Cortical blindness: a rare feature of seropositive neuromyelitis optica

Abstract Background Neuromyelitis Optica (NMO) is an autoimmune neurological disorder affecting the central nervous system mainly the spinal cord and optic nerves. Typically, patients develop a severe optic neuritis and/or a longitudinally extensive transverse myelitis. Nevertheless, unusual presentation may occur especially related to lesions in brainstem or affecting large cerebral areas. Cortical blindness is very uncommon in NMO. Case presentation We report the case of a 65-year-old woman admitted to our department for acute-onset bilateral blindness followed by paraplegia and bowel dysfunction. On examination, she had a flaccid paraplegia with pyramidal syndrome and a sharp T6 sensory level. Her ophthalmological examination revealed a markedly reduced visual acuity with a normal anterior ocular segment and fundus examination and normal response to light. Brain and spine Magnetic Resonance Imaging showed large extensive lesions affecting both occipital lobes along with longitudinally extensive myelitis suggestive of NMO. The patient was positive for anti-aquaporin 4 antibodies. After IV methylprednisolone and plasmapheresis then oral corticosteroids and azathioprine, her visual acuity significantly improved but she was left with a spastic paraplegia. Conclusion visual impairment typically occurs in patients with NMO as part of an optic neuritis. However, in the presence of severe bilateral visual loss and the lack of signs of optic nerve damage, cortical blindness should highly be considered and Brain imaging should be performed in order to locate lesions within occipital lobes.