[Chronic hydrocephaly in adults. A diagnostic and therapeutic challenge]

To describe the main clinical features of the different conditions which present as chronic hydrocephaly, emphasising the diagnosis and treatment.

In the study of any dementia syndrome, normotensive hydrocephaly (HN) is of particular interest since this condition may be treated and cured. However, prediction of which cases will benefit from surgery is one of the most important aspects of diagnosis. The development of paraclinical investigations of the dynamics of cerebrospinal fluid (CSF) has led to great advances in the management of these chronic forms of hydrocephaly, since they are the best parameters for prognosis when deciding whether to insert a by pass. The treatment of post traumatic hydrocephaly has also benefited from these studies, since the cases of simple atrophy may now be distinguished from those which follow a clinical course similar to HN. Recently, two types of hydrocephaly have been identified as being very different from the typical forms. These are external hydrocephaly, in which CSF accumulates in the convexity of the cerebral hemispheres, and long term ventriculomegaly, in which severe ventricular dilation is accompanied by cognitive alterations and features of acute hydrocephaly.

Treatment of each of these conditions is a challenge. Therefore careful analysis of the clinical features, imaging studies and CSF dynamics is essential when deciding whether or not to use by pass treatment.