Non-communicating hydrocephalus due to megadolichobasilar artery--case report.

A 72-year-old female presented with non-communicating hydrocephalus due to megadolichobasilar artery manifesting as drowsiness and Parinaud's sign. Neuroimaging demonstrated enlarged third and lateral ventricles and the tortuous, elongated basilar artery compressing the interpeduncular segment of the midbrain, resulting in occlusion of the aqueduct. Emergency ventricular drainage subsequently replaced by a ventriculoperitoneal shunt achieved complete resolution of the enlarged ventricles. This is the first report of megadolichobasilar artery causing this type of obstruction and manifesting as rapidly progressive hydrocephalic symptoms.