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

Abstract Seizure is one of the manifestations of central nervous system 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 nonprovoked seizures, mainly attributed to autoimmune‐associated epilepsy, occur in the nonacute phase of the diseases. Seizures in MS/AQP4‐NMOSD/MOGAD mostly have a focal onset. MS patients with concomitant systemic infections, earlier onset, and greater disease activity are more likely to have seizures, whereas factors such as greater MS severity, the presence of status epilepticus, and cortical damage indicate a greater risk of developing epilepsy. In MOGAD, cerebral cortical encephalitis and acute disseminated encephalomyelitis (ADEM)‐like phenotypes (predominately ADEM and multiphasic disseminated encephalomyelitis) indicate a greater 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 consists of 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 diseases are outlined. We also highlight pitfalls and challenges in managing such patients and future research perspectives to address unsolved questions.