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Welcome to the neuro transmitters, a podcast about everything neurology with the goal of reducing your neur a phobia. I'm your host, Dr Michael Ken Trees. And today we're talking about evaluating someone with the first time seizure. So let's start off with some basic definitions. What is a seizure? So in the journals, they would define it as quote a transient occurrence of signs and or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. So that's kind of our textbook definition there, right? So we have this electrical activity occurring in the brain that manifests itself in some sort of clinical uh physical manifestation. And that can be in a myriad of ways which is part of what makes identifying a seizure in the first place. So challenging because there are a lot of things that can mimic seizures. So a lot of times when someone comes in with a quote first time seizure as a neurologist, my first question is, was it really a seizure? Obviously, that's not what I asked, but that's the thought process that, that you have to approach it with, right? So let's go through some of the things that might help lead us towards whether it's something was a seizure or one of the many mimics of seizures that can occur. So most seizures are going to occur very abruptly. They tend to have very sudden onset and they will typically self terminate, they'll end on their own after about two minutes or so. Now, those obviously there are exceptions and if someone's going for longer, that starts to edge into what we call status epilepticus, which is a very obviously dangerous event because you have this uncontrolled seizure activity. So if you're having prolonged events, again, you have to come back to that same question. Is this a seizure or is it not? Now one of the more common things that can mimic a sort of status epilepticus type event are non epileptic seizures or dissociative seizures, functional seizures. There's several different names of people use. And uh these will often have different types of clinical phenomena of or what we call in epilepsy. See me ology, which is the study of the signs associated with it. So some of the more common things you'll see are kind of these uh starting and stopping of events, uh forced i closure. If you go in and try and look at their pupils, they'll resist you. They tend to have asynchronous movements, which is to say that the frequency of the movements in say the right arm will be different than the movement frequency of the movement in their left leg. Um There are numerous signs that can be, there's an entire branch of epilepsy, epileptologist that is devoted to this uh eye fluttering pelvic thrusting again. However, I do want to emphasize that no single one signed by itself is going to be 100% definite. So it's taking all these things together and putting together into one clinical picture that really uh is going to lead you most accurately towards the right diagnosis and then you can institute the correct treatment. There have been multiple studies done. Uh more one of the more recent ones looking at ems in particular, you know, emergency medical services and their accuracy, identifying epileptic versus non epileptic seizures. They were about 46% in their accuracy, which you know, when we're talking about administering things like benzodiazepines or other medications that could have some serious implications, especially in terms of breathing suppression. Uh it's not particularly hard names, but I know that, you know, education is one of the things we're here for, right. So again, nonepileptic seizures or functional seizures. These are one of the more common things that we'll see, especially with these prolonged episodes. However, there are numerous other things. Um one thing that you might not think about would be a transient ischemic attack or a ti a, right? This is kind of like a mini stroke if you will. So you may be thinking to yourself, well, how the heck would a ti a or a stroke look like a seizure. Those, those things aren't going to look very much alike at all. And normally I would say you're right. Right. We tend to think of seizures as having what we call positive symptoms, which is a increase in something, an increase in movement, in increasing uh some sort of symptom. Whereas we tend to think of strokes as having negative neurologic symptom, which is the loss of something like weakness, the loss of motor control, the loss of sensation, etcetera. But there there is one entity that I think could mimic a seizure and that's something called a quote limb shaking ti A and it's just like what it sounds, right? People will have an episode where the like an arm or a leg starts shaking and they usually don't have the, you know, alterations in consciousness that often will accompany a seizure, but that's again, not 100%. So like I look for these stroke, risk factors like, you know, history of heart disease, high BP, diabetes, etcetera, etcetera. And you know, put it in the correct clinical context. Another entity that I would put kind of in the cardiovascular or cerebrovascular if you will, a family of mimics for seizures is syncope, right? Syncope. A transient loss of consciousness usually due to some sort of drop in blood pressure, heart rate. Um what we're going to call vasovagal syncope. A lot of times if the story sounds like the person with maybe getting their blood drawn or what happened in an intense emotional situation where they're experiencing fear, pain. Uh You can also get cops syncope or micturition, syncope. Um A lot of times people pass out in the bathroom when they're urinating or having a bowel movement or having another type of situation where they might do a valsalva. So increasing that abdominal pressure. So all of those can lead to a syncopal episode where someone can pass out. So why would we think that's a seizure? Well, we have this loss of consciousness. However, when it really becomes uh more confusing is when we get what's called convulsive syncope. And this is where people will typically have a single episode and they'll jerk several times. And I've seen some video recordings of this over the years where, you know, just by looking at it, you wouldn't know it was a seizure. But again, it all comes back to putting it in the context. How did the person feel before? Did they have any sinkerball prodrome? You know, the sort of dizziness feeling hot, looking, pale clammy, uh anything like that that would suggest that there was a transient drop in their BP that would have led to this episode in the first place. And we contrast this with typical epileptic auras which can be quite varied. But in adults, temporal lobe epilepsy is one of the more common ones. You think of things like a sensation of deja vu or a sort of uh feeling in their stomach, right, in epigastric or a that rises up towards their face uh from the parietal lobe, you might get parasthesia is tingling, occipital lobe seizures, you can get visual distortions. These tend to be relatively simple visual phenomenon, like geometric shapes, colors, things like that, not usually very complex visual phenomenon, like not a complete scene or a person or things like that, that would be somewhat atypical. Um and in the, you know, in the frontal lobe with motor seizures, right, you can have isolated jerking and this usually a clonic type of jerking, although again, not always. So it's again taking all of these pieces together and putting them together in a way that can make sense and get the right answer for the clinical situation. Panic attacks can also sometimes mimic a seizure. However, panic attacks tend to last a bit longer. They don't usually have the loss of awareness there various sleep disorders that can also mimic a seizure. I think of like narcolepsy, cataplexy, various types of um like rem sleep behavior disorder where people kind of act out their dreams, they act very violently in their sleep, uh different types of movement disorders, uh like dyskinesias where you get these uncontrolled twisting, turning types of movements of the head arm or even the whole body in some severe episodes. And one last potential mimic that I want to mention is migraine with aura which can cause a lot of different uh type of phenomenon. It could cause motor phenomena, sensory phenomenon, visual phenomenon, you know, visual aura, probably being one of the more common. And you know, occasionally you'll get what's called a brain stem aura where you can get some confusion, disorientation as well. So it's just another one of those things that goes on the list of potential seizure mimics. So after gathering apart history, let's say yes, we're convinced this does sound like a seizure. Then the next question that inevitably follows is, well, why did this seizure occur? Was there something that may have provoked it? Right? Certain metabolic or electrolyte abnormalities like excessively high or low glue coast or sodium as well as several other electrolyte abnormalities um where they started on a new medication. Some examples could include anti psychotics like closet peen uh antibiotics like cephalosporins or floor quinolones, antidepressants like appropri in pain medications, traMADol, in particular, um several illicit drugs like cocaine amphetamines. Um Do they have a history of alcohol abuse? Are they in withdrawal? Have they been sleep deprived for a prolonged period of time if they're a child? Uh do they have an excessively high fever that may have triggered this seizure? These are just some of the things that you want to think about in terms of a provoked seizure, something similar, but a little bit different is what we would call an acute symptomatic seizure. And this is due to some sort of insult to the brain that renders it a little more susceptible to having a seizure in that acute period. Say an acute ischemic stroke, a central nervous system infection like an encephalitis or even a traumatic brain injury. And just to be specific in acute symptomatic, see, seizure is defined as a crying within the first week after one of these inciting events if the first seizure occurs after that first week. However, then the risk for subsequent seizure starts to increase. And that's when we start to talk about a single seizure versus a diagnosis of epilepsy. For instance, for stroke. From that same paper in epilepsy, a the risk of subsequent unprovoked seizure for each of these for a stroke, 33% for a first accused symptomatic seizure. But if you had a seizure later was 71 point 5%. Uh for a traumatic brain injury or TBI, it was 13.4% for recurrence after an acute symptomatic seizure, but 46.6% after a more remote seizure and for CNS infections, it was 16.6% for a first acute symptomatic seizure that increase to 63.5% for a first unprovoked seizure down the road. Some other pieces of history that you want to try and gather is if the person has any history of seizures as a child, particularly uh what we call complex febrile seizures. Uh If they have any history of CNS infections as a child, history of head injuries, uh even concussions. Some other pieces of history that you want to try and gather is if the person has any history of seizures as a child, particularly uh what we call complex febrile seizures. Uh if they have any history of CNS infections as a child, history of head injuries, even things like concussions with loss of consciousness. A history of strokes, brain tumor's, Do they have a history of dementia or other nerve degenerative processes? As all of these can be potential risk factors for epilepsy. This kind of brings us to our next point, which is an acute symptomatic seizure or provoked seizure don't necessarily count as epilepsy because most people aren't going to have a recurrent seizure. It's estimated about one out of 10 people at some point in their life will have a seizure, but only 1 to 3% of those people who have had a seizure will go on to develop epilepsy. So, not everybody gets placed on anti seizure medication right from the beginning. And nor should they be because if you're doing that, you're putting a lot of people who have had a single seizure on medication that they may not actually need in the long term. So how can we best risk stratify those patient's who are at higher risk of having seizure recurrence, who should be on anti seizure medication versus those who might be in the lower risk category and we can take a conservative observation approach to their care. So we're gonna bring that back around to the history again for a moment. So a lot of times when people come in with a quote unquote first seizure, if you dig into that history a little bit, what we're really seen when they present most of the time is a first generalized tonic clonic seizure or bilateral tonic clonic seizure, grand mall, whatever phrase uh you care to use. And if you dig into the history a little bit, you may find like, oh yeah, they've been having staring spells or you're kind of acting unusually for several months or weeks. So if you find in your history that yes, there are these episodes going back that are suspicious for some type of epileptic event, then this is in fact, not a first time seizure. And you should start anti seizure medications at that point in time. And that can be very tricky unless you get a really strong story. So you really have to dig into that information and see if there's anything there. And you really in that situation are dependent on hopefully a family member or close friend who is observing this person on a regular basis, who can give you a report that is hopefully reliable. So we're checking for anything that might have provoked a seizure. We're checking our complete blood cell count were checking a complete metabolic panel. It's also usually a good idea to check a urine drug screen to make sure that there's nothing that may have provoked a seizure. There, either a word of caution regarding the amphetamine on most urine drug screens has a very high false positive rate. I made that mistake as a resident and one of my patient's became very upset with me and rightfully so I have to admit later on in my training, I learned that the amphetamine S A has a very high false positive rate and often cross reacts with numerous over the counter medications including anti histamines as well as many prescription medications. So I would highly recommend before jumping to conclusions just looking at their medication list or ask about any over the counter or even herbal supplements that are potential cross reacting with that essay. Obviously, if the patient looks like they're sick, if they look like they have stiffness in the neck fevers, confusion, you know, you do have to get some head imaging there and a lumbar puncture to check for any signs of infection in the spinal fluid. Uh for encephalitis meningitis, all that bad stuff. Lastly, I would mention this is not necessary for a first time seizure patient, but for someone with a history of epilepsy who is on anti seizure medication, you do want to check blood levels of uh they're anti seizure medication. Some of those you need metabolites. Uh We'll talk about that at a later podcast, most likely but unfortunately, one of the most common reasons for patients to have breakthrough seizures that bring them to the emergency department is medication issues, whether that's not getting their medication missing a dose. So if you find that it is something as they forgot to take a dose of their medication, then you don't necessarily need to put them through the whole work up again and kind of try and retweet their medications. You can just focus on what can we do to make sure that this person is getting their medications regularly in. Can we help in any way in terms of, you know, reminders, etcetera that can help with medication adherence, moving on to our further diagnostic work up. Uh Imaging is going to be a significant piece of that, right. We want some sort of neuro imaging of the brain. So a lot of patience when they first come in with a seizure to the emergency department. If that's where you're seeing them, they have had a ct of the head usually without contrast. And this is good, you know, you want to rule out any intracranial hemorrhages or things like that that could be happening acutely. A lot of times though the definition is not going to be sufficient to our purpose is to identify a lot of the more subtle abnormalities. So the more definitive testing in this category is going to be an MRI of the brain usually with and without contrast and there are different strengths of MRI, you know, 1.5 Tesla, three Tesla, uh some large academic centers, even seven Tesla. But uh one thing you'll be requesting specifically for a new onset seizure is something called an epilepsy protocol. And most hospitals should have this built into their suite of programs. And what it essentially is is you're taking a sequence on MRI called T to flare and you're asking them to do thin slices through the hippocampus in the Corona section. And this is because in adults, one of the more common reasons for new onset seizures that you can find a structural abnormality for is mesial temporal sclerosis, which is essentially you have this little bit of bright signal on the flare, which indicates a little bit of scarring or perhaps some structural abnormality in that mesial temporal lobe. Obviously, there are many other things that can also cause seizures in an adult, right, focal cortical dysplasias, vascular malformations, cavernous malformations, maybe evidence of an old stroke and a whole host of other things that could potentially be epileptogenic. So what is the actual risk if we see something on the MRI that is a potential seizure focus? So there was a study that looked at this and essentially they found the seizure recurrence at 124 years. The hazard ratio increase was 2.44 and the 95% confidence interval was 1.09 to 5.44 compared to those without imaging abnormality. So it is a fairly high risk recurrence uh above and beyond that. And the second test that we normally look at right, this is our structural one. But the second one we normally look at would be reg and most eegs we're talking about a routine eeg which is going to be somewhere between 20 to 30 minutes in duration. The problem with this duration is that EEG is much more sensitive in detecting epileptiform abnormalities, things like spikes, sharp waves, polyspike and wave discharges, focal rhythmic delta activity. All of these things that indicate an increased potential for seizure generation from a certain area are more apparent during sleep. So there's a very good chance that you may not capture sleep, at least not deeper sleep on a routine study. So you kind of have to know what the utility of your test is. So all that means that how good is an eeg at picking up an epileptiform abnormality on a routine study and helping guide our decision making in this initial encounter. So, there's an old study from 1987 in epilepsy. A uh Alinsky at all. Uh The title of the study was effectiveness of multiple eegs in supporting the diagnosis of epilepsy in operational curve. This was an old V A study and so what it showed was essentially in 50% of patient's with interictal epileptiform abnormalities. The abnormality was present on the first record in 84% of these patient's by the third and in 92% by the fourth. So further routine eg is beyond that point, weren't super helpful. So we're kind of using this population and that's kind of where we get to that 50% sensitivity. Although some adult studies, the sensitivity and specificity with a 95% confidence interval was about 17 and 94% sensitivity and specificity respectively. So the main thing for eg is that the specificity is much, much, much higher than the sensitivity. So a normal eeg does not eliminate seizures or epilepsy as the diagnosis. A an abnormal study is much more useful than a normal study in these types of situation where your clinical suspicion is very high for a seizure. So let's say the EG shows some sort of epileptiform abnormality. One study showed a seizure recurrence rate, relatively speaking at 1 to 5 years of 2.16 compared to those without eeg abnormality. So again, significantly higher than in those with a normal eg. So let's say we get someone, there's no predisposing history, know predisposing uh risk factors on imaging or on eg first time seizure. As best you can determine by your history. These patient's typically you will not start on any anti seizure medications and you will observe them for a period of 3 to 6 months, we're going to still recommend seizure safety precautions because even with a normal MRI and normally eg these patient's can still have a recurrence. As we mentioned before. The sensitivity on eeg is not particularly high so you can get false negatives. So, seizure safety precautions. Some of the general ones that we always talk about driving restrictions, avoid open heights, avoid swimming. Essentially any situation where a sudden loss of consciousness could result in injury to the patient or somebody else. That's the general rule of thumb that I usually thought follow in counseling people in this situation, different states have different driving laws for people who have had a seizure. So actually epilepsy dot com has a lot of that information on there and can direct you towards appropriate information. So I definitely recommend checking out epilepsy dot com and the resources in terms of the driving laws if you have to counsel somebody uh regarding when they can, when they can't drive legally. Now, let's consider the alternative situation, maybe you have an MRI that shows an abnormally or the eg that shows some potential increased risk for seizures. And that brings us back to what is the definition of epilepsy as opposed to a seizure. So, epilepsy is clinically defined as two or more unprovoked seizures or one unprovoked seizure with a greater than 50% risk of recurrence. And that's from the international you against epilepsy. So in that situation, you would recommend beginning some sort of anti seizure medication. And again, you're still going to follow those same seizure safety precautions and we'll go in next time about medication selection for different seizure and epilepsy types. And what are the pros and cons and what are some considerations that we want to keep in mind when we're selecting are anti seizure medication? Because there are a lot of them and that can become a topic all on its own. I think we're going to end there for the evaluation of a first time seizure. If you enjoy this podcast, please leave a five star review on Apple itunes, Spotify or wherever you're getting your podcast and please don't forget to share and subscribe for future episodes. I hope this information is providing some value to you, to your patient's and to your practice. You can reach me on Twitter at Doctor Ken Trees. That's Drkentris or by email at the Neuro transmitters podcast at gmail dot com. Thank you again for listening and I'll see you next time.