FLAIR-hyperintense lesions in anti-MOG-associated encephalitis with seizures (FLAMES) unmasked by withdrawal of immunosuppression for Crohn's disease?

A 31-year-old pregnant woman presented with headache, fever and left-sided focal motor seizures, which progressed to bilateral tonic-clonic seizures. Her medical history included Crohn's disease treated with azathioprine and adalimumab, which were discontinued when she became pregnant. Her cerebro-spinal fluid was entirely normal and viral PCR negative. Extensive testing for infectious, autoimmune or malignant causes of encephalitis were non-revealing. MRI head showed unilateral cortical FLAIR-hyperintensity which on interval scans was seen bilaterally. Anti-myelin-oligodendrocyte glycoprotein (MOG)-IgG was positive leading to a diagnosis of cortical FLAIR-hyperintense lesions in Anti-MOG-associated Encephalitis with seizures (FLAMES).

Automated summary

A 31-year-old pregnant woman presented with headache, fever, and seizures, which were diagnosed as cortical FLAIR-hyperintense lesions in Anti-MOG-associated Encephalitis with seizures (FLAMES). Extensive testing did not reveal any infectious, autoimmune, or malignant causes of the encephalitis.