Miller-Fisher Syndrome Presenting with Bilateral Pseudo-Internuclear Ophthalmoplegia

Bilateral internuclear ophthalmoplegia (INO) refers to a specific gaze abnormality of bilateral adduction deficits, often accompanied by dissociated abducting nystagmus, caused by medial longitudinal fasciculus lesions usually due to multiple sclerosis or stroke. We report a 63-year-old man with clinical features of Miller-Fisher syndrome (MFS), consisting of ataxia, areflexia, and external ophthalmoplegia which mimicked bilateral-INO without an identifiable central lesion. Although bilateral adduction deficits are usually caused by central lesions, peripheral nervous damage by MFS is needed to be considered.