Temporal trends of epilepsy in multiple sclerosis

Coexistence of epilepsy or seizure and multiple sclerosis; review of the literature with a single center experience

OBJECTIVES

There is evidence that the inflammatory demyelinating disorder in Multiple Sclerosis (MS) is associated with acute seizures and epilepsy. Additionally, the likelihood of developing epilepsy increases with neurodegeneration. This study aims to reveal the clinical and radiological features of MS-epilepsy/seizure coexistence.

METHODS

Among all patients diagnosed with MS that we followed in our center between April 2002 and July 2023, patients with a single seizure history or diagnosed with epilepsy (MS-seizure/epilepsy) were randomized 1:1 in terms of age and gender with MS patients without a diagnosis of epilepsy or seizures. Clinical (comorbidities, annualized relapse rate, disability, seizures during attacks, initial diagnosis, disease duration, disease-modifying therapies (DMTs), refractory epilepsy, anti-seizure drugs), electroencephalography (EEG) and MRI (lesion localization and new lesion(s)) data were retrospectively evaluated.

RESULTS

The mean EDSS was 4.07±2.81. 29.4 % of patients had progressive MS (n = 10). Refractory epilepsy was 52.9 % (n = 18), and SE history was 14.7 % (n = 5). Pathology was detected in 69.7 % (n = 23) of patients in the EEG. The most common slow wave activation was detected in 51.5 % (n = 17). Refractory epilepsy was more common in cases under 45 and patients with lesions in thalamic localization. Lesions in the temporal and thalamic regions and cerebral atrophy were more common in the MS-seizure/epilepsy group.

CONCLUSION

Patients with demyelinating lesions in the temporal and thalamic regions should be questioned more carefully for epilepsy, and an EEG should be performed in case of clinical suspicion. Since thalamus lesions are more common in patients with refractory epilepsy, anti-seizure treatment strategies should be applied more carefully. The presence of atrophy on MRI confirms the link between neurodegeneration processes and the development of epilepsy.

Environmental factors related to multiple sclerosis progression

Multiple Sclerosis (MS) is a complex neurological disease which prevalence is increasing worldwide. The impact of environmental factors on MS susceptibility has already been defined and highlighted in many previous reports, particularly vitamin D or ultraviolet B light exposure, Epstein-Barr virus (EBV) infection, obesity, and smoking. There is increasing evidence that environmental and lifestyle factors are not only important in triggering MS but are also implicated in MS progression. Low sun exposure and vitamin D deficiency exhibit a strong relationship with disease progression in both animal and human studies. The gestational period seems also to impact long-term disease progression as January's babies had a higher risk of requiring walking assistance than those born in other months. The implication of EBV in neurodegeneration and MS progression was also suggested even though its specific targets and mechanisms are still unclear. Cigarette smoking is correlated with faster clinical progression. The association of obesity and smoking seems to be associated with a faster progression and an increased rate of brain atrophy. Although the effect of air pollution on MS pathogenesis remains not fully understood, exposure to polluted air can stimulate several mechanisms that might contribute to MS severity. People with MS with active disease have an altered microbiota compared to patients in the remission phase. Cardiovascular comorbidities, epilepsy, and depression are also associated with a more severe disability accrual. Knowledge about MS modifiable risk factors of progression need to be incorporated into everyday clinical practice in order to ameliorate disease outcomes.

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.