Delirium – Causes, Symptoms, Diagnosis, Treatment and Ongoing care



  • A neurologic complication of illness and/or medication(s) especially common in older patients
  • 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 high-risk older patients


  • 10% in older emergency room patients
  • 10–40% in hospitalized older patients
  • 25% in older post–acute care patients
  • Highest rates (>50%) in intensive care unit (ICU), post-hip fracture repair, post-cardiothoracic surgery

Risk Factors

  • Predisposing risk factors:
    • Advanced age
    • Prior cognitive impairment
    • Functional impairment
    • High blood urea nitrogen: Creatinine ratio
    • Dehydration
    • Malnutrition
    • Hearing or vision impairment
    • Frailty
  • Precipitating risk factors:
    • Severe illness in any organ system(s)
    • Need for a urinary catheter
    • >3 medications
    • Specific medications, especially long-acting sedative hypnotics (e.g., diazepam and flurazepam), narcotics (especially meperidine), and anticholinergics (especially diphenhydramine)
    • Pain
    • Any adverse iatrogenic event

General Prevention

Follow treatment approach.


  • Neuropathophysiology is not clearly defined; cholinergic deficiency is a leading hypothesis.
  • Multicomponent approach addressing contributing factors can reduce incidence and complications.


  • Usually multifactorial
  • Often interaction between predisposing and precipitating risk factors
  • With more predisposing factors (i.e., frail patients), fewer precipitating factors needed to produce delirium
  • If few predisposing factors (e.g., very robust patients), more precipitating factors needed to manifest delirium

Commonly Associated Conditions

Multiple, but most common are:

  • New medicine or medicine changes
  • Infections (especially lung and urine, but meningitis needs consideration as well)
  • Toxic-metabolic (especially low sodium, elevated calcium, renal failure, and hepatic failure)
  • Heart attack
  • Stroke
  • Alcohol or drug withdrawal
  • Preexisting cognitive impairment increases risk.

Delirium, Central nervous system, Intensive-care unit, hip fracture repair, blood urea nitrogen, flurazepam, meperidine, vision impairment, diphenhydramine, cognitive impairment, sedative,


  • The Confusion Assessment Method (CAM) may be used either pre- or post-hospital, or in hospital, and has been adapted for ICU setting (CAM-ICU).


  • Key diagnostic features of the CAM (1):
    • Acute change in mental status that fluctuates
    • Abnormal attention and either disorganized thinking or altered level of consciousness
  • Any of the following nondiagnostic symptoms may be present:
    • Short- and long-term memory problems
    • Sleep-wake cycle disturbances
    • Hallucinations and/or delusions
    • Emotional lability
    • Tremors and asterixis
  • Subtypes based on level of consciousness:
    • Hyperactive delirium (15%): Patients are loud, rambunctious, and disruptive.
    • Hypoactive delirium (20%): Quietly confused; may sit and not eat, drink, or move
    • Mixed delirium (50%): Features of both hyperactive and hypoactive delirium
    • Normal consciousness delirium (15%): Still display disorganized thinking, along with acute onset, inattention, and fluctuation


  • Time course of mental status changes
  • Recent medication changes
  • Symptoms of infection
  • New neurologic signs

Physical Exam

  • Comprehensive cardiorespiratory exam is essential.
  • Focal neurologic signs usually absent
  • Formal mini mental state exam is not diagnostic, but is helpful as structured interview and followed serially over time.

Diagnostic Tests & Interpretation

Electrocardiogram as necessary


Guided by history and physical exam

Initial lab tests

  • Complete blood count
  • Electrolytes, blood urea nitrogen, and creatinine
  • Urinalysis, urine culture
  • Medication levels (digoxin, theophylline where applicable)

Follow-Up & Special Considerations

If the above does not indicate a precipator of delirium, consider:

  • Arterial blood gases
  • Troponin
  • Toxicology screen
  • Liver panel
  • Thyroid-stimulating hormone


Guided by history and physical exam

Initial approach

  • Chest radiograph for most
  • Other if indicated by history and exam

Follow-Up & Special Considerations

Non-contrast-enhanced head computed tomography scan if:

  • Unclear diagnosis
  • Recent fall
  • Receiving anticoagulants
  • New focal neurologic signs
  • Need to rule out increased intracranial pressure before lumbar puncture

Diagnostic Procedures/Surgery

  • Lumbar puncture:
    • Rarely necessary
    • Perform if clinical suspicion of a central nervous system (CNS) bleed or infection is high
  • Electroencephalogram:
    • Rarely necessary; consider after above evaluation if:
      • Diagnosis remains unclear
      • Suspicion of seizure activity

Differential Diagnosis

  • Depression (slow onset, disturbance of mood, normal level of consciousness, and fluctuates over weeks to months)
  • Dementia (insidious onset, memory problems, normal level of consciousness, and fluctuates over days to weeks)
  • Psychosis (rarely sudden onset in older adults)


  • Stabilize vitals if needed.
  • Ensure immediate evaluation. Addressing 6 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%.


  • Nonpharmacologic approaches are preferred for initial treatment.
  • Medications often treat only the symptoms and do not address the underlying cause.

First Line

Support's development and hosting
  • Neuroleptics:
    • Haloperidol (Haldol): Initially, 0.25–0.5 mg p.o./IM/IV unless urgent sedation needed; reevaluate and potentially redose hourly
    • Quetiapine (Seroquel): 25 mg/d to b.i.d.
    • Risperidone (Risperdal): 0.25–0.5 mg/d p.o.
  • Short-acting benzodiazepines if neuroleptics do not work or should be avoided:
    • Lorazepam (Ativan): Initially, 0.25–0.5 mg p.o./IM/IV q6–8h; may need to adjust to effect (caution in patients with impaired liver function)
  • Contraindications: Avoid neuroleptics in patients with parkinsonism or Parkinson disease
  • Precautions: Neuroleptics may cause extrapyramidal effects, and benzodiazepines may lead to sedation. Both increase the risk of falls.

Second Line

  • Olanzapine (Zyprexa): 2.5–5.0 mg/d p.o.
  • Despite multiple trials there is no evidence to support the use of cholinesterase inhibitors in the prevention or treatment of delirium,

Additional Treatment

General Measures

  • Postoperative patients should be monitored and treated for the following:
    • Myocardial infarction/ischemia
    • Pulmonary complications/pneumonia
    • Pulmonary embolism
    • Urinary or stool retention (attempt catheter removal by postoperative day 2)
  • Anesthesia route (general epidural) does not affect the risk of delirium.
  • Multifactorial treatment: Identify contributing factors and provide preemptive care to avoid iatrogenic problems (1,2)[A] with special attention to:
    • CNS oxygen delivery (attempt to attain the following):
      • SaO2 >90% with goal of SaO2 >95%
      • Systolic blood pressure <2/3 of baseline or >90 mm Hg
      • Hematocrit >30%
  • Fluid/electrolyte balance:
    • Sodium, potassium, and glucose normal (glucose <300 mg/dL in diabetics)
    • Treat fluid overload or dehydration.
  • Treat pain:
    • Schedule acetaminophen (1 g q.i.d.) if daily pain
    • Morphine or oxycodone for breakthrough pain if acetaminophen ineffective


  • Avoid meperidine (Demerol) (2)[A].
  • Eliminate unnecessary medications:
    • Investigate new symptoms as potential medication side effects.
  • Regulate bowel/bladder function:
    • Bowel movement at least every 48 hours
    • Screen for urinary retention or incontinence, especially after catheter removal.
  • Prevent major hospital-acquired problems:
    • 6-inch-thick foam mattress overlay or a pressure-reducing mattress
    • Avoid urinary catheter.
    • Incentive spirometry, if bed-bound
    • SC heparin 5,000 U b.i.d., if bed-fast
    • Environmental stimulation:
      • Glasses and hearing aids
      • Clock and calendar
      • Soft lighting
      • Radio, tapes, and television, if desired
    • Sleep:
      • Quiet environment
      • Soft music
      • Therapeutic massage
  • Restraints do not reduce risk of falls/injury:
    • Use only in the most difficult-to-manage patients, as briefly as possible

Issues for Referral

Psychiatric and/or neurologic assessment helpful if delirium not easily explainable after full evaluation

Additional Therapies

Early mobilization critical:

  • Out of bed on hospital day 2 (or postoperative day 1) if no contraindications
  • Out of bed several hours daily if able
  • Daily therapy if not ambulating independently
  • Daily therapy if not functionally independent

In-Patient Considerations

General measures described above are also applicable to delirium prevention.

Admission Criteria

New delirium is a medical emergency and requires admission, except in the setting of palliative home care.

IV Fluids

As needed for dehydration


  • Institute skin care program for patients with established incontinence.
  • Turning regimen if at risk of pressure ulcers
  • Soft restraints are acceptable for a short time only if needed for protection of patient and others.

Discharge Criteria

  • Resolution of precipitating factor(s)
  • Safe discharge site if still delirious

Ongoing Care

Follow-Up Recommendations

  • If delirium at discharge, will usually be followed in post-acute facility
  • If no delirium at discharge, follow up with primary care physician in 1–2 weeks.
  • As tolerated
  • Early physical therapy consultation to prevent deconditioning

Patient Monitoring

  • Evaluate and assess mental status daily.
  • Depends on specific conditions present


  • Dentures used properly
  • Proper positioning for meals
  • Assistance with meals when necessary
  • Nutritional supplements (1–3 cans daily) if intake is poor
  • Temporary nasogastric tube if unable to eat and bowels working


  • Usually improves with treatment of underlying condition, but may become chronic
  • Delirium complicating medical illness significantly increases a person’s chance of dying from that illness


  • Falls
  • Pressure ulcers
  • Malnutrition
  • Functional decline
  • Oversedation
  • Polypharmacy


1. Fong TG, Tulebave SR, Inouye SK. Delirium in elderly adults: Diagnosis, prevention, and treatment. Nature Reviews Neurology 2009;5:210–220.

2. Hopkins RO, Jackson JC. Assessing neurocognitive outcomes after critical illness: are delirium and long-term cognitive impairments related? Curr Opin Crit Care. 2006;12:388–94.

Additional Reading

Hshieh TT, Fong TG, Marcantonio ER, Inouye SK et al. Cholinergic deficiency hypothesis in delirium: a synthesis of current evidence. J Gerontol A Biol Sci Med Sci. 2008;63:764–72.

van Eijk MM, van Marum RJ, Klijn IA, de Wit N, Kesecioglu J, Slooter AJ et al. Comparison of delirium assessment tools in a mixed intensive care unit. Crit Care Med. 2009;37:1881–5.

Yang FM, Marcantonio ER, Inouye SK, Kiely DK, Rudolph JL, Fearing MA, Jones RN et al. Phenomenological subtypes of delirium in older persons: patterns, prevalence, and prognosis. Psychosomatics. 2009;50:248–54.

See Also (Topic, Algorithm, Electronic Media Element)

Substance Use Disorders; Dementia; Depression

Algorithm: Delirium



  • 293.0 Delirium due to conditions classified elsewhere
  • 293.1 Subacute delirium
  • 293.9 Unspecified transient mental disorder in conditions classified elsewhere
  • 291.0 Alcohol withdrawal delirium
  • 291.2 Alcohol-induced persisting dementia
  • 292.81 Drug-induced delirium
  • 290.0 Senile dementia, uncomplicated
  • 780.09 Alteration of consciousness, other


  • 2776000 Delirium (disorder)
  • 8635005 Alcohol withdrawal delirium (disorder)
  • 191461002 Senile dementia with delirium (disorder)
  • 191492000 drug-induced delirium (disorder)

Clinical Pearls

  • The Confusion Assessment Method (CAM) criteria for delirium are acute onset of fluctuating mental status, inattention, disorganized thinking, AND EITHER disorganized thinking or altered level of consciousness.
  • In the absence of active monitoring, the hypoactive subtype of delirium can easily be missed.
  • Addressing 6 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%.
  • Delirium may not resolve as soon as the treatable contributors are fixed; resolution may take weeks or months. Rarely will become chronic.
  • Avoid diphenhydramine in older patients. Nonpharmacologic measures are preferable as a sleep aid, but if needed, zolpidem (5 mg hs) or trazodone (25 mg hs) are reasonable alternatives.

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