The concept of delirium has developed historically from the prototype of acute confusion with psychomotor agitation. While the modern view of delirium recognizes four core features (disturbance of consciousness, disturbance of cognition, limited course and external causation), their operationalization can produce a misleading picture of the most common manifestations of delirium in elderly people.

Alert to the diagnosis of delirium in elderly patients.

Review of relevant literature.

Delirium is a multifactorial syndrome, involving the interrelationship between patient vulnerability, predisposing factors at admission, and the noxious insults and aggravating factors during hospitalization. A significant proportion of elderly patients are either delirious on admission to hospital, or develop delirium at some point during their hospital stay. The clinic needs to be alert to the predisposing and precipitating factors, which have the potential to identify those at risk of delirium and to prevent it occurring, like age, sex, dementia, psychiatric disorders and physical illness. Another important phase of assessment is the differential diagnosis that includes most other organic and functional psychiatric disorders (but it's necessary to remember that their presence does not exclude the possibility that the subject is delirious as well), especially depression, dementia or dysphasia due to a cerebrovascular accident.

Complications arising from the delirious state in elderly patients prolong hospital admission and contribute to adverse functional outcomes, notably increased dependency and higher rates of institutionalization.