A Case of Optic Neuritis Concomitant with Pituitary Tumor During Pregnancy

Optic neuritis (ON) is unilateral painful optic nerve inflammation in a young healthy female diagnosed by excluding glaucoma. ON onset during pregnancy is rare, with only 2 cases reported to date.

A 35-year-old previously healthy parous woman who was pregnant with her second child suffered rapidly progressive visual acuity loss. Magnetic resonance imaging (MRI) revealed a pituitary tumor. Emergency surgery was performed for optic nerve compression; however, her visual impairment worsened. Postoperative diffusion-weighted MRI showed high intensity in the bilateral optic nerves, and ON was diagnosed. Administration of methylprednisolone was effective, and her visual acuity recovered over 6 months.

Associated pituitary macroadenoma complicated the true diagnosis of ON, because contrast medium cannot be used in pregnant women. The diffusion-weighted MRI findings were useful for diagnosing this complex clinical condition.