Bilateral internuclear ophthalmoplegia due to acute cervical hyperextension without head trauma.

A 58-year-old woman developed bilateral internuclear ophthalmoplegia, probable right oculosympathetic paresis (Horner's syndrome), and right facial dysesthesias with acute cervical hyperextension upon sustaining a rear-end automobile collision. There was no head trauma. A nuclear magnetic resonance scan revealed a discrete area of increased signal in the tegmentum of the pons to the left. Extensive recovery was noted 1 year later. The acute cervical hyperextension suggested acute shearing and stretching of axons from brain stem deceleration rather than transient vertebral artery ischemia. Internuclear ophthalmoplegia representing intracranial pathology without direct head trauma has not previously been described with acute cervical hyperextension injury.