Communicating hydrocephalus as a cause of aqueductal stenosis

Abstract

Eleven cases of presumed aqueductal stenosis with onset of symptoms after the first decade were reviewed. Ten patients had complete occlusion and one a high-grade stenosis. In 10, the dilated lateral ventricles caused a marked inferior displacement of the third ventricle. Postshunting diagnostic studies on six of these patients revealed ascent of the third ventricle, and in three of these the aqueduct was shown to be patent. It appears that in some cases of advanced communicating hydrocephalus the descending third ventricle kinks or pinches shut the aqueduct, adding an obstructive component which accelerates the clinical picture. The mechanism and clinical features of this process are discussed.

How should primary aqueductal stenosis in adults be treated? - A review

“…Another hypothesis (24) argues that AS is a secondary phenomena to an initially communicating hydrocephalus and results from a compression of the midbrain that obstructs the aqueduct (25)(26)(27).…”

Observations on the Activation of Chronic Compensated Hydrocephalus in Adult Patients

“…16) Knol et al 9) suggested a greater enlargement of the third than of the fourth ventricle is compatible with a CSF block not only intraventricular but also in the subarachnoid space. Nugent et al 12) reported even communicating hydrocephalus may cause a secondary occlusion of aqueduct. AS cannot explain all the triventriculomegaly and its diagnosis should be decided quite deliberately.…”

Advances and Technical Standards in Neurosurgery

“…Head trauma, a small subarachnoid hemorrhage or a viral infection with benign meningitis have all been claimed as anatomic causes of aqueductal stenosis decompensation (Cinalli et al 2004a, Jellinger, 1986, Lapras et al 1986. A functional mechanism might also contribute: progressive enlargement of the lateral and third ventricles would lead to a distortion of the brainstem and kinking of the aqueduct (Nugent et al 1979, Raimondi et al 1976). …”