Background: Isolated internuclear ophthalmoplegia (INO) after traumatic brain injury (TBI) is rare, with most reported patients having minor head injuries. We report a patient with INO after a massive supratentorial epidural hematoma. We review the literature published since 1966, to summarize the mechanisms of injury and clinical outcomes of INO after TBI.
Case description and literature review: A 54-year-old woman had isolated INO 10 hours after emergent evacuation of a massive supratentorial epidural hematoma. The brainstem displacement caused by downward herniation led to a deficient blood supply. Magnetic resonance imaging showed an infarct at the right dorsal-medial pons. Her symptoms partially improved by 1.5 months postoperatively. A total of 27 patients, including ours, with INO after TBI have been reported over the past 50 years. Young male patients (mean age, 30.8 years; male, 67%) are more common, and INO tends to be bilateral (67%). Infarction, hemorrhage, and fiber injury are nearly equally responsible for causing INO (35%, 35%, and 30%, respectively). Most patients recover spontaneously; 65% gain full recovery at a median time of 3 months, and 91% have at least partial recovery at 4.5 months. The median time for full recovery after infarct, hemorrhage, and fiber injury is 12, 90, and 150 days, respectively.
Conclusions: INO should be in the differential diagnosis of patients with TBI with an adduction deficit, despite the rarity of the condition. Isolated INO is a relatively benign sequela of TBI, with all but 1 reported patient achieving at least partial recovery over 12 months.
Keywords: Brainstem infarction; Internuclear ophthalmoplegia; Medial longitudinal fasciculus; Traumatic brain injury.
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