AGS GEM Tool: Delirium

March 16, 2017

American Geriatrics Society (AGS)

AGS GEM Tool: Delirium


  • Synonyms: acute confusional state, acute mental status change, toxic or metabolic encephalopathy
  • Predictor for future cognitive and functional decline as well as diminished lifespan
  • Found in 1/3 of hospitalized medical patients older than age 70
  • Found in 15% of patients older than age 70 presenting to emergency departments
  • Under-recognized: only 12%–35% of all cases recognized in routine care
  • Failure to diagnose/manage delirium leads to costly, life-threatening complications; loss of function and independence; and increased risk of death.


  • NOTE: The concept of “differential diagnosis of delirium/dementia/depression” can be misleading—conditions may coexist and are risk factors for one another.
  • To distinguish between delirium, dementia, and depression, the clinician must ascertain the patient’s baseline status and the timeframe of cognitive changes. Information from family members and caregivers can be essential.


  • DSM-5 criteria for delirium highlight that it is an acute and fluctuating syndrome of impaired attention and awareness.
  • Patients at risk for delirium should be screened at least daily.
  • Time course of the changes in mental status and their association with other symptoms or events (eg, fever, shortness of breath, medication change) should be documented.
  • Systematic reviews recommend the Confusion Assessment Method (CAM) as the most useful bedside assessment tool for delirium.
  • 3D-CAM is a brief diagnostic tool that is highly sensitive and specific for diagnosing delirium in hospitalized patients.
  • The CAM-ICU is an adaptation for intubated patients only that does not require verbal responses.
  • The CAM-S is a validated delirium severity measure that does not diagnose delirium but can be used in conjunction with a CAM diagnostic tool to quantify the intensity of delirium symptoms.

Confusion Assessment Method (CAM): Diagnosis requires #1 and #2 and either #3 or #4.

1. Acute change in mental status and fluctuating course:

  • Is there evidence of an acute change in cognition from the patient’s baseline?
  • Does the abnormal behavior fluctuate during the day (tend to come and go, or increase or decrease in severity)?

2. Inattention:  Does the patient have difficulty focusing attention? Can use one of the following tests for attention:

  • Digit span up to 5 forward, 4 backward
  • “World” backward
  • Days of the week backward, months of the year backwards
  • Continuous performance task such as “Vigilance A”

3. Disorganized thinking: Is the patient’s thinking disorganized or incoherent (rambling or irrelevant conversation, unclear or illogical flow of ideas, unpredictable switching from subject to subject)?

4. Altered level of consciousness: Is the patient’s mental status anything other than alert (vigilant, lethargic, stuporous, comatose)?



  • As the number or severity of predisposing factors for delirium increase, a decreased number or reduced severity of precipitating factors are required to initiate delirium.
  • Predisposing factors: advanced age, dementia, prior delirium, dependency in activities of daily living (ADLs), medical comorbidities, history of alcohol abuse, male gender, diminished vision and/or hearing

Precipitating Factors (Mnemonic for Some Causes of Delirium)


  • Any new additions, increased dosages, or interactions
  • Consider over-the-counter drugs and alcohol
  • Consider especially high-risk drugs (see “Medications,” next page)

Electrolyte disturbances:

  • Especially dehydration, sodium imbalance
  • Thyroid abnormalities

Lack of drugs:

  • Withdrawal from chronically used sedatives, including alcohol and sleeping pills
  • Uncontrolled pain


  • Especially respiratory, skin, and urinary tract infections

Reduced sensory input or mobility:

  • Poor vision, poor hearing
  • Use of restraints, bedbound status


  • Rare: consider only if new focal neurologic findings or suggestive history, or diagnostic evaluation is otherwise negative
  • Infection, hemorrhage, tumor, stroke

Urinary, fecal:

  • Urinary retention (“cystocerebral syndrome”)
  • Fecal impaction
  • Urinary catheterization

Myocardial, pulmonary:

  • Myocardial infarction, arrhythmia, exacerbations of congestive heart failure or COPD, hypoxia


  • Incidence of delirium:
    • 15% after elective noncardiac surgery
    • Up to 50% after cardiac bypass, abdominal aortic aneurysm or hip fracture repair


  • Vital signs, including oxygen saturation
  • Thorough physical examination with focus on neurologic and mental status examination; both hyperactive and hypoactive subtypes are described.


Alcohol, anticholinergics (oxybutynin, benztropine), anticonvulsants (primidone, phenobarbital, phenytoin), antidepressants (amitriptyline, imipramine, doxepin), antihistamines (diphenhydramine), anti-inflammatory agents (prednisone), antiparkinsonian agents (levodopa carbidopa, dopamine agonists, amantadine), antipsychotics, barbiturates, benzodiazepines (triazolam, alprazolam, diazepam, flurazepam, chlordiazepoxide), H2-antagonists (cimetidine, ranitidine), opioid analgesics (especially meperidine)


  • Complete blood count
  • Thyroid function test
  • Serum drug levels
  • Chest radiograph
  • Complete metabolic panel
  • Urinalysis
  • Arterial blood gases
  • ECG
  • Serum calcium
  • Blood cultures
  • Ammonia
  • Blood alcohol levels
  • Cerebral imaging rarely helpful, except with head trauma or new focal neurologic findings.
  • EEG and CSF analysis rarely helpful, except with associated seizure activity or signs of meningitis.



  • Strategies to prevent and manage delirium are often the same, but prevention of delirium leads to better patient outcomes than management once delirium has occurred.
  • There is insufficient evidence to recommend for or against the use of antipsychotic medications prophylactically in older patients to prevent delirium.
  • Multifactorial approach to management is most successful because multiple factors contribute to delirium; thus, multiple interventions, even if individually small, can yield marked clinical improvement:

delirium prevention management


  • Treatment with pharmacologic agents (eg, antipsychotics) should only be employed in patients who are severely agitated or distressed, and are threatening substantial harm to self and/or others when behavioral interventions have failed or are not possible.
    • The lowest dose of the least toxic pharmacologic agent should be used for the shortest possible time and discontinued when target symptoms are no longer present.
    • Indications for pharmacologic interventions should be clearly identified and documented, and need for ongoing use should be reassessed daily with in-person examination of patients.
  • Cholinesterase inhibitors should not be newly prescribed to prevent or treat delirium.

Pharmacologic therapy of agitated delirium


  • Symptoms of delirium may persist for weeks to months in a substantial portion of affected individuals.
  • An episode of delirium is a risk factor for subsequent episodes: documentation is critical.
  • A history of delirium is a risk factor for dementia: education and follow-up are important.


This AGS GEM Tool and other tools like it can be found on the AGS-sponsored website along with many other helpful tools for clinicians.

American Geriatrics Society (AGS) Geriatrics Evaluation and Management Tools (Geriatrics E&M Tools) support clinicians and systems that are caring for older adults with common geriatric conditions.

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