Delirium / acute confusion: workup and approach
Acute fluctuating disturbance of attention and awareness. Delirium is a medical emergency with an underlying cause, often more than one. Screen with CAM, look systematically for causes, and manage without sedatives where possible.
Presenting complaint
Adult · US guidelines
Draft · awaiting physician review
01Orient
What's new in the evidence
- AGS 2025 companion to the Beers Criteria: multicomponent nonpharmacologic care (e.g., HELP) first; no medication is recommended routinely
- Antipsychotics only short-term (hours to days) for severe, dangerous agitation, with documented risks and a stop plan
- Haloperidol does not prevent delirium; ICU meta-analyses suggest possible benefit for treatment without clear harm
Differential diagnoses
- Infection (UTI, pneumonia, sepsis)
- Medications: anticholinergics, opioids, benzodiazepines, steroids
- Alcohol or benzodiazepine withdrawal
- Metabolic: hypo/hyperglycemia, hyponatremia, hypercalcemia, uremia, hepatic encephalopathy
- Hypoxia or hypercapnia
- Urinary retention, constipation, pain
- Stroke, subdural hematoma, seizure (non-convulsive)
- Underlying dementia (risk factor, not cause)
02Assess
Risk scores and decision tools
- 4AT or CAM (CAM-ICU in ICU)
- RASS for arousal
- Medication review against the 2023 Beers Criteria
Key history questions
- Collateral: baseline cognition and function, onset and fluctuation
- Medication changes, especially new psychoactive drugs
- Alcohol use and last drink
- Falls or head injury
- Urinary and bowel habits, pain
- Infection symptoms
Examination findings
- Attention tests (months backwards); CAM or 4AT
- Vitals, SpO2, glucose
- Focal neurology, meningism
- Palpable bladder, fecal impaction
- Signs of withdrawal: tremor, sweating, tachycardia
03Investigate
Initial investigations
- Fingerstick glucose
- CBC, BMP, calcium, magnesium, LFTs
- Urinalysis (only treat with urinary symptoms or sepsis)
- Chest X-ray, ECG
- Medication review
- Bladder scan
Advanced investigations
- CT head if focal signs, fall, anticoagulation or no cause found
- Blood gas, ammonia (if liver disease), TSH, B12
- EEG for suspected non-convulsive seizures
- Lumbar puncture if meningitis or encephalitis suspected
04Treat
Immediate management
- Treat the cause(s)
- Stop or reduce deliriogenic drugs
- Ensure safety without restraints where possible
First-line treatment
- Non-drug measures: reorientation, glasses and hearing aids, family presence, sleep hygiene, early mobilization
- Treat pain, retention and constipation
- Hydration and nutrition
Second-line treatment
- Low-dose antipsychotic only for severe distress or danger (e.g. haloperidol 0.5-1 mg); check QTc
- Avoid antipsychotics in Parkinson's or Lewy body dementia
- Benzodiazepines only for alcohol or benzodiazepine withdrawal
Specialist referrals
- Geriatrics or psychiatry liaison for complex delirium
- Neurology for seizures or focal deficits
05Disposition
Admission criteria
- New delirium in almost all cases
- Unclear cause, or cause needing inpatient treatment
- Unsafe at home
Safe discharge criteria
- Cause treated and cognition back to baseline (or improving with support)
- Safe home environment with carers informed
Follow-up timing
- Primary care within 2 weeks; cognitive review at 3 months
Patient instructions
- Carers to watch for recurrence of confusion
Monitoring
- Daily CAM or 4AT
- Sleep, bowel and urine output charts
Clinical pearls and pitfalls
- Hypoactive delirium is common and frequently missed
- Delirium may take weeks to clear and raises dementia and mortality risk
RefGuidelines and landmark evidence
For education only. Typical adult starting points; confirm doses against renal function, allergies, interactions and your institution's protocols. Not a substitute for clinical judgment or senior review.