• Definition
    • Delirium is sudden severe confusion due to rapid changes in brain function that occur with physical or mental illness.

  • Alternative Names
    • Acute confusional state; Acute brain syndrome

  • Causes
    • Delirium is most often caused by physical or mental illness, and is usually temporary and reversible. Many disorders cause delirium. Often, these do not allow the brain to get oxygen or other substances. They may also cause dangerous chemicals (toxins) to build up in the brain.

      Causes include:

  • Symptoms
    • Delirium involves a quick change between mental states (for example, from lethargy to agitation and back to lethargy).

      Symptoms include:

      • Changes in alertness (usually more alert in the morning, less alert at night)
      • Changes in feeling (sensation) and perception
      • Changes in level of consciousness or awareness
      • Changes in movement (for example, may be slow moving or hyperactive)
      • Changes in sleep patterns, drowsiness
      • Confusion (disorientation) about time or place
      • Decrease in short-term memory and recall
      • Disorganized thinking, such as talking in a way that doesn't make sense
      • Emotional or personality changes, such as anger, agitation, depression, irritability, overly happy
      • Incontinence
      • Movements triggered by changes in the nervous system
      • Problem concentrating
  • Exams and Tests
  • Treatment
    • The goal of treatment is to control or reverse the cause of the symptoms. Treatment depends on the condition causing delirium. The person may need to stay in the hospital for a short time.

      Stopping or changing medicines that worsen confusion, or that are not necessary, may improve mental function.

      Disorders that contribute to confusion should be treated. These may include:

      Treating medical and mental disorders often greatly improves mental function.

      Medicines may be needed to control aggressive or agitated behaviors. These are usually started at very low dosages and adjusted as needed.

      Some people with delirium may benefit from hearing aids, glasses, or cataract surgery.

      Other treatments that may be helpful:

  • Outlook (Prognosis)
    • Acute conditions that cause delirium may occur with chronic disorders that cause dementia. Acute brain syndromes may be reversible by treating the cause.

      Delirium often lasts about 1 week. It may take several weeks for mental function to return to normal. Full recovery is common, but depends on the underlying cause of the delirium.

  • Possible Complications
    • Problems that may result from delirium include:

      • Loss of ability to function or care for self
      • Loss of ability to interact
      • Progression to stupor or coma
      • Side effects of medicines used to treat the disorder
  • When to Contact a Medical Professional
  • Prevention
    • Treating the conditions that cause delirium can reduce its risk. In hospitalized people, avoiding or using a low dosage of sedatives, prompt treatment of metabolic disorders and infections, and using reality orientation programs will reduce the risk of delirium in those at high risk.

  • References
    • Irwin SA, Pirrello RD, Hirst JM, Buckholz GT, Ferris FD. Clarifying delirium management: practical, evidenced-based, expert recommendations for clinical practice. J Palliat Med. 2013;16:423-435. PMID: 23480299

      Mendez MF, Padilla CR. Delirium. In: Daroff RB, Jankovic J, Mazziotta JC, Pomeroy SK, eds. Bradley's Neurology in Clinical Practice. 7th ed. Philadelphia, PA: Elsevier; 2016:chap 4.

      Smith JP, Seirafi J. Delirium and dementia. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 8th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 104.