> Table of Contents > Delirium
Whitney A. Gray, CRNP
Katrina A. Booth, MD
image BASICS
  • A neurologic complication of illness and/or medication(s), especially common in older patients, manifested by new confusion and impaired attention
  • A medical emergency requiring immediate evaluation to decrease morbidity and mortality
  • System(s) affected: nervous
  • Synonym(s): acute confusional state, altered mental status, organic brain syndrome, acute mental status change
  • Predominant age: older persons
  • Predominant sex: male = female
  • >50% in older ICU patients
  • 11-51% in postoperative patients
  • 10-40% in hospitalized older patients
  • 8-17% in older ED patients
  • 14% in older postacute care patients
  • Multifactorial: believed to result from a decline in physiologic reserves with aging, resulting in a vulnerability to new stressors
  • Neuropathophysiology is not clearly defined; cholinergic deficiency, dopamine excess, and neuroinflammation are the leading hypotheses.
  • Often interaction between predisposing and precipitating risk factors
  • With more predisposing factors (i.e., frail patients), fewer precipitating factors are needed to cause delirium.
  • If few predisposing factors (e.g., very robust patients), more precipitating factors are needed to cause delirium.
  • Multicomponent approach addressing contributing factors can reduce incidence and complications.
  • Predisposing risk factors (1)
    • Advanced age, >70 years
    • Preexisting cognitive impairment
    • Functional impairment
    • Dehydration; high BUN:creatinine ratio
    • History of alcohol abuse
    • Malnutrition
    • Hearing or vision impairment
  • Precipitating risk factors
    • Severe illness in any organ system(s)
    • Environmental irritants (urinary catheter, restraints)
    • Polypharmacy (≥5 medications)
    • Specific medications, especially benzodiazepines, opioids (meperidine), and anticholinergics (diphenhydramine)
    • Pain
    • Any iatrogenic event
    • Surgery
    • Sleep deprivation
Follow treatment approach.
Multiple but most common are the following:
  • New medicine or medicine changes
  • Infections (especially lung, urine, and blood stream, but consider meningitis as well)
  • Toxic-metabolic (especially low sodium, elevated calcium, renal failure, and hepatic failure)
  • Heart attack or stroke
  • Alcohol or drug withdrawal
  • Preexisting cognitive impairment increases risk
Diagnosis is made using a careful history, behavioral observation, and cognitive assessment.
  • DSM-5 is the current standard; diagnostic criteria include (2):
    • Disturbance in attention and awareness
    • Change in cognition not due to dementia
    • Onset over short (hours to days) period and fluctuates during course of day
    • Evidence from history, exam, or lab that disturbance is caused by physiologic consequence of medical condition, intoxicating substance, medication use, or more than one cause
  • The confusion assessment method (CAM) is the most well-validated and tested clinical tool and has been adapted for ICU setting in adults (CAM-ICU) and children (pediatric CAM-ICU [pCAM-ICU]) (3)[B].
  • Comprehensive cardiorespiratory exam is essential.
  • Focal neurologic signs are usually absent.
  • Mini-mental state exam (MMSE) is the most wellknown and studied cognitive screen, but it may not be the most appropriate in an acute care setting; shorter cognitive screens have been studied in delirious patients (i.e., short blessed test [SBT], Brief Alzheimer's Screen [BAS], and Ottawa 3DY) and may be helpful if performed serially over time. Most patients will perform poorly if delirium is present; dementia cannot be diagnosed during delirium.
  • GI/GU exam for constipation/urinary retention
  • Depression (slow onset, disturbance of mood, normal level of consciousness, fluctuates weeks to months)
  • Dementia (insidious onset, memory problems, normal level of consciousness, fluctuates days to weeks)
  • Psychosis (rarely sudden onset in older adults)
Initial Tests (lab, imaging)
  • Guided by history and physical exam
    • CBC with differential
    • Comprehensive metabolic panel (CMP)
    • Urinalysis, urine culture, blood culture
    • Medication levels (digoxin, theophylline, antiepileptics where applicable)
  • Chest radiograph for most
  • ECG as necessary
  • Others, if indicated by history and exam
Follow-Up Tests & Special Considerations
  • If lab tests listed above do not indicate a precipitator of delirium, consider
    • Arterial blood gases
    • Troponin
    • Toxicology screen
    • Ammonia
    • Thyroid-stimulating hormone
  • Noncontrast-enhanced head CT scan if
    • Unclear diagnosis
    • Recent fall
    • Receiving anticoagulants
    • New focal neurologic signs
    • Need to rule out intracranial mass before lumbar puncture
Diagnostic Procedures/Other
  • Lumbar puncture (rarely necessary)
    • Perform if clinical suspicion of a CNS bleed or infection is high.
  • EEG (rarely necessary)
    • Consider after above evaluation if cause remains unclear or suspicion of seizure activity.
  • The best treatment is prevention (4)[A].
  • Addressing six risk factors (i.e., cognitive impairment, sleep deprivation, dehydration, immobility, vision impairment, and hearing impairment) in at-risk hospitalized patients can reduce the incidence of delirium by 33%.
  • Principles: Maintain safety, identify causes, and manage symptoms.
  • Stabilize vital signs and ensure immediate evaluation.
  • Postoperative patients should be monitored and treated for
    • Myocardial infarction/ischemia
    • Infection (i.e., pneumonia, UTI)
    • Pulmonary embolism
    • Urinary or stool retention (attempt catheter removal by postoperative day 2)
  • Anesthesia route (general vs. epidural) does not affect the risk of delirium.
  • ICU sedation-avoidance of benzodiazepines may reduce risk (5)[B].
  • Multifactorial treatment: Identify contributing factors and provide preemptive care to avoid iatrogenic problems, with special attention to
    • CNS oxygen delivery (attempt to attain):
      • SaO2 >90% with goal of SaO2 >95%
      • Systolic BP <2/3 of baseline or >90 mm Hg
      • Hematocrit >30%
  • P.263

  • Fluid/electrolyte balance
    • Sodium, potassium, and glucose normal (glucose <300 mg/dL in diabetics)
    • Treat fluid overload or dehydration.
  • Treat pain
    • Schedule acetaminophen (650 mg QID) if daily pain
    • Opioids alone (morphine) or in combination (oxycodone, hydrocodone) may be used for breakthrough pain.
  • Nonpharmacologic approaches are preferred for initial treatment, but medication may be needed for agitation management, especially in the ICU setting (6)[C].
  • Medications treat only the symptoms and do not address the underlying cause.
  • No medication is FDA approved for delirium.
  • Medications should not be used prophylactically.
First Line
  • Antipsychotics
    • Haloperidol (Haldol): initially, 0.25 to 0.5 mg PO/IM; reevaluate and potentially redose hourly. Critical care guidelines do not support use of antipsychotics for prevention of ICU delirium (5).
    • Quetiapine (Seroquel) 12.5 to 25 mg PO BID
    • Risperidone (Risperdal) 0.25 to 0.5 mg/day PO
  • Benzodiazepines should be avoided except in alcohol withdrawal or if patient taking at baseline because delirium could be a sign of withdrawal.
  • Lorazepam (Ativan): initially, 0.25 to 0.5 mg PO/IM/IV q6-8h; may need to adjust to effect (caution in patients with impaired liver function)
  • Contraindications: Avoid typical antipsychotics in patients with Parkinsonism or Parkinson disease.
  • Precautions: Typical antipsychotics may cause extrapyramidal effects; benzodiazepines may cause delirium. Both increase fall risk. Antipsychotics may prolong the QT interval.
Second Line
  • Olanzapine (Zyprexa) 2.5 to 5.0 mg/day PO
  • Multiple trials demonstrate adverse events with cholinesterase inhibitors in the management of delirium; evidence does not support their use.
Geriatric, psychiatric, or neurologic consultation is helpful if delirium is not easily explainable or resolving after full evaluation. Interprofessional team approach is best.
Early mobilization critical
  • Out of bed several hours daily starting on hospital day 2 (or postoperative day 1) if no contraindications
  • Daily therapy if not ambulating or functioning independently
General measures described earlier are also applicable to delirium prevention.
Admission Criteria/Initial Stabilization
New delirium is a medical emergency and requires admission, except in the setting of palliative home care.
IV Fluids
As needed for dehydration
  • Screen for development of delirium.
  • Assessment of precipitants/contributing factors (pain, constipation, urinary retention)
  • Reorient; maintain day/night orientation.
  • Institute skin care program and turning regimen for immobile patients.
  • Maintain and encourage mobility.
  • Encourage family presence and participation.
Discharge Criteria
  • Resolution of precipitating factor(s)
  • Safe discharge site if delirium is slow to resolve
  • If delirium at discharge, often needs postacute facility and ongoing assessment for resolution
  • If no delirium at discharge and going home, follow-up with primary care physician in 1 to 2 weeks
Patient Monitoring
  • Evaluate and assess mental status daily.
  • Continued evaluation for precipitating cause(s)
  • Liberalize diet to increase oral intake
  • Nutritional supplements (1 to 3 cans/day) if intake poor
  • Consider temporary nasogastric tube if unable to eat and bowels working.
  • May take weeks/months to fully resolve
  • Usually improves with treatment of underlying condition(s); can lead to chronic cognitive impairment
  • Delirium significantly increases a person's chance of dying even up to 1 year later.
1. Inouye SK, Westendorp RG, Saczynski JS. Delirium in elderly people. Lancet. 2014;383(9920):911-922.
2. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 5th ed. Arlington, VA: American Psychiatric Association; 2013.
3. van Eijk MM, van Marum RJ, Klijn IA, et al. Comparison of delirium assessment tools in a mixed intensive care unit. Crit Care Med. 2009;37(6):1881-1885.
4. Reston JT, Schoelles KM. In-facility delirium prevention programs as a patient safety strategy: a systematic review. Ann Intern Med. 2013;158 (5 Pt 2):375-380.
5. Kalabalik J, Brunetti L, El-Srougy R. Intensive care unit delirium: a review of the literature. J Pharm Pract. 2014;27(2):195-207.
6. Barr J, Fraser GL, Puntillo K, et al. Clinical practice guidelines for the management of pain, agitation, and delirium in adult patients in the intensive care unit. Crit Care Med. 2013;41(1):263-306.
Additional Reading
  • Inouye SK, Robinson T, Blaum C, et al. Amercian Geriatrics Society abstracted clinical practice guideline for postoperative delirium in older adults. J Am Geriatr Soc. 2015;63(1):142-150.
  • National Clinical Guideline Centre. Delirium: Diagnosis, Prevention, and Management. London, United Kingdom: National Clinical Guideline Centre; 2010.
  • Quinlan N, Marcantonio ER, Inouye SK, et al. Vulnerability: the crossroads of frailty and delirium. J Am Geriatr Soc. 2011;59(Suppl 2):S262-S268.
See Also
  • Dementia; Depression; Substance Use Disorders
  • Algorithm: Delirium
  • R41.0 Disorientation, unspecified
  • F19.931 Oth psychoactive substance use, unsp w withdrawal delirium
  • F10.231 Alcohol dependence with withdrawal delirium
Clinical Pearls
  • The CAM criteria for delirium are acute onset of fluctuating mental status, inattention, and either disorganized thinking or altered level of consciousness.
  • Hypoactive subtype of delirium can easily be missed.
  • Addressing six risk factors (i.e., cognitive impairment, sleep deprivation, dehydration, immobility, vision impairment, and hearing impairment) in hospitalized patients can reduce the incidence of delirium by 33%.
  • Delirium may not resolve as soon as the treatable contributors resolve; may take weeks or months
  • Avoid diphenhydramine and benzodiazepines in older patients. Nonpharmacologic measures are preferable as a sleep aid.