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Hello, everyone and welcome back to the neuro transmitters, a podcast about everything related to clinical neurology. With the goal of reducing your neur a phobia. I'm your host, Dr Michael Ken Trees. And today I wanted to talk about stroke. Stroke is one of the more common things that we see in the hospital. And one of the common reasons that the neurology services consulted in the hospital. So one of the first questions usually is is this presentation a stroke? Now that can come in two flavours, there's the hyper acute code stroke or stroke alert type presentation where people are coming in and being considered acutely for thrombolytic therapy. And then there's the more insidious patient was found somewhere by family friends, uh someone in the community. And the question is still the same. What is wrong with this patient? Is it a stroke? Is it something else? Is it neurologic? Is it not? So I always remember what one of my attendings asked me as a resident when we were talking about the indications for giving uh tea pee or thrombolytic therapy. And yeah, it was somewhat tongue in cheek. But the first indication at least from a urologic perspective is, do you think the patient is having a stroke? Because if you don't, then that takes you down in an entirely different diagnostic and therapeutic pathway. So when someone comes in with a stroke, it is important to differentiate from one of the many mimics that can present acutely and it is estimated that, you know, 2030% of acute stroke presentations are eventually found to be one of these mimics. So as clinicians, what does that mean for us, how can we differentiate a true stroke syndrome from one of the many things that could mimic it as with creating any neurologic differential diagnosis, it really comes down to two pieces. Can you come up with a reasonable neuro an atomic localization? And to what is the timeline or the tempo of the onset of the symptoms? Stroke typically is a hyper acute onset or you know, sometimes the history is not known or the patient may wake up with some deficits. So in those situations, the timeline is less clear. So the other piece of that is can you localize it to somewhere in the cerebral hemispheres, being able to localize the symptoms to one hemisphere or the other, such as right arm and face weakness from the left middle cerebral artery territory or other such localization. Those have a very good predictive value for stroke. Whereas someone with kind of generalized weakness, confusion a little harder to pin down. Not as clearly lateral izing. Although there are always exceptions, aren't, they're always. So what are the clinical characteristics that will help us to differentiate a mimic from a true esque emmick vascular cerebral vascular event? So, there was a study done called distinguishing between stroke and mimic at the bedside of the brain attack study. Uh This is from 2006 published in stroke and I'll have links to the articles that I mentioned in the show notes as well. But essentially, they had 350 presentations by 336 patient's. The diagnosis was stroke in 241 that 69% and mimic in 31%. So there were 40 for events labeled possible stroke or TI A and those were in the mimics. So eight items independently predicted the diagnosis in patient's presenting with brain attack, cognitive impairment and abnormal signs and other systems that is organ systems suggested to mimic. Whereas signs suggesting stroke included in exact time of onset, definite focal symptoms, abnormal vascular findings. That's something on the CT angiograms. Uh presence of neurological signs, being able to lateral eyes, the signs to the left or right side of the brain and being able to determine a clinical stroke, sub classification suggested stroke. So essentially, if you have cognitive impairment and abnormal signs and other organ systems mimic is going to be favored over an ischemic stroke. So I think that is an important thing to take away as well as all the other signs. I mentioned that 0.2 or words stroke. So again, this was a nice study. That was, it was an observational, but it does have some useful clinical ramifications. So what are some of these mimics that may present in such a fashion? So in this same study, they have it broken down a little bit and that's actually nice to have it within six hours and after six hours as well if you look at their data. But some of the top things that are showing up here, uh seizures, sepsis, toxic or metabolic ideologies, space occupying lesion, that's going to be things like brain masses, neoplasms, syncope, pre syncope, vestibular dysfunction, different flavours of vertigo, uh dementia, migraine, uh spinal cord lesions, acute onset neuropathies, poststroke recrudescence is another entity to always keep in mind. This is essentially someone who has had a stroke in the past and they've recovered to a degree and they come in with another acute medical problems such as infection or metabolic abnormalities. And essentially those symptoms rise back to the surface, they kind of decompensate. So if the symptoms are very much the same as what they came in with their initial stroke, post stroke, recrudescence is certainly on the list of possibilities and I would be remiss if I didn't also mention functional neurologic disorders as well, which is a fairly common stroke mimic also depending on what data set you're looking at again, a lot of this differentiation is going to come down to what is the history and what is your exam look like? If you're able to lateral eyes, the symptoms, if the presentation matches a stroke syndrome, then obviously you're going to go down that pathway. When patient's do come in acutely, they usually are going to get some type of neuro imaging oftentimes that's going to be a CT head, maybe with a CT angiogram of the head and neck, depending on their kidney function, as well as the acuity with their own individual timeline as to when symptoms began and whether they're a candidate for any emergent therapies. So it's also important to rule out things like intracranial hemorrhages, like subdural hemorrhage is uh and so on. So it is appropriate to get imaging in these patient's. But this is why it's ultimately important to come to the right diagnosis in these patient's right. If someone has a diagnosis of epilepsy, we don't want them every time they have a breakthrough seizure to get a CT Scan of their head, right, we're going to increase the radiation dose. These tests are not without long term consequences, potentially. So we need to come to the right diagnosis, especially if this is something that is potentially a recurrent event. So we've talked a little bit about mimics. Now, there's another term floating around in the stroke literature called stroke chameleon's and a chameleon is essentially the opposite of a mimic. This is something that, uh, someone comes in with a problem to the hospital and it is thought that they did not have a stroke and then later down the road, it is found. Yes. In fact, this person did have a stroke. So what does that look like clinically? And how does that different from our typical strokes and are stroke mimics? Now, there have been several paper, I was looking at this phenomenon as well and this is where things get a little hairy because some of these chameleons are initially diagnosed as altered mental status, syncope, hypertensive emergency, systemic infections or even acute coronary syndrome. So as you may recall from just a few minutes ago, many of these things are also things that can present as stroke mimics. So where is the overlap? How can we differentiate? And sometimes the answer is that there isn't a good way clinically. So you just have to maintain a high index of suspicion again, if it's not fitting the appropriate pattern. One paper I want to go into a little bit more in depth is called acute stroke chameleons in a university hospital, risk factors circumstances and outcomes. Uh This is from 2015 in the journal Neurology and this was a pretty robust retrospective study I thought at least so they had 2200 acute ischemic stroke patient's and out of these 47 or 2.1% were initially missed. So when they looked back, there were a few factors that tended to correlate with this initial missed diagnosis. So they looked at a few factors that tended to correlate. So the traditional ischemic stroke group tended to have more eye deviation paralysis, uh sensory deficits, they also had more of your traditional uh stroke risk factors including hypertension, uh use of antihypertensive medications, lipid lowering drugs and smoking. Whereas that was less common in the Chameleon group, the Chameleon group was also more likely to have a cardiac cause or dissection as the cause of stroke rather than atherosclerosis or lacuna strokes. So this is kind of interesting. So one of the things they looked at was the patterns in the diagnostic process leading to missing acute ischemic strokes. So in 80% of these missed cases, the stroke was uh symptom attributed to another disease. Uh and that included other neurologic diseases, a nonneurologic disease and then just an unexplained, decreased level of consciousness. So that altered mental status pattern. And there are some studies that show that there are a typical patterns of stroke. Those are typically going to be sort of bilateral cardioembolic type patterns or sometimes nondominant parietal infarcts. Uh I've certainly seen that a few times in my own practice where you get this abrupt change in mental status and you end up finding it is a uh parietal infarct. So I know I mentioned that a lot of these stroke chameleons can also be the same or very similar to the stroke mimics. But there was an article in the journal of stroke and cerebrovascular diseases from 2014 where they were looking at what is the positive predictive value of of one of these diagnoses actually ending up being in a scheme extra. So this was a smaller study, 94 cases in this particular case. So for altered mental status, the positive predictive value for stroke was 7% for syncope, 4% hypertensive emergency, 8% systemic infection, 1% and suspected acute coronary syndrome, 1%. So a few of these things, they're certainly can be a suspicion, a not insignificant number. And having that again, that high degree that high index of suspicion is going to be important to identify these patient's right, altered mental status with no other cause. Yeah, we should probably be working that up just to make sure we're not missing something same thing for hypertensive emergency because that can also cause press seizures and that can just confound things even further. So what's the big takeaway from talking about mimics and chameleons? So, on the inpatient neurology service stroke is by far one of the most common things that we see and deal with on a day to day basis and having that high degree of suspicion as to does this pattern that the patient present with fit into a stroke? Or is it more suspicious for a non stroke neurologic issue or even a non neurologic issue altogether. So being able to differentiate and go down those right diagnostic pathways is going to be important. And unfortunately, because there is some crossover in terms of these populations, sometimes we have to get an MRI of the brain to help differentiate, right, a thalamic lesion and non dominant parietal lesion. They may not have very clear physical findings on exam. You know, if someone has hemi neglect, yeah, most people are going to be able to pick that out on a bedside examination. But if the main thing is just a decreased level of consciousness to the point where maybe they're even on a ventilator, the exam is very limited and there can be things that are obscured by the other ongoing medical issues. So just having that index of suspicion when something isn't going the way that you would expect it to in the course of your normal work up and treatment of a patient that is always something to keep in mind. Is there something going on in the background that I haven't picked up on that is being obscured by the other medical issues at hand. So I'm going to leave you with those thoughts here and going forward. I do want to go more into the weeds in terms of different types of stroke presentation ti A is acute ischemic stroke, all that kind of stuff going forward. I want to keep these more information dense recordings, a little smaller a little shorter and hopefully you guys enjoy this format. If you do, let me know if you don't let me know that too. But I think going forward, we're going to try and hit more basic neurology topics, anatomy, um very fundamental concepts. I know I've been doing some interviews lately, but I think it's important to kind of always reorient and get back to our original mission statement, which is to help people with neuro phobia and understanding these common basic problems and the basic approaches to them is going be very fundamental, very important to improving people's clinical acumen when it comes to neurology. And ultimately, that is our goal here. As always. Thank you for listening. I appreciate you all taking the time. I know there's a lot of options out there and it's very meaningful that you all take the time to listen to what I have to say. If you did enjoy it, please leave us a five star review wherever you get your podcasts, Apple Spotify everywhere. Fine podcasts are distributed, share with your friends and subscribe for future episodes. You can find me on Twitter at Doctor Ken Trees. That's Drkntris or by email at the Neuro transmitters podcast at gmail dot com. Please feel free to reach out with any questions or future show suggestions. I'll see you all next time.