Teaching NeuroImages: Bilateral optic neuritis: When to suspect anti-MOG antibodies.

A 6-year-old girl developed sudden onset painless loss of vision with swelling of both optic discs. Brain MRI demonstrated bilateral extensive optic nerve involvement with perineural enhancement (figure). Her vision recovered completely after treatment with IV methylprednisolone.1 Serum myelin oligodendrocyte glycoprotein (MOG) antibodies tested positive.