Pediatric multiple sclerosis revealed by severe optic neuropathy: clinical observation and literature review

Pediatric multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system, rare before adolescence and often presenting with atypical features. We report a rare and severe inaugural case revealed by unilateral optic neuropathy. A 15-year-old girl with no significant medical history presented with sudden right-eye vision loss evolving over less than twelve hours, without pain on eye movement. She also reported bilateral hand paresthesia, without motor or sphincteric symptoms. Neurological examination showed complete right-eye blindness. Ophthalmological evaluation confirmed loss of vision and visual field on the right, while the left eye retained 9/10 visual acuity with a normal fundus. Macular OCT was normal. Brain MRI revealed multiple periventricular and subcortical demyelinating lesions, some enhancing after contrast injection, and a hyperintense lesion at the upper cervico-dorsal level (C2–C4). Cerebrospinal fluid analysis showed an inflammatory profile with oligoclonal bands, indicating intrathecal IgG synthesis, while autoimmune screening was negative. Visual evoked potentials demonstrated bilateral conduction abnormalities, consistent with recent demyelinating optic neuropathy, predominant on the right. Anti-MOG and anti-AQP4 antibodies were negative. Treatment with intravenous methylprednisolone (1 g/day for 5 days) led to partial visual recovery, notably improved color perception. This case illustrates a rare and severe inaugural form of pediatric MS revealed by unilateral optic neuropathy. Differential diagnosis with neuromyelitis optica (NMO) and MOG-antibody-associated disease (MOGAD) remains crucial. Early diagnosis and rapid immunomodulatory treatment are key to preventing long-term visual and neurological disability.