Age-dependent Changes of Cerebral Ventricular Size, Part I: Review of intracranial fluid collections

Abstract

The medical literature was reviewed to ascertain the age distributions for the incidence of communicating hydrocephalus, slit-ventricle syndrome, pseudotumor cerebri, and chronic subdural hematoma. The incidence of each appeared to be age-related: hydrocephalus and chronic subdural fluid collections predominated in children less than two years of age and adults older than 55 years, while slit-ventricle syndrome and pseudotumor cerebri occurred mainly in children older than two years and young adults. In the presence of decreased cerebrospinal fluid absorption, patients in the latter age category show a greater resistance to the development of ventriculomegaly. The brains of the very young and the elderly more readily give way to expanding collections of fluid within the ventricles or the subdural space. In the neonatal stage the cranial sutures are open, thus readily allowing intracranial expansion. During the first two to four years of life the brain water content decreases, glial cell composition matures, axonal myelination increases, and cranial sutures close. This corresponds to the age at which the ventricular system resists expansion. With aging after fifth to sixth decades there is gradual brain atrophy. The enlarging ventricles and subarachnoid spaces yield more readily to expanding fluid collections in accordance with the principles of LaPlace’s law.