• Clinical science



Delirium is a neurocognitive disorder characterized by impaired attention, awareness (reduced orientation to the environment), and other disturbed cognitive functions (e.g., memory, language, or perception). Symptoms develop acutely and tend to fluctuate throughout the day. Delirium occurs as a direct physiological consequence of another medical condition. It is most often a complication of polypharmacy, especially in elderly patients, and is also commonly seen in patients admitted to the ICU. Although delirium is a reversible confusional state, it warrants urgent medical attention because it may be the first sign of serious underlying disease. Treatment of delirium focuses on treating the underlying illness and reducing exposure to exacerbating factors. Antipsychotic medications are used for the treatment of agitation in delirious patients.


I WATCH DEATH: Infection, Withdrawal, Acute metabolic disorder, Trauma, CNS pathology, Hypoxia, Deficiencies, Endocrine, Acute vascular, Toxins/drugs, and Heavy metals are the major causes of delirium.

Clinical features

  • The main symptom is an acute (hours to days) alteration in the level of awareness and attention.
  • Other features may include:
    • Disorganized thinking
    • Illusions
    • Hallucinations (mostly visual)
    • Cognitive deficits (e.g., memory)
    • Reversal of the sleep-wake cycle
    • Emotional lability
    • Agitation, combativeness
    • Alterations in psychomotor activity may occur.
  • The severity of symptoms fluctuates throughout the day and worsens in the evening (termed sundowning).
  • Symptoms are reversible; their duration and severity depend on the underlying illness.
  • Delirium is commonly described based on the type of alteration that is seen:
Psychomotor activity Patient groups
Mixed type delirium Fluctuates or stays at baseline Most common type in the general population
Hypoactive delirium Decreased Most common type in the elderly population
Hyperactive delirium Increased (agitation) Usually seen in delirium due to substance use or substance withdrawal


Differential diagnoses

In older patients, it is important to differentiate delirium from dementia.

Delirium vs. dementia
Delirium Dementia
  • Insidious
  • Rapid and fluctuating
  • Hours to days
  • Slowly progressive deterioration
  • Months to years
Level of consciousness
  • Decreased
  • Intact
  • Impaired (fluctuating)
  • Usually alert
  • Impaired in the advanced phase
  • Recent, then remote memory loss
Thought process
  • Disorganized
  • Impoverished
  • Present (often visual or tactile)
  • Can be present in advanced disease
Psychomotor activity
  • Increased or decreased
  • Usually normal
  • Usually abnormal
  • Usually normal
  • Reversible
  • Usually irreversible

The differential diagnoses listed here are not exhaustive.


  • Identify and treat the underlying cause (e.g., discontinue causative medications such as anticholinergics)
  • Supportive medical care
    • Manage agitation initially with nonpharmacologic strategies (see “Prevention” below).
    • Administer antipsychotics if the patient is agitated and/or poses harm to themselves or others.
    • Initiate cognitive stimulation therapy to improve cognitive function.
    • Reduce pain, preferably with nonopioid medications.
    • Prevent aspiration, incontinence, and skin breakdown.

Benzodiazepines are deliriogenic. Do not treat delirious patients with benzodiazepines unless the delirium is due to alcohol or benzodiazepine withdrawal, in which case haloperidol is contraindicated because it lowers the seizure threshold!


  • Nonpharmacologic approach
    • Reduce exposure to modifiable risk factors.
    • Reorient the patient regularly.
      • Keep a clock and/or calendar near the patient to help with orientation.
      • Provide visual and hearing aids for patients with impairments.
    • Reduce the amount of noise, procedures, and medication administration occurring at night.; (because delirium more frequently occurs and worsens at night, uninterrupted sleep is important for both prevention and management of delirium)
    • Arrange for regular visits from family and friends.
    • Arrange for constant observation, preferably by a family member or friend.
    • Provide physical and occupational therapy to mobilize the patient as soon as possible.
    • Minimize the use of physical restraints as much as possible.
  • Pharmacologic [3]
  • 1. Ganti L, Kaufman MS, Blitzstein SM. First Aid for the Psychiatry Clerkship. McGraw Hill Professional; 2016.
  • 2. Ropper A, Klein J, Samuels M. Adams and Victor's Principles of Neurology 10th Edition. McGraw-Hill Education / Medical; 2014.
  • 3. Fong TG et al. Delirium in elderly adults: diagnosis, prevention and treatment. Nature Reviews Neurology. 2009; 5(4): pp. 210–220. doi: 10.1038/nrneurol.2009.24.
last updated 10/12/2020
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