Chief Concern Series: Dizziness

Dr. Anand Bery joins us today to talk about how to approach dizziness without making your head spin!

We share a step-by-step way to approach dizziness without getting lost in vague symptoms, moving from red flags to timing, triggers, and targeted bedside exams. When should use the HINTS exam, Dix-Hallpike, and practical tips help to help you identify strokes vs causes of peripheral causes of vertigo, and improve care.

You can find futher resources for dizziness below:

We have some further resources recommended by Dr. Bery to further your dizziness knowledge!

Dr. Peter Johns' YouTube channel (Ottawa, Canada) - I recommend novices start with "Popular Videos"

I recommend Dr. Dan Gold's entire collection

• the "Test Your Knowledge" videos (like the one linked here) are particularly helpful for getting comfortable interpreting HINTS. 
  • Putting the following term in the search bar brings a wealth of videos -- creator_t:"gold" hints

Neurology Exam Prep Podcast Episodes

• Acute Vestibulopathy
• Episodic Vertigo

Transcript

Michael Kentris: 0:05

Hello and welcome back to the neurotransmitters. Uh we are continuing our chief concern series today. Uh we are your hosts, I'm Dr. Michael Kentris, and I'm joined by my co-host for this series, Dr. Galena Geikman. Galena, how are you doing today?

SPEAKER_00: 0:20

Hey Michael, I'm well. It's a cold February morning, but I'm excited and for the, you know, all the learning we're gonna do today that's really gonna bring the energy in. And I was gonna say, we initially started this series with like six topics that we were gonna do, and we it was hard to choose which. And then we are been really excited to see the response and that people seem to be enjoying it. And so I'm feeling extra happy that we're able to extend it and continue to learn more. And today we are going to be talking about dizziness. So this is extremely exciting. Um, this is a topic that is uh feared by many non-neurologists and even some neurologists, and so we're really excited to have none other than one of our local experts here at Mass General Brigham demystify dizziness. We're gonna be talking with Anand Berry, who is one of our neuroontologists, works at the Mass Sign Ear, and also works within our department of neurology, and really is really the expert when it comes to this. Um, you know, you can't really think of anyone better to uh demystify things and sort of unspin the spin when it comes to dizziness uh than Anand. So welcome.

SPEAKER_02: 1:29

Thank you for having me. It's really a pleasure to be here and always love talking about dizziness. So one of the things that, you know, you alluded to, Galina, is that I think when a lot of folks sort of see dizziness come in the door as a chief complaint, whether it's in the ED, whether it's in the outpatient setting, there is sometimes a little bit of this fear response that that comes in. And what I'm hoping to get out of today is to sort of change that a little bit, to sort of help us come up, you know, with a bit of an algorithm that that we can apply when we have a patient with dizziness, kind of step by step. So we have a plan when dizziness comes in the door. So that's that's really my goal today.

Michael Kentris: 2:12

No, that's great. And I think dizziness, it's one of those things, because you know, I I'm covering the inpatient service, and I'm sure that this week I will have at least a couple dizziness complaints on my docket. And it always feels like it's one of those topics where the person with the symptoms and the person assessing them aren't speaking the same language necessarily. So I think a a good starting point might be like when people say they're dizzy, that can mean a lot of things. So how do you, as a neuroontologist, kind of approach that kind of broad, broad list of possibilities?

SPEAKER_02: 2:47

It's a great point, and I'm glad we're starting there. So some of the terms that we use around dizziness do have specific definitions. So if you go and look at the international classification of vestibular disorders, it will tell you that vertigo is a symptom where there's illusion of self-motion or environment motion when that motion doesn't exist. So that could be illusory motion of the head or body or of the environment. We would call that vertigo. And vertigo can be spinning or non-spinning. And so if the patient's telling you that, you know, the room is spinning around them, you know, that would be kind of spinning vertigo. Dizziness is a little bit more general. So dizziness is a sense of impaired, and so dizziness is impaired uh perception of one's own spatial orientation uh without vertigo. What I will say is that as a neuroontologist, uh I actually try not to spend too much time focusing on the quality of the patient's symptoms. Uh, and there are a couple of reasons for that. One is that, you know, I think it's helpful to understand where our patients are coming from, and I really want to understand what their experience is. But a lot of evidence over the last decade in particular has shown us that symptom quality actually doesn't help with diagnosing dizziness, with figuring out what the cause is. And that's because I think, you know, patients use different terms sometimes. Of course, they're not reading the textbooks and the classification of vestibular disorders. You know, sometimes we're imprecise in our, you know, in our definitions as well. And I think the other thing is that when when good studies have gone and, you know, for example, looked at patients in in cardiology clinics who are having dizziness and really asked them to rate symptom quality, and then have gone to ENT clinics and neurology clinics and asked those patients, we really find that, you know, patients, you know, as they should, are using all kinds of different terms to describe their experiences. So, yes, there are specific terms for for dizziness in vertigo, but really what I'm trying to, you know, emphasize today is that instead of using symptom quality, we use other other features, sort of the timing and triggers approach that that we're gonna get into today.

SPEAKER_00: 5:07

One of the things that we sometimes associate with dizziness is trouble with balance or kind of instability or like disequilibrium. So I'm curious, these triggers and timing of information that we're gonna talk about, does that also apply to that, or does the factor of balance, if that comes into the question, does that change how you're thinking? Is it just a marker of severity, or is it like always part of the syndrome or not always part of it?

SPEAKER_02: 5:33

Yeah, really, really good question. So one of the things, not to steal our own thunder, I mean one of the things that we're gonna get into is sort of the timing, right? Are we talking about a process that's sort of acute and continuous, a process that that's episodic, uh, or or sort of a more chronic process? And I would say that imbalance can kind of come in at any of those points. If you imagine someone's got acute, you know, dizziness or vertigo, comes on suddenly, persists for a day, they're definitely going to be off balance. And in that bucket, in that category, the acute syndrome, very, very severe imbalance makes me think about something worrisome. So we'll, we'll, we'll, you know, talk about how that would be a red flag. Particularly severe truncataxia, meaning you get the patient to even sit by the end of the bed and they're not able to keep their posture. That would be a red flag in the in the acute setting for me. You know, episodic things, you know, if we think about BPPV, benign paroxysmal positional vertigo, crystals in the ears, almost all the time when someone is having crystals in in the inner ear that that move when they move their head, you know, they're gonna have dizziness or vertigo when they turn over in bed or when they do those movements. Almost all the time they're gonna be off balance, you know, in between those attacks, particularly uh, you know, patients more advanced in in age are gonna have off, you know, imbalance. And then I would say kind of, you know, as we move into the the chronic side of things, you know, most causes of uh of sort of chronic dizziness in vertigo are gonna have imbalance with them. But if the primary symptom is sort of difficulty with balance, a lot of difficulty, you know, being able to walk in a straight line or to stay upright or frequent falls, it's a perhaps a slightly different list of things than kind of the the dizziness, more what I would uh the way I would ask my patient is is it a feeling in in your head, or is it just just imbalance? And I will say that a lot of the time those two things can be very difficult to disentangle. So I'm kind of in my head thinking about all the things, you know, broadly when it's dizziness, vertigo, or imbalance.

SPEAKER_00: 7:44

That's a it's a perfect comment and a nice space learning with our gate uh episode where Dr. May Bo Haire also said, is it a problem in your head or in your feet? So if listeners haven't uh heard that one, please check it out. But let's let's move um right to your framework, Ananda. I'm curious uh about this timing and triggers questions that you ask on history. So can you walk us through that?

SPEAKER_02: 8:06

Yeah, absolutely. So, you know, the the way I I kind of begin is to really think about, you know, what are what are some you know red flags, you know, first before we even begin, before we even get to thinking about kind of dizziness, vertigo as a symptom. And so, you know, if a patient's coming in and they're having dizziness, I really want to make sure before I go down kind of the vestibular pathway that, you know, I'm I'm not missing something else. And so, you know, questions that I would ask myself, you know, are particularly around associated symptoms. You know, things like headache. Does the patient have a new headache, kind of a different headache? Is it sort of headache and dizziness? Because that's gonna lead me a little bit down a different pathway. Now, if they have a history of migraine, you know, we'll talk a little bit about vestibular migraine, that is an entity. But if it's a new headache, the patient doesn't have a history. So I want to think about other things, more acute things that that might cause kind of you know, headache plus dizziness. If the patient has neck pain, new neck pain, you know, that's a red flag for me. Thinking about something like a dissection of the vertebral artery or one of the cervical arteries that maybe then led to sort of a stroke, for example, rare, but but of course something to always think about. Are there other features? You know, is there change in mental status that might you know make me think about a toxic exposure or a vitamin deficiency, something like, you know, deficiency of thiamine, which can cause Wernicke's encephalopathy? You know, are there other features, just you know, thinking broadly about all the different things? Is there chest pain that might point me towards a PE or a myocardial uh infarction? So really thinking broadly, making sure that I'm I'm not missing associated symptoms. So uh thinking through that, you know, let's say, you know, for for the purposes of this that, you know, we're not having other red flag symptoms and we're really dealing just with with dizziness uh and vertigo. So then the the kind of first you know question that I'm gonna try to ask is, you know, are there some features here that make me think that this might be vestibular? Vestibular meaning inner ear or brain, you know, those balance organs that live inside our inner ear that sort of you know tell us where our head is in space, give us our sense of upright. The way I describe the vestibular system to patients is it's sort of like the gyroscope and accelerometer that lives in our iPhone. It kind of, you know, gives us a sense for for where upright is and it gives us a sense for motion. So, what are some features, you know, of the patient coming in that make us think that maybe their problem is vestibular? And so things that make me think about a vestibular cause are features like head motion intolerance. So patients who are having a vestibular syndrome really don't like to move their head. They really prefer to say, still, anytime they move their head, that tends to worsen symptoms. Again, it doesn't cause symptoms, which we'll get into in a minute, but it worsens symptoms. So they don't like to move their head. And another feature that that is helpful, but not always present, is nausea. That tends to be associated with vestibular syndromes. So I kind of, you know, just in the back of my head, am I thinking, you know, are there features here that that are vestibular? And then really the first most important question that I want to get at is the timing of symptoms. So I want to really get at, is this problem acute and continuous or is it episodic? We'll spend less time on the chronic, you know, branch of the tree in in this podcast, but really trying to get at the timing of triggers, sorry, the timing of symptoms. And so the way I'll typically ask patients this, you know, of course, I want to know the cadence and how did it come on. But one way to ask this question that can be really helpful is to ask the question if you're sitting still with your eyes closed, are you still having symptoms? And if the answer is yes, I'm thinking much more about uh the acute vestibular syndrome. So acute continuous dizziness. If the answer is, you know, no, you know, when I'm sitting still with my eyes closed and my head still, then I'm thinking, you know, more about the episodic vestibular syndrome. And I will say it can be quite difficult to disentangle because I've certainly had patients who have, you know, crystals in the ear, which is an episodic disorder that we'll talk about, sitting there in front of me. And when you ask this question, it really can feel like an acute syndrome. Um, but you know, little questions, little ways to tease it out, you know, really to ask them, how are they feeling when their head is still in there and their eyes are closed?

Michael Kentris: 13:01

That's something I always struggle with, is that it'll sound for all the world like like BPPV, right? Your classic acute episodic vertigo. And you ask about, you know, like reduction or resolution with, you know, not moving. And people will say, like, oh no, the the dizziness was going on for, you know, hours and hours or a whole day. And I'm like, well, that doesn't really fit. And I don't know, in terms of like the qualitative symptoms that people report to you, sometimes I have to pare it down to like, well, is there a reduction? Which I know even that doesn't really differentiate that well, because what patient with vertigo doesn't feel better when they're not moving? So I find that, like you were saying, really hard to tease out. And I don't know, do you have any tricks to to disambiguate that?

SPEAKER_02: 13:49

That's a great, uh, great point. It comes up all the time. Another one I would say is that certainly patients with non-positional causes of dizziness, whether it's an acute process like vestibular neuritis or stroke or vestibular migraine, as you say, they really don't like to move their head. And sometimes it can have a very positional quality. You know, migrainers sometimes don't like to lie in certain positions. But if there's a really positional quality, like, you know, the patient's telling you, I don't want to lie on my left side, or, you know, the last three nights I've been sleeping only on my right side, I have to be really careful when I get out of bed. That for me is kind of pointing towards, okay, there's something here that I've I've got to check, right? And that's really where the exam is really helpful. So one principle that was really inculcated and instilled in me, you know, during during my fellowship training was, you know, if the patient's giving you a trigger, and we're going to talk about trigger systematically in a minute, you really want to seek out that trigger. So whatever you can do in the office to try to bring that trigger on, go and do that. And you'll be surprised sometimes, you know, just okay, you know, tell the patient. Now, obviously, I'm very fortunate in my clinic. I have all the fancy tools. I have goggles that that blow up the size of the eyes so I can really see what's going on. But I would say in in any clinic, in any setting, try to have the patient do what brings on their dizziness. Sometimes it can sound funny, lying prone, doing funny things. Try to, you know, turn on the lights, really advantage yourself of being able to look at their eyes, um, but try to bring it on. And so if there's a new process and it sounds positional and you're able to confirm it with exam, and then, you know, in many of these cases, we can actually treat it. If you can resolve the problem, then then you have your answer. But it can be very difficult on the history sometimes to disentangle. Thank you.

SPEAKER_00: 15:47

One question I had further on history before we shift to to exam is kind of you mentioned toxic exposures. And I think medication exposures is something that I feel like is taught in every textbook. And if you search, you know, medications diseanist, the list will just go on and on. You can't scroll far enough down. And so I'm curious like to what extent you consider that. I mean, I feel like most of the time when someone has come to me, there isn't usually a clear culprit, like recent medication. Sometimes I'll maybe hypothesize, okay, maybe it's that benzo that used to be once in a while, but now is every night, you know, like, and I'm just curious how you think about that and how much you take stock of that or or try to do the experiment of weaning things off before pursuing other possibilities.

SPEAKER_02: 16:34

Yeah, it's a great question. I think part of what's interesting about, you know, the setting in terms of where we practice. I mean, there's a lot of diagnosis by curriculum, and you know, there's a lot of referral pattern bias. And, you know, I think because the wait list to get in to see another neurologist is quite long, uh, and and you know, folks often have very good, you know, primary care, you know, often that process will already kind of, you know, have been gone through. But, you know, the thing I always think about is, you know, temporal relationship, right? You know, has there been a recent change in medication? You know, are there features, again, we're we're talking a lot about vestibular disorders, but you know, does the dizziness have a postural quality, an orthostatic quality? Uh, you know, and certainly I would try to remove benzodiazepines, vestibular suppressants, you know, really pair that stuff away, kind of even as I'm I'm sort of going through the diagnostic process, you know, to the degree that's possible, you know, want to eliminate that as much as possible. I will say, just as an interesting point, there have been a couple of times where I've had a patient with, you know, episodic vestibular symptoms and, you know, they're on sort of an anti-epileptic medication, whether it's a sodium channel block or otherwise, you know, they're on an anti-seizure medication. And um, in rare cases, uh the levels of an anti-seizure medication, maybe from a drug-drug interaction, maybe from something the patient ate, can really fluctuate throughout the day. Um, and so one of the things that I also often will tell my outpatients to do, um, if they have kind of spontaneous dizziness, you know, that comes on in episodes, I'll tell them to take a video of their eyes, you know, during, during the episode. So I'll get them to, you know, make sure they have good lighting. I'll kind of coach them through holding the smartphone up to their eyes. And in a couple cases, I've actually been able to catch downbeat nystagmus. So for those listeners, this is a form of nystagmus of of sort of movement of the eyes that points to uh sort of the the back part of the brain, the cerebellum being affected. And in some rare cases, it's actually been kind of them going super therapeutic, kind of above the level on their on their anti-seizure medication. So that's again a rare cause. It's not something we're going to be thinking about kind of first brush, but always want to have medication, possible medication effect, possible exposures on the list.

SPEAKER_00: 19:02

I'm I'm so glad you mentioned that because I have this one case from my residency, it was an inpatient consult, and it was for direction-changing nystagmus. And uh, lo and behold, it was a carbamazophine toxicity for the patient, unfortunately. Um, but also fortunately, because we're like just down the, you know, down the dose and it'll be okay. But um, you know, it was the right call by the clinicians about being concerned for a central cause and a good teaching point that medications and toxidromes will be essentially mimicking a central cause because they're affecting those systems. We'll get to the exam in a little bit, but I think, as you said, timing and then the nature of the symptoms potentially.

SPEAKER_02: 19:39

Absolutely. It's a great point about medications, and I'm glad you brought it up to emphasize again.

Michael Kentris: 19:45

Uh you had also mentioned triggers. Obviously, I think everyone knows about movements, but what are the other kinds of triggers that you'll usually ask about?

SPEAKER_02: 19:54

Yeah, that's a that's a great question. What might be helpful is if we let's talk about the acute arm first, and then we can talk about episodic and and triggers is like the 100% key thing that that we we gotta talk about. Does that does that sound okay if we go in that order? Yeah. So if we go down the sort of acute, so let's say, you know, we've asked the patient and you know they're telling you, doc, you know, when I when you know, still with my eyes closed, the room is still going around, you know, there's worsening with head movement, but there's not like this strict positional quality. So then we're dealing with the acute vestibular syndrome. So the acute vestibular syndrome, you know, has a formal definition. It's you know, continuous dizziness in vertigo that comes on acutely and persists for a day or more. But of course, if we're you know working in the ED or in urgent care and the patient comes in and you know they've got acute continuous vertigo, we're not going to wait for 24 hours. But the point is that it's sort of continuous at the time that we see the patient. You know, there's often a lot of nausea, vomiting. We talked about head motion intolerance. And in the strict definition of acute vestibular syndrome, we often talk about spontaneous nystagmus. So this movement of the eyes, you know, where there's a slow drift in one direction and then a catch-up. So it's sort of this, you know, almost rhythmic movement of the eyes, a slow phase in one direction, the slow phase is the problem, and then a quick reset back. So if we look at the patient's eyes, particularly in the first few days, we're going to see nystagmus, you know, just looking at at the patient. So that's the acute vestibular syndrome. And the question, you know, the key question that we're trying to answer in acute vestibular syndrome is you know, is this something dangerous? You know, central causes are usually dangerous. We think about central. So for example, uh, you know, an acute ischemic stroke, or is this an inner ear mimic, you know, a process from the inner ear that might be mimicking uh a stroke? And the classic example. Of that would be a peripheral, acute peripheral vestibulopathy, or most commonly a vestibular neuritis. So an inflammation of the balanced part of the eighth cranial nerve that's often postviral or idiopathic and it causes a particular sort of syndrome. And so what do we use? I mean, we want to answer this question. Is it stroke? Is it inner ear? And so we're lucky in our field that, you know, we now have a good validated bedside exam that's more sensitive and specific than MRI in the early period. And that's what's known as the hints exam. And we think that the hints exam is more sensitive and specific because the physiology changes immediately, right? The pathology happens and the findings that we see change immediately, whereas MRI can take some time to change. And so that's really what gets me so excited about this field that we're able to see the changes kind of in real time by looking at the patient's eyes, looking at the physiology.

SPEAKER_00: 23:01

And on that.

SPEAKER_02: 23:02

So we're going to go ahead, Elian.

SPEAKER_00: 23:04

Just a quick question. In that case, do you often hear a prior history of URI? I mean, I feel like sometimes I have like that perfect story where there's been an illness and then there developed the dizziness, but sometimes I don't. And so how often is that, is there almost like a spontaneous kind of vestibulopathy that is peripheral and is maybe potentially a vestibulitis? I mean, I do think about, you know, we think about demyeline disease, can be rare, young patient. But say we have our more typical older patient. Um, is that something you've seen?

SPEAKER_02: 23:37

Yeah, it's a great question. I will often for interest ask, you know, in the last two weeks, you know, have you had a cold or flu? I mean, it'll it's also, again, curricular, right? Depending on what time of year you ask that question, you know, you're gonna get a little bit of a different answer uh, you know, in the summer versus otherwise. But I will ask it for interest. If it's of relevance, I'll kind of note it, note it down. I wouldn't I wouldn't use it, you know, as you say, to to sort of you know make make a diagnosis one way or another, but I think it's kind of a useful thing, useful thing to ask for sure. You know, there's some interest actually in some of these sort of antibodies, you know, uh, but but I think it's a good question and and and I think it's something to note on the history if it's relevant, but sometimes you don't, you know, you don't always get that that nice history.

Michael Kentris: 24:26

So you brought up I'm a huge fan of the hints exam, and I'm less a fan of the fact that I have to teach it uh so often to the IM and ED residents who rotate with me. Because it is one of these things where it seems that like it's it's very straightforward, just a few components to the exam, uh especially if we're talking about like the hints plus, but it seems like a lot of people are very uncomfortable with the assessment, particularly of like the character of the Nystagmus. So to challenge your uh since we're an audio-only podcast, to challenge your descriptive skills and on, tell us a little bit about the hints exam and kind of what do you find are best practices? Because I know there are some variations in how you can perform it, but what do you find to be the most useful?

SPEAKER_02: 25:12

Yeah, great, great question. So, you know, the first thing I'll say about the hints exam is I I I want to sort of reiterate back to you and to acknowledge that, you know, this, you know, it is it is difficult in the sense that it's really the kind of thing that getting familiar with it and practicing it in in as many settings as you can is really helpful. And so, you know, I'll I'll often tell you know, colleagues in in other specialties, trainees, like really use the opportunity. If you have a patient who's dizzy, even if you kind of know what else is going on, you know, go ahead and practice the the hints exam. Get get comfortable with it. And you know, the other thing is to look, to look at videos online. We're really lucky. There are a lot of great videos online. One of my colleagues uh from up in Canada, Dr. Peter Johns, has just amazing resources on on YouTube. You know, he'll show different kinds of nystagmus, he'll show the head impulse test. My mentor Dan Gold at Dr. Dan Gold at Hopkins has his website through through novel. Uh, we can provide links to some of these resources. Uh, and he actually has videos where you can test your understanding. So you can watch the video through and pause it at certain points and and sort of ask yourself. So it's really one of those things where getting comfortable kind of slowly by by practicing, you know, looking at what what normal is like is really helpful so that when you're in that moment where where you're on service and you know, it becomes more automatic for you, I think, I think is really, really crucial. So the hints exam, of course, is is an acronym, so it's kind of helpful to walk through it. So the the HI stands for for head impulse. So there we're we're checking the head impulse test. And so the head impulse test is really testing this evolutionarily old and important reflex that we all have as humans, which is our vestibulo reflex. That's the reflex that lets us keep our eyes on a target when we're moving our head. So if you can imagine, if you know you're looking at a target across the room and you move your head quickly to the right, you're moving your head to the right, but your eyes have to move to the left. And that reflex, you know, when it's working, is you know, one-to-one. You know, you're moving your head to the right and your eyes are moving to the left more or less at the same, same speed. So it's really when it's working well, it's a very, very good reflex. And so what we're doing with the head impulse test is we're we're really pushing that system. So we're asking the patient to look at a target across the room. We're, you know, sort of holding their head. I really like to hold their head quite high up so that you know, all that movement that you're doing is translating right, right to their head. I'll always warn the patient what I'm doing. I'll kind of make a few small movements. And then what I'm doing, you know, they're looking at the target across the room, but I'm looking at their eyes and I'll warn them what I'm about to do. I'll tell them, you know, I'm not gonna hurt you. And what I often do is, you know, what I'm looking for is kind of a small movement of the head, just 15 to 20 degrees, really pretty brief. And often what I what I tell folks who are learning the hints exam for the first time is I like them to start a little bit eccentric and end in the midline. Okay, and there are a couple of reasons for that, but kind of the simple reason is that, you know, we have a much better instinctual sense for where midline is. So it's very difficult to kind of over over overshoot. So, you know, lateral to midline, and we want to be a little bit unpredictable. Because if, you know, this our brains are so good at predicting, you know, what's happening in terms of our patient. So if we just go left, right, left, you know, the patient's gonna catch on pretty quickly. You know, I want to kind of mix it up. And so, you know, that's how we perform the head impulse test. It's a short, kind of small, relatively small amplitude, 15, 20 degrees impulse. We really want to go pretty, pretty quickly, unpredictably, and we're looking at the patient's eyes. Now, the challenge about the head impulse test is that what we're looking for on the head impulse test is a corrective saccade. So when the eyes slide off the target and then they have to shoot back, you know, they haven't been able to stay on the target when the head is being moved. And the presence of a corrective saccade actually points towards a peripheral process. So it's a little bit counterintuitive. The finding, identifying a corrective saccade is actually pointing towards a peripheral or inner ear process. And that that's what's challenging. So, you know, Michael, if I did uh, you know, head impulse on you right now, there wouldn't be a corrective saccade. But in the acute vestibular syndrome, that's not reassuring. That's actually pointing towards something that's not a peripheral cause, not not a um, not a neuritis, for example. So the presence of a corrective saccade is what we're looking for to rule in vestibular neuritis.

Michael Kentris: 30:20

Excellent description.

SPEAKER_02: 30:22

So then we move to the to the next part of the acronym. We're now at N. So we did HI, now we're at N. And so in N, we're we're looking at nystagmus. And for nystagmus, it's really the pattern of nystagmus that we're looking for. And so the way I describe it to folks is I really describe the pattern of nystagmus that, again, is gonna reassure us. And that's what we call unidirectional nystagmus. So we look at the patient straight ahead, and let's say for the purpose of this example, that they've got a right beating nystagmus. So, what's that gonna look like? They're gonna have a slow drift of the eyes towards the left and a quick beat to the right. So the beating is gonna be to the right, so it's right beating. So they're looking straight ahead. You know, we've got nice light. I always like to advantage myself when I'm looking at nystagmus, bring the patient up to eye level, add some light, you know, it can be hard in the ED, you know, bring out a pen light, or, you know, if all you've got is your smartphone light, you know, bring it so we can really see the eyes. And they've got this slow drift to the left, right beating. And then I ask the patient to look in different positions. And unidirectional means that nystagmus doesn't change what it's doing depending on where I look. So I have them look to the right and it's still right beating. I have them look to the left and it's still right beating, up it's still right beating, down, it's still right beating, it's unidirectional. There may be some positions where it gets a bit less. There might be some positions where it gets a little bit more, but it's it remains the same direction. That is unidirectional nystagmus, and that's the pattern we have to see to be able to call it a peripheral process. Any other pattern, it's not peripheral. We can't rule in peripheral. And so if you're seeing vertical nystagmus, okay, the slow phase is down and it's beating up or it's beating down. Or, Kalina, as you alluded to earlier, if it's changing direction, if the patient's looking to the left and it's left beating when they look to the left, then they look to the right and it's right beating when they look to the right, it's like X, no, okay, not peripheral. So we really want to, you know, identify, okay, yes, it's this one pattern that that tells us it's peripheral. So that's what we're looking for with nystagmus. And then the last part of the acronym is TS for test of skew. And with test of skew, we're looking for, you know, is there a misalignment of the eyes, particularly, you know, vertically? And this is a little bit of a difficult one to explain just with audio. So it encourage folks to kind of check out, you know, the videos of Dr. Peter Johns on YouTube or some of the videos from Dr. Dan Gold and his novel uh collection. What we're doing is we're we're basically telling the patient to fixate on a target. Usually I'll try to find something across the room. You know, if you're in the ED, is there something kind of across the room or in the exam room? Sometimes you'll see in my exam room, I put an X on a post-it note. I'm giving them a target kind of a, you know, a little bit of a distance away. And then what I do is I sort of I alternately cover the eyes while they're looking at that target. So I'll you know, be covering their left eye, and then I'll move over to the right and I'll go back and forth. And what I'm doing is I'm looking at that eye as I'm uncovering it. Is there a movement? Is the eye moving anywhere? Because if you think about it, when the eye is covered, or the way I think about it is when the eye is covered, it goes to its normal position. And then when I uncover an eye, if the eyes are not kind of in the same spot, they may have to move to pick up fixation again. And so as I'm uncovering the eye, if it moves, that's telling me that, you know, the eye is having to move to pick up, you know, fixation. And so what we're looking for on the test of skew is a vertical movement. Lots of us have little horizontal, you know, movements or deviations, let's say, of the eyes, or eyes may be a little bit pointed out, a little bit pointed in. That can be very normal. But it's much more unusual to have a vertical difference between the eyes. So if I'm uncovering one eye and I see it's moving down or it's moving diagonal, if there's a vertical component, and then I cross back and the other eye, you know, moves up. So if there's a vertical movement, you know, one way or the other, that's that's kind of pointing central for me. That that's gonna be stroke basically until proven otherwise. So the way to think about the hints exam is we want to have an all clear. We want the head impulse. Again, we want to see a corrective saccade, a positive finding. We want the nystagmus to be unidirectional, same direction wherever the patient's looking. And on the test of SKU, there should be no vertical misalignment. So it should be green, green, green, all clear, all through. If any part of the hints exam is pointing central, then we've got to treat it central until proven otherwise. So this is a test that's maximized to pick up stroke. So we're extra conservative on the hints exam.

Michael Kentris: 35:25

No, that's excellent. And you know, I've heard some people say, and I'm curious what your opinion is, that if you're if you're doing the hints exam, you probably don't also need to be doing a, which we haven't talked about yet, a Dix-Hallpike exam, and vice versa. What are your thoughts on that? And or do you modify your exam based on like is there active dizziness versus kind of the you're seeing them inter-attack?

SPEAKER_02: 35:51

Yeah, it's it's a very, very good question. You know, I would say it depends a little bit on the context in which you're seeing the patient. So kind of in in my clinic, you know, where the patients, you know, probably it's not their first couple hours, you know, worth of dizziness vertigo. I'm kind of trying to remove any contributor. And, you know, I will I will often check kind of dick the you will do the dixolpike on on many of my patients, you know, unless it's it's very, very clear that that that it's not. You know, I would say in the in the ED, I really want to simplify things for for folks, you know, in the sense that if the patient's sitting in front of you and they've got spontaneous nystagmus and you know, the last five hours they've been you know dizzy the whole time, I think that really is the patient where you want to um, you want to go down the hints pathway as long as they meet the criteria and there are no red flags and you know there isn't a strong positional flavor to it. I mean, they're just sitting there and they're feeling really dizzy. But I would say in cases where you're not sure, you know, it's not fully conforming to acute vestibular syndrome, kind of you've done your due diligence about removing red flags. I think that's a patient really where where you want to be thinking outside the box, doing a Dix Hallpike. Sometimes, particularly in elderly folks, BPPV can be an incidental finding. So want to be careful about that too, that if the syndrome isn't completely fitting with it. But as we said, sometimes BPPV could present as kind of imbalance all the time. And so it's treatable. So it's certainly something that, you know, that you want to look for. Um, so I would say it depends a little bit on the context. Um, you know, one of my mentors in in Ottawa, Canada had a great rule, um, Dr. Darren Shay. He said, any patient over the age of 65, it doesn't matter how they describe their dizziness. I'm gonna do a Dix Hallpike because you would be so surprised sometimes how often. So I would say it's always better to do something than to check for something when someone isn't completely missing a conforming to a syndrome because you never know what you're missing. But where where I hesitate a little bit is in that acute setting, I want to really make sure that that people aren't that that they're checking for spontaneous nystagmus. Because if we think if a patient's got upbeat nystagmus when they're sitting there in front of you, you know, they're just sitting on the bed and they've got upbeat, that's not BPPV, right? And so if we then go into a Dix Hallpike and we see upbeat nystagmus, we may incorrectly attribute that to BPPV when there's something else, you know, going on. So to the degree possible, I would say, particularly if it's kind of new, acute, you know, dizziness vertigo, that's really where we want to apply hints. But if the syndrome doesn't entirely fit, there may be a positional quality, you know, that's where we want to do the dixalt bike, especially if we're, you know, we're confident that there wasn't spontaneous dystagmus, you know, uh, and we we know what we're looking for on the on the Dixalt bike.

Michael Kentris: 38:49

No, that's great information. Thank you.

SPEAKER_00: 38:50

Anon, can I just wrap up the conversation on the hints exam before we shift to that other arm of triggers? So you gave us the example of a right beating nystagmus and how we would need to have all green flags to identify it as peripheral. Can you just finish with that last segment about how do we localize um, say that right beating nystagmus? Is that a problem on the right inner ear or on the left? And can you work us through that complexity if we haven't lost people already?

SPEAKER_02: 39:21

Absolutely. But one thing that I would say is that if coming out of this discussion, you know, you've, you know, you've you've heard a little bit about how to do these exams. You're now gonna look online kind of at the technique, you're gonna practice with your patients. We've now talked about kind of how we work through kind of the diagnostic algorithm, thinking about head impulse, nystagmus, test of skew. I, you know, and you're working in a generalist setting, I am over the moon. Okay, I'm gonna be supremely happy that you're in a position to apply this. Now we're gonna take it a little bit a step further for for the nerds out there, okay, in terms of the physiology and then sort of the localization. So, you know, when when we think about kind of, you know, where where is the problem and all of this, I find it helpful to start with a side. So let's talk about a side that's affected and think about why the findings you know would point in that direction. And then we can always flip it, you know, to think about the other side. So let's imagine that we have an inner ear process going on on the left side, okay, a process affecting our balanced vestibular system on the left side. That could be the end organ, the vestibular apparatus, or or more commonly, the nerve, like in a left vestibular neuritis. So on the head impulse test, you know, when we move the head quickly to the left, that's where we're going to see the corrective saccade because our system is wired in such a way that more of the response is being driven by exciting that that ear. So when we move the head to the left, yes, information is going into the right ear, but the left is maximally excited. Excite, excitation is more powerful in this case than inhibition. So we're really pushing the left ear when we move the head quickly to the right. So we're gonna see a problem come out when we move the head quickly to the left. That left ear reflex can't keep up, and the eye is gonna slide back to the target. So that's pointing towards sort of a left uh sided vestibulopathy, a head impulse test with a corrective saccade to the left. Then in the nystagmus, we're actually gonna see a nystagmus that beats away from the ear. And again, if if you want kind of practical clinical, just close your ears for this one because I don't want to, you know, uh unnecessarily confuse people. But if we think about what's happening when we inactivate the left ear, the right ear is active at baseline, at tone. The patient's just sitting there, that right ear is active. And activation is the signal of the head moving towards the active side. So the brain, if you will, thinks that the head is moving to the left. So if the head is moving to the left, the sorry, the head is moving to the right, the eyes have to move left to stay on the target. The head thinks it's moving left, the head thinks it's moving right, the eyes are moving left, and then they have to saccade back. So there's a slow drift to the left and then a right beat. So you get a right beating nystagmus from a left-sided vestibulopathy because the head thinks it's moving to the active side, the eyes do the opposite to the left, and then there's beating to the right. All you have to remember, you know, in the clinic when you're seeing the patient is that the beating is going to be opposite. It's going to be unidirectional opposite. And then the test of skew, without getting too much into detail, peripheral processes tend to cause small skew deviations, whereas central processes tend to cause bigger ones. And it just so happens that that threshold is at the limit of detection by testing. So a test of skew is a central. The eyes tend to beat away from the ear that's down. So left peripheral vestibulopathy, left-sided vestibular neuritis, you get a right beating nystagmus.

SPEAKER_00: 43:11

Thank you. I appreciated that review.

Michael Kentris: 43:14

I know. I feel like I have to look up Alexander's law like every few months to remember my left and right.

SPEAKER_02: 43:21

Exactly.

SPEAKER_00: 43:22

So let's go down that other arm of the algorithm quickly. I'd love to talk about the triggers that we had started up with kind of the acute vestibular syndrome side, and now for the episodic or the triggers you asked for in history, and then tell us about that special exam that we've been name-dropping that we do in this case.

SPEAKER_02: 43:42

So now, you know, we're talking about episodic vestibular syndrome. So, you know, discrete episodes, again, it can be tough on the history to disentangle, but you're getting the sense that kind of, you know, there may be a little bit of baseline dis, but you know, a big part of this is sort of episodic. And so the first question I try to ask in in the episodic vestibular syndrome is are those episodes triggered by something? Is there something on history that you can bring out, namely change in head position relative to gravity or posture? You know, if the patient kind of stands up, particularly if they go from lying to to sitting, lying to standing, or are the episodes kind of spontaneous, right? Regardless of what the patient does, you know, though their episodes are are coming on. And so if the kind of episodic dizziness or vertigo is triggered, you know, then I ask kind of what what does it sound like the trigger is? So if it's, you know, head movement relative to gravity, sort of turning over in bed, looking up, looking down, you know, one of the things that I would be thinking about would be this entity called BPPV or benign paroxysmal positional vertigo, where sort of calcium crystals where where debris wreak havoc inside the inner ear, they go swimming in the canals. And every time the patient moves, those those crystals move and it causes both vertigo, room spinning, or sometimes described by patients as dizziness, or an istagmus. In a related way, the other thing that I'm thinking about when when there's a trigger is it is it postural? Could there be orthostatic hypotension? Patients standing up and their sort of their perfusion or at least you know their blood pressure is dropping and that's causing their their dizziness. So those are kind of the things with triggered. So when it's triggered, I really want to do those exam maneuvers. So I want to do kind of a Dix hallpike. And so the Dix Hallpike is a provocative test for BPPV for crystals in the ears. So what we're basically trying to do is to reproduce the symptoms by getting those crystals to move. And crystals can get into a few different canals inside the inner ear, but the most common one in an outpatient setting would be those posterior canals. And so what we're doing with the Dix Hallpike maneuver and certainly would encourage people to look at some of the great videos out there on how to do it is, you know, let's say we're testing the right side, okay, the right posterior canal. So what we're doing is we're having the patient sit, you know, on the bed and we're having them turn their head 45 degrees to the affected side. So if we're testing the the right side, they're going to be sitting on the bed with their head 45 degrees to the right and we relatively quickly bring them back. So their head is then extended lying over the edge of the bed. And what we're doing is we're looking for a nystagmus. We're looking for the nystagmus that we would expect with crystals moving in that posterior canal, with activation of that canal. And that happens to be an upbeat and a torsional nystagmus. So we look at what that top pole of the eye is doing and it's, you know, we're looking for it to move towards the affected side in this case the right side. And that nystagmus is usually quite brief, almost always less than a minute or two, sometimes 30 seconds, sometimes 15 seconds, it should reproduce the patient's symptoms and it often has this crescendo decrescendo quality. It really kind of picks up to a crescendo and then it kind of decresh decrescendos as those crystals are moving. So that's what we're looking for on the Dix-Hallpike test. If we see upbeat or torsional nystagmus that has that quality to it, there's there's almost nothing else that that's going to do that. And that's where we want to we're not talking as much about treatment but that's where we would we would treat the patient for for BPPV. If we're not seeing stuff on the Dix Hallpike, you know the symptoms sound more postural, that's where you would want to do orthostatic vitals, check the patient's blood pressure lying and then have them standing at one take it again at one minute and then at three minutes and if you're seeing a sort of a drop in blood pressure, you'd be thinking more along the lines of an orthostatic cause. So that's the triggered episodic vestibular syndrome.

SPEAKER_00: 48:04

I'm so glad you walked us through that because I think it's not enough people are confident in doing it. But I do remind them when I'm teaching about it that you could potentially really make a difference. And so I try to frame it a little bit that way like this might feel bad, but if we find something that feels exactly like what you're experiencing at home, then we can do something about it.

SPEAKER_02: 48:36

And unless you've experienced BPPV, it's it's hard to imagine kind of how strong that feeling is how prominent those symptoms are sometimes and so I I really love that that you brought that up in terms of really explaining to the patient, you know, we're not just trying to kind of stir this up, we actually have, you know, treatments for it. And how many things are there in medicine where you know just your hands and the tape, like we can, we can in many, many cases, you know, resolve it just doing maneuvers. Very few things like that in in medicine. So yeah, so that's the triggered you know episodic vestibular syndrome. And then you know if the episodes are spontaneous, so we're thinking more episodes that just come on, other entities that we we we won't delve into today, but things to be thinking about would be Meniere's disease, which is an episodic kind of ear-based process, if you will, where folks have spontaneous episodes of vertigo and and we really like to see kind of prominent ear symptoms either around the time of the attack or sort of on their own, hearing loss, fullness in the ear, tinnitus, you know, often defining that affected ear where the meniers is coming from. And typically, you know, as menires progresses, we will be able to document hearing loss. Initially it can be very, very much fluctuating, but over time we see it kind of persist on the audiogram. So that would be one cause. And then one very common and underrecognized cause of spontaneous episodes of dizziness in vertigo would be vestibular migraine, which is spontaneous episodes of vertigo typically or dizziness typically lasting hours to days. Often we like to see a personal history of migraine or migraine features during the attacks, but you know, migraine is a great mimicker of many things. So something to think about, but just to emphasize the point that if someone's coming to you with acute vestibular syndrome and it's their first attack, you know, that's a setting where we would want to be conservative, apply hints, uh, you know, think about all the possible central causes including stroke, you know, when when it's that that first episode and that can be challenging first episode meniers or or migraine.

SPEAKER_00: 50:51

Well this has been such a whirlwind tour of dizziness probably should be expected. But I've really enjoyed learning from you Anand and I really like that framework that you've provided us for any provider who's beating someone coming, as you said, with dizziness coming through the door, at least initially what to look out for red flags and then how to proceed down that path, whether it's an acute vestibular syndrome and what that leads to us leads us to think about differential-wise and how to do the exam versus these episodic uh episode episodic uh dizziness and again what we should think about in terms of differential and and how to differentiate on exam and a little bit about treatment. I think we're gonna need to have you back to talk more about management and and I I I know I personally have some of my more advanced uh neuroontology questions for you so we're gonna have to have you back for version two.

Michael Kentris: 51:44

Aaron Ross Powell the chronic dizziness is I think what a lot of us as neurologists are seeing in the office. And that is a a whole different kettle of fish. So I would definitely love to pick your brain about that at a future date. But but yes, this is very bread and butter stuff that you know every physician should know I think it's just such a common complaint. There's not enough neurologists to to manage it. And a lot of times as you said it's the ED physicians the primary care physicians who are seeing these patients and I think having the tools as you said right with your hands and your eyes and brain to fix this for a lot of people can be very powerful.

SPEAKER_02: 52:22

Absolutely trying to get the the word out because as you say there are very few of us who do this every day. Obviously we we love what we do but you know I I see part of my my mission as empowering everyone to have an approach and I encourage folks to to practice just whenever you have an opportunity practice get a sense for kind of what normal looks like check out the many many resources that are out there we're so lucky online now we have a lot and that that would be my wish list.

SPEAKER_00: 52:52

I was gonna say sometimes I tell my residents practice phidoscopy on everyone in this case they don't even have an excuse because you don't need a device you can just do the hands. Exactly a hundred percent a hundred percent yeah Nan, do you have um we'll make sure to put links to those resources you mentioned in the show notes but any other cool projects coming down the pipeline or could people follow you online or anything else?

SPEAKER_02: 53:14

Yeah great point um one one plug that I'll I'll I'll maybe make is that you know Galena you and I are investigating kind of different modalities that you know might help our patients with with dizziness. So we're we're gonna be piloting a trial on dancing again that for dizziness that's more in the in the chronic situation but that you know that's that's one exciting thing. And then you know if folks are interested, you know, maybe those that have more of a neurology background there are some episodes also that we've done for the neuroexam prep podcast out of Yale on both acute and episodic vertigo we we do a little bit of a deeper dive into into each of those syndromes. So would in encourage folks to to take a listen to those as well.

Michael Kentris: 53:58

I think I listened to those episodes before and they were quite good. Well as always thank you to everyone for listening and thank you to Dr. Anand Berry for all this information. You can always find our old podcasts on your podcast listener where I assume you're listening to this you can also find our stuff at neurotransmitters dot com and you can find us on X at neuro underscore podcast. Feel free to send any questions other suggestions for shows and so forth and you know thank you everyone again thanks everyone all right