Delirium in older adults

Delirium is the highest-yield acute cognitive syndrome in old-age psychiatry. FRANZCP MEQs demand the CAM rule, hypoactive miss, a named prevention package, cause-first management, and honest antipsychotic trial evidence. MRCPsych CASC stations test carer communication and capacity. ABPN items test multifactorial risk and restricted pharmacotherapy. This leaf is written for older adults specifically — frailty, dementia overlap, residential care, postoperative pathways, and start-low prescribing.[3][4][5]

Overview and definition

Delirium is a clinical syndrome of acute onset (hours to days), fluctuating course, and core disturbance of attention and awareness, with additional cognitive change (memory, orientation, language, visuospatial ability, or perception), attributable to a direct physiological consequence of a medical condition, substance intoxication or withdrawal, toxin, or multiple etiologies.[3][4][5]

In older adults it is common, under-recognised (especially hypoactive forms), multifactorial, and independently associated with death, institutionalisation, and later dementia. Psychiatry owns detection, behavioural safety, capacity opinions, medication rationalisation, and liaison while medicine reverses precipitants.[3][12]

Classification and diagnostic criteria

DSM-5-TR (operational summary)

ICD-11 frames delirium similarly as an acute neurocognitive disturbance with impaired attention and awareness. State which manual you are using when duration language is examined.[5]

Confusion Assessment Method (CAM)

The CAM remains the examiner gold standard for non-psychiatric detection. Positive when features 1 and 2 are present and either 3 or 4 is present: (1) acute onset and fluctuating course, (2) inattention, (3) disorganised thinking, (4) altered level of consciousness.[1]

Original validation showed high sensitivity and specificity with trained raters; performance collapses without attention testing and training.[1] The 3D-CAM structures a roughly 3-minute diagnostic interview with high accuracy against a reference standard — practical for busy geriatric wards.[14]

4AT (rapid screen)

Four items: Alertness, AMT4 (age, date of birth, place, current year), Attention (months of the year backward), and Acute change or fluctuating course. Score 4 or more suggests possible delirium and triggers full assessment.[13]

Motor subtypes — hypoactive is the exam trap

Meagher and colleagues showed motor subtype instability within an episode — do not lock a single label for the whole admission.[15]

Epidemiology and risk

[3] [12] [2] [11]

Predisposing factors (vulnerability): advanced age, pre-existing dementia or mild cognitive impairment, sensory impairment (vision/hearing), frailty, polypharmacy, prior delirium, alcohol use disorder, and reduced physiological reserve.[3][4][18]

Precipitating factors (Inouye multifactorial model): infection (including UTI and pneumonia), medications (anticholinergics, benzodiazepines, opioids, antihistamines, steroids), surgery/anaesthesia, pain, hypoxia, metabolic disturbance (sodium, glucose, calcium), dehydration, constipation, urinary retention, stroke, and environmental disruption (ward moves, ICU, sleep loss, restraints).[18][3][5]

Mnemonic frameworks examiners accept when expanded correctly include PINCH ME (Pain, Infection, Nutrition, Constipation, Hydration/Hypoxia, Medication, Environment) and I WATCH DEATH (Infection; Withdrawal; Acute metabolic; Trauma; CNS pathology; Hypoxia; Deficiencies; Endocrine; Acute vascular; Toxins/drugs; Heavy metals).[3][4]

Pathophysiology

No single pathway explains all geriatric delirium. Converging models include neuroinflammation, cholinergic deficit (critical in anticholinergic burden), monoamine imbalance, oxidative stress and impaired cerebral metabolism, and disrupted large-scale connectivity affecting attention and arousal networks. The practical model is vulnerability times precipitating load — frail brains tip into delirium with smaller insults than younger adults.[5][4][18]

Longer delirium duration associates with worse long-term cognition after critical illness: treat duration as a modifiable risk, not a cosmetic label.[11]

Clinical presentation

Tempo. Hours to a few days; family report of "not themselves last night" is gold. Fluctuation across a shift is typical — a single lucid moment does not exclude the diagnosis.[3][1]

Core signs. Inattention, altered awareness (hypervigilant to drowsy), disorganised thinking, sleep-wake reversal, perceptual disturbance (especially visual hallucinations and illusions), emotional lability, and autonomic features when toxic or withdrawal causes dominate.[3][4][5]

High-miss presentations in older adults. Hypoactive patients labelled "depressed" or "tired"; postoperative "slow to wake"; residential care residents with silent infection; delirium superimposed on dementia (DSD) where only serial comparison with collateral baseline detects change.[3][4]

Differential diagnosis — discriminators

[3] [4] [5]

Also consider: primary late-onset psychosis (clearer sensorium — still exclude organic first); alcohol/benzodiazepine withdrawal; Wernicke encephalopathy; non-convulsive status epilepticus; autoimmune encephalitis; catatonia; manic agitation without medical precipitant.[3][4][5]

Bedside assessment

1. ABCDE and immediate life threats (hypoxia, hypoglycaemia, sepsis).
2. Collateral for baseline cognition and time of change — essential in dementia.
3. Structured screen: CAM, 3D-CAM, or 4AT on wards.[1][13][14]
4. MSE: attention tests, orientation, thought form, perception, insight, risk (falls, wandering, vulnerability, violence, absconding).
5. Medication reconciliation: anticholinergics, benzodiazepines, opioids, corticosteroids, antihistamines, new starts and withdrawals.
6. Capacity for each specific decision.
7. Legal/least-restrictive framework under local mental health and guardianship law — state principles; do not invent foreign section numbers.[3][4]

Investigations

Treat the probable cause in parallel with testing. Normal CT does not exclude delirium.[3][4]

Management — resuscitation first

Immediate geriatric bundle: oxygen and airway protection as needed; correct hypoglycaemia; sepsis pathway when indicated; stop or minimise deliriogenic drugs; treat severe pain; bladder scan for retention; relieve constipation; ensure hearing aids and glasses; safe environment with continuous observation if high risk; parenteral thiamine when malnutrition or alcohol risk before prolonged carbohydrate loads; if alcohol or benzodiazepine withdrawal, use a benzodiazepine protocol plus thiamine — not antipsychotic monotherapy.[3][4]

Management — prevention and definitive care

Multicomponent non-pharmacological care is first-line (and prevention)

The Yale/HELP multicomponent model targets cognitive orientation, sleep, mobility, vision/hearing, and hydration. Inouye and colleagues showed reduced delirium incidence in hospitalised older adults with a structured multicomponent intervention.[2] Meta-analyses support multicomponent non-pharmacological strategies and HELP programme effectiveness.[16][17]

Practical ward package examiners expect: reorientation (clocks, calendars, name boards), family presence, day-night lighting, minimise overnight interruptions, early mobilisation, sensory aids, hydration and nutrition, avoid unnecessary catheters and restraints, constipation and retention protocols, and aggressive medication review.[2][3][4][16]

Treat the cause — antipsychotics do not treat the syndrome

Every reversible precipitant must be addressed. Systematic reviews do not support routine antipsychotic prevention or treatment as primary therapy.[9][10]

Landmark trial messages for viva (antipsychotics are not first-line disease-modifying therapy): MIND-USA (2018) — in ICU delirium, haloperidol and ziprasidone did not significantly alter days alive without delirium or coma versus placebo; AID-ICU (2022) — IV haloperidol did not improve days alive and out of hospital versus placebo; Agar et al. (2017) — in palliative care, risperidone and oral haloperidol were associated with worse delirium symptom scores than placebo; Cochrane (Burry 2018) and Neufeld 2016 — insufficient evidence supporting antipsychotics as primary treatment or prevention.[6][7][8][9][10]

Avoid benzodiazepines (except withdrawal)

Do not use benzodiazepines for non-withdrawal geriatric delirium — they worsen confusion, sedation, falls, and often prolong the syndrome. Exceptions: alcohol or benzodiazepine withdrawal, seizures, or selected palliative terminal distress pathways under specialist guidance.[3][4]

Low-dose antipsychotics carefully — last line for safety or severe distress

When still considered: severe agitation or distress posing imminent danger to self/others after non-drug measures and cause-directed care, and when not better explained by untreated pain, hypoxia, retention, or withdrawal. Use the lowest effective dose for the shortest time, review daily, and document target symptoms (safety/distress — not "cure confusion").[4]

Illustrative geriatric starting ranges (check local formulary, ECG/QTc, EPS risk, and product information; start at the bottom of the range in frailty): haloperidol 0.25–0.5 mg PO/IM; olanzapine 2.5–5 mg PO (or IM where protocolised); quetiapine 12.5–25 mg PO — with QTc/EPS monitoring, avoid combining IM olanzapine with parenteral benzodiazepines, and never use antipsychotic monotherapy for alcohol withdrawal.[4]

Subtypes and scenarios

Delirium superimposed on dementia (DSD)

Harder to detect. Require collateral baseline, serial CAM/4AT, and a low threshold for medical work-up when function drops acutely. Do not attribute every change to "progression of dementia."[3][4]

Postoperative delirium

Common after orthopaedic, cardiac, and major abdominal surgery in older adults. Prevention: avoid unnecessary deep sedation and benzodiazepines, optimise analgesia, early mobilisation, sensory aids, and geriatric co-management.[3][4]

Residential aged care and hospital transfer

High baseline vulnerability. Silent infection, constipation, dehydration, new anticholinergic medicines, and environmental change are classic. Communicate with facility staff about baseline and medication list.[3][4]

Palliative and terminal delirium

Treat reversible contributors when consistent with goals of care. Agar trial cautions against assuming antipsychotics improve delirium scores in advanced illness.[8]

Alcohol withdrawal in older adults

Still a benzodiazepine-plus-thiamine pathway, but lower physiological reserve means closer monitoring for oversedation, aspiration, and Wernicke. Antipsychotics are not monotherapy.[3][4]

Complications and pitfalls

Classic pitfalls: missed hypoactive delirium; labelling as primary "psychosis" without medical work-up; benzodiazepines for non-withdrawal delirium; high-dose antipsychotics without non-drug care; physical restraint without de-escalation; missed Wernicke encephalopathy; capacity and unsafe discharge errors; ignoring sensory impairment and sleep disruption; assuming a normal CT excludes organic disease.[3][4][10]

Prognosis and disposition

Delirium is often reversible if precipitants reverse, but recovery of cognition may lag medical recovery by days to weeks. Witlox meta-analysis: independent associations with mortality, institutionalisation, and dementia after discharge.[12] BRAIN-ICU: longer delirium linked to worse global cognition and executive function at 3 and 12 months.[11]

Disposition plan: complete medical treatment, fall-prevention, deprescribing, cognitive follow-up (especially new impairment), carer education on fluctuating course, and step-down geriatric or CL review when indicated. Do not discharge a still-delirious older adult alone without a safety net.[3][12]

Capacity, risk, and the old-age psychiatry role

Capacity is decision-specific and time-specific. Delirium commonly impairs understanding, retention, weighing, and communication for complex decisions (self-discharge, refusing IV antibiotics). Document the decision, information given, functional abilities demonstrated, and fluctuating course (reassess when lucid). Use least-restrictive emergency treatment principles under local law; involve substitute decision-makers when criteria met. Risk assessment covers falls, wandering, violence, sexual vulnerability, absconding, and self-harm while confused.[3][4]

Old-age psychiatry adds: syndrome confirmation, DSD refinement, medication rationalisation (including anticholinergic burden), behavioural plan, capacity opinions, family communication, and liaison when mental health legislation is considered.[3][4]

Evidence summary for viva

Exam pearls

Exam traps: hypoactive disease is the most missed presentation in older adults; antipsychotics are not disease-modifying; alcohol withdrawal is not a primary antipsychotic pathway; capacity can be lost even if the patient "agrees cheerfully"; and PINCH ME / I WATCH DEATH mnemonics only score if expanded accurately.[1][3][4][6]

References

1. [1]Inouye SK, van Dyck CH, Alessi CA, et al. Clarifying confusion: the confusion assessment method. A new method for detection of delirium Ann Intern Med, 1990.PMID 2240918
2. [2]Inouye SK, Bogardus ST Jr, Charpentier PA, et al. A multicomponent intervention to prevent delirium in hospitalized older patients N Engl J Med, 1999.PMID 10053175
3. [3]Marcantonio ER Delirium in Hospitalized Older Adults N Engl J Med, 2017.PMID 29020579
4. [4]Oh ES, Fong TG, Hshieh TT, et al. Delirium in Older Persons: Advances in Diagnosis and Treatment JAMA, 2017.PMID 28973626
5. [5]Wilson JE, Mart MF, Cunningham C, et al. Delirium Nat Rev Dis Primers, 2020.PMID 33184265
6. [6]Girard TD, Exline MC, Carson SS, et al. Haloperidol and Ziprasidone for Treatment of Delirium in Critical Illness N Engl J Med, 2018.PMID 30346242
7. [7]Andersen-Ranberg NC, Poulsen LM, Perner A, et al. Haloperidol for the Treatment of Delirium in ICU Patients N Engl J Med, 2022.PMID 36286254
8. [8]Agar MR, Lawlor PG, Quinn S, et al. Efficacy of Oral Risperidone, Haloperidol, or Placebo for Symptoms of Delirium Among Patients in Palliative Care: A Randomized Clinical Trial JAMA Intern Med, 2017.PMID 27918778
9. [9]Burry L, Mehta S, Perreault MM, et al. Antipsychotics for treatment of delirium in hospitalised non-ICU patients Cochrane Database Syst Rev, 2018.PMID 29920656
10. [10]Neufeld KJ, Yue J, Robinson TN, et al. Antipsychotic Medication for Prevention and Treatment of Delirium in Hospitalized Adults: A Systematic Review and Meta-Analysis J Am Geriatr Soc, 2016.PMID 27004732
11. [11]Pandharipande PP, Girard TD, Jackson JC, et al. Long-term cognitive impairment after critical illness N Engl J Med, 2013.PMID 24088092
12. [12]Witlox J, Eurelings LS, de Jonghe JF, et al. Delirium in elderly patients and the risk of postdischarge mortality, institutionalization, and dementia: a meta-analysis JAMA, 2010.PMID 20664045
13. [13]Bellelli G, Morandi A, Davis DH, et al. Validation of the 4AT, a new instrument for rapid delirium screening: a study in 234 hospitalised older people Age Ageing, 2014.PMID 24590568
14. [14]Marcantonio ER, Ngo LH, O'Connor M, et al. 3D-CAM: derivation and validation of a 3-minute diagnostic interview for CAM-defined delirium: a cross-sectional diagnostic test study Ann Intern Med, 2014.PMID 25329203
15. [15]Meagher DJ, Leonard M, Donnelly S, et al. A longitudinal study of motor subtypes in delirium: frequency and stability during episodes J Psychosom Res, 2012.PMID 22325705
16. [16]Hshieh TT, Yue J, Oh E, et al. Effectiveness of multicomponent nonpharmacological delirium interventions: a meta-analysis JAMA Intern Med, 2015.PMID 25643002
17. [17]Hshieh TT, Yang T, Gartaganis SL, et al. Hospital Elder Life Program: Systematic Review and Meta-analysis of Effectiveness Am J Geriatr Psychiatry, 2018.PMID 30076080
18. [18]Inouye SK, Charpentier PA Precipitating factors for delirium in hospitalized elderly persons. Predictive model and interrelationship with baseline vulnerability JAMA, 1996.PMID 8596223