Delirium and agitation at the end of life.

Delirium is the abrupt onset of fluctuating confusion, inattention, and reduced awareness of the environment. Symptoms can affect different areas of cognition (memory, orientation, language, visuospatial ability, or perception) and may include hallucinations and disturbances in the sleep-wake cycle (box 1). Delirium can therefore be distressing to people who experience it and those around them.Delirium is classified into hyperactive (restlessness and agitated behaviour predominate), hypoactive (drowsiness and inactivity predominate), and mixed subtypes. The more subtle changes associated with the hypoactive form are often missed.