Isolated nuclear oculomotor nerve syndrome due to mesencephalic hematoma.

Unilateral third nerve palsy with bilateral superior rectus paresis and bilateral ptosis is a typical condition for nuclear oculomotor nerve syndrome. We report a case of nuclear oculomotor nerve syndrome due to midbrain hemorrhage, as a rare cause. A 73-year-old man presented with an abrupt onset of double vision and difficulty opening his eyes. He had uncontrolled hypertension in his history. Neurological examination revealed right oculomotor palsy with impairment of bilateral upward gaze and bilateral ptosis. MRI showed a mesencephalic area of increased T1 signal and decreased T2 signal consistent with a subacute hematoma. It is emphasized that isolated mesencephalic hemorrhage may be the cause of the nuclear oculomotor nerve syndrome without associated neurological signs.