An Approach to Acute Weakness with Dr. Derrick Cheng

Dr. Derrick Cheng joins us today for an approach to acute onset weakness!

Join us as on our treatment journey from onset to treatment, and think about what you might do if encountering the same clinical situation.

Important points we discuss in this episode:

• The tempo of the disease onset
• Where can we localize the symptoms?
• Fatigue vs weakness
• Triaging patients with acute onset weakness
• Stabilization and management of acute weakness

Follow Dr. Cheng at x.com/dlchengmd

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Chapters

• 14:13 [Ad] Screen Deep
• 14:51 (Cont.) An Approach to Acute Weakness with Dr. Derrick Cheng

Transcript

Michael Kentris: 0:02

Hello and welcome back to the Neurotransmitters, your source for everything related to clinical neurology. I'm joined today for a hopefully new and continuing segment with Dr Derek Chang. Thanks for joining us today.

Derrick Cheng: 0:16

Thanks so much for having me.

Michael Kentris: 0:17

So Derek reached out to me online, as so many things. We meet a lot of our folks online through either email or Twitter, so always happy to meet new people coming to me all the way from the West Coast at UCSF. So thank you for waking up post-call, dealing with the time difference today. So Derek reached out and this is a concept that I've been wanting to work with a while is kind of the chief complaint oriented way to organize your thoughts, and so Derek did all this heavy lifting on writing up a kind of a schema, if you will. So we're going to kind of go through some exercises today and talk about how we could approach in real time some chief complaints and kind of give some little pauses throughout. You know, let the listener you, our dear listeners listen and think and hopefully come to some conclusions on your own and then see if you agree with us. Does that sound about right, dirk?

Derrick Cheng: 1:14

That sounds exactly right. One of my goals for putting this together was to put some more listeners in the driver's seat and let them think through a resident's thought process as we approach some of these consults at different stages of the consult, whether it's the initial page, when we're approaching our patients to talk about a history and exam, and how we formulate the question and think about our next steps in terms of diagnostics and treatment.

Michael Kentris: 1:36

Excellent. Yes, and this is something that, for those who maybe are more junior in their medical journey, that neurologists love to do, whether they are teaching on the wards or in morning report or in a hundred other settings. I think this is a pretty standard neurology fair. So this is kind of how we learn and then subsequently teach as we get more senior down the road. So I think this is a great idea and I'm looking forward to it. So Derek has been generous enough to put me in the driver's seat, at least initially, so I'm going to crib off of his work here. So we start off by getting a page because we still use in medicine in some areas, and it says new neuro consult 57-year-old female with new weakness. And it says new neuro consult 57 year old female with new weakness. So with nothing else, what are the first?

Derrick Cheng: 2:31

things that, uh, that your mind goes to. So I feel like I've gotten this page 10 times in the past couple of weeks, um at minimum, and we hear this console question all the time. One of the first things that I always wonder about when I hear this question of new weaknesses is this even a neurologic problem? A lot of folks come in with sepsis and have generalized weakness, or they have a heart failure exacerbation and have fatigue and shortness of breath, though our ED medicine, other consulting colleagues are pretty good about parsing these things out early on. So other questions that I'd be thinking about early on are time course. When did this start? How quickly did it progress? Because their tempo can really help triage and really help us with our diagnosis.

Derrick Cheng: 3:19

As we go forward, I want to know about what things they're actually having difficulty doing. Are there particular muscle groups that are affected? Is this a symmetric issue? Can they walk? Are they having issues standing up from a chair or reaching up over their head, or are there certain times during the day where I feel like this is worse? This all helps me put this patient together into a different illness script. And then, finally, I'd want to know about what other symptoms are going on. The presence of kind of some of these other symptoms or the absence of other symptoms can really help me localize this to different parts of the interaxis. Are they having blurry vision, diplopia? Are they having bulbar symptoms and respiratory issues? Are they having new numbness, tingling or sensory changes? All of these can really help me shape what I ask the patient and how I approach them when I go down to do my physical exam I think that's.

Michael Kentris: 4:09

That's very, very well put um and to.

Michael Kentris: 4:13

If I, if I may try and condense the, the general thought process, right, we talk about the tempo or the, the timing of the onset, as well as the where of it, and then what's the associated.

Michael Kentris: 4:26

So I always had one attending who was like you, got to be like a reporter who, what, when, where and why. The why is usually up to you, but the rest of it it guides you there, and so I do find that a lot of times the localization, the where, and then the timing, the when, tend to be the two questions that we usually start with in neurology and those really do guide a lot of our especially in the initial acute phase, kind of a lot of our management and triaging. So next up you get a little more history. You talk to the ED provider and the story's a little thin to start. So they say the weakness started two to three days ago, mostly in the proximal muscles, now impairing their ability to walk, some shortness of breath also noted and nothing obviously precipitating it. No recent trauma, afebrile, normal vital signs and initial labs, including CBC BMP, are unremarkable.

Derrick Cheng: 5:22

Perfect. So this is often where we are when we first talk to our ET colleagues, and there's a little bit of a story, but some of the details aren't so clear. Just hearing this brief snippet, though, there are a few things that jump out at me as being a little concerning. You know, this patient is having new shortness of breath. They've got this new what sounds like a muscular weakness with this proximal muscle involvement, and it sounds like it's relatively quick onset. So I would start putting them into a bucket at least in my head as I'm getting ready to go down and see them of rapidly progressive weakness.

Michael Kentris: 5:55

Yeah, and I think you'll probably mention this more as we go on, but the where of the weakness and, as you said, the what are they unable to do? One thing that I think we often run into is is this is like the difference between fatigue versus weakness, right, when very often you know, as you said earlier, if someone has sepsis or some other acute like heart failure or a kidney injury or some other metabolic process going on, they may seem quote-unquote weak, but it's more related to they're more fatigued or feeling unwell, more generally speaking, rather than true muscular weakness. They can still generate the force, just they become more fatigued more easily, which sometimes can be, especially in some diagnoses, a bit of a fine line to walk. But it's something that we run into a lot, especially with some of our patients with neurologic disorders who are on the more chronic side, so like people with, like myasthenia gravis or multiple sclerosis or kind of these chronic diseases where weakness is certainly a very concerning symptom. So you always have to parse that out very clearly.

Derrick Cheng: 7:00

Absolutely.

Michael Kentris: 7:02

So you get in there, you're talking with the patient. So otherwise, no significant past medical history related to these types of symptoms. Overall, fairly healthy recent treatment for UTI and they've noted this sudden onset and progressive proximally predominant weakness. Initially they thought this was just fatigue. I might have given the game away when getting up out of a chair over the past several days. Now they're noticing some other things, such as slurred speech and a little shortness of breath when you ask them specifically and I think this emphasizes the importance between open versus closed-ended questions they also note some double vision before bed. So, again, more in the evening than in the morning and that's not something that patients normally will volunteer. So being very direct with some of these questions when you are building your illness script in your head For sure. So, all that being said, what are you thinking and what are the most important exam findings that you're looking for in this patient?

Derrick Cheng: 8:02

Sure. So there are a few highlights out of this that I'm picking up on. Just like you said, some of this proximal, predominant stuff. When you hear about difficulty getting out of a chair, you're thinking about some of their proximal or extremity strength, and then some of this slurred speech and the shortness of breath is cueing me in towards. Could there be a bulbar symptoms? Could there be some kind of respiratory involvement, something that might make me triage them differently when I'm starting to staff them with my attendant? The double vision before bed is really interesting.

Derrick Cheng: 8:33

I definitely want to dig a little bit more into that, especially when I'm doing my physical exam, seeing if there's a fatigability component in this, whether this is something else. So when I go downstairs to do my neurologic exam or to do my exam in general, I'd be looking at a few things in particular. In addition to doing a kind of a basic neuro exam, I'd be wanting to kind of get a better understanding of what muscles are involved. I also feel like a cardiorespiratory exam is a little bit of a lost art in neurology sometimes, but I still carry around my stethoscope and I encourage everyone to listen to heart and lungs and make sure there's nothing crazy going on. But outside of that, there are a few more specific things that I want to do. First, looking at the patient. How do they look? Do they look like they're using their accessory muscles to breathe? Do they look really ill? That can always help push you in one direction or another. And then some more specific testing that I might look at as a neurology resident include things like their cranial nerves. So you've mentioned their diplopia. I'd want to make sure there's no new cranial nerve palsy. Make sure their eyes are moving in all the correct directions. See if they have any diplopia on end, gaze in any direction, things like that. See if they have any diplopia and gaze in any direction, things like that. I'd be looking for ptosis if they have drooping of their eyelids, if they have dysarthria some of these patients can start having a very nasal speech or they might have a very guttural dysarthria where they're having difficulty with sounds from the back of their throat. And I'd be looking at things like facial strength. So putting this together, all of the different cranial nerves. One little tidbit I heard once is that you can get a good understanding of facial strength by having some of these patients whistle or seeing if they can whistle Other things that I'd be looking for really hone in on this respiratory component.

Derrick Cheng: 10:19

So one thing I like to test in all of my patients with new onset weakness is something called a breath count, where I have them take a deep breath and count as high as they can. You and I should be able to get up above 25. When patients start to get lower and lower, we start wondering if they have respiratory compromise, whether there's someone who's going to need additional respiratory support, going to need additional respiratory support. And on the same vein, I like to text their neck flexion and their neck extension. Neck flexion is when we have them take their chin, try to touch their chest, push forward with their head while you provide resistance. Neck extension is the exact opposite, where they bring their head back into the bed or the chair and you provide resistance and you really shouldn't be able to overcome them.

Derrick Cheng: 11:01

Folks with neck flexion weakness in particular are some of the people who we might be more worried, have a respiratory involvement or might be needing to go to an ICU or at least need some additional respiratory support. Similarly, in terms of the motor exam, I'm looking to test their proximal muscles, looking specifically at things like their shoulder girdle, their hip girdle, looking at things like fatigability If I'm pushing on one side multiple times, are they going to be more weak on that side? As well as sustained up gaze. That's a test where we have the patient look up and keep looking up and look for kind of a drift downwards in their eyes or their eyelids specifically. Some of us carry around ice packs because it's a test that we can use to parse out myasthenia. I don't do this often, but a couple of times over the course of my residency. So that's kind of the more muscular and the cranial nerve components.

Michael Kentris: 11:55

And I will say just a life hack for the residents out there that I've done and maybe some other folks have come to the same idea If you don't have an ice pack on hand is getting an exam glove and filling it at the nurse's station with some ice water and then tying that off like a water balloon can sometimes be a decent improvised test, especially in the middle of the night if you're on call. So I've definitely done that more than a few times myself.

Derrick Cheng: 12:25

That's a great idea. It's something that I've never tried before, but it's definitely something I'm going to do. I spend a decent amount of time running around looking for ice packs.

Michael Kentris: 12:33

Right, anyway, sorry to interrupt.

Derrick Cheng: 12:36

No, no, thank you so much. There are a couple of other final things closing out. I know we talked about their cranial nerve exam, their motor exam. Other things that I like to look for in these patients are paying special attention if there's any sensory involvement, if I'm thinking about a muscular problem or a neuromuscular junction problem, these should really spare your sensation, whereas a problem. A lot of these patients will present with new sensory deficits, new numbness, and would push you away from a muscle problem, for example. So that can really help you differentiate between a couple of causes of weakness. And, as always, we carry around our trusty reflex hammers. So I often, or always, check their reflexes and see if there's areflexia or hyporeflexia, things that might be making me more concerned for things like GBS or demyelinating polyneuropathies.

Michael Kentris: 13:28

Excellent. No, I think those are all great things, especially when we're talking about what sounds like more of a peripheral nervous system, which is kind of the bane of a lot of people. A lot of even neurologists are more focused on the central nervous system, right, which is kind of the bane of a lot of people, right, a lot of even neurologists are more focused on the central nervous system. So let's go back to our patient here. So we've got a patient, some fatigable weakness on the exam. It does seem to be more proximal than distal. A bit of weakness with neck flexion. They have a breath count of 25 at this point in time. On sensation exam there are no abnormalities, pinprick, vibration etc. Reflexes also normal, no fasciculations, no atrophy. Where does that guide your thoughts in terms of ruling things more?

Michael Kentris: 14:09

in up, or I should say up or down, in your differential diagnosis.

Derrick Cheng: 14:43

Perfect. So so far we've kind of framed this patient as a progressive rapid-onset neuromuscular weakness. And one of the things that I like to do after I've finished seeing my patient, I'm going upstairs, I'm writing my note, I just think through all of the different parts of the neuraxis. Could this be a brain problem? You know, probably not. A lot of people will say you know, some bulbar symptoms can be related to a brainstem, but that might be a red herring. Here. Some bulbar symptoms can be related to a brainstem, but that might be a red herring. Here, you know, we'd probably expect some other features, some other localizing, some lateralizing deficits, something on one side or the other. And similarly, a spinal cord problem might look similar. You might have some spasticity, some hyperreflexia, something that looks more like what we call myelopathic picture. Then, going on to some of our more peripheral nervous system, like you mentioned, it's a little bit harder to parse out for some of us and it can definitely be tricky to figure out what's what. So, thinking through the different parts of the peripheral nervous system, could it be a motor neuron process? Could this be something like ALS?

Derrick Cheng: 15:44

You know, maybe we often hear about the combination of bulbar symptoms and weakness. We can certainly keep this on our differential, but you might expect to see some more mixtures of some upper motor neuron features, where we might see things like spasticity or hyperreflexia, and lower motor neuron features, things like muscle atrophy, fasciculations. Could this be a nerve problem? Anytime we hear about rapidly progressive weakness, we always want to include Guillain-Barre syndrome or AIDP or all of those cousins of nerve problems, even with these bulbar symptoms that you might not classically hear about with ascending symptoms. But, importantly, not all of these patients have this classic story of a preceding infection followed by ascending numbness and ascending weakness.

Derrick Cheng: 16:34

One key takeaway that I've learned is that many of these nerve problems involve both sensory and motor function. You know there are some variants of Yom Beret that are motor only, but these patients will often almost always have hyporeflexia or areflexia. Sometimes that might not show up early on in the disease process. So it's something I think about, definitely want to rule out. And then, more importantly, could this be a neuromuscular junction problem?

Derrick Cheng: 17:03

You mentioned myasthenia earlier on today and that's something that I'm worried about hearing this case, because we're hearing about things like fatigability. They're getting weaker as you examine them. They're getting weaker as the day goes on, as well as bulbar symptoms, motor-only symptoms. It doesn't really sound like some of the other neuromuscular junction processes that you hear about. Don't commonly see things like botulism or Lambert-Eaton, and that would probably be more of a topic for another day, but something to always think about when you hear these patients with new progressive weakness. And then, finally, could this be a muscle problem? Could this be a myopathy or a myositis? There are some things that kind of line up with that. In this presentation We've heard about things like some difficulty standing up from a chair, some motor-only symptoms. So it's something that I'm thinking about, but isn't necessarily the highest on my differential.

Michael Kentris: 17:58

Excellent summation and I think that's an excellent example of how a neurologist thinks about these things, in terms of what to prioritize, what's most likely, what are the can't-miss kinds of things. So, speaking of things that we can't miss when we're triaging this patient in the acute stages, what are the first things that you're thinking of, like your top three? And then what are the first things you're going to be doing to make sure this patient doesn't have any rapid decline or make sure that they're stabilized to the best of your ability?

Derrick Cheng: 18:31

Absolutely so. With these patients who are having rapidly progressive or rapid onset weakness. In this case, we've talked about how we might be worried that this patient might have myasthenia, specifically if they're having a myasthenia flare or they're having a myasthenia crisis, one of the first things that I'll always do, especially as someone who's going to eventually become an ICU physician, is to think about where this patient is going to go in the hospital. Is this someone that I can send to the floor with Q2, q4 neurochecks, or is this someone that I need to be keeping a really close eye on? Moving to the ICU, maybe thinking about intubating them? When I think through these problems, there are a couple of things that I like to do in the emergency department to really help me triage. First of all, doing things like our classic ABCs, our airway breathing circulation. Thinking about whether or not they have a lot of secretions, whether they're controlling their secretions, what their bulbar function is looking like. We've already talked a little bit about some exam maneuvers that can help us push in one direction or another. Thinking about what they look like in terms of their breathing, whether they have stridor or using accessory muscles to breathe, and there are some tests, specifically pulmonary function tests in the ED and some labs that can help us triage this as well.

Derrick Cheng: 19:48

One of the things that we often look for as neurologists is a NIF or a MIF, which is kind of our maximum inspiratory force, as well as our vital capacity, our functional vital capacity. What we're looking for is essentially the strength that a patient has when they're taking a deep breath in. What we normally want to see for our MIFs is a value of negative 40, something like that at least. Though when our patients start having MIFs of negative 30, or especially when our MIFs start having MIFs of negative 20, we want to start thinking about whether or not they're going to need additional respiratory support, be intubated or be moved to an ICU.

Derrick Cheng: 20:29

Similarly, their vital capacity. We would want to have at least 20 mils per kg, which would equate to about a liter and a half, a liter to a liter and a half, and once patients start to be under that, that's a point at which I become concerned. So, looking through, I make sure the emergency department checks in the FVC as well as the VBG Once their oxygen saturations start to drop. It's starting to be way too late that some of these patients can have hypercapnia. So a couple of high-yield exam maneuvers and high-yield tests that I'd want to make sure I think through before I really start triaging this patient.

Michael Kentris: 21:07

Those are all great points and I think a lot of these fundamental principles are able to be cross-applied to other forms of neuromuscular respiratory failure as well Someone like with motor neuron disease, like ALS or other kinds of neuromuscular myositis-type processes. Certainly, these are the things that we always think about. And to your earlier point, when we were talking about visually assessing the patient, we talked about accessory muscle usage, and one thing that I've always been taught and have seen as well is that a lot of times, the problem and why we see these changes on blood gases so late is because it's the muscles, not the lungs, right, so the muscles fail before the gases change significantly, depending again on the person and the rapidity of their decline. So it is one of those things where you definitely have to keep that on your radar and it's like those respiratory vitals and that single breath count test are absolutely essential for identifying these patients and if they do need an airway, being able to do that in a controlled fashion makes everyone's lives so much more straightforward as opposed to having to try and do that emergently. So I think those are all excellent points.

Michael Kentris: 22:23

So in this case we have someone, a relatively young woman, who has new onset weakness, no prior history of any autoimmune or neurologic disorders. So a kind of a new diagnosis, a relatively progressive weakness that we suspect is a neuromuscular junction disorder, very possibly myasthenia gravis. So when we're thinking about because most of the time we will see, maybe people have some, some bulbar symptoms, usually, you know, ocular, some intermittent diplopia, things like that may be going on for weeks to months, but it's, it's. It is somewhat unusual for people to present with kind of acute onset respiratory failure. So what are some things that perhaps she has been? Let's, let's hype, you know's, play a hypothetical scenario here, let's say that she maybe, after everything's stabilized you find out. Yeah, maybe I have been having some intermittent I thought it was just blurred vision for a few months. What could have happened that may have tipped her over the edge into this more acute transition in terms of her weakness?

Derrick Cheng: 23:30

in terms of her weakness. Totally. Every time someone comes in with a history of myasthenia and they're doing worse, we always go looking for what triggered it, what might've caused some of these things. You know there are a lot of. There's a long list of offending agents. You know there's in this case, maybe recent antibiotics, but a long list of other medications, including antibiotics, beta blockers, that can all precipitate myasthenia, flares or worsening of myasthenia. When I think about some of these patients in the acute setting, I am also trying to be very cognizant about what we're giving them and how we could potentially make this worse. So things like steroids, especially in the acute phase, or neoperitostigmine, and causing secretions, and things like steroids, especially in the acute phase, or neoprotostigmine, and causing secretions and things like that, or if they're going to the, or if they're getting intubated, things like neuromuscular blocking agents all of these things can make this presentation look much scarier, Absolutely so we mentioned earlier this patient.

Michael Kentris: 24:27

they got some initial labs.

Derrick Cheng: 24:39

What are the other kinds of studies that we really want to be checking into in the kind of next steps? Presented the tempo and your constellation of different symptoms, could this be a nerve or a neuromuscular junction or muscle issue? And while we think that neuromuscular junction is probably the highest on our differential, I'd probably send off some basic labs. Look for other causes of weakness in addition to some of our neuromuscular values.

Derrick Cheng: 25:04

Neuromuscular labs that would include our acetylcholinase receptor antibodies, binding antibodies, blocking antibodies, modulating antibodies, as well as our anti-musk. Those are some of our classic myasthenia labs, especially if this is a patient who's never been diagnosed with myasthenia before, at least formerly. Other things that I'd be looking for include a CK that can help us figure out whether or not there's myopathy or myositis going on, even though that's a little lower on our differential. And there's always labs that we can send off for acute onset neuropathies, things like heavy metals, esr and CRP. Often these patients will undergo CSF testing as well, and in any patient with a new diagnosis of myasthenia, one thing I'm always curious about is whether or not they've had a CT of their chest in the past, looking for something like a thymoma, because that would really change our management.

Michael Kentris: 26:01

Excellent points. That's always the problem. I work at a smaller hospital, so when I suspect myasthenia gravis and I order acetylcholine receptor antibodies of the various stripes, in 7 to 14 days I'll have those results. So it very much is one of those things where you can certainly have a suspicion, but the diagnostic lag can certainly be challenging in a real-world scenario. So you're very often, if there isn't a pre-existing diagnosis, then you kind of have to follow your clinical acumen and decide do I start this person on an acute treatment or not, as the case may be, and that's certainly challenging because none of our treatments are entirely without risk, although I would say that risk versus benefit for most people certainly weighs in favor of treatment. Tell us a little bit about well, actually, before we go on. You mentioned the musk antibodies. I thought that was obviously that's very important this patient in particular. Could you just talk a little bit about musk versus the more generic acetylcholine receptor antibodies?

Derrick Cheng: 27:09

So musk is an antibody called the muscle-specific kinase and it's an antibody that we can see in some of these patients who are presenting like myasthenia.

Michael Kentris: 27:20

So musk specifically, they do have a much higher preponderance of bulbar symptoms as opposed to the more traditional acetylcholine receptor antibodies. So in someone who has very prominent bulbar onset at the beginning, you do keep that in the back of your mind, especially if they have early dysphagia and ventilation issues. Musk is certainly high on the list, although very often we check you can still get the atypical presentation of the regular acetylcholine receptor antibodies as well. But if those are negative you definitely want to get that musk in there and they keep finding new antibodies every year or two. So there are some other ones floating around out there that I haven't had too much occasion myself clinically to play around with, but they do exist.

Michael Kentris: 28:06

But that being said, let's say clinically this looks like myasthenia. You threw an ice pack on that eye with the ptosis. That ptosis popped right back up. You know, after holding it there for two to five minutes you're like nothing else is going to be except neuromuscular junction. How do we proceed in terms of stabilizing this patient, getting them back on their feet both literally and figuratively, and kind of starting the course of treatment down the road?

Derrick Cheng: 28:33

So first this patient would likely be admitted to the neurology service whether or not that's the ward service or the ICU kind of depending on their respiratory function and how some of those labs and those tests looked earlier on and then we'd be thinking about treating them. Usually when these patients are coming in with new flares'd be thinking about treating them. Usually when these patients are coming in with new flares. We're thinking about IVIG, which is intravenous immunoglobulin, versus PLETS, which is plasma exchange. There are pros and cons to each one.

Derrick Cheng: 29:00

There's a lot of debate about which one is better, which one works faster.

Derrick Cheng: 29:04

There's some folks who say that PLETS works a little bit faster, can have a little bit of a quick onset, can keep people in the ICU for less time, but it requires a large line, can be harder to arrange, can be more logistically challenging for a lot of different reasons. You'd want to make sure all of your prior testing is sent first, because IVIG is essentially a combination or a solution of human autoantibodies and can create a lot of false positives and false negatives in your testing if you haven't sent off all of the antibodies that you want already. So picking between the two of them is a little bit more institution-specific, logistic-specific, provider-specific, but we'd usually treat with one of those two and then start them back on their steroid regimen as well as think about coming down the road what they would want to be treated on as an outpatient, whether this is some kind of disease modifying therapy or whether we'd want to just continue them on steroids long term you make it sound so, so straightforward and simple in reality.

Michael Kentris: 30:07

right, we both know that it can be messy, with many blind rabbit trails that we go down, depending on the stories that we get and the fluctuation in the examination and how clear-cut the exam findings are. There's all these gray areas in the diagnostic workup, a challenging presentation and one that, as you said, we encounter very frequently. So, just to put a nice bow on all of it for us, what are the key takeaways, after kind of going through this thought exercise, that you would hope our listeners would take with them?

Derrick Cheng: 30:41

So some of the key takeaways that I'm hoping our listeners take away include that first, not all weakness is neurologic. A lot of the times, other patients can present with other things that can look weak Similarly. The next thing is that time, course and tempo can really help us both triage our patient as well as help us with our differential for these patients with new onset weakness. Next, the presence or absence of certain exam findings things like sensory changes or reflexes can help put you into different buckets and different localizations of neurologic problems. With weak patients in particular, breath count and neck flexion are two particularly good exam maneuvers in the emergency department or when you're first seeing them to help triage these patients and in the ED. Some key things to remember include looking at your A's, b's and C's, checking a MIF and an FBC and using that piece of information to help figure out whether a patient needs ICU or additional respiratory support.

Michael Kentris: 31:43

Excellent summary. A challenging, I think, all of us going through our training in medical school and even as a junior neurology residence. Peripheral nervous system issues are always kind of a little more scary because we don't necessarily get that till later in our neurology training. And I think you summed it up pretty well a nice algorithmic way to approach these problems, with plenty of whittle room for variations there. So thank you very much. I really appreciate you taking all this work and you know you guys can't see he put together this huge outline is very thorough. I'm very impressed. So thank you, derek, I really appreciate all the work you put into this.

Derrick Cheng: 32:27

Thanks so much for having me. I've been wanting to join you on one of these podcasts long-time listener, long-time fan and really excited to see how this came together.

Michael Kentris: 32:34

Absolutely, and anything you want to plug. Where should people find you online, any projects you're working on, shoutouts, etc.

Derrick Cheng: 32:43

So I have lots of shoutouts to all of my mentors here at UCSF. I have lots of shout outs to all of my mentors here at UCSF. You can find me on Twitter, I guess at D-L-C-H-E-N-G-M-D. I think that's my Twitter handle and then otherwise no. Thank you so much for having me on this podcast. It's been a lot of fun thinking about how to approach some of these challenging cases.

Michael Kentris: 33:06

Well, hopefully this is just the first of many and I'll definitely give a call out to anyone who's listening. If you have an interesting case or approach to certain kinds of chief complaints and you're interested in coming on, just shoot us an email at contact at the neurotransmitterscom. Or you can also direct message me on Twitter, slash X at D-R-K-E-N-T-R-I-S, that's Dr Kentris or to the podcast social group directly at neuro underscore podcast. And, of course, you can always find our stuff, including links to different episodes at the neurotransmitterscom on the website. So, derek, again thank you and we'll talk again real soon, I hope.

Derrick Cheng: 33:51

Absolutely.

Michael Kentris: 33:53

All right, take care.