ABSTRACT
Delirium Delirium is characterised by disturbances of consciousness in addition to changes to attention, perception, thinking, memory, psychomotor behaviour, emotion and the sleep-wake cycle. It may occur at any age but is most common after the age of 60 years. Characteristically, it has a rapid onset with diurnal fl uctuations lasting less than 6 months. Symptoms include impairment to consciousness, ranging from general clouding of counsciousness to coma, and impairment to attention, with reduced ability to focus and shift attention, making patients easily distracted. There is also a global disturbance of cognition with short-term memory and recent memory impair ment but with preservation of remote memory. This often leaves the patient disorientated to time, place and person. Language is often affected with incoherent speech and impaired ability to understand. Other key features of delirium include perceptual distortions, ranging from misinterpretations and illusions to visual hallucinations, as well as psychomotor disturbances, ranging from under-to hyperactivity with an enhanced startle reaction. Delirious patients often suffer from mood disturbances, with bouts of depression, anxiety, irritability, euphoria and apathy as well as sleep-wake cycle disturbances ranging from disturbed sleep and insomnia to reversal of the sleep-wake cycle, including daytime drowsiness, disturbing dreams or nightmares.
