Delirium is a serious neuropsychiatric syndrome characterized by an acute confusional state with global impairments in attention and cognition.[1] Delirium is often associated with a disturbance in the sleep-wake cycle, including daytime sleepiness, nighttime agitation, insomnia, excessive sleepiness, or wakefulness throughout the night. In some cases, complete reversal of the night-day sleep-wake cycle can occur.
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Modifiable Essentials | • Sensory impairment (hearing or vision) • Immobilization (catheters or restraints) • Environment (for example, admission to an intensive care unit) • Pain • Emotional distress • Sustained sleep deprivation |
Modifiable Medical | • Medications (e.g. - sedative hypnotics, narcotics, anticholinergic drugs, corticosteroids, polypharmacy, alcohol withdrawal or other drugs) • Acute neurological diseases (e.g. - acute stroke [usually right parietal], intracranial hemorrhage, meningitis, encephalitis) • Ongoing illness (e.g. - infection (UTI), iatrogenic complications, acute illness, anemia, dehydration (often giving IV fluids will improve things), poor nutrition, trauma, fractures, HIV) • Metabolic derangement • Surgery |
Non-modifiable | • Dementia or cognitive impairment • Advancing age (>65 years) • History of delirium, stroke, neurological disease, falls or gait disorder • Multiple comorbidities • Male sex • Chronic renal or hepatic disease |
A disturbance in attention (i.e. - reduced ability to direct, focus, sustain, and shift attention) and awareness (reduced orientation to the environment).
The disturbance develops over a short period of time (usually hours to a few days), represents a change from baseline attention and awareness, and tends to fluctuate in severity during the course of a day.
An additional disturbance in cognition (e.g. - memory deficit, disorientation, language, visuospatial ability, or perception).
The disturbances in Criteria A and C are not better explained by another preexisting, established, or evolving neurocognitive disorder and do not occur in the context of a severely reduced level of arousal, such as coma.
There is evidence from the history, physical examination, or laboratory findings that the disturbance is a direct physiological consequence of another medical condition, substance intoxication or withdrawal (i.e. - due to a drug of abuse or to a medication), or exposure to a toxin, or is due to multiple etiologies.
Specify if:
Specify if:
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Name | Rater | Description | Download |
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Confusion Assessment Method (CAM) | Clinician | The Confusion Assessment Method (CAM) is a standardized evidence-based tool that allows clinicians to identify and recognize delirium quickly and accurately in both clinical and research settings. It has a sensitivity of 94‐100% and specificity of 90‐95%.[11][12] See the training guide for full instructions. | Short Version Critical Care Version |
AIDA
can be used to remember the core features of delirium. Remember you need features 1 AND 2, plus 3 OR 4 for an individual to be positive for delirium on the Confusion Assessment Method (CAM).A
- Acute and fluctuating (a change from baseline, AND a change during the day)I
- Inattention (difficulty focusing/keeping track, drifting off to sleep, easily distracted)D
- Disorganized thinking (incoherent, rambling, irrelevant, illogical, circumstantial, vague)A
- Altered level of consciousness (lethargic, vigilant, stuporous, drowsy, agitated)Obtaining a good history is key and should be the first step when seeing a patient with delirium. Do not rely on just self-report by the patient. Use as many collateral sources as possible, including family, staff, and the chart.
The following items on history should always be obtained:
Before even considering pharmacologically managing delirium, always think about what could be causing delirium in the first place! First consider the non-medical issues that could cause an altered level of consciousness, including: pain, vision deficits, hearing deficits, hunger, constipation (i.e., fecal loading), or urinary retention. Then consider the medical etiologies below. In geriatric populations, also consider the geriatric giants.
DIMS-R
can be used to remember the common causes of delirium and provide a structured approach:
D
- Drugs: Is there a drug intoxication, or conversely, a drug withdrawal? Look for sedating medications, anticholinergic medications, and never forget alcohol withdrawalI
- Infections: Is the genitourinary system, chest, skin/soft-issue, or blood infected? If so, consider CXRs or further infectious work up if needed.M
- Metabolic: Are there any changes to glucose, electrolytes, extended electrolytes, creatinine, liver enzymes, VBG CO2, TSH, or B12 that would reflect endocrinopathies, renal failure, or liver failure?R
- Retention: Is there fecal impaction or urinary retention? If so, consider abdominal X-rays, palpation, DRE, disimpaction.A non-exhaustive list of potential causes for delirium include:
Course of Delirium | Examples | Consider if: |
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Drug-induced | Sedative-hypnotics, anticholinergics, opioids, anticonvulsants, anti-parkinsonian agents | The drug in question has central nervous system effects; a toxic level is documented or there is improvement with dose reduction or discontinuation; and, the time course coincides with the use of the drug. |
Alcohol and drug withdrawal | Alcohol, benzodiazepines | Recent and long-term use of alcohol or sedative drug; evidence of withdrawal (e.g., autonomic hyperactivity, seizure) or improvement when the same or similar agent given; and, delirium occurs within week of cessation. |
Post-operative delirium | - | Delirium occurs shortly after surgical procedure. |
Infectious | Lower respiratory tract infection, urinary tract infection | Signs of infection present; infection is confirmed by cultures or other indicators; and, the temporal course coincides with the infection. |
Fluid-electrolyte disturbance | Dehydration/hypovolemia (hyponatremia) | Clinical evidence of changes in hydration status present (e.g., history of GI losses, signs of hypovolemia/dehydration, signs of volume overload); abnormal laboratory studies (e.g., abnormal electrolytes, high urea/ creatinine ratio); and, temporal course coincides with the abnormality |
Metabolic/endocrine | Uremia, hepatic encephalopathy, hypo/hyperglycemia, hypo/hyperthyroidism, adrenal insufficiency, hypercalcemia | The metabolic abnormality is known to induce a change in mental status; clinical and laboratory confirmation of the disturbance; and, the temporal course coincides with the disturbance. |
Cardiopulmonary (hypoperfusion and/or hypoxia) | Congestive heart failure/pulmonary edema, shock, respiratory failure | Clinical evidence of a low cardiac output/hypotension or pulmonary compromise; laboratory or radiographic evidence of suspected abnormality (e.g., arterial blood gases); and, the time course coincides with cardiopulmonary disturbance. |
Intracranial | Stroke, traumatic brain injury, cerebral edema, subdural hematoma, meningitis, seizures | Clinical evidence of an intracranial process has occurred; laboratory or radiological evidence of the suspected abnormality; and, time course coincides with the disturbance. |
Sensory/Environmental | Visual/hearing impairment, physical restraint use, bladder catheter use, settings (acute care, especially ICU) | There is evidence of a pre-existing dementia and/or significant auditory/visual disturbance; mental status improves with orienting stimuli; and, mental status worsens with recent environmental changes or occurs predominantly at night. |
Delirium | Dementia | Depression | |
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Cardinal feature | Confusion and Inattention | Memory loss | Sadness, anhedonia |
Onset | Acute or subacute | Insidious | Slow |
Course | Fluctuating, often worse at night | Chronic, progressive (but stable over the course of a day) | Single or recurrent episodes; can be chronic |
Duration | Hours to months | Months to years | Weeks to years |
Level of Conciousness (LOC) | Impaired, fluctuates | Normal in early stages | Normal |
Attention (i.e. - able to focus on tasks) | Poor | Normal (except in late stages) | May be impaired |
Orientation (i.e. - date, location) | Fluctuates | Poor | Normal |
Memory (i.e. - short-term memory) | Poor | Poor | May be impaired |
Hallucinations | Common (visual) | Rare, except in late stages (and depends on type of dementia) | Not usually (only if psychotic depression) |
Delusions | Fleeting, non-systematized | Often absent | Not usually (only if psychotic depression) |
Psychomotor | Increased (hyperactive) or reduced (hypoactive) | No | Yes |
Reversibility | Yes | Rarely | Yes |
EEG Findings | Moderate to severe background slowing | Normal or mild diffuse slowing | Normal (usually) |
In non-ICU setting patients, always start with non-pharmacological interventions first, both in the prevention and management of delirium.[27][28][29] Multiple risk factors should be mitigated as suggested by the table below:
Risk Factor | Intervention |
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Cognitive impairment | Orient the patient by having a clock, watch, or calendar. Have a board with team member names, a schedule, ongoing communication to reorient them (e.g. - remind the patient where they are, get a sitter, asking family members to stay, asking family to bring items that can keep patient occupied). Do therapeutic activities including: cognitively stimulating activities TID (e.g. - current events, word games, structured reminiscence [get them to recall events in the past]). |
Sleep deprivation | Warm drinks, relaxation tapes, back massages at night. Enhance sleep by implementing unit‐wide noise reduction and schedule adjustments to allow sleep. Coordinate schedules (drugs, vitals, procedures) to allow uninterrupted sleep at night (low noise and lighting). Encourage normal sleep–wake cycles (open blinds, encourage wakefulness and mobility during daytime) |
Immobility | Implement early mobilization including ambulation or active range of motion exercises TID. Minimize use of catheters, IVs, and restraints. |
Visual impairment | Make sure they have visual aids such as glasses, and other adaptive equipment. Reinforce use of aids daily. |
Hearing impairment | Make sure they have hearing aids, portable amplifying devices, earwax disimpaction if needed, and special communication techniques. Reinforce use of aids daily. |
Volume depletion | Early recognition and repletion with fluids |
Enivronment | Avoid putting delirious patients in the same room together, and minimize room changes |
Sedative-hypnotics | • Benzodiazepines • Barbituates • Antihistamines (e.g. - diphenhydramine) |
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Narcotics | • Meperidine appears to be particularly likely to precipitate delirium |
Drugs with anticholinergic effects | • Oyybutynin • Tolteridine • Anti-nauseants (antihistamines, antipsychotics) • Promotility agents • Tricyclic antidepressants (especially tertiary amine tricyclic agents such as amitriptyline, imipramine and doxepin) • Antipsychotics (e.g. - low potency neuroleptics such as chlorpramazine) • Cumulative effect of multiple medications with anticholinergic effects |
Histamine-2 Blocking agents | • Cimetidine |
Antiparkinsonian medications | • Dopamine agonists • Levodopa-carbidopa • Amantadine • Anticholinergics • Benztropine |
Anticonvulsants | • Mysoline • Phenobarbitone • Phenytoin |
Medication | Use | Recommended Dosing | Side Effects | Clinical Pearls |
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Haloperidol | First-line | 0.5‐1 mg PO/IM bid and q4h PRN | Extrapyramidal Symptoms (EPS) at higher doses (> 3mg), QTc prolongation, and neuroleptic malignant syndrome, somnolence, falls. | Both typical and atypical antipsychotics increase the risk of death and cerebrovascular events, compared with placebo in elderly patients (> 65 years) with dementia.[39] In the elderly with Parkinson's disease or Lewy Body Dementia, atypical antipsychotics are preferred. |
Risperidone | First-line | 0.5 mg BID | Extrapyramidal Symptoms (EPS) (less likely than typicals like haloperidol, but still a risk, especially at higher doses), QTc prolongation, neuroleptic malignant syndrome, somnolence, falls. | Both typical and atypical antipsychotics increase the risk of death and cerebrovascular events, compared with placebo in elderly patients (> 65 years) with dementia.[40] In the elderly with Parkinson's disease or Lewy Body Dementia, atypical antipsychotics are preferred. |
Olanzapine | First-line | 2.5‐5 mg PO daily | Same as risperidone | Both typical and atypical antipsychotics increase the risk of death and cerebrovascular events, compared with placebo in elderly patients (> 65 years) with dementia.[41] In the elderly with Parkinson's disease or Lewy Body Dementia, atypical antipsychotics are preferred. |
Quetiapine | First-line | 25 mg BID | Same as risperidone | Both typical and atypical antipsychotics increase the risk of death and cerebrovascular events, compared with placebo in elderly patients (> 65 years) with dementia.[42] In the elderly with Parkinson's disease or Lewy Body Dementia, atypical antipsychotics are preferred. |
Lorazepam | Second-line | 0.5‐1 mg PO q4h PRN | Paradoxical reactions, respiratory depression, sedation/somnolence, falls. | Lorazepam may worsen or prolong delirium! Although a recent network meta-analysis suggested the use lorazepam in delirium, this result cannot be generalized to routine clinical practice because the result was derived from only one study.[43][44] Lorazepam should only be used for patients with alcohol withdrawal, or patients with antipsychotic sensitivity (i.e. - Parkinson's or Lewy Body) |
Misconception/Myth | Best Evidence |
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This patient is oriented to person, place, and time. They’re not delirious. | Delirium evaluation minimally requires assessing attention, orientation, memory, and the thought process, ideally at least once per nursing shift, to capture daily fluctuations in mental status.[48] |
Delirium always resolves. | Especially in cognitively vulnerable patients, delirium may persist for days or even months after the proximal “causes” have been addressed. |
We should expect frail, older patients to get confused at times, especially after receiving pain medication. | Confusion in frail, older patients always requires further assessment. |
The goal of a delirium work-up is to find the main cause of delirium. | Delirium etiology is typically multifactorial. |
New-onset psychotic symptoms in late life likely represents primary mental illness. | New delusions or hallucinations, particularly nonauditory, in middle age or later deserve evaluation for delirium or another medical cause. |
Delirium in patients with dementia is less important because these patients are already confused at baseline. | Patients with dementia deserve even closer monitoring for delirium because of their elevated delirium risk and because delirium superimposed on dementia indicates marked vulnerability. |
Delirium treatment should include psychotropic medication. | The role of psychotropic medications in delirium remains unclear. They are best used judiciously, if at all, for specific behaviors or symptoms rather than delirium itself. |
The patient is delirious due to a psychiatric cause. | Delirium always has a physiological cause. |
It’s often best to let quiet patients rest. | Hypoactive delirium is common and often under-recognized. |
Patients become delirious just from being in the intensive care unit. | Delirium in the intensive care unit, as with delirium occurring in any setting, is caused by physiological and pharmacological insults. |
Guideline | Location | Year | Website | |
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Canadian Coalition for Seniors' Mental Health (CCSMH) | Canada | 2006, 2014 | • 2014 Update • 2006 Guideline • Pocket Card | CCSMH Delirium |
National Institute for Health and Care Excellence (NICE) | UK | 2010, 2019 | - | Link |
American Geriatrics Society (AGS) | USA | 2015 | - | Link |
Clinical Practice Guidelines for the Management of Pain, Agitation, and Delirium in Adult Patients in the ICU | USA | 2018 | - | Link |
Journal of the American Medical Association (JAMA) | USA | 2017 | - | Link |
American Psychiatric Association (APA) | USA | 1999, 2004 | - | • Guideline (1999) • Guideline Watch (2004) • Quick Reference |
Clinical Practice Guidelines for the Management of Delirium in Older People | Australia | 2008 | - | Link |