Association Between Neurodegenerative Diseases and an Increased Risk of Epilepsy Based on Single Nucleotide Polymorphisms: A Mendelian Randomization Study

Epilepsy is a common neurological disorder characterized by transient brain dysfunction, attributed to a multitude of factors. The purpose of this study is to explore whether neurodegenerative diseases, specifically Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS), have a causal effect on epilepsy. Mendelian randomization (MR) methods were used to analyze the causal association between neurodegenerative diseases (AD, PD, ALS, and MS) and epilepsy based on single nucleotide polymorphisms from genome-wide association studies, including inverse-variance weighted, weighted median, MR-Egger, and weighted mode methods. The reliability and stability of the MR analysis results were assessed by the MR-Egger intercept, MR-PRESSO, and heterogeneity tests. Forty-three SNPs were selected for the MR analysis of MS and epilepsy. The inverse-variance weighted method showed a significant causal association between MS and increased risk of epilepsy (odds ratio 1.046; 95% confidence interval 1.001-1.093; P = 0.043). However, AD (P = 0.986), PD (P = 0.894), and ALS (P = 0.533) were not causally associated with epilepsy. Sensitivity analysis showed that the results were robust. The MR study confirmed the causal relationship between genetically predicted MS and epilepsy but did not support the causal relationship between genetically predicted AD, PD, and ALS on epilepsy.

Seizures in inflammatory demyelinating disorders of the central nervous system

BACKGROUND

Multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) may be associated with acute symptomatic seizures and chronic epilepsy as well. The clinical features of the seizures and/or accompanying epilepsy seen in each disease group may vary. In this study, we aimed to contribute to the existing literature by describing the clinical features of seizures and epilepsy in our demyelinating patient population.

METHODS

We retrospectively analyzed patients who were followed up in our tertiary referral center neurology demyelinating diseases outpatient clinic between 2019 and 2024. Patients who had at least one seizure before, simultaneously, or after the diagnosis of demyelinating disease were included in the study.

RESULTS

Among 1735 patients with MS, 40 had experienced at least one epileptic seizure (2.3 %). Thirty patients (1.7 %) had seizures that could not be explained by another factor than MS. When secondary progressive MS (SPMS) and relapsing-remitting MS (RRMS) were compared, the interval between MS-epilepsy diagnosis was longer and seizure recurrence was more in SPMS. However, the prognosis of epilepsy was good in both subtypes. There were 21 patients followed up with antibody-positive neuromyelitis optica spectrum disorder. No patient had a seizure during the follow-up. We identified 56 patients who fulfilled the criteria for MOGAD with high antibody titers. Seizures were observed in three of them (5.4 %). All of them had status epilepticus either at the onset or during the course of the disease.

CONCLUSION

Even rare, seizures constitute one of the important clinical features of the inflammatory demyelinating disorders of the central nervous system. The pathophysiologic mechanism underlying seizures in MS is still not clear. Seizures may occur through different mechanisms in patients where seizures are the initial symptom or a sign of relapse and those that occur spontaneously during the progressive course of the disease. Prevalence of status epilepticus was common in MOGAD patients. Given the rarity of the seizures in CNS demyelinating disorders, it is difficult the define clinical and pathophysiological characteristics of accompanying seizures and epilepsy. Future studies conducted on large patient groups will contribute to the existing literature.

Clinical characteristics, course and prognosis of Multiple Sclerosis patients with epilepsy. A case control study: MS and epilepsy

BACKGROUND AND PURPOSE

Although more common than in the general population, seizures are an atypical manifestation of multiple sclerosis (MS) and their pathophysiology is not well understood. This study aims to examine the prevalence, clinical characteristics, brain imaging findings and course of epilepsy, presenting in patients with MS.

METHODS

Observational retrospective study of MS patients evaluated at a single MS reference center in Buenos Aires, Argentina, between 2011 and 2022, focusing on those who developed epilepsy (EMS). Clinical, demographic, and prognostic factors were evaluated and compared to a control group of non-epileptic MS patients (NEMS). To analyze specific epilepsy characteristics, a second control group of patients with non-lesional focal epilepsy (FNLE) was also included.

RESULTS

Twenty-five patients (18 women), were diagnosed with epilepsy, corresponding to a prevalence of 1.95%. Comparison of brain imaging characteristics between EMS and NEMS patients showed brain atrophy (32% vs 6.1%, p<0.01), as well as cortical (26% vs 4%, p=0.03) and juxtacortical lesions (84% vs 55%, p=0.05), were more frequent in EMS patients. However, after multivariate analysis, cortical atrophy was the only variable linked to a significant increase in risk of epilepsy (OR 24, 95%CI=2.3-200, p<0.01). No significant differences in clinical characteristics, disease activity, disability levels, response to disease modified treatment (DMT) or lack of DMT efficacy were observed between MS patients with or without epilepsy. Most patients received anti-seizure medication (ASM), and seizure control was better in EMS than in FNLE patients (92% vs 58%, p=0.022) with no differences found in drug resistance. We did not find predictors of seizure recurrence in the population studied.

CONCLUSION

We observed a lower prevalence of epilepsy in this group of MS patients, compared to other reported cohorts. Although epilepsy seems to have a benign course in MS patients, cortical atrophy appears to be an important contributor to the development of secondary epilepsy in MS patients. Further investigations will be necessary to identify risk factors or biomarkers predicting increased epilepsy risk in MS.

Multiple sclerosis and seizures: A retrospective observational study in a multiple sclerosis autoimmunity center of excellence

PURPOSE

The prevalence of epilepsy in patients with multiple sclerosis (MS) is three to six times the prevalence in the general population. Mechanisms resulting in increased seizure risk are not fully understood. Our objective is to characterize patients with MS and epilepsy regarding timing of diagnoses, MS and seizure (SZ) type, EEG findings suggesting cortical dysfunction, frequency of status epilepticus (SE), and seizure freedom.

METHODS

This was a single center retrospective study. Cases were obtained via DataDirect via the University of Michigan electronic medical record from January 1, 2006 through October, 12, 2016. The University of Michigan Health System is a large academic institute with a tertiary referral center and an Autoimmunity Center of Excellence. Patients were included if chart listed one or more of the top 62 epilepsy, and one or more of the top 2 MS, most frequently entered ICD9 and ICD10 codes. Patients with alternative epilepsy etiology were excluded. 74 of 361 patients were included. We collected information regarding demographics, MS and SZ type, age at diagnosis, imaging, EEG, seizure freedom, medications, and SE.

RESULTS

We found a high percentage of patients with SE. Most patients with imaging had multiple lesions at seizure onset. 27/54 of patients with EEG data showed electrographic evidence of cortical dysfunction. 6/8 of EEGs in PPMS showed features consistent with cortical dysfunction, followed by 9/17 in SPMS and 11/23 in RRMS. 7/8 of patients with PPMS showed EEG evidence of temporal lobe dysfunction.

CONCLUSION

Time of seizure onset relative to MS diagnosis varied with MS type suggesting distinct pathophysiology. EEG results correspond with reports of increased cortical damage and temporal dysfunction in PPMS, but are unique as a functional modality (EEG) as indicator of gray matter dysfunction. EEG findings differed in RRMS and progressive MS suggesting possibility of supportive diagnostic marker. Our data suggests higher risk of SE in progressive MS and diminished rate of seizure freedom for MS patients with SE. We conclude that early treatment with antiseizure medication would be beneficial for MS patients with SE and with progressive MS forms and SZ, in agreement with previous studies.

Assessment of bidirectional relationships between multiple sclerosis and epilepsy: A two-sample Mendelian randomization study

BACKGROUND AND OBJECTIVE

Epidemiological studies indicate that multiple sclerosis (MS) is associated with epilepsy. However, the causality and directionality of this association remain under-elucidated. This study aimed to reveal the causality between MS and epilepsy.

METHODS

A two-sample Mendelian randomization (MR) analysis was performed by using summarized statistics derived from large genome-wide association studies of MS and epilepsy. We used the inverse variance weighted method as the primary approach, and then four other MR methods to bidirectionally evaluate the causality of the association between MS and epilepsy. Additional sensitivity analyses were performed to measure the robustness of the findings.

RESULTS

Genetically predicted MS was positively correlated with developing all epilepsy [odds ratio (OR) = 1.027 (1.003-1.051), P  =  0.028] and generalized epilepsy [OR = 1.050 (1.008-1.094), P = 0.019]. In the reverse MR analysis, all epilepsy [OR = 1.310 (1.112-1.543), P = 0.001], generalized epilepsy [OR = 1.173 (1.010-1.363), P = 0.037], and focal epilepsy [OR = 1.264 (1.069-1.494), P  =  0.006] elevated the risk of developing MS. The result remained robust and congruous across all sensitivity analyses conducted.

CONCLUSIONS

MS is potentially associated with a higher risk of developing epilepsy. Furthermore, epilepsy may be a causal determinant of MS risk. These findings may further the understanding of the interaction of the two conditions.

Prognosis of adults and children following a first unprovoked seizure

BACKGROUND

Epilepsy is clinically defined as two or more unprovoked epileptic seizures more than 24 hours apart. Given that, a diagnosis of epilepsy can be associated with significant morbidity and mortality, it is imperative that clinicians (and people with seizures and their relatives) have access to accurate and reliable prognostic estimates, to guide clinical practice on the risks of developing further unprovoked seizures (and by definition, a diagnosis of epilepsy) following single unprovoked epileptic seizure.

OBJECTIVES

1. To provide an accurate estimate of the proportion of individuals going on to have further unprovoked seizures at subsequent time points following a single unprovoked epileptic seizure (or cluster of epileptic seizures within a 24-hour period, or a first episode of status epilepticus), of any seizure type (overall prognosis). 2. To evaluate the mortality rate following a first unprovoked epileptic seizure.

SEARCH METHODS

We searched the following databases on 19 September 2019 and again on 30 March 2021, with no language restrictions. The Cochrane Register of Studies (CRS Web), MEDLINE Ovid (1946 to March 29, 2021), SCOPUS (1823 onwards), ClinicalTrials.gov, the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). CRS Web includes randomized or quasi-randomized, controlled trials from PubMed, Embase, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (ICTRP), the Cochrane Central Register of Controlled Trials (CENTRAL), and the Specialized Registers of Cochrane Review Groups including Epilepsy. In MEDLINE (Ovid) the coverage end date always lags a few days behind the search date.

SELECTION CRITERIA

We included studies, both retrospective and prospective, of all age groups (except those in the neonatal period (< 1 month of age)), of people with a single unprovoked seizure, followed up for a minimum of six months, with no upper limit of follow-up, with the study end point being seizure recurrence, death, or loss to follow-up. To be included, studies must have included at least 30 participants. We excluded studies that involved people with seizures that occur as a result of an acute precipitant or provoking factor, or in close temporal proximity to an acute neurological insult, since these are not considered epileptic in aetiology (acute symptomatic seizures). We also excluded people with situational seizures, such as febrile convulsions.

DATA COLLECTION AND ANALYSIS

Two review authors conducted the initial screening of titles and abstracts identified through the electronic searches, and removed non-relevant articles. We obtained the full-text articles of all remaining potentially relevant studies, or those whose relevance could not be determined from the abstract alone and two authors independently assessed for eligibility. All disagreements were resolved through discussion with no need to defer to a third review author. We extracted data from included studies using a data extraction form based on the checklist for critical appraisal and data extraction for systematicreviews of prediction modelling studies (CHARMS). Two review authors then appraised the included studies, using a standardised approach based on the quality in prognostic studies (QUIPS) tool, which was adapted for overall prognosis (seizure recurrence). We conducted a meta-analysis using Review Manager 2014, with a random-effects generic inverse variance meta-analysis model, which accounted for any between-study heterogeneity in the prognostic effect. We then summarised the meta-analysis by the pooled estimate (the average prognostic factor effect), its 95% confidence interval (CI), the estimates of I² and Tau² (heterogeneity), and a 95% prediction interval for the prognostic effect in a single population at three various time points, 6 months, 12 months and 24 months. Subgroup analysis was performed according to the ages of the cohorts included; studies involving all ages, studies that recruited adult only and those that were purely paediatric.

MAIN RESULTS

Fifty-eight studies (involving 54 cohorts), with a total of 12,160 participants (median 147, range 31 to 1443), met the inclusion criteria for the review. Of the 58 studies, 26 studies were paediatric studies, 16 were adult and the remaining 16 studies were a combination of paediatric and adult populations. Most included studies had a cohort study design with two case-control studies and one nested case-control study. Thirty-two studies (29 cohorts) reported a prospective longitudinal design whilst 15 studies had a retrospective design whilst the remaining studies were randomised controlled trials. Nine of the studies included presented mortality data following a first unprovoked seizure. For a mortality study to be included, a proportional mortality ratio (PMR) or a standardised mortality ratio (SMR) had to be given at a specific time point following a first unprovoked seizure. To be included in the meta-analysis a study had to present clear seizure recurrence data at 6 months, 12 months or 24 months. Forty-six studies were included in the meta-analysis, of which 23 were paediatric, 13 were adult, and 10 were a combination of paediatric and adult populations. A meta-analysis was performed at three time points; six months, one year and two years for all ages combined, paediatric and adult studies, respectively. We found an estimated overall seizure recurrence of all included studies at six months of 27% (95% CI 24% to 31%), 36% (95% CI 33% to 40%) at one year and 43% (95% CI 37% to 44%) at two years, with slightly lower estimates for adult subgroup analysis and slightly higher estimates for paediatric subgroup analysis. It was not possible to provide a summary estimate of the risk of seizure recurrence beyond these time points as most of the included studies were of short follow-up and too few studies presented recurrence rates at a single time point beyond two years. The evidence presented was found to be of moderate certainty.

AUTHORS' CONCLUSIONS

Despite the limitations of the data (moderate-certainty of evidence), mainly relating to clinical and methodological heterogeneity we have provided summary estimates for the likely risk of seizure recurrence at six months, one year and two years for both children and adults. This provides information that is likely to be useful for the clinician counselling patients (or their parents) on the probable risk of further seizures in the short-term whilst acknowledging the paucity of long-term recurrence data, particularly beyond 10 years.

Prognostic impact of epileptic seizures in multiple sclerosis varies according to time of occurrence and etiology

BACKGROUND AND PURPOSE

Epileptic seizures occur more often in patients with multiple sclerosis (MS) than in the general population. Their association with the prognosis of MS remains unclear. This study was undertaken to evaluate whether epileptic seizures may be a prognostic marker of MS disability, according to when the seizure occurs and its cause.

METHODS

Data were extracted from a population-based registry of MS in Lorraine, France. Kaplan-Meier curves and log-rank tests were used to compare the probability of different levels of irreversible handicap during the course of MS in patients who experience epileptic seizures or do not, according to the chronology and the cause of the first epileptic seizure.

RESULTS

Among 6238 patients, 134 had experienced at least one epileptic seizure (2.1%), and 82 (1.2%) had seizures secondary to MS. Patients with epileptic seizure as a first symptom of MS (14 patients) had the same disease progression as other relapsing-remitting MS patients. Patients who developed epileptic seizures during the course of MS (68 patients) had a higher probability of reaching Expanded Disability Status Scale = 3.0 (p = 0.006), 6.0 (p = 0.003), and 7.0 (p = 0.004) than patients without an epileptic background. Patients with a history of epileptic seizures unrelated to MS also had a worse prognosis than patients without an epileptic background.

CONCLUSIONS

Epileptic seizures might be viewed as a "classic MS relapse" in terms of prognosis if occurring early in MS, or as a marker of MS severity if developing during the disease. Epileptic diseases other than MS may worsen the course of MS.

Seizures and multiple sclerosis‑more than an epidemiological association (Review)

In order to increase the quality of life of patients with epilepsy, it is essential to develop tools that facilitate early disease diagnosis and encourage the use of individualized therapies. The association between seizures and other neurological pathologies is well known but incompletely explained, with multiple sclerosis (MS)-seizures correlation being a relevant example. In this context, the present review aimed to highlight the most important facts related to the association between the heterogeneous group of epileptic pathology and MS, in order to provide initial directions for establishing a diagnostic and therapeutic protocol. The first part reviewed the most relevant epidemiological and clinical data on seizures; MS association. Subsequently, it highlighted the most common and actually accepted pathophysiological mechanisms that try to explain the association between the two pathologies. Finally, the importance of paraclinical investigations and the optimal choice of antiseizure-based therapies with respect to seizures associated with MS are presented, also revealing several directions that should be explored in the near future.

Seizures and epilepsy in multiple sclerosis, aquaporin 4 antibody-positive neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein antibody-associated disease

Seizure is one of the manifestations of central nervous system (CNS) inflammatory demyelinating diseases, which mainly include multiple sclerosis (MS), aquaporin 4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). "Acute symptomatic seizures secondary to MS / AQP4-NMOSD / MOGAD" occur in the acute phase of the diseases, and are more frequent in MOGAD. In contrast, recurrent non-provoked seizures, mainly attributed to "autoimmune-associated epilepsy", occur in the non-acute phase of the diseases. Seizures in MS / AQP4-NMOSD / MOGAD mostly have a focal-onset. MS patients with concomitant systemic infections, an earlier onset and a higher disease activity are more likely to have seizures, whereas factors such as higher MS severity, the presence of status epilepticus and cortical damage indicate a greater risk of developing epilepsy. In MOGAD, cerebral cortical encephalitis, acute disseminated encephalomyelitis (ADEM)-like phenotypes (predominately ADEM and multiphasic disseminated encephalomyelitis) indicate a higher seizure risk. Multiple relapses with ADEM-like phenotypes predict epilepsy in pediatrics with MOGAD. Pathophysiologically, acute symptomatic seizures in MS are associated with neuronal hyperexcitability secondary to inflammation and demyelination. Chronic epilepsy in MS is largely due to gliosis, neuronal dysfunction and synaptic abnormalities. The mainstay of treatment for seizures secondary to MS / AQP4-NMOSD / MOGAD include immunotherapy along with antiseizure medications. This critical review discusses the most-updated evidence on epidemiology, clinical correlates, and inflammatory mechanisms underlying seizures and epilepsy in MS / AQP4-NMOSD / MOGAD. Treatment cautions including drug-drug interactions and the impact of treatments on the other are outlined. We also highlight pitfalls and challenges in managing such patients and future research perspectives to address unsolved questions.

Treatment of pilocarpine-induced epileptic seizures in adult male mice

Epilepsy is one of the most common neurological disorders affecting most social, economic and biological aspects of human life. Most patients with epilepsy have uncontrolled seizures and drug side effects despite the medications. Patients with epilepsy often have problems with attention, memory, and information processing speed, which may be due to seizures, underlying causes, or anticonvulsants. Therefore, improving seizure control and reducing or changing the anti-epileptic drugs can solve these problems, but these problems will not be solved in most cases. In this work, we looked at the effects of pioglitazone, a Peroxisome Proliferator-Activated Receptor agonist used to treat type 2 diabetes, on pilocarpine-induced seizures in mice. The Racine scale was used to classify pilocarpine-induced convulsions. After that, all of the animals were beheaded, and the brain and hippocampus were dissected. Finally, biochemical techniques were used to determine the levels of Malondialdehyde and Catalase activity, as well as Superoxide Dismutase and Glutathione Reductase in the hippocampus. The results of this investigation suggest that pioglitazone's antioxidant action may play a key role in its neuroprotective properties against pilocarpine-induced seizure neuronal damage.

Altered grey matter integrity and network vulnerability relate to epilepsy occurrence in patients with multiple sclerosis

BACKGROUND

To investigate the relevance of compartmentalized grey matter (GM) pathology and network reorganization in MS patients with concomitant epilepsy.

METHODS

From 3T MRI scans of 30 MS patients with epilepsy (MSE; age 41±15 years, 21 females, disease duration 8±6 years, median Expanded Disability Status Scale (EDSS) 3), 60 MS patients without epilepsy (MS; age 41±12 years, 35 females, disease duration 6±4 years, EDSS 2), and 60 healthy subjects (HS; age 40±13 years, 27 females) regional volumes of GM lesions and of cortical, subcortical, and hippocampal structures were quantified. Network topology and vulnerability were modeled within the graph theoretical framework. The receiver operating characteristic (ROC) analysis was applied to assess the accuracy of GM pathology measures to discriminate between MSE and MS patients.

RESULTS

Higher lesion volumes within the hippocampus, mesiotemporal cortex, and amygdala were detected in MSE compared to MS (all p<0.05). MSE displayed lower cortical volumes mainly in temporal and parietal areas compared to MS and HS (all p<0.05). Lower volumes of hippocampal tail and presubiculum were identified in both MSE and MS patients compared to HS (all p<0.05). Network topology in MSE was characterized by higher transitivity and assortativity, and higher vulnerability compared to MS and HS (all p<0.05). Hippocampal lesion volume yielded the highest accuracy (area under the ROC curve 0.80 [0.67-0.91]) in discriminating between MSE and MS patients.

CONCLUSIONS

High lesion load, altered integrity of mesiotemporal GM structures, and network reorganization are associated with a greater propensity of epilepsy occurrence in MS.

Recurrence risk after a first remote symptomatic seizure in adults: Epilepsy or not?

The ILAE practical definition of epilepsy has a one seizure possibility to diagnose epilepsy after a first seizure if the recurrence risk is very high. The recurrence risk after a first seizure in brain disorders (first remote seizure) is often high, but varies with etiology, so more specific information is needed for clinical practice. This review describes etiology-specific recurrence risks in adults with a first remote seizure in stroke, traumatic brain injury, infections, dementia, multiple sclerosis, and tumors. Most studies are short, single center, and retrospective. Inclusion criteria, outcome ascertainment, and results vary. Few patient categories are clearly above the epilepsy threshold of recurrence risk, and there are surprisingly little data for important etiologies like brain infections. Beside stroke, severe TBI could have a sufficiently high recurrence risk for early epilepsy diagnosis, but more studies are needed, preferably prospective ones. The literature is uninformative regarding which seizures qualify as remote. The clinical implication of the low level of available evidence is that for other etiologies than stroke, seizure recurrence remains the most appropriate indicator of epilepsy for most patients with a first remote seizure. Nonetheless, there are worrying indications of a diagnostic drift, which puts patients with a preexisting brain disorder at risk of misdiagnosis. Although there are drawbacks to an intermediate term like "possible epilepsy," it could perhaps be useful in cases when the recurrence risk is high, but epilepsy criteria are not definitely met after a first remote seizure.

Retention of antiseizure medications for epilepsy in multiple sclerosis: A retrospective observational study

PURPOSE

Epilepsy in multiple sclerosis (MS) is rare, and longitudinal clinical studies evaluating treatment with antiseizure medications (ASMs) are difficult to conduct. We instead designed a nationwide register study to estimate retention rates of ASMs prescribed as initial monotherapy for epilepsy in MS and investigated factors influencing their retention.

METHODS

multiple sclerosis patients with a first prescription of ASM for epilepsy were identified by cross-referencing the Swedish MS register with comprehensive national registers. One and five-year retention rates of ASMs were estimated using Kaplan-Meier analysis. Cox proportional regression was employed to estimate hazard ratios (HR) of discontinuation for different ASMs as well as for baseline predictors.

RESULTS

One hundred and twenty-nine MS patients were included. The most commonly prescribed ASMs were: carbamazepine (n = 38, 29.5%), lamotrigine (n = 33, 25.6%) and levetiracetam (n = 19, 14.7%). One-year retention rates (95% CI) were: lamotrigine 87.5% [76, 98.9], carbamazepine 60.5% [45, 76], levetiracetam 60.2% [37.2, 83.2], valproate 51.3% [23, 79.6] and phenytoin 44.4% [11.8, 77]. Fiveyear retention rates (95% CI) were: lamotrigine 74.4% [57.3, 91.5], carbamazepine 52.2% [34.9, 69.4], valproate 51.3% [23.1, 79.5] and phenytoin 14.8% [0, 40.9]. With carbamazepine as reference, lamotrigine was the only ASM that displayed a lower hazard of discontinuation, HR 0.41 [0.17, 0.99]. We could not identify any baseline factors that influenced the risk of discontinuation.

CONCLUSION

Lamotrigine displayed the lowest risk of discontinuation when prescribed as initial monotherapy for epilepsy in MS. Newer ASMs generally compared well to older ones, at least suggesting non-inferiority.

A minority of patients with functional seizures have abnormalities on neuroimaging

OBJECTIVE

Functional seizures often are managed incorrectly as a diagnosis of exclusion. However, a significant minority of patients with functional seizures may have abnormalities on neuroimaging that typically are associated with epilepsy, leading to diagnostic confusion. We evaluated the rate of epilepsy-associated findings on MRI, FDG-PET, and CT in patients with functional seizures.

METHODS

We studied radiologists' reports from neuroimages at our comprehensive epilepsy center from a consecutive series of patients diagnosed with functional seizures without comorbid epilepsy from 2006 to 2019. We summarized the MRI, FDG-PET, and CT results as follows: within normal limits, incidental findings, unrelated findings, non-specific abnormalities, post-operative study, epilepsy risk factors (ERF), borderline epilepsy-associated findings (EAF), and definitive EAF.

RESULTS

Of the 256 MRIs, 23% demonstrated ERF (5%), borderline EAF (8%), or definitive EAF (10%). The most common EAF was hippocampal sclerosis, with the majority of borderline EAF comprising hippocampal atrophy without T2 hyperintensity or vice versa. Of the 87 FDG-PETs, 26% demonstrated borderline EAF (17%) or definitive EAF (8%). Epilepsy-associated findings primarily included focal hypometabolism, especially of the temporal lobes, with borderline findings including subtle or questionable hypometabolism. Of the 51 CTs, only 2% had definitive EAF.

SIGNIFICANCE

This large case series provides further evidence that, while uncommon, EAF are seen in patients with functional seizures. A significant portion of these abnormal findings are borderline. The moderately high rate of these abnormalities may represent framing bias from the indication of the study being "seizures," the relative subtlety of EAF, or effects of antiseizure medications.

Prevalence of Seizure/Epilepsy in Patients with Multiple Sclerosis: A Systematic Review and Meta-Analysis

Background

Seizure and epilepsy are among the initial symptoms of multiple sclerosis (MS), yet different prevalence rates are reported for them in the previous studies. The goal of this systematic review is to estimate the pooled prevalence of seizure and epilepsy in patients with MS.

Methods

We searched PubMed, Scopus, EMBASE, Web of Science, google scholar, and gray literature including references from identified studies and conference abstracts published up to October 2019. The search strategy included the MeSH terms and text words as ((Epilepsies OR Seizure Disorder OR Seizure Disorders OR Awakening Epilepsy OR Epilepsy, Awakening OR Epilepsy, Cryptogenic OR Cryptogenic Epilepsies OR Cryptogenic Epilepsy OR Epilepsies, Cryptogenic OR epilepsy OR seizure) AND (Multiple Sclerosis OR Sclerosis, Multiple) OR Sclerosis, Disseminated) OR Disseminated Sclerosis) OR MS (Multiple Sclerosis)) OR Multiple Sclerosis, Acute Fulminating).

Results

The literature review resulted in 4860 articles; 2593 articles remained after eliminating the duplicates. For the final analysis, 39 articles were included, 9 of which were conference abstracts. The pooled prevalence of seizure in MS cases was 2%, 95% confidence interval (CI)(1%-3%) (I² = 91.8%, P < 0.001). The pooled prevalence of epilepsy in MS cases was 3%, 95% CI (2%-4%) (I2 = 92.9%, P < 0.001). The pooled prevalence of epilepsy in Asia, Europe, and America was 6%, 3%, and 3%, respectively. The level of heterogeneity decreased after subgroup analysis in Asian and American subgroups. Meta-regression analysis showed continent is not a source of heterogeneity (coefficient = -0.007, P = 0.6).

Conclusions

The result of this systematic review shows that the pooled prevalence of seizure and epilepsy among MS patients is 2% and 3%, respectively.

Management of seizures in patients with multiple sclerosis; an Iranian consensus

PURPOSE

Cooccurrence of a seizure in a patient with multiple sclerosis (MS) may complicate the management process. Questions, which may complicate the management process of a patient with MS and seizure, include "how should we approach to the patient", "how should we treat the patient", "how should we modify the patient's MS treatment strategy", etc. METHODS: We searched the electronic database PubMed on March 30, 2018 for articles in English that included the following search terms: "epilepsy" AND "multiple sclerosis" or "seizure" AND "multiple sclerosis" since 2013, to obtain the best recent relevant scientific evidence on the topic. A working group of 6 epilepsy and 5 MS experts took part in two consensus workshops in Tehran, Iran, in 2018. The final consensus manuscript was prepared and approved by all participants.

RESULTS

The search with words "seizure" and "multiple sclerosis" yielded 121 entries; 10 were relevant to the topic. The search with words "epilepsy" and "multiple sclerosis" yielded 400 entries; 7 were relevant to the topic. We reviewed these 17 articles and also some other references, derived from these articles or relevant to the topic, for the purpose of our review.

CONCLUSION

Cooccurrence of a seizure in a patient with MS may complicate the management process. In this review, we tried to provide answers to the frequently asked questions, considering the best available scientific evidence and expert opinion.

Patients With Epileptic Seizures and Multiple Sclerosis in a Multiple Sclerosis Center in Southern Germany Between 2003-2015

Background: So far, many studies have shown that the risk of developing seizures and epilepsy is higher among patients with multiple sclerosis (MS) than in the general population. However, the causal link between these two diseases is still unclear. In addition, it is not clearly understood whether and to what extent the manifestation of seizures and epilepsy in patients with MS affects the clinical course and the long-term prognosis of the disease. We aimed to retrospectively identify and describe patients with MS and with seizures and epilepsy which were seen at the Department of Neurology of the University of Regensburg in Germany between the years 2003-2015. Methods: With the help of the electronic documentation system of hospital admitted patients followed by scrutinizing medical records of patients with MS for evidence of seizures and epilepsy, we identified patients with MS and seizures or epilepsy. Results: We identified 22 individuals (1.74%) out of 1,267 patients with MS with seizures or epilepsy. 18 of these 22 individuals met criteria for epilepsy (1.42%). Nine MS patients (40.9%) suffered from relapsing-remitting MS (RRMS) whereas 11 MS patients (50.0%) showed a secondary progressive disease course (SPMS). Five of those (45.5%) converted from RRMS to SPMS before they acquired epilepsy. None of the identified patients with MS and seizures or epilepsy suffered from primary progressive MS (PPMS). Moreover, two MS patients (9.1%) had a history of seizures before MS onset. Seizures were of focal onset in 17 patients with MS (77.3%). Fourteen out of these 17 MS patients presented with focal to bilateral tonic-clonic seizures (82.4%). Five MS patients (22.7%) showed tonic clonic seizures of unknown onset. Status epilepticus was reported in three patients with MS (13%), for one patient the data was inconclusive. Conclusion: The occurrence of seizures and epilepsy was higher than in the general population, suggesting a causal relationship between both diseases. In most cases, seizures occurred after the first manifestation of MS. The high frequency of focal seizures supports the concept of cerebral lesions in patients with MS playing an important role in precipitation of seizures and epilepsy.

Seizures and epilepsy in multiple sclerosis: epidemiology and prognosis in a large tertiary referral center

BACKGROUND

Seizures and epilepsy may substantially add to the burden of disease in multiple sclerosis (MS), whereas the exact prevalence and prognosis of seizures and epilepsy in patients with MS remains largely unknown.

OBJECTIVES

We aimed to investigate the epidemiology and prognosis of seizures and epilepsy in MS.

METHODS

We retrospectively analyzed a cohort of 4078 MS patients from a single tertiary referral clinic.

RESULTS

After excluding 37 patients with unconfirmed MS and alternative seizure etiologies, we found seizures attributable to MS in 1.5% and epilepsy in 0.9% of patients. 40.4% of patients with a follow-up of at least twelve months experienced only a single seizure and 59.6% had recurring seizures. 39% of patients with recurrent seizures were considered drug-resistant, with 9.7% experiencing status epilepticus. Seizure recurrence after a first seizure depended significantly on the MS subtype and was seen more often if the first seizure occurred simultaneously with a MS relapse than in the absence of a relapse.

CONCLUSION

Our study shows a lower number of seizures and epilepsy in MS than previously reported. While a single seizure in MS usually has a good prognosis, relapse-associated seizures and established epilepsy in MS may not be as benign as previously assumed.

Characteristics of Seizure and Antiepileptic Drug Utilization in Outpatients With Autoimmune Encephalitis

Autoimmune encephalitis (AE) is one kind of encephalitis that associates with specific neuronal antigens. Most patients with AE likely suffer from seizures, but data on the characteristics of seizure and antiepileptic drugs (AEDs) utilization in this patient group remains limited. This study aimed to report the clinical status of seizure and AEDs treatment of patients with AE, and to evaluate the relationship between AEDs discontinuation and seizure outcomes. Patients with acute neurological disorders and anti-N-methyl-D-aspartate receptor (NMDAR), γ-aminobutyric acid B receptor (GABA_BR), leucine-rich glioma inactivated 1, or contactin-associated protein-like 2 (CASPR2) antibodies were included. As patients withdrew from AEDs, they were divided into the early withdrawal (EW, AEDs used ≤3 months) and late withdrawal (LW, AEDs used >3 months) groups. Seizure remission was defined as having no seizures for at least 1 year after the last time when AEDs were administered. Seizure outcomes were assessed on the basis of remission rate. The factors affecting the outcomes were assessed through Spearman analysis. In total, we enrolled 75 patients (39 patients aged <16 years, male/female = 39/36) for follow-up, which included 67 patients with anti-NMDAR encephalitis, 4 patients with anti-GABA_BR encephalitis, 2 patients with anti-voltage-gated potassium channel encephalitis, and 2 patients with coexisting antibodies. Among the 34 enrolled patients with anti-NMDAR encephalitis who were withdrawn from AEDs, only 5.8% relapse was reported during the 1-year follow-up, with no significant difference in the percentage of relapse between the EW and LW groups (P = 0.313). Fifteen patients (an average age of 6.8, 14 patients with anti-NMDAR encephalitis and 1 patient with anti-CASPR2 encephalitis) presented seizure remission without any AEDs. Seventy five percent of patients with anti-GABA_BR antibodies developed refractory seizure. Other risk factors which contributed to refractory seizure and seizure relapse included status epilepticus (P = 0.004) and cortical abnormalities (P = 0.028). Given this retrospective data, patients with AE have a high rate of seizure remission, and the long-term use of AEDs may not be necessary to control the seizure. Moreover, seizures in young patients with anti-NMDAR encephalitis presents self-limited. Patients with anti-GABA_BR antibody, status epilepticus, and cortical abnormalities are more likely to develop refractory seizure or seizure relapse.