Evaluation of New Onset Seizures

The question of what to do with new onset seizures is a very common one in neurologic practice. Here we'll go through some common questions such as:

Was it a seizure? 
What can mimic seizures?
What kind of evaluation should be done to assess for the risk of a second seizure?

Did this podcast answer some of your most common questions about first time seizures? If so, great! If not, what aspects need more fully covered? Your feedback is always appreciated!

Find me on Twitter @DrKentris or send me an email at theneurotransmitterspodcast@gmail.com

-----------------------------------------------------
The views expressed do not necessarily represent those of any associated organizations. The information in this podcast is for educational and informational purposes only and does not represent specific medical/health advice. Please consult with an appropriate health care professional for any medical/health advice.

Diabetes dialogues podcast
Diabetes insights for HCPs. Dexcom’s expert-led podcast, Diabetes Dialogues.

Listen on: Apple Podcasts   Spotify

• Check out our website at www.theneurotransmitters.com to sign up for emails, classes, and quizzes!
• Would you like to be a guest or suggest a topic? Email us at contact@theneurotransmitters.com
• Follow our podcast channel on 𝕏 @neuro_podcast for future news!
• Find me on 𝕏 @DrKentris

The views expressed do not necessarily represent those of any associated organizations. The information in this podcast is for educational and informational purposes only and does not represent specific medical/health advice. Please consult with an appropriate health care professional for any medical/health advice.

Chapters

• 10:46 [Ad] Diabetes dialogues podcast
• 11:24 (Cont.) Evaluation of New Onset Seizures

Transcript

Dr. Michael Kentris [00:00:00]:

Welcome to The Neurotransmitters, a podcast about everything neurology with the goal of reducing your neurophobia. I'm your host, Dr. Michael Kentris, and today we're talking about evaluating someone with a 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 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, 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 ask, but that's the thought process that you have to approach it with. Right, so let's go through some of the things that might help lead us towards whether something was a seizure or one of the many mimics of seizures that can occur.

Dr. Michael Kentris [00:01:10]:

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, obviously there are exceptions and if someone's going for longer, that starts to edge into what we would 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 that people use and these will often have different types of clinical phenomena or what we call in epilepsy semiology, which is just the study of the signs associated with it. So some of the more common things that you'll see are kind of these starting and stopping of events, forced eye closure. If you go in and try and look at their pupils, they'll resist you.

Dr. Michael Kentris [00:02:13]:

They tend to have asynchronous movements, which is to say that the frequency of the movement in, say, their right arm will be different than the frequency of the movement in their left leg. There are numerous signs that can be there's an entire branch of epilepsy epileptology that is devoted to this eye fluttering, pelvic thrusting. Again, however, I do want to emphasize that no single one sign 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 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, one of the more recent ones looking at EMS in particular emergency medical services, and their accuracy identifying epileptic versus non epileptic seizures. They were about 46% in their accuracy, which, when we're talking about administering things like benzodiazepines or other medications that could have some serious implications, especially in terms of breathing suppression. It's not particularly hard names, but I know that education is one of the things we're here for. Right? So again, non epileptic seizures or functional seizures, these are one of the more common things that we'll see, especially with these prolonged episodes.

Dr. Michael Kentris [00:03:32]:

However, there are numerous other things. One thing that you might not think about would be a transient ischemic attack or a Tia, 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 Tia or a stroke look like a seizure? Those things aren't going to look very much alike at all. And normally I would say you're right. We tend to think of seizures as having what we call positive symptoms, which is a increase in something, an increase in movement, an increase in some sort of symptom. Whereas we tend to think of strokes as having negative neurologic symptoms, which is the loss of something like weakness, the loss of motor control, the loss of sensation, et cetera. But there is one entity that I think could mimic a seizure and that's something called a quote, limb shaking Tia. And it's just like what it sounds, right? People will have an episode where an arm or a leg starts shaking and they usually don't have the alteration in consciousness that often will accompany a seizure, but that's, again, not 100%.

Dr. Michael Kentris [00:04:32]:

So look for these stroke risk factors like history of heart disease, high blood pressure, diabetes, et cetera, et cetera, and put it in the correct clinical context. Another entity that I would put kind of in the cardiovascular or cerebrovascular, if you will, family of mimics for seizures is syncopy. Syncopy a transient loss of consciousness, usually due to some sort of drop in blood pressure, heart rate, what we can call vasovagal syncopy. A lot of times, if the story sounds like the person was maybe getting their blood drawn or it happened in an intense emotional situation where they're experiencing fear or pain, you can also get cough syncopy or Mictorition syncopy. 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 val salva. So increasing that abdominal pressure. So all of those can lead to a syncable episode where someone can pass out. So why would we think that's a seizure? Well, we have this loss of consciousness.

Dr. Michael Kentris [00:05:38]:

However, when it really becomes more confusing is when we get what's called convulsive syncopy. And this is where people will typically have a syncol episode and they'll jerk several times. And I've seen some video recordings of this over the years where 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 sinkable prodrome? The sort of dizziness feeling, hot looking, pale, clammy, anything like that, that would suggest that there was a transient drop in their blood pressure 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 feeling in their stomach, right? An epigastric aura that rises up towards their face. From the parietal lobe, you might get paresthesias tingling, occipital lobe seizures, you can get visual distortions.

Dr. Michael Kentris [00:06:42]:

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. And in the frontal lobe with motor seizures, you can have isolated jerking. And this be 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.

Dr. Michael Kentris [00:07:27]:

There are various sleep disorders that can also mimic a seizure. Think of like narcolepsy, cataplexy, various types of REM sleep behavior disorder where people kind of act out their dreams, they act very violently in their sleep. Different types of movement disorders 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 type of phenomenon. It can cause motor phenomena, sensory phenomena, visual phenomena, visual aura probably being one of the more common. And 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 a list of potential seizure mimics. So after gathering up our history, let's say yes, so 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.

Dr. Michael Kentris [00:08:31]:

Certain metabolic or electrolyte abnormalities like excessively high or low glucose or sodium, as well as several other electrolyte abnormalities where they started on a new medication. Some examples could include antipsychotics like closapine, antibiotics like cephalosporins or fluorquinolones, antidepressants like buproprion, pain medications, tramadol, in particular, several illicit drugs like cocaine, amphetamines. 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, 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, an acute symptomatic seizure is defined as occurring 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 seizures starts to increase.

Dr. Michael Kentris [00:09:48]:

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, the risk of subsequent unprovoked seizure for each of these. For stroke, 33% for a first acute symptomatic seizure. But if you had a seizure later was 71.5% 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 increased to 63.5% for a first unprovoked seizure down the road. Some other pieces of history that you'll want to try and gather is if the person has any history of seizures as a child, particularly what we call complex feverile seizures, if they have any history of CNS infections as a child, a history of head injuries, even concussions. Some other pieces of history that you'll want to try and gather is if the person has any history of seizures as a child, particularly what we call complex febrile seizures.

Dr. Michael Kentris [00:10:57]:

If they have any history of CNS infections as a child, a history of head injuries, even things like concussions with loss of consciousness, a history of strokes, brain tumors, do they have a history of dementia or other neurodegenerative 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 a 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 ten people at some point in their life will have a seizure, but only one to 3% of those people who have had a seizure will go on to develop epilepsy. So not everybody gets placed on antiseizure 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 patients who are at higher risk of having seizure recurrence, who should be on antiseizure 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 going to 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 seeing when they present most of the time is a first generalized tonic clonic seizure or bilateral tonic clonic seizure, grand mall, whatever phrase 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 kind of acting unusually for several months or weeks.

Dr. Michael Kentris [00:12:39]:

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 antiseizure 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. We're checking a complete metabolic panel.

Dr. Michael Kentris [00:13:21]:

It's also usually a good idea to check a urine drug screen to make sure that there's nothing that may have broke 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 patients became very upset with me, and rightfully so, I have to admit. Later on in my training, I learned that the amphetamine assay has a very high false positive rate and often crossreacts with numerous over the counter medications, including antihistamines, 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 reactants with that assay. Obviously, if the patient looks like they're sick, if they look like they have stiffness in the neck, fevers, confusion, you do have to get some head imaging there and a lumbar puncture to check for any signs of infection in the spinal fluid, for encephalitis meningitis, all that bad stuff. Lastly, I would mention this is not necessarily for a first time seizure patient, but for someone with a history of epilepsy who is on antiseizure medication you do want to check blood levels of their antiseizure medication. Some of those you need metabolites.

Dr. Michael Kentris [00:14:41]:

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 workup again and kind of try and retweak their medications. You can just focus on what can we do to make sure that this person's getting their medications regularly, and can we help? And in any way in terms of reminders, et cetera, that can help with medication adherence? Moving on to our further diagnostic workup, imaging is going to be a significant piece of that, right? We want some sort of neuroimaging of the brain. So a lot of patients, 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 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 purposes 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.

Dr. Michael Kentris [00:16:05]:

And there are different strengths of MRI 1.5 Tesla, three Tesla, some large academic centers, even seven Tesla. But 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 an MRI called T, two flare, and you're asking them to do thin slices through the hippocampus in the coronal 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 measial 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 measial 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 one to four years. The hazard ratio increase was 2.44, and the 95% confidence interval was 1.9 to 5.44 compared to those without imaging abnormalities.

Dr. Michael Kentris [00:17:44]:

So it is a fairly high risk recurrence 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 our EEG. 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, polyspikin 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 being said, 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 is an old study from 1987 in epilepsy, Solinsky et al.

Dr. Michael Kentris [00:18:58]:

The title of the study was effectiveness of Multiple EEGs in Supporting the Diagnosis of Epilepsy in Operational Curve. This was an old VA study and so what it showed was essentially in 50% of patients with interectal epileptic form abnormalities, the abnormality was present on the first record in 84% of these patients by the third, and in 92% by the fourth. So further routine EEGs beyond that point weren't super helpful. So we're kind of using this population and that's kind of where we get 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 EEG is that the specificity is much, much higher than the sensitivity. So a normal EEG does not eliminate seizures or epilepsy as the diagnosis. An abnormal study is much more useful than a normal study in these types of situations where your clinical suspicion is very high for a seizure.

Dr. Michael Kentris [00:20:08]:

So let's say the EEG shows some sort of epileptiform abnormality. One study showed a seizure recurrence rate, relatively speaking, at one to five years of 2.16 compared to those without EEG abnormalities. So again, significantly higher than in those with a normal EEG. So let's say we get someone there's no predisposing history, no predisposing risk factors on imaging or on EEG first time seizure, as best you can determine by your history. These patients typically you will not start on any antiseizure medications and you will observe them for a period of three to six months. We're going to still recommend seizure safety precautions because even with a normal MRI and normal EEG, these patients 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.

Dr. Michael Kentris [00:21:17]:

That's the general rule of thumb that I usually follow in counseling people in this situation. Different states have different driving laws for people who have had a seizure. So actually, epilepsy.com has a lot of that information on there and can direct you towards appropriate information. So I definitely recommend checking out epilepsy.com and their resources in terms of the driving laws, if you have to counsel somebody 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 abnormality or an EEG 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 Vehicle Against Epilepsy. So in that situation, you would recommend beginning some sort of antiseizure medication.

Dr. Michael Kentris [00:22:23]:

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 our anti seizure medications, 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 enjoyed this podcast, please leave a five star review on Apple, itunes, Spotify, or wherever you're getting your podcasts. And please don't forget to share and subscribe for future episodes. I hope this information is providing some value to you, to your patients, and to your practice. You can reach me on Twitter @drKentris or by email at the Neurotransmitterspodcast@gmail.com. Thank you again for listening and I'll see you next time.