Chapters Transcript Post-Stroke Epilepsy Course: The Cutting Edges in Stroke So first we'll talk about post-stroke seizures, which are acute symptomatic seizures that occur during the acute setting, um, right after the stroke, typically within less than 7 days. The incidence is about 6 to 8% in ischemic strokes and about 12% in hemorrhagic strokes. Typically acute symptomatic seizures occur a post stroke due to metabolic dysfunction, disruption of the blood brain barrier, inflammation along with release of um cytotoxic neurotransmitters due to the brain damage that happened from the stroke itself. Patients who have acute symptomatic strokes post stroke are at about 30% chance at risk for developing epilepsy. So what are some risk factors for those who develop post-stroke seizures? So having an NIH scale, a severity scale greater than 11, strokes caused by large artery, um, atherosclerosis, posterior circulation strokes, um, and there's been no increased risk seen. With either reperfusion treatments such as mechanical thrombectomy or with IV thrombolysis, post-stroke seizures can lead to increased metabolic stress and cell death, and this can then increase your infarct size, mortality rate, and also lead to poor functional outcome. And for this reason, post-stroke seizures are treated in the acute setting. However, what's unknown is how long do you continue treatment for. And there currently are no real guidelines to determine that and there is data being collected through the Passion Network, which is a post acute symptomatic seizure clinic network to help develop guidelines for the appropriate discontinuation of ASMs in this patient population. There was one study that looked at just practice of neurologists about who continues ASMs in these patients, and it was found that those at high risk for developing post-stroke epilepsy along with outpatient EEG findings of epilepti form discharges led to long term ASM continuation. So post-stroke epilepsy is remote symptomatic seizures. These are seizures that occur after the first week of your stroke, so typically greater than 7 days, and based on the ILE definition, these patients meet criteria for epilepsy. Um, so the ILE definition is patients who are greater than have a greater than 60% chance of having seizure recurrence, and that's typically in the setting of one unprovoked seizure and either an abnormal MRI or abnormal EEG. So the incidence of post-stroke epilepsy is about 5 to 9% um in survivors of stroke patients and it's about 30 to 50% of new onset epilepsy seen in patients greater than 65 years of age. Typically this is due to persistent changes in neuronal excited. Um, excitability and gliotic scarring typically formed by reactive astrocytes, so post-stroke epilepsy warns treatment with ASMs, and the selection of ASM should be based on age, comorbidities, any concomitant medications, and ultra pharmodynamics in the elderly. You should always try for monotherapy and the aim should be to start at low dosages and to escalate the dosage, um higher dosages slowly. There's no studies that determine which medication is most effective or which is better for patients in treating them with post-stroke epilepsy. However, based on some clinical trials for ASMs, we do know that the elderly tolerate levetiracetam, lamotrigine, or glucosamide were better tolerated. And there was no difference in efficacy between any of these medications given a lot of drug to drug interactions, it's best to avoid enzyme inducing agents such as carbamazepine, Benitoin, phenobarbital, as well as primidone. Um, these medications can in uh uh impact and affect the. Metabolism of other drugs that these patients may be on and also they are also known to increase the serum levels of lipids, um, also avoiding enzyme inhibiting ASM such as alpuric acid also, um, should be avoided given their drug to drug interactions. So who develops post-stroke epilepsy and what are the predictors involved in this? So there was a multi-center study done that developed the select score which found a list of predictors for those who are at highest risk for developing post-stroke epilepsy. So a stroke severity NIH scale greater than 4, having large arterio um atherosclerosis, presence of clinical seizures, cortical involvement of the stroke itself, anterior circulation strokes, specifically the NCA territory along with either hemorrhagic, um, hemorrhagic strokes or hemorrhagic conversion, all of these were associated with higher risk of developing post-stroke epilepsy. So the select score was actually recently modified to the 2.0 prognostic model, and the only thing that was included in this model that's different from the previous is actually acute symptomatic status epilepticus which has a higher um point score which. I'll show you in a little bit and mainly that was because they saw that patients who presented, although it was a small number of patients that had acute symptomatic status, they had a higher mortality rate at 10 years and they also had a higher risk of developing post-stroke epilepsy at 10 years. So on the new scale, the select 2.0, if you have a score greater than 8, you have a greater than 60% chance of developing post-stroke epilepsy within 10 years. So this is showing you the old select score versus the new select score, and you can see that most of the parameters are exactly the same, um, as well as the number of points. The only thing that's different in the select 2.0 is the acute symptomatic status epileptic score, um, which has a higher point value at 7, so the select 2.0 is out of 13 points total and the original one was out of 9. This is showing you the risk of developing seizures um at 1 year, 5 years, and then over a 10 year period based on your select score and so as I stated, having a select score greater than 8 on the 2.0 model um had an increased chance of developing post-stroke epilepsy. So for hemorrhagic strokes there was a cave prognostic model that was developed and this the predictors for that for determining who would develop post-stroke epilepsy, you would get a point for if you were less than 65 years of age again cortical involvement, a hemorrhagic volume greater than 10 millimeters, and then acute symptomatic seizure, you got a point for that. The risk overall at 5 years for post-stroke epilepsy was about 12%. And so this is showing you the cave score itself, um, and also kind of the risk of remote symptomatic seizures and then this is showing you. Sorry, and then this is showing you the um. On the Y axis it's actually a seizure freedom so you can see the higher scores K3 and 4 were associated with a greater risk of developing post-stroke epilepsy. So what is the role of EEG in trying to help us determine who may or may not develop post-stroke epilepsy? We know that about 12% of ischemic strokes can have electrographic seizures on EEG. 25% of patients with ischemic stroke can show rhythmic patterns, and about 7% of patients will have non-convulsive status epilepticus. So when do you perform continuous EEG? Unfortunately there are no specific guidelines that are available, however. Through numerous papers there are suggestions that if a patient has a clinical seizure post stroke, then that's definitely somebody who should be connected to continuous EEG and if there's any concern that seizures or non-convulsive seizures may be contributing to continued altered mental status in a stroke patient, those are the ones that should be connected to EEG. So there was a study done that looked at if there could be EEG biomarkers that could help to determine who may develop post-stroke epilepsy, um, so this was done in Belgium and it was 81 patients that made, um, that were followed for greater than 1 year, and this is a retrospective study looking at ischemic patients who underwent continuous EEG monitoring. The patients at this institution that undergo monitoring are those with non-lacuar subttenorial strokes. Um, they had to have at least an NIH stroke scale score of greater than 8. They had an acute symptomatic seizure, typically a clinical one, hemorrhagic conversion, or they had unexplained neurologic deterioration. The median duration of monitoring was for approximately 2 days. So out of these 81 patients, approximately 19% of patients had electrographic seizures or some type of rhythmic patterns seen on continuous EEG, and about 50% of those patients actually had a clinical seizure prior to undergoing continuous EEG monitoring. 14% of patients were found to have attenuation of faster frequencies without any delta slowing seen on EEG. And then about 15% of these patients develop post-stroke epilepsy. Their study also found that higher select scores were associated with higher rates of post-stroke epilepsy. However, after they corrected for that, what they found in their study as an EEG biomarker is that if you had rhythmic or periodic patterns or regional attenuation without delta slowing on EEG, this was associated with about a 50% risk of developing um post-stroke epilepsy and so they stated this is class 3 evidence. Of early continuous EG findings or EEG biomarkers and helping to determine who will develop post-stroke epilepsy. So in conclusion, post-stroke epilepsy or seizures that occur after a week of uh post stroke. These seizures warrant treatment with ASMs and the choice of the anti-seizure medication should be based on efficacy and adverse event effects along with any altered form of dynamics in the elderly and vascular comorbidities that the patients may have. Acute symptomatic seizures occur within less than 7 days of the acute period of the stroke, and these seizures may not warrant long-term treatment with ASMs, but further, um. Studies are needed to determine in which patient population we can discontinue these medications in. The select score for ischemic strokes and the cave score for hemorrhagic strokes can predict the risk of developing post-stroke epilepsy, and the presence of seizures, rhythmic patterns, or regional attenuation without delta slowing on continuous EEG was associated with higher risk of post-stroke epilepsy. And that's it. Thank you. Published December 16, 2023 Created by Related Presenters Pue Farooque, DO View full profile
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