Sylvian Aqueduct Syndrome and Parkinsonism in Aqueduct Stenosis: Improvement in Global Rostral Midbrain Dysfunction Associated With Resolution of Abnormal Hyperintensity on MRI

Objective and Importance:Sylvian aqueduct syndrome (SAS) is associated with a complex clinical picture, which suggests global rostral midbrain dysfunction. Clinical Presentation:A 34-year-old woman developed SAS and Parkinsonism secondary to aqueductal stenosis and was treated by endoscopic third ventriculostomy (ETV) as an initial treatment, which led to the successful resolution of the symptoms. At admission, she exhibited only memory disturbance, slight cognitive impairment and urinary incontinence after recent childbirth. Magnetic resonance imaging (MRI) revealed aqueductal stenosis with the enlargement of the third and lateral ventricle with normal sized fourth ventricle. Several days later, the patient displayed upward gaze paralysis (Parinaud’s syndrome), Parkinsonian hands tremor, and somnolent confusional state. An MRI revealed abnormal intensity in the midbrain and upper pons as well as bulging of the posterior portion of the third ventricle. The dramatic resolution of the patient’s Parinaud’s syndrome, Parkinsonian tremor, and drowsy state after ETV was accompanied by the disappearance of the abnormal intensity in the midbrain and posterior bulging of the third ventricle. This characteristic change, which occurred simultaneously in both the clinical and MRI findings, revealed the lesion responsible for the SAS and Parkinsonism. A drastic change in the ventricular size or transtentorial pressure gradient might have also caused distortion and stretching of the midbrain. Conclusions:The simultaneous resolution of the clinical symptoms and abnormal MRI findings after ETV revealed the lesion responsible for this patient’s SAS and Parkinsonism. Early ETV allowed the reversal of the SAS and Parkinsonism and should be considered as the first-line treatment.