Myelin Oligodendrocyte Glycoprotein Optic Neuritis Presenting in Late Pregnancy.

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated optic neuritis is a demyelinating disease that shares clinical overlap with Neuromyelitis Optica Spectrum Disorder (NMOSD) and Multiple Sclerosis (MS). The immunosuppressive effects of pregnancy followed by a rebound in the immune system postpartum are thought to affect presentation and relapse rates of NMOSD and MS. Few studies exist describing pregnancy affecting MOG antibody-associated disease. In this case, a 29-year-old female from Ethiopia presented on postpartum day 8 with 4 weeks of progressive, painful bilateral vision loss that had acutely worsened over the past 6 days. Her visual acuity was light perception in the right eye and hand motion in the left eye with a right afferent pupillary defect. Dilated exam revealed bilateral optic nerve head elevation, vascular tortuosity, and macular folds. MRI of the brain and orbits with contrast revealed long segment bilateral optic nerve enhancement and nonspecific white matter changes. Serum MOG IgG was positive (1:160). Her vision rapidly improved with intravenous methylprednisolone 1000 mg daily for 5 days, followed by an oral prednisone taper. After 6 months, the patient's vision returned to 20/20 in each eye, and she has had no further clinical relapse. This case suggests that initial presentation of MOG optic neuritis may be affected by pregnancy. Physicians must appropriately triage patients with postpartum vision changes to ensure prompt treatment.