Etiology: unknown. Impairment of cerebral oxidative metabolism, excess release of dopamine. Dementia is leading risk of delirium, as well as pain and sleep deprivation.
Clinical Manifestations: hypo/hyperactivity, agitation, hallucinations, insomnia, loss of appetite, 2-3 day onset, 1-7 day duration up to months and years.
Diagnostic studies: Confusion Assessment Method (CAM). Diagnose and then find cause. Lab tests, physical exams, medication assessment, psychologic history, ECG, UA, basically every possible test.
Fix the underlying cause, delirium will go away and patient will go back to baseline.