Pathophysiology of long-standing overt ventriculomegaly in adults

Object. Long-standing overt ventriculomegaly in adults (LOVA) is a unique f orm of hydrocephalus that develops during childhood and manifests symptoms during adulthood. The aim of the present study was to analyze the specific pathophysiological characteristics of LOVA. Methods. The specific diagnostic criteria for LOVA include severe ventricul omegaly in adults that is associated with macrocephalus measuring more than two standard deviations in head circumference and/or neuroradiological evi dence of a significantly expanded or destroyed sella turcica. Twenty patien ts who fulfilled these criteria, 14 males and six females, were retrospecti vely studied. These patients' ages at diagnosis ranged from 15 to 61 years (mean 39.4 years). All had symptoms and/or signs indicating that hydrocepha lus first occurred at birth or during infancy in the absence of any known u nderlying disease. The authors performed a pathophysiological study that in cluded specific variations of magnetic resonance (MR) imaging, such as flui d-attenuated inversion recovery and cardiac-gated cine-mode imaging; intrac ranial pressure (ICP) monitoring; three-dimensional computerized tomography (CT) scanning; and other techniques. Hydrocephalus was caused by aqueductal stenosis in all patients. Severe ven triculomegaly involving the lateral and third ventricles was associated wit h a marked expansion or destruction of the sella turcica in 17 cases. Cardi ac-gated cine-MR imaging did not reveal any significant movements of cerebr ospinal fluid in the aqueduct. Three-dimensional CT ventriculography confir med that the expanded third ventricle protruded into the sella and, sometim es, extended a diverticulum. Fourteen patients revealed symptoms and signs that indicated increased ICP with prominent pressure waves. Dementia or men tal retardation was seen in 11 patients, gait disturbance in 12, and urinar y incontinence in eight; all three of these symptoms were observed in seven patients. Thirteen patients experienced visual disturbance. Nine patients underwent ventriculoperitoneal shunt implantation as the initial treatment, leading to postoperative subdural hematoma in all seven cases in which a d ifferential pressure valve was used. Nine patients, three of whom were init ially treated by shunt placement, underwent a neuroendoscopic procedure, ma inly for third ventriculostomy. Postoperatively, ICP returned to normal, an d marked to-and-fro pulsatile movements at the site of ventriculostomy were recognized on cine-MR imaging in patients treated endoscopically. However, the ventriculomegaly was little improved. Consequently, all patients event ually demonstrated improvement in response to either a shunt equipped with a pressure-programmable valve or an endoscopic procedure; however, depressi on appeared in six patients, who required psychiatric consultation or medic ation. Conclusions. Such remarkably decreased intracranial compliance but relative ly high ICP dynamics are the pathophysiological characteristics of LOVA. Th e therapeutic regimen should be determined based on the individual's specif ic pathophysiological makeup.