Unilateral Optic Neuritis in Children: Experience of a Tertiary Centre

Optic neuritis (ON) is an inflammation of the optic nerve that can be associated with a multitude of different systemic conditions and primary CNS disorders. In children, only around 25% of unilateral ON cases are considered idiopathic. Despite being considered a clinical diagnosis per se, neuroimaging plays a crucial role in the diagnostic pathway for these patients.

Demographic, clinical, and imaging data of all patients presenting with unilateral ON at a tertiary paediatric centre over 40 months (January 1, 2016, to April 30, 2019) were retrospectively analyzed.

A total of 10 patients filled the inclusion criteria. The average age of presentation was 14.1 years. Patients in this series had ON associated with multiple sclerosis (n = 2), anti-MOG demyelinating disorders (n = 2), and neuromyelitis optica with anti-AQP4 antibodies (n = 1). ON was determined to be secondary to Toxocara canis infection in 1 case and a side effect of anti-TNFα therapy (adalimumab) in another. MR imaging showed T2 hyperintensity and/or gadolinium enhancement of one of the optic nerves in all but 3 patients, and coincidently these were the cases with monophasic idiopathic ON (average follow-up period of 2 years). Additional brain MR findings directly contributed to the final diagnosis in half of the cases.

These cases are demonstrative of the wide range of possible causes of unilateral ON in the paediatric population. The absence of typical ON features in MR imaging was strongly suggestive of idiopathic ON in this cohort (p < 0.01).