Wall-Eyed Bilateral Internuclear Ophthalmoplegia as an Early Presentation of Multiple Sclerosis

Wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) is a rare neuro-ophthalmological condition in which there is ocular motility impairment characterized by bilateral adduction deficiencies, bilateral abducting nystagmus, and exotropia in primary gaze, and is often associated with multiple sclerosis (MS). This report describes a young female who presented with sudden onset of binocular diplopia and alternating exotropia for two days duration, which was associated with a history of intermittent headaches for one year before presenting complaints. Examination revealed alternating exotropia on the primary gaze with bilateral limitation of adduction and bilateral nystagmus on abduction. Other ocular and neurological examinations were unremarkable. Neuroimaging showed multiple white matter lesions that were consistent with demyelinating disease. Her symptoms completely resolved after the initiation of intravenous corticosteroid therapy. However, she developed left upper limb numbness four months later, and a repeat magnetic resonance imaging (MRI) of the brain showed the presence of multiple new brain lesions. Subsequently, she was diagnosed with MS and started on immunotherapy. Her symptoms resolved, with no residual ophthalmoplegia or any neurological symptoms.