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

Incidence and determinants of seizures in multiple sclerosis: a meta-analysis of randomised clinical trials

BACKGROUND

Seizures are reported to be more prevalent in individuals with multiple sclerosis (MS) compared with the general population. Existing data predominantly originate from population-based studies, which introduce variability in methodologies and are vulnerable to selection and reporting biases.

METHODS

This meta-analysis aims to assess the incidence of seizures in patients participating in randomised clinical trials and to identify potential contributing factors. Data were extracted from 60 articles published from 1993 to 2022. The pooled effect size, representing the incidence rate of seizure events, was estimated using a random-effect model. Metaregression was employed to explore factors influencing the pooled effect size.

RESULTS

The meta-analysis included data from 53 535 patients and 120 seizure events in a median follow-up of 2 years. The pooled incidence rate of seizures was 68.0 per 100 000 patient-years, significantly higher than the general population rate of 34.6. Generalised tonic-clonic seizures were the most common type reported, although there was a high risk of misclassification for focal seizures with secondary generalisation. Disease progression, longer disease duration, higher disability levels and lower brain volume were associated with a higher incidence of seizures. Particularly, sphingosine-1-phosphate receptor (S1PR) modulators exhibited a 2.45-fold increased risk of seizures compared with placebo or comparators, with a risk difference of 20.5 events per 100 000 patient-years.

CONCLUSIONS

Patients with MS face a nearly twofold higher seizure risk compared with the general population. This risk appears to be associated not only with disease burden but also with S1PR modulators. Our findings underscore epilepsy as a significant comorbidity in MS and emphasise the necessity for further research into its triggers, preventive measures and treatment strategies.

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.

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.

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.

Modulation of Pacemaker Channel Function in a Model of Thalamocortical Hyperexcitability by Demyelination and Cytokines

A consensus is yet to be reached regarding the exact prevalence of epileptic seizures or epilepsy in multiple sclerosis (MS). In addition, the underlying pathophysiological basis of the reciprocal interaction among neuroinflammation, demyelination, and epilepsy remains unclear. Therefore, a better understanding of cellular and network mechanisms linking these pathologies is needed. Cuprizone-induced general demyelination in rodents is a valuable model for studying MS pathologies. Here, we studied the relationship among epileptic activity, loss of myelin, and pro-inflammatory cytokines by inducing acute, generalized demyelination in a genetic mouse model of human absence epilepsy, C3H/HeJ mice. Both cellular and network mechanisms were studied using in vivo and in vitro electrophysiological techniques. We found that acute, generalized demyelination in C3H/HeJ mice resulted in a lower number of spike–wave discharges, increased cortical theta oscillations, and reduction of slow rhythmic intrathalamic burst activity. In addition, generalized demyelination resulted in a significant reduction in the amplitude of the hyperpolarization-activated inward current (I_h) in thalamic relay cells, which was accompanied by lower surface expression of hyperpolarization-activated, cyclic nucleotide-gated channels, and the phosphorylated form of TRIP8b (pS237-TRIP8b). We suggest that demyelination-related changes in thalamic I_h may be one of the factors defining the prevalence of seizures 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.

Serum Vitamin D Level among Multiple Sclerosis Patients in the Tropics: Experience from a Private Clinic in Addis Ababa, Ethiopia

Background

Multiple sclerosis (MS) is an immune mediated disabling neurological disorder. Very little is known about MS in Ethiopia. The objective of this study was to determine the prevalence of hypovitaminosis D and associated factors in cohort of MS patients in Ethiopia.

Method

A cross-sectional observational study was conducted among 25 multiple sclerosis patients at Yehuleshet Specialty Clinic, Addis Ababa, Ethiopia.

Results

The prevalence of vitamin D deficiency was 96% (n=24). The average serum vitamin D was 14.8 (±10.4) ng/mL. The mean age was 35.8 (±10) years. Females accounted for 80% (n=20). Relapsing and remitting MS was the commonest variant. Motor, sensory, and mixed symptoms accounted for 40% (n=10), 20% (n=5), and 24% (n=6), respectively. Cold or hot weather and stress were reported as worsening factors in 24% (n=6). Relapse rate was 44% (n=11). Fatigue and seizure disorder were reported by 80% (n=20) and 16% (n=4) respectively. Steroid is the commonest prescribed medication for the patients. A negative correlation was found between serum vitamin D and age (r = -0.062, p = 0.7). Similarly, a negative association was observed between vitamin D and duration of illness (r = -0.311, p = 0.1). Fatigue was reported by those with moderate hypovitaminosis compared to those having severe hypovitaminosis (p=0.002). Seizure was reported more by those with vitamin D below 10ng/mL compared to those having above 10 ng/mL (p=0.004).

Conclusion

Our study demonstrates a high prevalence of hypovitaminosis D in Ethiopian MS patients. Hypovitaminosis D was associated with increment in age and duration of illness.

Electroencephalographic evidence of gray matter lesions among multiple sclerosis patients: A case-control study

This study aimed to investigate evidence of gray matter brain lesions in multiple sclerosis (MS) patients by evaluating the resting state alpha rhythm of brain electrical activity.The study included 50 patients diagnosed with MS recruited from the MS clinic with 50 age and gender-matched control participants. The study investigated parameters of posterior dominant rhythm (PDR) in the electroencephalography (EEG) recordings including wave frequency and amplitude. Functional disability among the patients was evaluated according to the expanded disability status scale. Univariate statistical analysis was completed using one-way analysis of variance and t test with a P value of less than .05 to indicate statistical significance.Patients with MS had significantly lower PDR frequency and amplitude values compared to the controls (P value < .01) and 34% of the MS patients had a PDR frequency of less than 8.5 Hz. The PDR frequency was negatively associated with the level of functional disability among the patients (P value <.001) and 4% of the patients had abnormal epileptiform discharges.Background slowing of resting alpha rhythms and epileptiform discharges are suggestive of gray matter degeneration and may help in the prediction and follow-up of cortical damage and functional disabilities among MS patients. Therefore, electroencephalography monitoring of the PDR spectrum may serve as an alternative or complementary tool with other imaging techniques to detect and monitor cerebral cortical lesions.

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.

Neuroinflammation: A Signature or a Cause of Epilepsy?

Epilepsy can be both a primary pathology and a secondary effect of many neurological conditions. Many papers show that neuroinflammation is a product of epilepsy, and that in pathological conditions characterized by neuroinflammation, there is a higher probability to develop epilepsy. However, the bidirectional mechanism of the reciprocal interaction between epilepsy and neuroinflammation remains to be fully understood. Here, we attempt to explore and discuss the relationship between epilepsy and inflammation in some paradigmatic neurological and systemic disorders associated with epilepsy. In particular, we have chosen one representative form of epilepsy for each one of its actual known etiologies. A better understanding of the mechanistic link between neuroinflammation and epilepsy would be important to improve subject-based therapies, both for prophylaxis and for the treatment of epilepsy.

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.

The prevalence of epileptic seizures in multiple sclerosis in a large tertiary hospital in Australia

Rationale

To determine the prevalence of epileptic seizures in multiple sclerosis (MS) at an Australian tertiary hospital and to define their clinical features.

Methods

We retrospectively analysed adult patients at the Royal Melbourne Hospital electronically identified to have ICD codes for MS and seizures and/or epilepsy between 1996 to 2019, utilising paper and electronic-based records.

Results

Of the 2,125 MS patients identified, 16 (0.75%) experienced epileptic seizures during a mean follow-up period of 12.9 years. Median age of MS diagnosis (SD) was 38 (9.3) years. Four patients had relapsing remitting MS (25%), 10 secondary progressive MS (63.5%), and 2 primary progressive MS (12.5%). More than two-thirds of patients had seizure onset following the diagnosis of MS, and the majority of these had advanced disease (approximate EDSS >6) at the time of seizure onset. Focal onset-seizures occurred in 87.5% of patients with seizures.

Conclusion

The estimated prevalence of seizures in our cohort was lower than in previous studies (0.75 vs 2-4%). In most cases, seizures occurred after the diagnosis of MS in the context of advanced disease. Further studies are required to determine if MS disease modifying treatments reduce the risk of seizures in this cohort.

A hypothesis for the role of axon demyelination in seizure generation

Loss of myelin and altered oligodendrocyte distribution in the cerebral cortex are commonly observed both in postsurgical tissue derived from different focal epilepsies (such as focal cortical dysplasias and tuberous sclerosis) and in animal models of focal epilepsy. Moreover, seizures are a frequent symptom in demyelinating diseases, such as multiple sclerosis, and in animal models of demyelination and oligodendrocyte dysfunction. Finally, the excessive activity reported in demyelinated axons may promote hyperexcitability. We hypothesize that the extracellular potassium rise generated during epileptiform activity may be amplified by the presence of axons without appropriate myelin coating and by alterations in oligodendrocyte function. This process could facilitate the triggering of recurrent spontaneous seizures in areas of altered myelination and could result in further demyelination, thus promoting epileptogenesis.

Epileptic seizures in multiple sclerosis: prevalence, competing causes and diagnostic accuracy

Background

Multiple sclerosis (MS) is accompanied by an increased risk of epileptic seizures, but data with a detailed description of the competing causes are lacking.

Methods

We aimed to describe a cohort of patients with both MS and epileptic seizures in a retrospective, population-based study.

Results

We included 59 out of 2285 MS patients who had at least one epileptic seizure. Out of them, 22 had seizures before the diagnosis of MS, whereas epileptic seizures occurred after MS diagnosis in 37 patients, resulting in a total prevalence of epileptic seizures in MS of 2.6%. Competing causes could be found in 50.8% (30/59) of all patients, with 40.9% (9/22) compared to 56.8% (21/37) of the MS patients with seizures before vs after MS diagnosis. The main alternative causes were traumatic brain injury and cerebral ischemia accounting for more than 30% of the patients, with no difference between the subgroups. 33.3% and 55.6% of MS patients with seizures before/after MS diagnosis had documented pathological EEG alterations.

Conclusion

A remarkable percentage of MS patients with epileptic seizures do have alternative competing causes at the time of the first seizure. A detailed diagnostic setup including patient history, EEG and MRI is recommended in the evaluation and choice for the best treatment.