Internuclear ophthalmoplegia after head trauma.

Internuclear ophthalmoplegia results from impairment of the medial longitudinal fasciculus. Multiple sclerosis is usually the cause in bilateral cases while a vascular lesion is commonly implicated in unilateral cases. Head trauma is a rare cause. We describe the case of a 52-year-old man who developed unilateral internuclear ophthalmoplegia following a head injury suffered in an automobile accident. Gradual improvement in the internuclear ophthalmoplegia occurred over a six-month follow-up period. Review of the literature reveals only ten previous reports of internuclear ophthalmoplegia secondary to head injury. In seven of these cases the internuclear ophthalmoplegia was the direct result of the trauma and in three it occurred only after subdural hematoma formation. These ten cases are summarized. Several theories for the pathophysiology of trauma-induced internuclear ophthalmoplegia are presented.