Dementia, gait disturbance, incontinence and hydrocephalus.

Normal pressure hydrocephalus is frequently emphasised as a cause of reversible dementia, but is seldom encountered. Over a 2 year period, 5 patients presented with cognitive decline, and gait disturbance, with or without incontinence. CT head examination revealed hydrocephalus. Although none had symptoms of raised intracranial pressure on initial presentation, there were clinical or CT signs of raised intracranial pressure in 4 of the 5. Underlying pathologies were meningeal lymphocytic lymphoma, idiopathic meningeal fibrosis, periaqueductal glioma, basilar aneurysm and basilar invagination. All patients responded to the insertion of a shunt. Over the same period, only 1 patient was shunted for idiopathic normal pressure hydrocephalus, without improvement. We challenge the concept of idiopathic normal pressure hydrocephalus as a cause of cognitive deterioration.