DIP Episode 574 - Quick and Dirty Emergency Medicine For The USMLEs (Part 3)

Welcome to episode 574 of the Divine Intervention Podcasts. In today's podcast, we're going to be continuing the series on quick and dirty emergency medicine for the USML Es. Quick and dirty emergency medicine for the USML Es. So this is a podcast that will help you prepare for an EM shelf, a surgery shelf, a medicine shelf, and if you're starting for step two or step three, for sure. All right. So we've done part one and part two. So again, go back and listen to those if you've missed anything there. So what should you do on your exams when there's a concern, especially when a person like false from a height or whatever? What is one thing we're always worried about? Well, obviously we're worried about C-spine trauma. We're worried about cervical spine trauma. So typically what should you do on your ASCO? What's the most appropriate next step in management for ruling out cervical injury? What should you pick on your exams? I'll really hope you're going to pick the answer that says to do a cervical X-ray, a cervical X-ray. Right? And again, that's by what, because many resources say to use a CT scan. I wouldn't do a CT scan on the exam. I'd only do a CT if for some reason cervical neck X-ray or like lateral neck X-ray is not given as an answer. Right? Because the thing is that's by what many people, you know, would have you believe, cervical X-ray is actually very sensitive. In fact, they're almost, they are more than 90% sensitive for picking out C-spine trauma. Right?

And I guess as an added bonus for you all listening to this podcast, who else should get a cervical X-ray on your exams? Well, it should be the people that can have Atlanta axial sub-locsion, Atlanta axial sub-locsion. You know, sometimes, sometimes they call it Atlanta axial instability, right? Sometimes it's called C-1 C2 sub-locsion, right? So what are these people? Well, these are going to be people that have like rheumatoid arthritis, people that have Down syndrome, people that have unkelosing spine delitis. Maybe like these people have a very high risk of that C-1 C2 sub-locsion, right? Now, what should you consider in a trauma situation on your exams where the patient has like incontinence and they have like decreased rectal tone, right? So they say you're sticking your hands in their incessant. You know, you don't get that squeeze back from the incess, right? And they tell you that the person has impaired sensation in the sacrum, impaired sensation in the perineum. What should you be thinking about on your exams? I really hope you're saying, oh, divine, this sounds an awful lot like Koda equine syndrome because it is, right? Because it is. This person is going to need imaging pronto. What kind of imaging do they need? I hope you're saying divine. Let's get an MRI, right? And then that person is going to need neurosurgical consultation as quickly and efficiently as possible. All right.

Now, what if they give you a question about an individual and they tell you that all imaging shows that the patient has a cervical cord lesion, you know, less they got an MRI or something. And the person appears to have a cervical cord lesion at like C5 and above. And then they ask, what's the most appropriate next best step in management? I would really, really hope that you're saying divine in two bait, in two bait, in two bait, and do trickier intubation. Why? Well, think about it. If you damage C5 or higher, you've messed up the frenic nerve. Do you remember that numonic? You had to memorize early in med school. C345 keeps the diaphragm alive. C345 keeps the diaphragm alive. So the cervical levels 3, 4 and 5, you know, they give a supply to the frenic nerve. The frenic nerve is the primary inner vision to the diaphragm. All right. Now, when an individual, maybe let me take a small sidebar here and just talk about what you like a classic thing they love to put on the exams. When a person has spinal injury, when a person has spinal injury, when they have injuries to the spinal cord, one thing you should really expect is something known as a sensory level, a sensory level. You'll notice that below a certain level, below a certain level, all of one or multiple kinds of sensory modalities will be lost below the level of that lesion. Right? So let me say, oh, below the nepole line, that's the T4 spinal level. Right?

You know the lepole line, the person has lost all of pain, pain, pain, pre-contemporary sensation. That's a sensory level. It's almost like a sharp demarcation point in the body. Below which you lose all of one or more sensory modalities. When you see sensory levels, I strongly, strongly encourage you to think about a person having spinal cord injury. Another classic sign on the USMLE of spinal cord injury is that you're going to see pain and temperature loss on one side of the body. And then you're going to see other deficits on the other side. What are these other deficits going to be? Like deficits in vibration, fine touch and perception. Right? That's Dorsal Column Territory. Like you're going to see, you're going to see like, you know, like upper motor neuron symptoms, contralateral to where you have the pain and temperature losses. You're going to see low motor neuron symptoms, contralateral to where you have the pain and temperature losses. So it's almost like on one side, you see spinal phyllamic tract issues, loss of pain, prick, pain and temperature. And then on the other side, you're going to see Dorsal Column issues, right? So loss of fine touch, vibration and perception, you're going to see upper motor neuron symptoms, again, opposite where you have the spinal phyllamic tract issues. And you're going to see low motor neuron symptoms. Again, opposite where you see those spinal phyllamic tract issues. So why is that the case?

Well, remember, the only pathway that crosses in the spinal cord, at least that you need to know for your test, is the spinal phyllamic tract. Remember, it crosses in the anterior white commissure, right? So in front of the anterior white commissure. So it's going to give you a crossed findings. But all the other pathways I've mentioned, they do not cross in the spinal cord. The Dorsal Columns do not cross in the spinal cord, they cross in the medulla, right? So you're going to still see the lateral symptoms. The upper motor neurons, they have already crossed in the brain stem, they cross in the cordomodulla in the medallary pyramids, right? So they are not crossing in the spinal cord. So if you damage the spinal cord, you're going to have upper motor neuron symptoms on the same side as where you had the damage. And then also, your lower motor neurons, they don't cross at all, right? They go from the ventral horn, the anterior horn of the spinal cord, and they go straight up to the neuromuscular junction, right? So that's a very specific finding as well in spinal cord injury. Another finding I found to be pretty helpful is you're going to notice that they have lower motor neuron signs in upper parts of the body and upper motor neuron signs in lower parts of the body. I'm going to say that again, lower motor neuron signs in upper parts of the body. And upper motor neuron signs in lower parts of the body. Why does that happen?

Again, when you damage a certain level of the spinal cord, you're going to mess up the lower motor neurons at that level, right? That's obviously going to be elevated compared to lower levels in the body. The lower levels in the body, the upper motor neurons are still descending towards those. So you're going to start seeing the effects of killing those upper motor neurons at lower levels. If you see lower motor neuron symptoms, like at the level of the lesion and upper motor neuron symptoms below the level of the lesion at lower levels in the body, think of spinal cord injury. Again, I'm telling you this. These three things I mentioned of the sensory level, the lower motor neuron symptoms at upper regions of the body and upper motor neuron symptoms at lower regions of the body. And in this thing, I said about the crust findings for the spinal thalamic tract, but it's a lateral findings for the dorsal columns, the upper motor neurons, and the lower motor neurons. I'm telling you, if you see these things, you really should be thinking of some kind of spinal cord injury. All right. Now, what if they give you a question about a person that has had spinal cord injury, especially like injury to like the thoracic spinal cord? And then they give you that this person has very low blood pressures. They're like extremely hypotensive, they extremely pretty cardiac.

Then they then ask you, oh, which of the following is the most likely on the line cause of this patient's abnormal vital signs? Well, what should you think about? I would really hope that you're thinking about the person having neurogenic shock, right? Neurogenic shock. The thing is, you know, sometimes in the exams, they call the spinal shock. The thing is when you damage certain levels of the spinal cord, you're going to pretty much destroy the sympathetic nervous system. You're pretty much going to destroy the sympathetic nervous system. In fact, you may wonder, define how is it that destroying a certain level of the spinal cord is tantamount to destroying the sympathetic nervous system? Well, let me give you some clues here in some context here. The thing is an old school term that is actually used for the sympathetic nervous system is the term, thoracolombar outflow. We're going to say that again, thoracolombar outflow. You know, sometimes the parasympathetic system is called cranial secretal, because remember, your parasympathetic system, you know, works with many cranial nerves, like cranial tend, for example, and then some secretal nerve levels. But your sympathetic system works with certain thoracic levels of the spinal cord and certain lumbar levels of the spinal cord. That's why it's called thoracolombar outflow.

So if you damage the spinal cord, especially at the thoracic levels, you can go into shock, because your sympathetic nervous system has basically been severeed, and then your parasympathetic system is basically working on a post. It's working on a post. So the thing is, what are some things the sympathetic nervous system does for us? Well, it does things like constriction of vessels, both arteries and veins, both arteries and veins. So if your sympathetic nervous system is gone, you won't have that visomorotone, right? So let's start looking at some of the consequences of that problem, right? Like for example, if you cannot constrict your veins, remember, you need to constrict your veins. You need venoconstriction to send blood back to the heart, right? Those veins need to be constricted for blood to be sent back to the heart. And if you cannot constrict your veins, you literally will not be able to send blood back to the heart. And if you can't, what happens to your preload? Your preload drops like a stone, right? So you can pretty much say bye-bye to preload. And here's the thing. If you have no preload, are you going to have any kind of cardiac output? No. Your cardiac output is going to reduce. Okay. Now, let's look at things from the arterial side. If you don't have constriction of your arterial bed, are you going to have any kind of afterload? No. Your systemic vascular resistance is going to plummet. And think about it.

If your parasympathetic nervous system is basically working on a post, what do you think is going to happen to your heart rate? Your heart rate actually is going to be low. You're going to be pretty cardiac. You're going to be pretty cardiac. The reason I like to explain things is that when we start talking about treatments, it's going to make way more sense, right? So like for example, how do you think we manage a neurogenic shock? Well, give them fluids, right? Fluids are going to help with this preload problem that they have. Give them atropine. Atropine is a most chronic antagonist. It's going to speed up conduction down the EV node. It's going to help with a pretty cardiac. Right? And then these people don't have vascular tone. They don't have constrictive tone. So for those people, give them a pressure like neuropinephyrene. It's going to clamp down on their vessels and it's going to help with giving them vascular tone. Now, let's go to something else. There's kind of like a bizarre question that our friends at the MBME's may throw on an exam, right? So they may say that, you know, you have some patient that fell from a height and a cervical history was conducted. Or sometimes, these are the cervical history. They may use the term cervical survey was conducted and they'll say, oh, you know, imaging discloses a C spine fracture, a cervical spine fracture. And then they'll ask you, what is the most appropriate next best step in management?

I can almost promise you, they'll give you an answer that says to go to the operating room. But then there'll be another answer that says to get further imaging of the spine. Let me tell you something. Pick the answer choice that says to get further imaging of the spine, especially the lumber spine and the thoracic spine. See, let me tell you something. Whenever you have damage to the cervical spine, look for fractures elsewhere. Look for fractures elsewhere. In fact, in about one fifth of cases of cervical spine fractures, you're going to find fractures in thoracic in the thoracic spinal cord in the lumber spinal cord. This is very important. Again, they will try to make you to pick surgery first, but know all the fractures that exist before jumping to surgery. Why go to surgery and then start encountering fractures you did not expect or having to take the person to the OR twice. It doesn't make any sense, right? The only time you should pick the answer that says to go to surgery is if you don't see an answer choice that says to get further imaging of the thoracic and the lumber spine. Again, it's kind of a weird question. These are one of those things you probably will never find in any resource, but this stuff is very, very high to know for your exams. Right. Now, my next question for you is this. What is going to be the most common, this is like an epidemiology, epidemiology question. What is the most common region of trauma that leads to trauma-related deaths?

So just looking in terms of just regions of the body, regions of the body, right? Because they can give you a non-specific question about a person that is in trauma. And then they will ask, oh, you know, and they will give you like this person has like trauma in many regions in the chest, you know, in the chest, like in the thoracic region, in the abdominal region, they have extreme injuries and whatnot. And then they will say, oh, which of the following will be the most likely cause of mortality in this patient? This is a straight-up you either know it or you don't kind of question. If you want to pick an answer on your test, pick the answer that talks about chest trauma, right? Chest trauma, right? Some people that die from trauma, they die from issues within the chest. Why? Well, the reason in there is that there is just way too many high-value organs within your chest, right? Within your thoracic cavity. I mean, obviously there's your heart, then there's your lungs, right? And the also big problem, the other big problem will have there is that there's also a lot of high-value blood vessels in your chest, like what? Like your ayodor, right? You see many people, they have like high-speed trauma and they translate the ayodor. And that's obviously like almost like a death sentence with very few exceptions. All right. Now, what if they give you a question on your exam about a child that was, you know, kind of playing with toys?

And then that child is found on a responsive within a few minutes. He's like, wow, he's that noticed in five, you know, he's that was like, wow, I was playing happily with his toys like 10 minutes ago. And then he just found him suddenly being on a responsive. What's your diagnosis on your exam? I hope you're saying divine. This is actually a foreign-buddy ingestion. Right? And then they ask you, oh, you know, the patient is brought to the emergency room or whatever, and then they are asked which of the following is the most appropriate next best step in management? Well, I would really hope you're saying, oh, divine. I'm going to go ahead and perform flexible, allowing, goscopy, flexible, laryn, goscopy, flexible, laryn, goscopy. Right? And then they ask you, what is the most likely side of aspiration of this foreign-buddy? Right? I would hope you're going to pick the answer that says the right means stem broncus. Remember, the right means stem broncus is wider and is more vertical than the left means stem broncus. So, if you aspirate something, it's going to go into the right means stem broncus. Again, this is a very, very nice anatomy integration from step one. It's a very, very nice anatomy integration from step one. All right. Now, what if they give you a question about an individual that has, you know, sudden or session or breath after an EGD, after an esophageal gastro-dwanoscopy?

They tell you that this person is profoundly hypotensive and that this person has unilaterally absent breath sounds. Well, I'm sure many of you know exactly what this is, right? This is going to be a tensionymothorax. This is an obvious tensionymothorax, right? And many of you have probably memorized that, ooh, the most appropriate next step in management is to do some kind of needle-thoracostomy, right? Needle-thoracostomy, which we call a needle decompression. Now, let me tell you this. The NBM Es, they are not stupid. They know that most of you listening to this podcast, most of you taking the exam, have memorized this. So what kind of supplemental question may you see with stuff like this? Well, they can ask you a subsequent question. In fact, they can make this a two-part question. You know, they'll make your life easy for the first part. You know, pick needle-thoracostomy as the answer or whatever, right? But they can ask you and say, they can make this into an anatomy question and say, where do you insert the needle in needle-thoracostomy? I would really hope that you're picking the answer that says to insert the needle in the second intercostal space in the mid-clavicular line. Second intercostal space in the mid-clavicular line. Second intercostal space, mid-clavicular line. And remember, you want to insert that needle above the rib, not below the rib. Above the rib, not below the rib. So you probably want to insert it just above rib three, right?

Just above rib three. Because remember, the second intercostal space is below rib two. But you don't want to go directly below, so that intercostal space, that second intercostal space below rib two includes the region basically between rib two and rib three. But you don't want to go directly under rib two and that's for an intercostal space because you're going to damage the intercostal vessels. The intercostal vein, the intercostal artery, the intercostal nerve. You want to go just above rib three because just above rib three, that's still the second intercostal space, that's still in the mid-clavicular line. Right? But you're going just above the rib so that you can spare damage to the intercostal vessels, to the intercostal vessels. Right? And remember, after you have done the needle thorough costomy, your next step on the exam will be to please a chest tube for attention in the thorax. Right? You will be to please a chest tube, which we also call a tube thorough costomy, tube thorough costomy. Right? You want to do that to more conclusively deal with the problem. Right? So, you need to do a definitive management with a chest tube, which again we call what? Tube thorough costomy. Right? Again, you'd be quite amazed at the number of applied anatomy questions that our friends at the MBA Mies love to throw the EM shell into the tube. Right? So, you need to do a definitive management with a chest tube, which again we call what? Tube thorough costomy. Right?

Again, you'd be quite amazed at the number of applied anatomy questions that our friends at the MBA Mies love to throw the EM shell of the surgery shelf and step two and step three as well. Right? So, again, I'll encourage you like don't ignore these basic sciences. That's why you see I tell people, if you have a poor foundation from step one and you're taking step two or step three or level two or three, then you should really consider my 25-hour step one review. It's a class that will really, really help you with getting these basic science foundations up to, up to snuff. All right. Now, next question I want to go into. I'm going to discuss this from kind of a weird perspective, but how is the chest supposed to move during the respiratory cycle? What do you think? How is the chest supposed to move during the respiratory cycle? Well, if you think about this and you can do a randomized control trial, I guess it's not so randomized, but you can do a control trial on yourself. Your chest is supposed to move outward with inhalation and inward with exhalation. You should move externally with inhalation and you should move internally with exhalation. Just remember your ease and eyes are flipped and you're going to be good to go, right? Literally try this out with your chest. Take it a deep breath. You see your chest gets bigger. Blow it out. You see your chest kind of goes in, right? So as you exhale, your chest goes inward as you inhale, your chest goes external.

It goes outward, right? Again, don't just memorize something. You can easily understand and just prove with an easy physical exam on yourself, right? So now that I've given that foundation, imagine they give you a trauma question and they tell you that the patient has like severe chest pain, severe shortness of breath. The patient is very hypoxic, right? And then they tell you that on inspiration, the person has an inward moving chest and on expiration, the person has an outward moving chest. Oh, that's not good. That's not good. This person's chest is moving paradoxically. This person's chest is moving contrary to what you would expect. What should you be thinking about on your exams? What diagnosis should you entertain? I would really hope you're saying, ooh, divine. This person likely has something called a flail chest. A flail chest. A flail chest. How is flail spelled? Flail is spelled as F L A I L. Flail chest. Flail chest. Flail chest. Flail chest. Right? Usually we're going to see this when you've had like more than two rib fractures. And for each of those ribs that you've fractured, you've fractured them in multiple places. Right? So you may think that this is not a big deal, but this is actually a really big deal. This stuff is actually super dangerous. You know why? Because you have these rib fragments that can literally start slicing and dicing your lungs, injuring your lungs. Right?

In fact, the most common cause of death, or we can even say like the most common cause of morbidity. In a person with flail chest is a pulmonary contusion. A pulmonary contusion. A pulmonary contusion. So how do we manage these people with a half flail chest? One, number one, give them oxygen. Number two, give them fluids. Give them judicious fluid replenishment. Number three, give them pain control. Right? If this were, and for most people, this is going to work. This is going to work for most people. But if these people keep crashing and they're not getting better, they're going to be that you want to strongly consider some kind of positive pressure ventilation like endotracheal intubation for these folks. All right. Now, let's talk about another physiological phenomenon. Right? I kind of want to use these to discuss in this podcast. Right? So normally, normally when you're taking a deep breath, when you inhale, when you inspire, what happens to your juggler veins? Are they supposed to relax? Why they're supposed to expand? I hope you're saying divine. Your juggler veins as opposed to relax on inspiration. Well, why does that make any sense? Well, that makes sense because when you inhale, right? Think about it. I said, hey, on inhalation, your chest wall moves outward. Right? Your chest wall is moving outward. Your diaphragm is going down. Right? So what's happening to your intracorasi volume? Your intracorasi volume is increasing. Right? And if you remember, boils law.

That pesky boils law that he had you memorize in college. Right? As volume increases, what do you think happens to pressure? Pressure is going to go down. Right? Remember, volume and pressure are inversely related. So your pressure is going to go down. So your intracorasic pressures go down. And if your intracorasic pressures go down, everything within the thorax is going to be at a lower pressure. You're creating a low pressure system for many things in the thorax. That's why, for example, air rushes into your lungs because remember, flow happens from high pressure to low pressure. So since you've made your lungs a lower pressure system, air is going to rush right in. Right? Now, you've also, what other big organ is in the thorax? Well, it's going to be your heart. Well, since your heart is now a low pressure system, blood is going to be willing to rush into that heart. Okay? Blood is going to be willing to do what? Rush into that heart. That blood is going to rush in. Right? From, you know, every vein possible. Right? For example, from like your juggler veins. So if blood is rushing from your juggler veins into the heart because the heart is now a lower pressure, then your juggler veins blood is being emptied from them. Right? So you're supposed to collapse. Right? That's what we call that's the normal situation. But let's say you inspire and you actually have an expansion of your juggler veins instead of a collapse of your juggler veins.

What should you be thinking about on your test? I would hope you're saying divine. That's what we call a Cosmo sign. Right? And let me tell you something here, you're going to see a Cosmo sign whenever you have a situation with your pericardium. Whenever you have a situation with your pericardium or your pericardial space. Because basically those things will prevent the heart from relaxing. You're like, oh, I'm inspiring. I'm inspiring. I'm inspiring. So my heart is becoming a low pressure system. Well, not so fast. If for example, your heart cannot relax. So say for example, you have like constrictive pericarditis where you've calcified the walls of the pericardium. Right? Or say for example, you have cardiac tamponad where you have all this fluid that has filled up your pericardial space. And you have those things you will have Cosmo sign. Because even if you're inhaling, even if you're inspiring, your heart cannot relax because there's just stuff that's literally compressing and preventing its relaxation, preventing its chilling out from the outside. Right? So don't forget constrictive pericarditis can absolutely cause Cosmo sign. That's probably the most common cause of Cosmo sign on the USML Es. But do not forget that Cosmo sign may also be found with cardiac tamponad, with cardiac tamponad, with cardiac tamponad. Okay? Remember, for pericardial tamponad, you're going to do a pericardial synthesis and you're going to give them fluids.

Fluids are a big part of the management of cardiac tamponad. You want to try to force it as much fluid as possible into their hearts so that you can maintain their blood pressures. All right. So I think I'm going to go ahead and stop here. Again, I have a bunch of classes that are coming up this week. I have a social sciences, hospital medicine, quality improvement and ethics class taking place today actually in the evening on virus zooms. It starts around 5 p.m. Eastern. And then that's for step one, all the way to step three. And then I have a last minute review tomorrow. And then next week, I have a 20 hour step two, step three, level two, level three class. The last minute review tomorrow is for step two and step three and level two and three. And then the week after that, the first week of the month of March, I have a 25 hour step one review. And then in June, the first weeks of June, I have this very grand 50 hour review. Again, I've made podcasts where I talk about these classes, what you hope, what you should get from them and how they differ from my podcasts like the benefits of taking these classes, the advantages that my classes offer over my podcasts. So just listen to that podcast and it gives you more information on those. And then I also offer a one-on-one tutoring for all the US Emilian complex exams. And again, remember, I have this podcast on Apple Google and Spotify. So check those out. I have a You Tube channel where I post the videos that I make.

And then I also help with like mock interviews, personal statements, rec letters and things of that nature. And then another thing I'll say is I have another website called divineinterventionlifelessens.com. Divine intervention, lifelessens.com. There's actually an Apple podcast associated with that website, the Divine Intervention Life Lessons podcast. You know, many of you know I'm a Christian. Every week I post like one, two, sometimes three podcasts where from a biblical perspective address a life lesson. Again, many people listen to this podcast daily and they find it to be very, very helpful. Actually, just put a podcast on yesterday. Have almost 310 podcasts as of this recording. So thank you for listening to me today. I will see you God willing in episode 575. So have a wonderful rest of your day. God bless you. Wish you the best on your exams and bye for now. Thank you.

Cervical X-ray (It has >90% sensitivity).

Atlantoaxial subluxation (C1-C2 instability).

MRI (Suggests Cauda Equina Syndrome).

Phrenic nerve function (C3-C5 supply diaphragm).

Chest trauma (Due to high concentration of vital organs and major vessels like the aorta).

Second intercostal space, mid-clavicular line, above the rib.

Cervical X-ray (Sensitivity >90%).

Rheumatoid arthritis, Down syndrome, and Ankylosing spondylitis.

Sensory level (sharp demarcation), UMN signs above lesion/LMN signs below lesion, and specific sensory loss patterns (e.g., lateral vs dorsal column).

Loss of sympathetic nervous system tone (Thoracolumbar outflow disruption).

Atropine (Muscarinic antagonist).

Cosmo Sign (Indicates inability of the heart to relax and fill normally).

The right mainstem bronchus (It is wider and more vertical than the left).

Cervical X-ray (Sensitivity >90%).

Rheumatoid arthritis, Down syndrome, and Ankylosing spondylitis.

Sensory level (sharp demarcation), UMN signs above lesion/LMN signs below lesion, and specific sensory loss patterns (e.g., lateral vs dorsal column).

Loss of sympathetic nervous system tone (Thoracolumbar outflow disruption).

Atropine (Muscarinic antagonist).

Cosmo Sign (Indicates inability of the heart to relax and fill normally).

The right mainstem bronchus (It is wider and more vertical than the left).