Late-onset neuromyelitis optica spectrum disorder mimicking a non-arteritic anterior ischemic optic neuropathy – case report

A 60-year-old Caucasian female presented to the emergency department with painless decrease of the visual acuity of the left eye (LE). The diagnosis of a non-arteritic anterior ischaemic optic neuropathy (NAION) in the LE was established on the clinical picture and the results of static perimetry, fluorescein angiography (FA), visual evoked potential (VEP), and magnetic resonance imaging (MRI) of the brain and orbit.

6 months later, the woman reported visual impairment in the right eye (RE). The best-corrected visual acuity (BCVA) in the RE was 5/10. Gadolinium-enhanced MRI (GD-MRI) showing inflammation of both optic nerves and the optic chiasm in correlation with positive results of IgG antibody against aquaporin 4 (AQP4) allowed the diagnosis of LO-NMOSD. The large-dose intravenous methylprednisolone therapy followed by oral tapering was applied, and an oral azathioprine treatment was started to reduce the risk of further relapse. At discharge, the BCVA was 5/5 in the RE. The patient remains under the care of neurological and ophthalmological clinics, with no recurrences for two years.

The possibility of NMOSD-ON in older patients is important in the differential diagnosis of ischaemic optic neuropathy.