Oculomotor Nerve Palsy Presented with Isolated Unilateral Ptosis and Minimal Upgaze Palsy.

This case with unilateral complete blepharoptosis and slight limitation of upgaze as ocular findings due to midbrain infarction represents an unusual form of intra-axial oculomotor nerve involvement. A 65-year-old man was admitted with acute unilateral ptosis of the left eyelid and gait ataxia. He had chronic hypertension in the medical history. The neurologic examination revealed that he had a complete ptosis of the left eyelid, slight limitation of elevation in the left eye, bilateral dysmetria, and gait ataxia. Magnetic resonance imaging showed acute infarction in the central part of midbrain tegmentum. Previous models for arrangement of oculomotor fascicle in the midbrain suggest that a lesion involving the most caudal fibres for levator palpebrae and superior rectus without affecting other extraocular muscles and pupillomotor fibres is the most likely aetiology.