Abstract
A 66-year-old woman with angina pectoris was admitted to our hospital because of dizziness and right ptosis. She noticed those symptoms one hour after percutaneous transluminal coronary angioplasty. Neurological examination on admission revealed right ptosis, selective bilateral paralysis of downgaze, and bilateral cerebellar ataxia. Cranial routine diffusion and T2 weighted magnetic resonance imaging (MRI) with horizontal section on admission showed no abnormality in the brainstem. However, serial diffusion and T2 weighted MRI with coronal and horizontal section demonstrated a left paramedian infarction of lacunar size located in the caudal mesencephalon. Therefore, she was diagnosed as having a midbrain infarction and was treated with anti-platelet therapy. She was discharged on the 9th day as downward gaze palsy and cerebellar ataxia had disappeared on the 5th day. The present case suggests that only selective bilateral downward gaze palsy could be developed by a lesion of unilateral midbrain infarction.
