Minor head trauma and isolated unilateral internuclear ophthalmoplegia.

Internuclear ophthalmoplegia is a syndrome that develops due to a lesion of the medial longitudinal fasciculus. This lesion is mostly caused by multiple sclerosis (usually bilaterally), and only rarely by head injury. A case is presented of unilateral internuclear ophthalmoplegia as an isolated sequel of minor head trauma, which eventually resolved. A 40-year-old woman with isolated internuclear ophthalmoplegia secondary to closed head trauma with anatomical lesions of the mesencephalon in the region of medial longitudinal fasciculus is described. A minor contusion was detected by magnetic resonance imaging. Diplopia resolved in 5 months. In conclusion, internuclear ophthalmoplegia should be considered in the differential diagnosis in patients with recent head injuries showing adduction impairment. The connection between the clinical picture and anatomical lesions is visualized by magnetic resonance imaging.