A flames-like presentation in a young child: an uncommon MOG associated disease phenotype

*Correspondence: [e-mail].

Abstract

Case Presentation: A previously healthy 4-year-old bolivian girl presented to our hospital with right-sided weakness and ipsilateral ataxia, preceded by 3 days of acute headache and mild lethargy. Two weeks before she had had flu-like symptoms. Parents denied seizures or fever. Brain MRI with gadolinium showed left superior frontal gyrus and perirolandic area hyperintensity on T2-FLAIR, without overlying leptomeningeal enhancement. Electroencephalography showed anterior left frontal disorganization without epileptiform activity. Serologies were negative. Lumbar puncture revealed normal parameters, including no CSF-specific oligoclonal bands (OCB). With suspicion of a possible demyelinating event, MOG-IgG was tested and came positive. Intravenous methylprednisolone 30 mg/kg daily was started for 5 days, with complete clinical recovery. In the last follow-up she was asymptomatic, without immunotherapy of maintenance and 6-month-follow up brain MRI disclosed only a subtle left frontal cortical hyperintensity.

Discussion: Unilateral cortical FLAIR-hyperintense lesions anti-MOG-associated encephalitis with seizures (FLAMES) is a rare anti-MOG phenotype first described in 2017 and observed in young adult patients. Key clinical features include seizures (85%), headache (70%), fever (65%) and cortical symptoms referable to the FLAIR hyperintense location (55%) and 95% subjects satisfied at least two findings, like our patient, although she remained seizure-free. At present, none of the reviewed patients in literature with anti-MOG antibody negative presented FLAMES. CSF usually discloses pleocytosis and negative OCB. Although initially described as a unilateral cortical encephalitis, bilateral cortical involvement and possible meningeal inflammation cited may reflect a broader disease spectrum. The syndrome is highly steroid-responsive and the majority of cases showed a full recovery with IVMP, so early identification will lead to prompt treatment.

Final Comments: We described a case similar to FLAMES, a rare presentation of anti-MOG disease. Improved awareness about it is fundamental to guarantee correct diagnosis and institution of immunotherapy, particularly in more severe cases.

Publication History

Article published online:
12 May 2025