Status MOGanosus: A Case of Cerebral Cortical Encephalitis-related MOGAD Mimicking Hemiplegic Migraine
Background:
Cerebral cortical encephalitis (CCE) is a rare phenotype of myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) distinguished by radiographic findings of cortical T2/FLAIR hyperintensity on brain MRI. These findings may overlap with other neurological conditions making initial diagnosis challenging. We describe a unique case of unilateral cerebral encephalitis mimicking radiographic and clinical findings of hemiplegic migraine.
Results:
A 17-year-old female with history of migraine headaches presented for 2 weeks of severe headache and new-onset left hemiparesis following accidental ingestion of 14 sumatriptan tablets. Emergent neuroimaging revealed no diffusion restriction but right supra-tentorial hemispheric cortical thickening on T2/FLAIR and increased vascular enhancement and hyper-perfusion, highly suspicious for hemiplegic migraine. Given recent upper respiratory infection, additional serology and CSF studies were obtained. CSF analysis showed pleocytosis, raising the suspicion for encephalitis. Her left extremity hemiparesis resolved within 24 hours, though she still had persistent headaches and was discharged with amitriptyline and close follow-up. Serological studies later revealed Mycoplasma pneumonia IgM and IgG antibodies positivity and positive MOG serum antibody with titer of 1:160. She was re-admitted for persistent headache and given a 3-day high dose methylprednisolone with prednisone taper, with complete resolution. Whole genome sequencing was negative for CADISIL and familial hemiplegic migraine. The presentation was consistent with CCE likely triggered by Mycoplasma pneumonia infection.
Conclusions:
There were multiple factors confounding the initial diagnosis. While sumatriptan overdose may produce transient neurological deficits, it is less commonly associated with imaging findings such as cerebritis. Hemiplegic migraine may show cortical swelling on T2/FLAIR sequencing making it difficult to distinguish from CCE. In our case, the history of recent infection and normal genetic testing lowered the suspicion for hemiplegic migraine. Thus, we emphasize the importance of considering CCE related to MOGAD in the differential for patients presenting with persistent headaches and unilateral neurological deficits.
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