A state of acute mental confusion often brought on by a physical illness. Symptoms usually vary according to environment, personality and the severity of the illness. Affected persons may fail to understand events or remember what has happened; have mood swings, hallucinations, panic and restlessness. Fever and disturbances of body chemistry are common contributory factors.
Older people and children are more susceptible to delirium than any other age group, especially as a result of infection, when there is pre-existing brain disturbance and following surgery. Alcohol, drugs and poisons are frequent precipitants.