Confusion — Acute Confusional State
GP assessment of acute vs chronic confusion — delirium, dementia and organic causes
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The full reasoning pathway — first split acute (delirium — a medical emergency, hunt the cause) from chronic (dementia work-up), screen the killers, find & treat the precipitant or run reversible-cause bloods, then manage, refer and safety-net.StartDecisionInvestigateActionReferStop / Admit
PresentationConfusion
Collateral history is essential — acute (hours–days, fluctuating) vs chronic (months, progressive)? Time course, drugs, alcohol, function. Examine, full obs, capillary glucose, screen with 4AT.
Drug or alcohol withdrawal (delirium tremens, Wernicke's), opioid/anticholinergic toxicity
ACUTE — delirium
Stop · actTreat cause / admit
4AT positive + acute onset → delirium. Treat hypoglycaemia/hypoxia/sepsis now; admit if unwell, unsafe, or cause not treatable in the community. Wernicke's → IV thiamine.
999 if reduced consciousness, focal neurology, fever + neck stiffness, or new seizure. Same-day if confusion worsens, new fever, or unsafe at home. Review: delirium should improve as the cause is treated — if it doesn't fully resolve, reassess (occult cause, or underlying dementia unmasked); chase reversible-cause bloods and arrange cognitive follow-up.
⚠️ New confusion is delirium until proven otherwise: acute fluctuating inattention demands a hunt for an organic precipitant — never assume it is "just dementia". Always check a glucose, screen for sepsis, and review the drug chart.
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Safety
Red Flags — Life-Threatening Causes of Confusion
First, establish: Is this acute (delirium) or chronic (dementia)? Delirium is a medical emergency until proven otherwise.
Fever + confusion + neck stiffness Bacterial meningitis / encephalitis → 999 + IM benzylpenicillin 1.2 g before transfer (do not delay for LP)
Hypoglycaemia BM <4 mmol/L + confusion → check glucose immediately. Glucogel PO if swallow safe; 999 if not. Most reversible cause.
Stroke — acute onset FAST positive + confusion → 999. Posterior circulation stroke commonly presents with confusion without obvious motor signs.
Head injury Subdural haematoma — lucid interval then deteriorating consciousness. Any confusion post-head injury → CT same-day
Bacterial meningitis kills within hours — IM benzylpenicillin must be given before transfer if there is any suspicion (rash, fever, neck stiffness, photophobia, confusion) and should not wait for LP. Hypoglycaemia is the most common and instantly reversible cause of acute confusion — blood glucose must be checked at every confused patient assessment. Sepsis-related confusion (acute brain dysfunction in sepsis) carries 40% mortality — early antibiotics and fluid resuscitation are time-critical. Serotonin syndrome is increasingly common as SSRI prescribing grows — the clonus on neurological examination (sustained rhythmic ankle/patella clonus) distinguishes it from neuroleptic malignant syndrome.
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Diagnose
Delirium vs Dementia vs Psychiatric — Key Distinction
This distinction drives the entire management pathway. Collateral history is essential.
Delirium (acute)
Onset hours–days. Fluctuating course — waxes and wanes during the day. Disturbed attention and arousal. Always has a precipitant. Treat the cause. (NICE CG103)
Dementia (chronic)
Onset months–years. Gradual progressive decline. Memory, language, executive function impaired. No fluctuation at baseline (unless Lewy body). No acute precipitant.
Delirium on dementia
Most common presentation in hospital elderly — background cognitive impairment + acute deterioration. Always investigate for precipitating cause even in known dementia.
Always obtain from family/carer — baseline cognitive function, timeframe of change, medications, falls, infections, alcohol use
The distinction between delirium and dementia is clinically critical — delirium is a medical emergency requiring identification and treatment of the precipitant, while dementia is a chronic condition requiring a different management pathway. The key discriminating features are: onset (acute vs gradual) and fluctuation (delirium fluctuates during the day — patients may be lucid at some times and confused at others). The 4AT takes <2 minutes and has been validated in multiple settings (sensitivity 76–88%, specificity 88–99%). Delirium on background dementia is the most common presentation in elderly hospital admissions — even patients with known dementia always warrant investigation for a precipitating cause.
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Diagnose
Find the Cause — PINCH ME Framework
Use PINCH ME to systematically identify delirium precipitants.
P — Pain
Uncontrolled pain is a common and often unrecognised cause of delirium in non-verbal patients (dementia, stroke). Examine systematically for painful conditions.
I — Infection
UTI (most common in elderly women), pneumonia (may be afebrile in elderly), cellulitis, dental abscess, biliary. Dipstick + MSU + CXR + FBC + CRP
Anticholinergics (oxybutynin, amitriptyline, chlorphenamine), opioids, benzodiazepines, digoxin toxicity, steroids, new medication started recently → stop/review
E — Environment
Unfamiliar environment, sensory deprivation (no glasses/hearing aids), immobility, catheter, Foley — all contribute to and worsen delirium
PINCH ME is a validated memory aid used in NICE CG103 education. Dehydration is the most common single precipitant of delirium in the community — simple oral or IV rehydration resolves confusion in many cases. Anticholinergic burden is a major contributor to delirium and chronic cognitive impairment — oxybutynin, chlorphenamine, and tricyclics all cross the blood-brain barrier. The ACB (anticholinergic cognitive burden) score helps quantify total anticholinergic load. Constipation causes delirium through pain, metabolic disturbance, and autonomic effects — it is underdiagnosed in non-verbal patients.
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Diagnose
Targeted Examination
4AT / cognitive screen
4AT score. If chronic confusion: MoCA (10 minutes) or MMSE. MoCA <26/30 = cognitive impairment. MMSE <24/30 = significant impairment.
Dipstick at bedside — leucocytes + nitrites = UTI likely. Note: asymptomatic bacteriuria in elderly does not cause confusion and should not be treated.
Skin
Cellulitis, pressure sores, rashes (meningococcal, drug reaction), jaundice, signs of liver disease, signs of alcohol dependence
Asymptomatic bacteriuria (positive urine dipstick in an elderly patient without urinary symptoms) is extremely common (30–50% of elderly women) and is not a cause of confusion — treating it with antibiotics contributes to antibiotic resistance without benefit. Pneumonia in the elderly frequently presents without fever (40% are afebrile) — CXR is essential. Urinary retention causes severe pain and delirium in non-verbal patients — suprapubic palpation + bladder scanner should be performed in all confused elderly patients, especially men with BPH on anticholinergics or opioids.
Urine drug screen · Paracetamol level (occult overdose in elderly) · Digoxin level if applicable · Alcohol
Neuroimaging
CT head — if focal signs, post head-trauma, papilloedema, anticoagulated, or no cause found. Not required for all delirium. Organised in hospital.
Dementia bloods
For new dementia assessment: FBC, U&E, LFTs, TFTs, B12, folate, glucose, lipids, CRP, syphilis serology, HIV (selective). Then MRI brain via memory clinic.
Bedside glucose testing is mandatory in every confused patient — hypoglycaemia is instantly fatal if not corrected and instantly reversible if it is. ECG is important in acute confusion — silent MI (particularly inferior MI) commonly presents with confusion in elderly patients without chest pain; AF causes reduced cardiac output and cerebral hypoperfusion. B12 deficiency causes a reversible dementia-like picture — levels should be checked in all new memory complaints. Paracetamol overdose (deliberate or accidental excess in the elderly) causes confusion through incipient liver failure — serum paracetamol level should be checked in any unexplained elevated LFTs with confusion.
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Refer
Referral Criteria
999
Meningism + fever, stroke (FAST+), seizures, severe hypoglycaemia unresponsive to oral glucose, opioid toxicity (naloxone), serotonin syndrome, haemodynamic instability
Same-day hospital
Acute delirium with unidentified cause, electrolyte abnormalities requiring IV correction, severe dehydration, sepsis, alcohol withdrawal, falls risk with confused patient alone
Urgent memory clinic
New dementia suspected — refer via GP using local pathway. NICE NG97 recommends referral within 6 weeks of identification. MoCA/MMSE + dementia bloods done first.
Old age psychiatry
Dementia with severe BPSD (behavioural and psychological symptoms), suspected dementia + psychosis, diagnostic uncertainty
Confused patient unsafe at home alone — urgent social care assessment. Safeguarding referral if self-neglect or suspected abuse. Mental Capacity Act (MCA) assessment if needed.
Community delirium management (treating the cause at home) is appropriate only when: the patient is safe, the cause is identified and treatable at home, adequate supervision exists, and the patient can be monitored. Any uncertainty → hospital admission. Memory clinic referral should not be delayed — early diagnosis of dementia allows advance care planning, medication initiation (donepezil), carer support, and legal planning (LPA, advance directives) while the patient has capacity. Mental Capacity Act assessment is required before any major decisions are made for an incapacitous person — GPs play a central role in assessing capacity.
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Treat
Management — Delirium & Dementia
Delirium — treat cause
Antibiotics / rehydration / analgesia
Treat the identified precipitant: IV/PO antibiotics for infection, IV fluids for dehydration, opioid reduction for drug-induced, bowel care for constipation. Non-pharmacological first.
Agitation in delirium (severe)
Haloperidol 0.5 mg PO
Last resort. Contraindicated in Parkinsonism/Lewy body. Lowest effective dose, shortest duration. NICE CG103. Lorazepam 0.5 mg if Parkinsonism or alcohol withdrawal.
Alzheimer's dementia
Donepezil 5 mg nocte
Initiated by memory clinic. Review at 3–6 months. Increase to 10 mg nocte if tolerated after 4 weeks. GI side effects (nausea, diarrhoea) common. Check HR (bradycardia risk).
UTINitrofurantoin 100 mg MR BD for 5 days (if eGFR >30) — first-line per local antibiogram. Trimethoprim 200 mg BD if nitrofurantoin not suitable. Avoid antibiotics for asymptomatic bacteriuria.
Hepatic encephalopathyLactulose 15–30 ml BD–TDS (target 2 soft stools/day to clear ammonia). Rifaximin for recurrent episodes (specialist initiated).
B12 deficiencyHydroxocobalamin 1 mg IM on alternate days × 6 doses then 3-monthly. Cognitive improvement expected over 3–6 months.
Non-pharmacological delirium management (HELP — Hospital Elder Life Program principles: reorientation, sleep preservation, mobilisation, hydration, sensory aids) reduces delirium duration by 30% and is safer than pharmacological sedation. Haloperidol does not shorten delirium duration but reduces severity of agitation — it should be used only when non-pharmacological measures fail and the patient is at risk of harm. Donepezil in Alzheimer's reduces MMSE decline by 2–3 points at 6 months (NNT ~3 for any benefit) and delays nursing home placement — it is clinically meaningful despite modest effect sizes.
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Lifestyle
Delirium Prevention & Dementia Support
Orientation aids Familiar clock, calendar, family photos, natural light. Orient patient to time and place at every interaction. Family presence reduces distress and confusion duration.
Sensory aids Ensure glasses and hearing aids are worn — sensory deprivation worsens confusion. Check batteries. Loss of aids is common in hospital and community settings.
Hydration Offer fluids regularly — aim 1.5–2 litres/day. Dehydration is both a cause and consequence of delirium. Thirst sensation diminishes with age.
Medication review Anticholinergic burden review (ACB calculator) — reduce or stop opioids, benzodiazepines, anticholinergics where possible. Polypharmacy is a major risk factor for delirium.
Sleep preservation Regular day/night routine — lights on during day, quiet at night. Avoid unnecessary medication at night. Melatonin 2 mg modified-release for sleep regulation in delirium prevention (evidence in elderly).
Mobilisation Prevent bed rest — encourage movement, physiotherapy. Immobility worsens delirium and accelerates muscle loss. Delirium prevention includes falls prevention.
Carer education Explain delirium is a brain response to illness, not madness — reduces carer distress. Provide written information. Alzheimer's Society (0333 150 3456) and Dementia UK Admiral Nurses (0800 888 6678).
Advance care planning For dementia: Lasting Power of Attorney (financial + health/welfare), advance decision to refuse treatment (ADRT), preferred place of care. Ideally discuss while capacity is retained.
The HELP (Hospital Elder Life Program) multicomponent delirium prevention program reduces incident delirium by 33% and delirium duration by 30% using six non-pharmacological interventions: orientation, therapeutic activities, vision and hearing adaptations, sleep protocol, hydration, and early mobilisation. Anticholinergic cognitive burden (ACB scale) is important — total ACB score >3 is associated with 4× increased risk of cognitive impairment. Early Lasting Power of Attorney is one of the most important GP interventions in early dementia — 30% of patients with moderate dementia lack capacity to make LPA decisions. Early GP support facilitates this vital legal protection.
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Safety
Follow-Up & Safety-Netting
24–48 hours
Delirium: follow up urgently — is confusion improving? Cause identified and treated? Safe at home? Carer coping? If worsening → hospital admission.
1–2 weeks
Post-delirium review — cognitive baseline restored? Medication review completed? MoCA/MMSE to document cognitive state after acute illness resolves.
3–6 months
Post-delirium dementia risk: 25–40% of patients who have delirium subsequently develop dementia — monitor with MoCA. Refer to memory clinic if cognitive decline continues.
DVLA must be notified by patient with dementia — GP has duty to advise and document. If patient refuses → GP can inform DVLA without consent (patient safety). On-road driving assessment via DVLA.
999 safety-net
Sudden deterioration in consciousness, new focal neurological signs, high fever + neck stiffness, acute stroke symptoms, respiratory distress
Same-day GP
Worsening confusion despite treatment, unable to maintain safe home situation, new fall with injury, severe agitation, carer breakdown
Post-delirium cognitive vulnerability is a critical and underrecognised phenomenon — patients who experience delirium have a 2–5× increased risk of developing dementia over subsequent years. This is a biological relationship (delirium causes neuroinflammation and accelerated neurodegeneration) not just unmasking of pre-existing dementia. Driving with dementia is a major public safety issue — GPs have a legal and ethical duty to advise patients to stop driving when unsafe and to notify DVLA if the patient refuses. The Zarit Burden Interview is a validated carer burden tool — scores >40 indicate significant carer distress requiring support and respite services.
Educational use only. Based on NICE CG103 (Delirium, 2010), NICE NG97 (Dementia, 2018), NICE CG140 (Infection in Older People), British Geriatrics Society PINCH ME framework, Mental Capacity Act (2005). Always adapt to individual patient context and local pathways.