FLAIR-Hyperintense Lesions in Anti-MOG-Associated Encephalitis with Seizures: A Case Report

Abstract

Introduction: Myelin oligodendrocytic glycoprotein antibody-associated disease (MOGAD) is an immune-mediated demyelinating disorder of the central nervous system. We described, a case of encephalitis associated with anti-MOG antibodies with hyperintense lesions on FLAIR and seizures (FLAMES). Case Report: We report a case of a 5-year-old girl, with no significant personal or family history, who entered the emergency room with paroxysmal events and anarthria, in a febrile context. On neurological examination she presented right sided facial paresis and pyramidal signs on the right. Lumbar puncture (LP), showed pleocytosis, hyperproteinorrhaquia and the absence of oligoclonal bands. Electroencephalogram revealed encephalopathy and slow paroxysmal left frontal activity. The brain MRI detected hyperintense lesions, however, with an area of left frontal cortico-subcortical hyperintense signal on T2/FLAIR and diffusion restriction. Anti-MOG antibody was detected. These findings pointed to the diagnosis of FLAMES. She completed 7 days of methylprednisolone (30mg/kg/day), with a good response. On the day of discharge, a repeat EEG was conducted, demonstrating significant improvement compared to the initial one, with slightly slow wake and sleep patterns for her age, and no evidence of epileptic activity. She was assessed approximately four months post-hospitalisation and was found to be asymptomatic, with no focal neurological deficits. A further EEG was performed, which showed a structurally age-appropriate wake and sleep pattern with no abnormal graphoelements. Conclusion: We highlight a rare clinical-radiological entity, which is still poorly described, particularly in the paediatric population, known as FLAMES, with a favourable response to steroids. Early recognition and timely diagnosis of his condition improve clinical and therapeutic management and minimize neurological damage. Immediate initiation of appropriate treatment is important for achieving a favorable outcome.