Six Year Old With Chronic Headache: An Unexpected Meningitis Mimic.

The constellation of fevers accompanied by headache and vomiting is a red flag for clinicians that appropriately triggers evaluation for meningitis and other life-threatening diagnoses. When symptoms persist even after these conditions are ruled out, patient care becomes more challenging. We present the case of a 6-year-old male with a history of autism spectrum disorder who presented with 6 months of headaches and associated vomiting and intermittent fevers with negative infectious workup despite cerebrospinal fluid pleocytosis. Serial neuroimaging and laboratory evaluation ultimately led to a diagnosis of myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) presenting as aseptic meningitis. The clinical and radiographic findings of MOGAD are widely variable and overlap with several other inflammatory conditions, which makes diagnosis challenging. This case highlights the importance of recognizing this rare MOGAD presentation as an infectious meningitis mimic.