Levodopa effective parkinsonism associated with aqueductal stenosis: a case report and review of the literature.

A case of aqueductal stenosis (AS) associated with marked parkinsonism is described. A ventriculoperitoneal (V-P) shunt was performed in an 18-year-old female because of hydrocephalus associated with non-neoplastic aqueductal stenosis. The patient developed acute parkinsonism with Parinaud's sign after the shunt revision. She had a marked response to levodopa and the parkinsonism improved. Subsequently, levodopa therapy was gradually discontinued without any manifestation of parkinsonism. The pathophysiology of this type of parkinsonism probably involved presynaptic dopaminergic dysfunction. However, the etiology of this complication has not been confirmed.