127b: Cranial Nerves 1-5 PANCE Questions and Review

Hello and welcome to this companion episode of the Physician Assistant Exam Review Podcast. My name is Brian Wallace. I’m the host and creator here. And in these episodes, what I’m trying to do is offer you techniques, tools, and tips for how to get the information we cover in the, I don’t know, standard episodes to stick in your heads and make it available to you on test day. What I do here and what I do throughout everything I do is provide you with tools, techniques, and an assortment of ideas and philosophies for how to go about your work.

Now, not every idea is going to work for every person. I don’t mean to say that at all. But a lot of the ideas are going to be valuable across the board. And the one thing that I ask is that you try them out before dismissing them outright. Certainly toss aside the ones that won’t work for you. We all think a little bit differently. Our brains do not work the same.

It’s one of the main tenets of the 33 Days program as I explain how different people’s brains work, how different test takers work, how different learners work. And then I ask that you try out some of the tools for each of those types of thinking. And if you don’t like them, throw them away. Great, no problem. But definitely, definitely try them out first. But that’s really what these companion episodes are for, is for trying to test out some new ideas, some new techniques, and get things to sit a little bit differently in your brain than just sitting through a lecture or just sitting through the content.

Now, I missed last week’s episode. This is, we’re behind a week because I was up at Pace University last week. Quick shout out to the faculty and students there. I had an amazing time working with both the faculty and the students up there on, a lot of the things we talk about in these companion episodes on studying, on test taking, on the approach to these different things and getting to go over some ideas with them. And I love being in the room with the students because it lets me see what’s resonating, what’s helpful, what lights up their eyes. But I also love that I got some pushback on my ideas, right? I had a couple of students who were like, nope, that doesn’t work for me.

Nope, I do it this way. And I love having that back and forth conversation and being able to sharpen my thinking instead of this one-way podcast where it’s just me talking, right? And I kind of, I like having that ability to have people push back against what I’m saying so that I can refine it even more. Anyway, had an absolute blast up at Pace. But that being said, between going to Pace, going to Ashland earlier in the month, the norovirus that tore through my house, the upper respiratory viruses that have taken everybody down for the last three weeks, my house has been an absolute train wreck. And we are just now getting back on the right track. So this episode’s coming out, like I said, a week late.

I do apologize for that. But that is the, you know, the real simple reason is I just simply couldn’t get to it.

Okay, let’s jump in and talk about cranial nerve functions and cranial nerve palsies, but we’re going to stick to cranial nerves 1 to 4, I’m sorry, 5 in this because in episode 128, I’m going to cover cranial nerves 6 to 12. That’s going to be the plan for there.

All right. So one of the things I want you to think about as we go through this is how you’re going to remember the different cranial nerves, right? Are you going to use a mnemonic? Are you going to just understand what they do and use that to lock it in? I would recommend drawing pictures. I would recommend post-it notes up with all the different things. And I would recommend constant repetition here, right?

So we’re going to go over these real quick. Just one to five. So cranial nerve one is the olfactory nerve. Pretty straightforward. This one should be so easy. This detects odors and transmits them to the brain. Smell, right?

Optic nerve is cranial nerve two. Definitely need to know that one. Vision. Carries visual information from the retina to the brain. Cranial nerve three moves the eye in most directions, right? And also controls pupil constriction and eyelid elevation. The trochlear nerve, cranial nerve four is downward and inward eye movement.

So think reading or walking downstairs. And then the trigeminal nerve is number five. This does facial sensation and chewing. So for me, if I’m trying to memorize this, I don’t try to memorize all 12 at once. What I try to do is learn a couple of like anchors, I guess I would call them. Like I would definitely know one. I would definitely know two.

I would definitely know three. And then from there, I would start to branch out and learn the things that are more obvious and more solid, right? So that the cranial nerves that do one thing are easier to learn than the cranial nerves that do multiple things. At least I think that’s pretty straightforward. So I start with those and I would probably then just start with the first five and then grow into the second set. And that’s kind of like what I’ve done here.

All right, let’s talk about palsies. Cranial nerve palsies are a dysfunction of one or more cranial nerves causing motor, sensory, or autonomic deficits. So these can be broken up into sensory, motor, or mixed. For one to five, there aren’t really any mixed, straight mixed issues. So we’re just going to stick with sensory and motor here. So for cranial nerve one, two, and five, you’re going to have sensory palsies, right? You’re going to lose smell.

You’re going to lose vision. You’re going to lose the pupillary function. You can get facial numbness. And then for motor palsies, that’s going to be cranial nerve three, four, and five. You’re going to get ptosis with the oculomotor nerve being out. So down and out. Eye pupil dilation, if compressive.

You’re going to get a, with the trochlear nerve, cranial nerve four. You’re going to have difficulty looking down, and you’re going to get that head tilt to compensate we talked about last time. For cranial nerve five, the trigeminal branch for motor, you’re going to get weakness in chewing or jaw deviation toward the affected side. What can cause sensory, I’m sorry, what can cause cranial nerve palsies? Think about it for a second. What are some of the things that can cause cranial nerve palsy? Give me two.

There’s a bunch, but you can think of two. So we’d start with vascular, so stroke or giant cell arteritis, trauma, skull fractures, or direct nerve injuries. You can get infections like meningitis or Lyme disease, demyelinating issues. So really we’re talking about multiple sclerosis, mainly affecting cranial nerve two and five, and then tumors. So like an acoustic neuroma, compression of the… cranial nerve 5. So, those are through like more like a mass effect kind of situation.

So, as much as these are straight memorization, it’s kind of like if you can know a handful of them, you can use that to reduce the amount of things you get wrong. Tilt the odds in your favor. What you can do is you can start to eliminate other answer choices and narrow down your choices. So for me, this isn’t something I would try to get a 100% on. I talk about this a fair amount. My goal is not to get 100%. My goal is to learn the most important things that will help me get the highest score I can get without having to learn everything.

And I’m always discerning and looking and deciding what I’m going to focus on. So, what I mean by that is if I learn four or five of the cranial nerves really well, well, on most test questions then, I can eliminate those four or five from my answer choices and move me closer to an answer. So, even if I don’t know a particular answer, if I can eliminate one or two choices, I’m really moving in the right direction. And my belief is that if you can be moving in the right direction on your exams, and you can get the things that you know right and you know a fair amount, and then you get the ones that you don’t know, you get really close to an answer, so that you’re getting more and more percentage of those correct, that you’re going to wind up with some very good scores. And I know that’s a weird balancing act, but I believe very strongly in that philosophy.

All right, let’s run through some quick straightforward questions and see if we can lock some of this stuff in. If cranial nerve four wasn’t working, what would you expect to see in the patient? If cranial nerve four wasn’t working, what would you expect to see in the patient? In this case, they would have vertical diplopia or difficulty looking down, and you’d see the head tilt to the opposite side to compensate. Which cranial nerve is responsible for pupil constriction? We literally just said this. Which cranial nerve is responsible for pupil constriction?

Cranial nerve three, the oculomotor nerve. A patient presents with facial numbness and difficulty chewing. Which cranial nerve is most likely affected? Cranial nerve five, the trigeminal nerve. Now look, one of the things I want to make sure that you understand is that as we go through these, they seem really easy because we just covered it. But if you wait two weeks, if you wait a month and I come back with these same exact questions, they’re going to be very, very difficult. Or if they mix them into a 300-question test on all of medicine, suddenly they go from super easy to, oh, crap, this is a straightforward question, but I’m not sure what the answer is, right?

So that’s the jump you have to take. You can’t just assume you know them because you know them today, right? You can’t just assume you know them because you’re studying them and then you get questions on them. That’s where mixed practice and coming back to them over and over really helps. What tests can be used to assess cranial nerve 2 function? What tests did we talk about in the last episode that can assess cranial nerve 2 function? The swinging flashlight test.

Which cranial nerve is responsible for detecting odors? Which cranial nerve is responsible for detecting odors? Cranial nerve, one, the olfactory nerve.

Okay, so then what I like to do is take those super straightforward questions and turn them into PANCE questions. You can see how we build on layers. So, I think of those kind of questions we just went through as sort of like building blocks, as key terms, as ideas that you’re going to start. That’s your foundation. It’s not enough, but that’s where you begin. So, then we turn and we move these into PANCE type questions. And again, some PANCE questions will be straightforward, some will not be.

Which cranial nerve is most… Hang on one second. That question just got cut off in my notes, so I just had to grab it from somewhere else.

All right, let’s see. A 45-year-old man presents with complaints of double vision, particularly when reading or walking downstairs. He states that tilting his head to the right improves his vision while tilting to the left makes it worse. On exam, he has difficulty moving his left eye downward while looking inward. Which cranial nerve is most likely affected? Well, I put every single term in here that you could possibly want, right? So this is cranial nerve 4, the trochlear nerve is the one that’s most likely affected.

And again, not too tough because we just talked about it, but you’re going to need to review this regularly in order to keep that forgetting curve at bay.

Let’s try another one. A 60-year-old man presents with progressive vision loss in his right eye over the past month. Fundoscopic exam shows a pale optic disc. To further assess optic nerve function, you perform a swinging flashlight test. When shining a light in the left eye, both pupils constrict. When shining a light in the right eye, both pupils dilate. What does this finding indicate?

A, optic neuritis. B, relative afferent pupillary defect. C, oculomotor nerve palsy. D, glaucoma.

Now, again, pretty straightforward because you know it’s not glaucoma, right? Because we’re working on cranial nerves, not eyes. But on your PANCE, you’re not going to have that, right? So glaucoma is going to seem like, oh, crap, maybe that is it. I know it’s about pressure, but I’m not really sure how the eyes. So you understand how that works. So you have to know these a little more clearly when they’re up against other topics.

So in this case, the answer is B, relative afferent pupillary defect. This is an optic nerve dysfunction, right? Because I’m shining the light into the eye and the eyes aren’t, both eyes are dilating rather than constricting.

All right, next. A 55-year-old man presents with a loss of smell after a recent head injury. He denies nasal congestion or recent upper respiratory infections. Which cranial nerve is most likely affected? Pretty straightforward. Cranial nerve one. Good.

Well done. All right. Now let’s move into a little bit tougher territory. Again, we’re limited to cranial nerves 1 to 5, so there’s only so difficult that we can make these, but I think you get the idea. A 63-year-old woman presents with right-sided facial pain that feels like brief electric shocks. The pain is triggered by touching her cheek and brushing her teeth. Neurologic exam is otherwise normal, with no muscle weakness or sensory deficits.

Which condition is the most likely diagnosis? A, Bell’s palsy. B, trigeminal neuralgia. C, temporal arteritis. D, cluster headaches. And the answer here is B, trigeminal neuralgia, right? You get that electric shock feeling that is classic for this condition.

Next, a 40-year-old woman presents with double vision and difficulty reading. Good, so that should send off alarm bells, right? On physical exam, her left eye is unable to adduct when looking to the right, but convergence is intact. The right eye exhibits horizontal nystagmus when looking to the right. What now? This gets a little harder. What’s the most likely underlying cause of this presentation?

So this one’s a little bit tougher, right? It’s definitely cranial nerve three, but then they ask us for something more. It’s what’s the most likely underlying cause of this presentation? Well, this patient has impaired adduction of the affected eye with nystagmus of the contralateral eye on abduction. MS is the most common cause of this in a younger patient.

Now, a stroke might be in someone elderly, but not in a 40-year-old. So this is a little bit tough by all means. But because you know what you’re talking about, you should be able to eliminate some things, right? I would think you should be able to get rid of myasthenia gravis and get rid of diabetic neuropathy. And then you’d be left with stroke or multiple sclerosis, which does stink to get down to two. But like we said earlier, the goal is to improve your odds. It’s not always to get the right answer.

It’s to improve your odds on every single question.

Next, a 50-year-old man presents with ptosis, a dilated pupil, and his right eye deviated down and out. His symptoms began suddenly, and he reports a severe headache just before onset. Which of the following findings would help differentiate the most concerning cause of his condition? Again, a little bit tougher. Which of the following findings would help differentiate the most concerning cause of his condition? Let me read the question again because I know this one’s hard. A 50-year-old man presents with ptosis, a dilated pupil, and his right eye deviated down and out.

His symptoms began suddenly, and he reports a severe headache just before onset. This requires a bit deeper understanding, right? So this is also cranial nerve three. But because we have that dilated pupil, things change. That’s what tells us that we have some kind of compression going on. And often that’s an aneurysm. Most often it’s an aneurysm, which requires emergent evaluation.

So this one’s much, much tougher as far as I’m concerned. This is not a direct memorization question. This is understanding and taking this to a whole other level. So you, in this, in order to answer this correctly, you’d have to see the dilated pupil. You’d have to see, we’re talking about cranial nerve three. And you’d have to see that the most common cause of a dilated, of pupillary involved cranial nerve three palsy is an aneurysm that may require emergent surgery. That’s a lot of story, right?

That’s a lot of things. So although you could have pain, it’s not real specific, right? Right? So, and the other things really don’t point to that cranial nerve three palsy with the aneurysm. In this case, the bilateral symptoms wouldn’t affect the visual field loss, wouldn’t really be an issue, right? So it doesn’t make a whole lot of sense. What I want you to take away from this is just the idea that there are different levels of questions, different difficulties of questions, right?

We go from pure memorization to understanding to really a deep understanding and needing to know a whole lot more details to get some of these questions right. Ideally, that’s not how most of your questions will be on your PANCE, right? There’ll be a nice mix from one to another, but that’s sort of the idea. So I want to just run through, we’ll talk more next week about the rest of the cranial nerves and we’ll follow up that with a more comprehensive review of all 12, as I think I will handle it and move forward from there. But I’m really enjoying these companion episodes, and I’d love to hear from you what you think about them. If you know someone who’s struggling in school, who’s struggling to pass their PANCE, please pass this show along to them. Please show them some of the different things you’ve been learning, some of the different things we’ve been talking about as a way that might improve their scores.

And at the very least, like I said, just share the show, and maybe that’ll help them out. I appreciate it and I look forward to seeing you guys again next week. Take care. Best of luck.