Aetiology, pathogenesis, differential diagnosis and management of acute confusional state in the elderly

Drugs only as last resort) and it will answer every version. Extra recall points are given at the end. Q1. Aetiology, pathogenesis, differential diagnosis and management of acute confusional state in the elderly 18 High-Yield Points (Textbook)

Factor Key exam point

D Drugs & drug withdrawal Commonest reversible cause; high index of suspicion in the vulnerable brain E Eyes, Ears Visual/hearing impairment — mainly predisposing L Low O2 / low perfusion MI, pulmonary embolism, stroke, cardiac or pulmonary failure, anaemia, anoxia I Infection Even mild infection can precipitate delirium in the vulnerable; do not over-treat behaviour as "infection"

R Retention of urine Cystocerebral syndrome — sudden delirium, muteness, restlessness I Indwelling urinary catheter Infection risk + a "one-point restraint" that impairs mobility U Underhydration BUN : creatinine ratio > 17:1 is associated with delirium and delirium risk M Metabolic Hypercalcaemia, hypokalaemia, hyponatraemia, hypernatraemia, hyperammonaemia I Immobility & inactivity Early mobilisation reduces delirium rate and duration S Sleep problems Sleep deprivation, sleep–wake reversal, sleep apnoea V Vascular changes / volume loss on Predisposing when interpreted with the history CT-MRI E Endocrinopathies Thyroid and adrenal disorders, hyper- and hypoglycaemia R Restraints Wrist restraints, IV lines, catheters, pneumatic compression devices, casts Y psYchiatric disorders Anxiety, depression, schizophrenia, bipolar disorder — predisposing P Pain Uncontrolled pain precipitates; but do not use opioids for behaviour. Regular paracetamol reduces opioid need A Attachments IV lines, telemetry — anything that tethers or annoys the patient I Impaction Severe constipation / faecal impaction N Neurological injury Subdural haematoma, intracerebral bleed, head trauma, stroke, tumour, encephalitis, meningitis, seizures F Frailty Major predisposing factor U Undernutrition Contributor; alters protein binding of drugs L Lights, loud noises Environmental; sensory input is misperceived Table 2. Delirium vs Dementia (Kane's, Table 6-3)

Feature Delirium Dementia

Onset / course Hours to days; days to weeks duration; marked Gradual over months to years; slowly progressive fluctuation Consciousness Altered and changing Unchanged until very late Attention Short attention span (core deficit) Attention span preserved Psychomotor Marked change — lethargic or agitated Baseline activity maintained Speech Often incoherent Word-finding difficulty, aphasia Hallucinations Common, usually visual; illusions Unusual until late (except Lewy body dementia) Sleep–wake cycle Disrupted Sleep disturbed, but cycle less affected CAM screen Positive Negative Acute illness / drug Usually evident No evidence of acute illness Latest Updates (2023–Present)

APA Practice Guideline for the Prevention and Treatment of Delirium (Sept 2025) — the first full revision since 1999 (brief update 2004). It shifts the emphasis firmly to prevention, mandates a thorough medication and risk-factor history, restricts restraints to situations of "imminent harm", and adds structured guidance on transitions of care (medication reconciliation, delirium follow-up, patient and caregiver psychoeducation). NICE CG103 (updated January 2023) — new recommendations on assessing and diagnosing delirium; the 4AT is now the NICE- and SIGN-endorsed bedside tool.

SCCM PADIS Focused Update 2025 (Crit Care Med 2025) — suggests dexmedetomidine over propofol when light sedation and/or delirium reduction are priorities; suggests enhanced mobilisation/rehabilitation and melatonin; explicitly suggests not using haloperidol, atypical antipsychotics, dexmedetomidine, statins or ketamine to prevent delirium; and could issue no recommendation for or against antipsychotics for treatment because effects on outcomes are minimal.

AGS Beers Criteria 2023 — anticholinergics are now split into antihistamines, CNS antiparkinsonian agents and GI antispasmodics, with explicit warning that combined anticholinergic burden raises the risk of delirium, falls, cognitive decline and possibly dementia. The companion AGS Beers Alternatives List (2025) supplies safer substitutes for drugs used in insomnia, anxiety, delirium and chronic pain.

Epidemiology refresh: a 2025 systematic review and meta-analysis of 35 studies (12,097 medically hospitalised older patients) found a pooled prevalence of 23.6% and a pooled incidence of 13.5%, with frailty, physical restraints, previous falls, illness severity, cognitive impairment and older age as the leading risk factors — validating the Pathy risk-factor table.

Ormseth et al. (JAMA Network Open 2023) — large systematic review confirming that predisposing and precipitating factors are almost always multifactorial rather than single-cause.

Biomarkers: genetic and proteomic risk-factor studies (Nature Aging 2026) are beginning to define a biological risk signature for delirium — not yet clinically usable.

Indian data: tertiary-care studies continue to show marked under-recognition — delirium accounts for only about 0.4% of total inpatients when identified through psychiatry referral, but Indian ICU studies using CAM-ICU report ~30% prevalence in non-ventilated elderly ICU patients, with hypoactive delirium commonest (~45%). The gap between referral-based and screening-based figures is itself an exam point.

Current Practice Update

Issue Pathy 6th edition (textbook) Current practice (2023–2026)

Guideline anchor AGS/ACS 2015 postoperative delirium statement; APA 2025 delirium guideline + PADIS Focused SCCM PADIS 2018 Update 2025 + NICE CG103 (2023)

Antipsychotics for treatment Evidence does not support use; reserve for severe Position hardened — PADIS 2025 could issue no agitation recommendation either way; APA 2025 restricts to imminent harm Antipsychotics for prevention Not supported Explicitly recommended against, along with statins and ketamine Sedative of choice in ICU Propofol or dexmedetomidine over benzodiazepines Dexmedetomidine preferred over propofol when light sedation / delirium reduction are the priority (watch bradycardia)

Melatonin Not recommended Conditionally suggested in ICU patients (PADIS 2025)

Screening tool emphasis CAM family emphasised 4AT endorsed by NICE and SIGN for rapid ward and ED use Restraints Avoid; no evidence of benefit Restricted to "imminent harm" only (APA 2025) Discharge Comprehensive discharge planning Formal transition-of-care block — medication reconciliation, delirium follow-up, caregiver education Exam One-Liners — Q1 Delirium = acute brain failure; the core deficit is inattention, not agitation.

Pathogenesis = Systems Integration Failure Hypothesis (Maldonado).

Mnemonic = DELIRIUM IS VERY PAINFUL.

Cystocerebral syndrome = delirium from urinary retention.

BUN : creatinine > 17:1 = dehydration-associated delirium risk.

CAM: sensitivity 94%, specificity 89%.

Gold standard diagnosis = DSM-5 / ICD-10; CAM/4AT are screens.

Mainstay of treatment = multicomponent non-pharmacologic care; behaviour tool = T-A-DA. No drug is FDA/EMA approved for delirium; benzodiazepines only for alcohol or benzodiazepine withdrawal. Up to 30–40% of delirium is preventable.