[Cofeeman]

Delirium is a common and severe neuropsychiatric syndrome with core features of acute onset and fluctuating course, attentional deficits and generalized severe disorganization of behavior. It typically involves other cognitive deficits, changes in arousal (hyperactive, hypoactive, or mixed), perceptual deficits, altered sleep-wake cycle, and psychotic features such as hallucinations and delusions. It is often caused by a disease process outside the brain, such as infection (UTI, pneumonia) or drug effects, particularly anticholinergics or other CNS depressants (benzodiazepines and opioids). Although hallucinations and delusions are sometimes present, these are not required for the diagnosis, and the symptoms of delirium are clinically distinct from those induced by psychosis or hallucinogens (with the exception of deliriants.)

Peripheral Visual Distortion - resulting in perception imbalance most often described as a sensation of precieving bystanders on ones periphery.

Delirium may be caused by physical illness, which can be mild, or any process which interferes with the normal metabolism or function of the brain. For example, electric shock, fever.

Disturbance of consciousness (that is, reduced clarity of awareness of the environment, with reduced ability to focus, sustain, or shift attention)

Change in cognition (e.g., problem-solving impairment or memory impairment) or a perceptual disturbanceOnset of hours to days, and tendency to fluctuate.