FLAIR-hyperintense Lesions in Anti-MOG-associated Encephalitis with Seizures (FLAMES) Presenting with Psychosis and Refractory Seizures

ResultsA 35 year-old previously healthy man was admitted for focal motor seizures with secondary generalization and status epilepticus. His brain MRI showed bilateral, predominantly left, frontal cortical FLAIR hyperintensities with overlying leptomeningeal enhancement. His CSF studies showed a WBC of 3 with normal protein and negative oligoclonal bands. Serum MOG-IgG using Euroimmun fixed cell-based assay was initially reported inconclusive, while CSF testing was negative. Other encephalitis-related autoantibodies were negative in the serum and CSF. Screening tests for systemic autoimmune diseases, vasculitis and malignancy were negative. He was initially treated with acyclovir and required three anticonvulsants to control his seizures but later on developed psychosis. His repeat MRI showed more extensive cortical hyperintensities and leptomeningeal enhancement. The serum MOG-IgG was re-tested using the same cell-based assay and returned medium positive. His MRIs were then reviewed by a clinician with expertise in MOGAD and deemed consistent with FLAMES. He was then given IV methylprednisolone 1g for 5 days followed by a slow oral steroid taper with significant clinical improvement. 3 months later, he was readmitted for seizure recurrence and his repeat MRI showed new cortical FLAIR hyperintensities in the left temporal and occipital lobes signifying a disease flare. He is undergoing another course of IV steroids with IVIg at the time of writing. ConclusionsFLAMES should be considered in patients with encephalitis, seizures and cortical FLAIR hyperintensities with leptomeningeal enhancement in addition to infectious and other inflammatory causes. Testing (and when appropriate, re-testing) for MOG-IgG in the serum and possibly CSF using a cell-based assay should be performed as soon as possible to confirm the diagnosis. Prompt recognition and early initiation of immunotherapy may lead to better outcomes.