Medical Definition of Delirium

Delirium: A sudden state of severe confusion and rapid changes in brain function, sometimes associated with hallucinations and hyperactivity, during which the patient is inaccessible to normal contact. Delirium can be due to a number of conditions, including infection, drug toxicity or withdrawal, seizures, brain tumor, poisoning, head injury, and metabolic disturbances.

Source: MedTerms™ Medical Dictionary
http://www.medicinenet.com/script/main/art.asp?articlekey=23364
Last Editorial Review: 5/13/2016