Radiological assessment of hydrocephalus: new theories and implications for therapy

Abstract

It is almost a century since Dandy made the first experimental studies on hydrocephalus, but its underlying mechanism has been unknown up to now. The conventional view is that cerebrospinal fluid (CSF) malabsorption due to hindrance of the CSF circulation causes either obstructive or communicating hydrocephalus. Analyses of the intracranial hydrodynamics related to the pulse pressure show that this is an over-simplification. The new hydrodynamic concept presented here divides hydrocephalus into two main groups, acute hydrocephalus and chronic hydrocephalus. It is still accepted that acute hydrocephalus is caused by an intraventricular CSF obstruction, in accordance with the conventional view. Chronic hydrocephalus consists of two subtypes, communicating hydrocephalus and chronic obstructive hydrocephalus. The associated malabsorption of CSF is not involved as a causative factor in chronic hydrocephalus. Instead, it is suggested that increased pulse pressure in the brain capillaries maintains the ventricular enlargement in chronic hydrocephalus. Chronic hydrocephalus is due to decreased intracranial compliance, causing restricted arterial pulsations and increased capillary pulsations. The terms "restricted arterial pulsation hydrocephalus" or "increased capillary pulsation hydrocephalus" can be used to stress the hydrodynamic origin of both types of chronic hydrocephalus. The new hydrodynamic theories explain why third ventriculostomy may cure patients with communicating hydrocephalus, a treatment incompatible with the conventional view.

Endoscopic Third Ventriculostomy in Obstructive Infantile Hydrocephalus: Remarks about the So-Called ‘Unsuccessful Cases’

“…The hydrodynamic hypothesis suggested by Greitz et al [51 ]and Greitz [52 ]considers, in addition to a pure bulk flow problem, the dynamic pulsatile nature of the CSF movement in concert with the venous and arterial pulsatility and the pulsatile movement of the brain itself. The hydrodynamic viewpoint could explain how, apart from the intraventricular interruption of CSF bulk flow, an obstruction of the intraventricular and extraventricular CSF spaces changes local and global compliance and in consequence, pulsatility patterns, which leads to a hydrocephalic condition [51,52].…”

“…The hydrodynamic viewpoint could explain how, apart from the intraventricular interruption of CSF bulk flow, an obstruction of the intraventricular and extraventricular CSF spaces changes local and global compliance and in consequence, pulsatility patterns, which leads to a hydrocephalic condition [51,52]. Future therapy of pediatric hydrocephalus could be improved when more detailed knowledge of the CSF flow routes and cerebral hydrodynamics is forthcoming.…”

Endoscopic Third Ventriculostomy in Prepontine-Suprasellar Tuberculoma with Tuberculous Meningitis Hydrocephalus: A Case Report

“…Tubercular exudates gradually disappear over a period of time with ATT. Removing CSF in patients with pathological intracranial pressure, mainly in the first few days, may improve the outcome [9,10,11,12,13]. Visudhiphan and Chiemchanya [7] have used acetazolamide and repeated lumbar puncture as a treatment modality for TBMH in children.…”

Finite element analysis of periventricular lucency in hydrocephalus: extravasation or transependymal CSF absorption?

“…44 Therefore, the enlargement of ventricles should be understood as a volumetric reduction of brain parenchyma. 10,11 This volumetric reduction is only possible by the outflow of interstitial fluid (ISF), which makes the change in the TPG the most plausible explanation for the ventricular enlargement in hydrocephalus. The change in the TPG can be due either to the increased ventricular CSF pressure or the abnormal absorption of CSF.…”