Risk of Developing Epilepsy after Autoimmune Encephalitis.

Ariadna Gifreu,Mercè Falip,Marta Simó,Francisco Morandeira,Montserrat Fernández,Jacint Sala-Padró,Ángels Camins,Pablo Naval-Baudin,Misericordia Veciana,Neus Mongay,Belia Garcia,Jordi Pedro,Pablo Arroyo

doi:10.3390/brainsci11091182

Abstract

Background: Acute symptomatic seizures (ASS) are a common manifestation of autoimmune encephalitis (AE), but the risk of developing epilepsy as a sequela of AE remains unknown, and factors predisposing the development of epilepsy have not been fully identified. Objective: To assess the risk of developing epilepsy in AE and study related risk factors. Materials and methods: This was a retrospective single centre study including patients diagnosed with AE according to criteria described by Graus et al., with a minimum follow-up of 12 months after AE resolution. The sample was divided according to whether patients developed epilepsy or not. Results: A total of 19 patients were included; 3 (15.8%) had AE with intracellular antibodies, 9 (47.4%) with extracellular antibodies, and 7 (36.8%) were seronegative. During follow-up, 3 patients (15.8%) died, 4 (21.1%) presented relapses of AE, and 11 (57.89%) developed epilepsy. There was a significant association between the development of epilepsy and the presence of hippocampal atrophy in control brain magnetic resonance imaging (MRI) (p = 0.037), interictal epileptiform discharges (IED) on control electroencephalogram (EEG) (p = 0.045), and immunotherapy delay (p = 0.016). Conclusions: Hippocampal atrophy in neuroimaging, IED on EEG during follow-up, and immunotherapy delay could be predictors of the development of epilepsy in patients with AE.

Highlights

One patient was excluded because the diagnosis of autoimmune encephalitis (AE) was doubtful: while presenting with Acute symptomatic seizures (ASS) and the presence of a paraneoplastic Ab was detected, the patient did not meet the diagnostic criteria for AE because of a lack of clinical features or brain magnetic resonance imaging (MRI) changes suggestive of AE
It was not possible to determine whether or not 3 patients would have developed epilepsy as they died in the acute phase before
According to our inclusion criteria and because these patients could not be classified according to the outcome of epilepsy, they were excluded from the statistical analysis, and 19 patients were included

Summary

Introduction

Acute symptomatic seizures (ASS) are a common, well-recognised, and often prominent manifestation of AE [2,3,4], occurring during the acute or early stages of the disease in the majority of patients [3]. The definition of acute symptomatic seizures related to AE (ASAE) was proposed to differentiate the condition from a chronic condition called autoimmune-related epilepsy (ARE). ASAE are seizures occurring in the setting of the active phase of immune-mediated encephalitis, initially or in relapse, which sometimes take weeks or even months to resolve [4]. Acute symptomatic seizures (ASS) are a common manifestation of autoimmune encephalitis (AE), but the risk of developing epilepsy as a sequela of AE remains unknown, and factors predisposing the development of epilepsy have not been fully identified. During follow-up, 3 patients (15.8%) died, 4 (21.1%)

Methods

Results

Discussion

Conclusion