[Delirium in the elderly].

Delirium in the elderly is common but unfortunately underdiagnosed. The consequences could be significant such as an increase of the mortality in the hospital, loss of autonomy and increased risk to be institutionalized. The presentation of the delirium could be hyperactive, hypoactive or mixed. The predisposing and precipating factors are well known. The physiopathology is not yet well defined but the inflammation and the neuromediators are involved. It is important to develop primary and secondary prevention, but also to propose a follow in memory clinics for all elderly people who having suffered from delirium during hospitalization because a confusional state could be the first step towards future dementia.