Bilateral Optic Neuritis in Paediatric Acute Disseminated Encephalomyelitis: A Case Report of Clinical Challenges and Management Outcomes.

Paediatric optic neuritis is a rare inflammatory demyelinating condition that frequently presents with bilateral involvement and a generally favourable prognosis compared to adult-onset forms. We report the case of a seven-year-old boy with a history of thalassemia trait and mild autism who presented with a one-day history of sudden bilateral painful vision fluctuation, headache, and fever. Initial visual acuity (VA) was 6/12 in the right eye and 6/30 in the left eye, with normal optic nerve function test and fundoscopic examination indicating retrobulbar involvement. While initial computed tomography (CT) imaging was unremarkable, urgent magnetic resonance imaging (MRI) of the brain and orbit revealed features consistent with inflammatory demyelinating disease. Extensive investigations, including cerebrospinal fluid (CSF) analysis and testing for myelin oligodendrocyte glycoprotein (MOG-IgG) and aquaporin-4 (AQP4-IgG) antibodies, were negative, suggesting a seronegative monophasic demyelinating event such as acute disseminated encephalomyelitis (ADEM) spectrum. The patient was treated with high-dose intravenous methylprednisolone (IVMP) followed by a six-week oral steroid taper, resulting in a rapid recovery of VA to 6/6 bilaterally. At the six-month follow-up, the patient remained asymptomatic with stable neuroimaging. This case highlights the critical role of early contrast-enhanced MRI in diagnosing paediatric retrobulbar optic neuritis and the effectiveness of prompt, aggressive corticosteroid therapy in achieving excellent visual outcomes in seronegative paediatric demyelinating disorders.