Adult communicating hydrocephalus.

In patients with the triad of gait disorder, dementia, and incontinence and, in addition, a predisposing cause for the ventriculomegaly demonstrated on a CT scan and no mass, a shunt should be carried out. In cases in which there is no known aetiology for the ventricular enlargement, the cerebral sulci are widened, or the complete triad is not present, I would monitor intracranial pressure for 24--48 hours. It remains to be seen whether further quantification of the CT scan will supplant the need for intracranial pressure monitoring. Brain biopsy is not routinely performed. Many basic as well as clinical questions remain to be answered. For example, it is by no means certain that the natural history of NPH is one of progressive deterioration--some patients appear to remain stable (Hughes et al, 1978). An offer to carry out a shunt is made immediately on diagnosis in the belief that any deterioration that occurs through delay may not be reversible. Furthermore, how can patients with NPH who present with an atypical picture be identified (Crowell et al, 1973; Rice and Gendelman, 1973; Sypert et al, 1973)? Unfortunately, more liberal provision of CT scanning services will be required to tackle these problems. For the present we must be content with more detailed clinical analysis of these patients and a controlled trial to determine the best method of carrying out shunts.