[Delirium in older patients: clinical presentation and diagnosis].

Abstract Delirium is a mental disorder characterized by acute onset, fluctuating course and disturbances in consciousness, orientation, memory, thought, perception and behavior. This disorder occurs in hyperactive, hypoactive or mixed forms in up to 50% of older hospital inpatients, many with pre-existing dementia, and is independently associated with poor outcomes. Despite its clinical importance, delirium is often undetected or misdiagnosed as dementia or other psychiatric illnesses such as depression. The use of protocols to identify patients at high risk of delirium, systematic assessment of mental status in all older inpatients by healthcare professionals and the use of DSM-IV criteria may improve detection and diagnosis. Similar strategies may improve the detection and diagnosis of subsyndromal delirium.