Structural, Ultrastructural, and Permeability Changes in the Ependyma and Surrounding Brain Favoring Equilibration in Progressive Hydrocephalus

Abstract

IT HAS recently been shown¹that following effective obstruction of the fourth ventricle and caudal aqueduct, hydrocephalus develops as an acute, rapidly progressive process. The initial rate of progression is precipitous, and within a few hours the hydrocephalic changes are advanced. Thereafter, the rate of ventricular enlargement slows abruptly and continues to decrease until a moderate, stable, and chronically progressive rate is established. Within hours of complete ventricular obstruction, a number of changes, developing in response to acute ventricular enlargement, are seen in the ependyma and surrounding brain.²The changes are severe and are probably accompanied by a diffuse alteration in the permeability of the ventricular surface.³It was noted that once these changes are well established, the rate of ventricular enlargement slows perceptibly. The current paper reports some further observations on the structural and permeability changes of the ventricular surface in acute obstructive hydrocephalus. The