heat on both, and I do the same 100% type of thing. And why I say temperature, because I think temperature is more objective. So we are more used to feel as human beings temperature difference. That's why, you know, you go take a shower, you put your hands, or you put your foot. So anyway, we don't like to feel pain or pinbreak. We usually are not well and and well trained on differentiating those. So I just like temperature. I think temperature gives you a more specific exam. And uh and and if you do have neuropathy, you should have a temperature sensation diminished at the toes and the feet, especially if you're thinking about a small fiber neuropathy, which you know, again, by definition, you should have an abnormal exam even before you do any kind of testing. So we can talk about when you go testing. I have a spill on small fiber neuropathy to my fellows and everything, you know, on how to proceed. So let's not jump there now. But uh, but and then if you do like if you do light touch and you do one of those, temperature or or pimp prick, I think you're doing great. You know, it's much more than others. And remember for the primary care docs that the monofilament, 10 grams monofilament that you guys uh some of you have and use for diabetic neuropathy, that is not that great for the diagnosis of diabetic neuropathy. So that is more, I know the people have studied that, and that is a waste, even to know, but to be honest, I think that this is more, I just tells you more about you know kind of the risk of developing ulcers and you know, and uh kind of the planetary protection of the foods we call and they call. But uh so then I do not exam patients with a monofilament, okay? Because I feel that our exam is more sensitive. But a monofilament can be a tool you can use, and especially if you follow the protocols, they have a few, you know, that you have like five spots in the foot that you should test and the way you should do it, but it makes things more complicated, at least in my opinion. I think if you just do this quick exam of the toes, it's gonna be faster and uh easier, I feel.

Michael Kentris:

What are your thoughts on the uh broken tongue depressor as your pin, quote unquote?

SPEAKER_01:

Oh, oh, you I think anything that can can inflict some kind of pain. I think it's fine. Anything. I think creativity, you know, it's great, I think, you know, and uh and I'm I'm all down for anything that uh that you can adapt. So for example, in the in the hospital, Michael, I know the hospital. So I have used like uh like a diapepsican that just came and was kind of cold, and then I tested, you know, with the with with the diapepsican. I think. Just gonna be creative if if if you uh whatever you have available, you know, not gonna harm the patient. Yeah, sure do it.

Michael Kentris:

I know I've I've filled an exam glove up with ice water before. See you? See you? Yeah. So I have to, I know we're we're moving into our uh pro perception and vibration. What's the relative benefit? Do we need to do both on every patient? What's what's your perspective on that?

SPEAKER_01:

Yeah, that's a good question. I think if you are not a neurologist, you know, I think that uh because because pro perception exam is not easy, you know. So I I do I do I do I do uh at least four models of sensation in all of my age because I'm a neuropathy doctor, you know, so that's what I do for a living. Testing people's sensation, yeah, that's what I do. So then I I test in everyone uh uh vibration, eye touch, and temperature pimprick, and sometimes both. Okay, so four or five in almost everyone I see for neuropathy. But you know, I think vibration. I think if you are not a neurologist and you do vibration, you're doing great. And for and and you should you don't need to do pre perception. I think gonna be you know, gonna put a lot of uh subjectivity and complexity on doing, and you may find it abnormal when it's not abnormal, because you have to train the patient how to do because like I don't know if you guys have uh uh uh uh thought about it, but who uh tests for per perception, not neurologists, you know. So I do that in my daughter, she loves it, she's seven years old, she loves to do the test of the toe. She asks, let's do it again, dad, let's do it again because it's you know it's kind of fun, but no one does it. So people have like seven years old, they have never, no one has ever asked them to move their toe. So you have to to to stop to teach them how to do it, you know, and and be but so then I think vibration is better, and then vibration how to do it. So you get your turning fork, you can just slim that on the floor, okay? So we have to have a good one because otherwise you're gonna break it, okay? Because you can also hit on your hand, but then to hit like you have to hit it, it's a lot. So your hand is gonna be red and you know, kind of hurting after it. So you can just limit the floor and then then you test it. So I I I know people have studied this on the seconds people feel and all that. I don't like that. I think that's very subjective. So, what I usually do is I I slim my tiny fork on the ground, and then I put out the toe and say, Hey, do you feel it? And they say, Yeah, I feel it. Okay, and then I take it out, and then I do it again and compare the toe and the knee. Okay, and then I say, Hey, do you feel the same here and here? And if they say no, I say, Where did you feel more? And I say, Yeah, the knee. And they say, Okay, so if the knee is 100%, how much you give me at the toe? And that's how I do it. And then I usually attach the big toe, the ankle, and the knee. So if the person tells me that the toe is normal, I do not do the ankle or the knee. And for the evaluation of so in patients with posterior core myelopathy, they can have properception more affected than vibration, or sometimes both the same is equally affected. But for neuropathy, okay, you will essentially never see a patient that properception is more affected than vibration. So only doing vibration is completely fine.

Michael Kentris:

Now, a quick word. I've had students show up with different frequencies of tuning fork on their rotations from time to time. What's uh what's the gospel truth here for what frequency we should be using?

SPEAKER_01:

Yeah, I think I think one 128 or he and Mayo, we don't know anyway. I don't know why this one I even don't know why. I think it was Peter Jick. We use 165. You can never find it. You can only buy if you go to specific websites, but 128 to 165, I think you're fine. You should not use the 256 or the ones which are lower than 128.

Michael Kentris:

Excellent. Great point. Any other special maneuvers that you might do during your exam that's come up in edge cases or that you think that's could be a quick and dirty addition for our primary care colleagues?

SPEAKER_01:

So we're talking about the ankle weakness, we're talking about the reflex, we're talking about the sensation. I I yeah, we're talking about the if you if they ask you to repeat, it's gonna be normal, you know, and green as normal.

Michael Kentris:

That's a great one.

SPEAKER_01:

Uh I think that uh whenever you also like look at their feet, you know, this is obvious, but you know, I think it's important to say, you look at their feet and they have like an ulcer or they have like a pin on it, you know, like something because you just oh my god, I found it. It's very, very specific. They have a very they have a severe neuropathy, okay? Because whenever you have people have ulcers in their feet, okay, that's uh I think a good point. Whenever they have ulcers in their feet, it's usually not only sensory dysfunction, okay, it's usually sensory together with autonomic because also the healing is affected. Okay. So uh for example, you guys may have seen patients with CIGP, they don't have ulcers in their feet. You might have seen patients with uh like let me see other common neuropathy. You see nutritional neuropathy, alcohol neuropathy. You're not gonna see ulcer in their feet, alcohol nutritional if they don't have diabetes, okay? Because diabetes not only affects the sensory nerve fibers, also affects the autonomic nerve fibers, and that will affect the tissue healing, okay? And yeah, and if you have a patient with an ulcer on neuropathy, please send them to a neurologist, you know. Or if you know if they have diabetes, it's usually gonna be a poorly controlled diabetic, so you need to work with them on that. Or sometimes if you don't have diabetes, okay, oh that's a good pro. So if they don't have diabetes and they have ulcers in their feet and a neuropathy, long-standing neuropathy, this might be charcoma or tooth disease, because there is a specific genes that also they help with tissue healing. So, you know, there are specific forms of CMT that, or in some cases, they there is a sensory CMT called hereditary sensory and autonomic neuropathy, so that they may have very much of an increased risk of ulcers in the feet and amputations without having any other systemic cause. So the common questions they offer is they have this patient with a very healthy person and they keep having ulcers in their feet, it's so weird. And they we can't find a cause of neuropathy if we're looking for monoclonal proteins and all that, and even a nerve biopsy. Never do a nerve biopsy to these people because a nerve biopsy wound never gonna heal. Okay, they're gonna have a sepsis from it. Yeah, and that's an important point. So, but uh but uh if you have ulcers in the feet and no diabetes and no other clear cause, it might be inherited.

Michael Kentris:

So that that brings us to a great question. So let's say we're we're some sort of neuropathy is in front of us, whether it's small fiber, mixed fiber, large fiber, maybe. What kind of testing do we need to do after we've kind of seen them, taken the story, gotten an exam? What kind of testing has do we have in common between these different types of neuropathy that are kind of like good to do across the board?

SPEAKER_01:

Okay, so so I think that the and you can say yeah, mixed large and small fiber, because most of the neuropathies are mixed large and small fiber, okay? Very rarely neuropathies only affect the large fibers. Very rarely only affect the small fibers, you know. So isolated small fiber neuropathy is rare. So we did a study here, and I I wasn't on staff uh yet, but some of my colleagues did a study here in Homestead County, Minnesota, and they found that isolated small fiber neuropathy, which means people with parastites and or pain in the feet, abnormal sensory exam, and a confirmatory test, okay, either quantitative pseudomotor tests or QST or skin biopsy, okay, confirming the small fiber dysfunction and normal EMG, normal nerve conduction studies. So to be called isolated small fiber neuropathy or true small fiber neuropathy, you should have a normal EMG. That is rare, that's rarer than CIGP. Okay. So CIGP incidence in homocitic count is 1.6 per 100,000 of small fiber neuropathy is 1.3. So it's anyway, but some people think it's very common, you know. Usually the patients will also have the large fibers affected, which should be, you know. So uh then what tasks to do? So I think you don't know a blood workup is the most important for any kind of neuropathy. I think that uh I don't know, it's it's hard, I think, for I think a primary care provider, non-neurologist to phenotype a neuropathy. I have posts on it, it's just a little bit of a propaganda here, my thing, but it's not easy, okay? It's not easy. So I think that whenever a patient has like uh ankle weakness, whenever they have an abnormal gait, whenever they have the falls on neuropathy, they should be seen by a specialist, okay? And as you send them for a specialist, you also should send them for an EMG. Okay. So an EMG is only helpful in situations where you know I think you must refer your patient as a primary care doctor because they have diabetes and you exam them, they have some neuropathy. So why do an EMG on them? Oh, for baseline? You have your exam for baseline, you don't have to order an EMG for that. There is a lot of uh uh literature on this, and I do not recommend EMGs for those that the cause of neuropathy is obvious. For example, you have someone who started eating peanut butter, okay? This is a real case. The person decided to win vegan and they went vegan, but they also were only eating peanut butter, nothing else. Peanut butter and water. Like it was anyway, poor person. It wasn't a smart decision. This person developed a horrible, painful sensory neuropathy, okay, was a nutritional neuropathy because peanut butter doesn't have all the nutrients you need for your life. You know, this person didn't know that. So then uh, in this person, do they need an EMG? No, they don't. You know, it's kind of a you do, of course, the blood work we're gonna talk about here. Do you check for vitamins and you're gonna replace the vitamins and tell them to change the diet, please? But do they need an EMG? I don't think you need an EMG. And depends a lot where you are and and in your practice. But I think for the primary care docs and non-neurologists, I think you only need an EMG if you are referring them to someone, to be honest. I don't think you should wait the EMG results to refer to someone. And why? Because it depends on the know who's gonna do your EMG. Some neurophysiologists know they exaggerate when they're reporting severity of neuropathy. I also have posted about it. So uh if someone rely on a lower limb study only EMG to call someone having a severe neuropathy. Okay, so that's an important point. So if you think it's a bad neuropathy, do upper and lower limb. And why? Because if the upper limb conductions are normal or near normal, this is not a severe neuropathy. Okay, and again, it's been going back to the permacad doc. So, what kind of blood work to do? I think you should check, you know, a CBC. You should check, uh, I usually do a comprehensive metabolic panel because I also want to see the liver enzymes. Because if the liver enzymes are normal, this is not hepatitis, okay? If the kidney dysfunction that's normal, creatinine, all badge is normal, this is not chronic kidney disease. So, and then you do a CBC because you know, you may once in a blue moon, you may see someone with Palm syndrome, you know, or something very like a unicorn may show up to your office because unicorns live, you know, they still they exist. And then and then you will see like a mock lib normal CBC, okay, sure, you know, hematology or something, very profound anemia. So, you know, you oh you can have macrocytosis, you know, and then you're gonna do your B12, and then we're gonna find out so this is a B12 deficiency. So a CBC, metabolic panel. You also uh because also sometimes you know the metabolic panel is also gonna help you. For example, you have a very low B UN, this person, for example, from like monotrition, for example, you know. So I think uh this basic test help you a lot. And then I always do B12, fold H and B1 and B6 on people. And why you do that? And also do copper, you know, because maybe copper they may not need, but I would do copper and zinc, and why you do that? Because I feel that zinc is a great one for nutrition. So because usually you usually know this is of course never take that you know fully from on neurologic performance of neurology about nutrition. But if if you have a normal zinc, you're probably not malnourished, okay, to the point of just the malnutrition causes on neuropathy. But uh but uh but uh anyway. The the so again uh B12, uh B1, which is thiamine, uh copper, zinc, and uh and B6 and why B6? Because people take supplements, they don't tell you, they take the supplements, they buy online. You know, I always tell my patients never buy multivitamin online, never go to Costco, Walmart, Walgreens, buy the off-the-shelf ones, cheap ones, okay, because the super vegan, whatever, you know, they always come sometimes with a lot of vitamins, and then they can harm the patient because hyper B hyper vitamin O of B6 can cause neuropathy and a bad one, a sensory ganglionopathy. Okay, so that's what I usually do. Uh it's basic workup. And I don't think that any primary care doc needs to do uh if you're not referring a patient for neurology with a severe neuropathy, you don't need to do uh uh SPAP or immune fixation. And why I say that? I say because all these uh monoclonal associated neuropathies, you know, amyloidosis, palm syndrome, IgM associated neuropathy, they are all severe neuropathy, they're all progressive. Okay, so if you're not referring your patient to a neurologist, I don't think you need to look for an M-gUS because you're not gonna know how to interpret. And then you're gonna refer to hematology who will not like this referral, you know, because they don't like to see M-gUS. And I know that well because I know them. So I don't think you should. So if you do a basic metabolic panel, as I told you, CBC and the vitamins, and also, of course, check A1C and also check a lipid panel, okay? That's an important point, lipid panel, and why? That is growing evidence, especially coming from my friends from the University of Michigan, you know, Brian Kallanha, uh Melissa Elafros, Dr. Alva Feldman, that obesity, okay, hyperlipidemia is associated with neuropathy, especially in type 2 diabetics. So they can even make the neuropathy progress faster. So tell your patients to eat healthier, exercise. You know, even there is a person there, Stephanie, who does uh research in mice. So then she she kind of uh put them to exercise and change their diet and all these things, and she has shown improvement of neuropathy in just mice. They're doing trials now there with uh badatheric surgery, also GLP1 and all that, but improve your metabolism, you know, may also help you out with your neuropathy.

Michael Kentris:

Excellent. That's that's a ton of information. And you know, we've been kind of splitting these into two parters as far as like uh assessment and diagnosis, and then uh second part on treatment. So we're gonna have to ask you, can we have you back at some point in the future for to talk about some treatment management type strategies?

SPEAKER_01:

No, yeah, yeah, that yeah, that'll be great. Yeah. Yeah, because I think, yeah, because you know, yeah, we do I think neuropathy, there's a lot of uh education to educate your patient, you know. So you have to tell them a lot of things and and it's a lot of uh perspectives, you know, and and the patient needs to understand because they can get very frustrated, you know, because neuropathy, you know, I learned that in my fellowship that a lot of neuropathy management is patient coping with it, you know. So they need to understand well what you're saying, and uh so it'll be a be a pleasure. Yeah, let's let's schedule the next one.

Michael Kentris:

Yeah. And I know uh as a quick plug for Marcus' channel, I I've learned a lot of stuff. That's uh on X at Marcus V Pinto. I really enjoyed the one, especially, right? The kind of the number we always quote, uh, you know, one out of five cases end up being idiopathic. But with a little more legwork and uh skull sweat, uh you can sometimes get that number even lower. So uh very interesting stuff. I'm not gonna go into that because that gets a little more esoteric, but yeah, uh great online education to be found on Marcus's profile.

SPEAKER_00:

Marcus, thanks so much for joining us today. And I feel like we got a little window into what it's like to be one of your fellows and just dropping knowledge uh right and left. Thank you so much for those tips, pearls. I love, I can just imagine you, you know, depending on your kind of it's bending on a knee and putting a cotton ball against the toes and kind of revealing truth. So thank you so much for joining us. And I can't wait for part two. I couldn't agree with you more that the management depends so much on a partnership around education and really like progno prognostication, kind of talking about prognosis and and um love. Just want to underscore that tincture, you know, time is kind of part of our diagnostic uh process. So thanks again for for those tips.

SPEAKER_01:

My pleasure. Yeah, it'd be an honor to come back here. And uh my you know, one of my goals, and that's why I do this channel. I put politics aside, okay, because I use my Twitter as my neuropathy blog. I put everything aside and I try to help people, you know, because only at my office I won't be able to help as much as I want. So it's my pleasure to be here and uh we pleasure to come back.

Michael Kentris:

Awesome. Well, thank you everybody for listening. And make sure to tune in next time as we talk more about uh neuropathy management. And you can always find our stuff at the neurotransmitters.com, and we are also on x at neuro underscore podcast. So thank you both again, and we'll talk again real soon. Bye bye.

SPEAKER_00:

Bye.