Paramedian Midbrain Infarction Presenting with Bilateral Ptosis and Unilateral Median Longitudinal Fasciculus Syndrome: A Peculiar Midbrain Syndrome.

We report a case of bilateral ptosis due to paramedian midbrain infarction, which was associated with ipsilateral impaired adduction of the eye and contralateral ataxia. T2-weighted magnetic resonance imaging of the brain revealed a right paramedian midbrain infarction. The ptosis rapidly improved without a difference between the left and right sides, while the other symptoms mostly resolved within a month following treatment with antiplatelet agents and rehabilitation. An infarction of the paramedian dorsocaudal portion of the midbrain can involve both the central caudal nucleus and the median longitudinal fasciculus (MLF), causing a peculiar combination of symptoms, bilateral ptosis, and unilateral MLF syndrome.