Unilateral Internuclear Ophthalmoplegia in a 14-year-old Female

Abstract

Purpose: Internuclear ophthalmoplegia (INO) is an eye movement disorder caused by a lesion of the medial longitudinal fasciculus. It typically manifests bilaterally and is commonly caused by multiple sclerosis. We report a case of pediatric unilateral INO, which is rare in the pediatric population.Case summary: A 14-year-old female, with a history of traumatic head injury 9 days previously, presented with diplopia, nausea and vomiting for the past 5 days. Her ophthalmic examination revealed severely impaired adduction of the right eye and abduction nystagmus in the left eye. Orbital computed tomography showed no evidence of orbital wall fracture or muscle impingement. However, an magnetic resonance imaging of her brain demonstrated an infarct in the right paramedian midbrain, leading to a diagnosis of unilateral INO. Diplopia and impaired adduction of the right eye resolved completely 7 weeks after the trauma.Conclusions: Demyelinating diseases, such as multiple sclerosis, account for most of the pediatric INO cases. Although most of these cases are bilateral, this reports highlights a pediatric case of unilateral INO following head injury, which is an uncommon occurrence in this age group.