The confused patient (delirium)
New confusion is delirium until proven otherwise. Check the sugar, look for the cause, and calm without drugs first.
"Bed 22 is pulling out her cannula and shouting." She is 79, admitted two days ago with a fall, normally lives with her son and manages at home. Now she thinks the nurse is stealing from her.
What do you check first, and what do you avoid?
- Sugar firstBelow 4 mmol/L (72 mg/dL): treat it now.
- ObservationsSpO₂, temperature, BP, pulse, GCS.
- 4AT at the bedsideTakes 2 minutes. 4 or more suggests delirium.
- Find the causeInfection, drugs, retention, constipation, pain, low oxygen, salts, withdrawal.
- Calm without drugs firstFamily, light, glasses, hearing aid, quiet voice, one nurse.
- Drugs only for dangerSmall dose, one drug, written reason.
- Document and hand overWhat you found, what you gave, what to recheck.
- GCS falling or new focal weakness
- Low BP, fever or sepsis signs
- Risk to self or others despite non-drug measures
- Suspected alcohol withdrawal or Wernicke's
- Head injury from a fall on anticoagulants
| Low sugar | Below 4 mmol/L (72 mg/dL): treat before anything else |
| 4AT score | 4 or more: possible delirium, 1–3: possible cognitive impairment, 0: delirium unlikely |
| Low oxygen | SpO₂ below 92% on air (below 88% in a known CO₂ retainer) |
| Sodium | Below 125 mmol/L (mEq/L) or a fast fall can cause confusion |
| Urinary retention | Bladder scan above about 500 mL in a confused older patient |
| Alcohol | Last drink 6–72 hours ago: think withdrawal |
Check every dose against a current drug reference and your hospital protocol.
On this page
The 4AT in two minutes
| Item | How | Score |
|---|---|---|
| Alertness | Normal, or abnormal (drowsy or agitated) | 0 or 4 |
| AMT4 | Age, date of birth, place, current year | 0 (no mistakes), 1 (one), 2 (two or more) |
| Attention | Months of the year backwards from December | 0 (7 or more correct), 1 (starts but fewer than 7), 2 (can't start) |
| Acute change | New or fluctuating change in alertness or thinking | 0 or 4 |
Total 4 or more: possible delirium. Look for the cause.
Delirium or dementia?
| Feature | Delirium | Dementia |
|---|---|---|
| Onset | Hours to days | Months to years |
| Course | Fluctuates, worse at night | Slowly progressive |
| Attention | Poor | Usually preserved early |
| Alertness | Drowsy or agitated | Normal |
| Reversible? | Usually, if cause treated | No |
Dementia is the biggest risk factor for delirium. The family's answer to "Is this how she normally is?" is the most useful history you will take.
Find the cause
- PPainFracture, retention, constipation, wounds
- IInfectionChest, urine, skin, lines, meningitis rarely
- NNutrition and hydrationDry, low sodium, high calcium, low sugar
- CConstipationAsk, examine, rectal exam if needed
- HHypoxiaSpO₂, gas if low
- MMedicationOpioids, sedatives, anticholinergics, steroids, new drugs; withdrawal of alcohol or benzodiazepines
- EEnvironmentNew ward, night, no glasses or hearing aid, catheter, restraints
| Test | Why |
|---|---|
| Sugar, gas if low SpO₂ | Hypoglycaemia, hypoxia, CO₂ |
| CBC, CRP, cultures if febrile | Infection |
| Sodium, potassium, calcium, urea, creatinine | Salts, kidneys |
| LFTs, ammonia if liver disease | Hepatic encephalopathy |
| Urine dipstick only if urinary symptoms | Dipsticks are often positive in older people without infection |
| Bladder scan | Retention |
| CT head | Fall, anticoagulants, focal signs, falling GCS |
Calming without drugs
- Speak slowly, introduce yourself, explain where she is.
- One familiar person at the bedside (son, daughter).
- Glasses and hearing aid on. Lights on dimly at night.
- Remove what irritates: tight cannula, catheter if not needed, restraints.
- Same nurse where possible. Avoid moving beds at night.
When drugs are needed
Use one drug, the smallest dose, and review within hours. Sedation masks the cause and causes falls and aspiration.
Document
- 4AT score, what you think the cause is, what you checked.
- What you tried before drugs, what drug and dose you gave, and why.
- What the next team must recheck (sugar, sodium, scan, urine output).
Frequently asked questions
What is the treatment of delirium?
Treat the cause (infection, drugs, retention, constipation, hypoxia, salts, withdrawal) and use non-drug calming. Use a small dose of haloperidol only for severe distress or danger, and avoid it in Parkinson's disease.
What is the difference between delirium and dementia?
Delirium starts suddenly, fluctuates and impairs attention; it is usually reversible. Dementia is slow and progressive with attention preserved early on.
What is the 4AT?
A two-minute bedside screen for delirium: alertness, four orientation questions, months backwards and acute change. A score of 4 or more suggests delirium.
Test yourself
Exam-style questions on this guide, from our two question banks. Choose an answer to see why each option is right or wrong.
1. A 79-year-old woman becomes newly agitated at night. Bladder scan shows 900 mL. What is the next step?
Answer: Catheterise. Urinary retention is a common, quickly reversible cause of delirium.
- CT head: Not the first step.
- Restraints: Harmful.
- Antibiotics: No infection evidence.
- Haloperidol: Treat the cause first.
2. A patient with Parkinson's disease is agitated and hitting staff despite non-drug measures. Which drug should be avoided?
Answer: Haloperidol. Antipsychotics can cause severe rigidity and worsen Parkinson's disease and Lewy body dementia.
- Family at the bedside: Fine.
- Low-dose lorazepam: Can be used cautiously.
- Treating constipation: Fine.
- Paracetamol for pain: Fine.
3. A man with heavy alcohol use is confused, ataxic and has nystagmus. What should be given before glucose?
Answer: IV thiamine. Possible Wernicke's encephalopathy: give IV thiamine before glucose.
- Folic acid only: Thiamine is the key.
- Flumazenil: No.
- Naloxone: Not opioid.
- Haloperidol: Doesn't treat the cause.
4. An 82-year-old admitted with pneumonia becomes acutely confused at night, inattentive and agitated, then drowsy by day. What is the first priority?
Answer: Find and treat the cause. Delirium is an acute fluctuating disturbance of attention and awareness due to a medical cause: infection, drugs (anticholinergics, opioids, benzodiazepines), dehydration, electrolytes, urinary retention, constipation, hypoxia, pain, alcohol withdrawal. Manage with non-pharmacological measures (orientation, family, glasses/hearing aids, sleep hygiene) and treat causes. Low-dose haloperidol only for severe distress or risk. Avoid benzodiazepines except in alcohol withdrawal.
- Start donepezil: Donepezil is a dementia drug.
- Restrain physically: Restraint worsens delirium.
- Give haloperidol as first step: Haloperidol is used only if the patient is distressed or dangerous.
5. A malnourished alcoholic admitted with vomiting becomes confused, ataxic and has nystagmus with lateral rectus palsy. What should be given before glucose?
Answer: IV thiamine (Pabrinex). Wernicke encephalopathy (thiamine deficiency): triad of confusion, ataxia and ophthalmoplegia (nystagmus, lateral rectus palsy) — often incomplete. Seen in alcohol misuse, hyperemesis, malnutrition, bariatric surgery. Give high-dose IV thiamine before or with glucose. Untreated → Korsakoff syndrome (anterograde amnesia with confabulation), mammillary body damage.
- Oral folic acid: Folic acid is not urgent.
- IV dextrose alone: Glucose first can precipitate Wernicke encephalopathy.
- Chlordiazepoxide only: Chlordiazepoxide does not treat Wernicke.
6. Benzodiazepines, barbiturates and some anticonvulsants work by enhancing which neurotransmitter?
Answer: GABA. GABA is the main inhibitory neurotransmitter of the brain. Benzodiazepines increase the frequency of GABA-A chloride channel opening; barbiturates increase its duration. More chloride enters neurons, which become harder to excite. Flumazenil reverses benzodiazepines.
- Glutamate: The main excitatory transmitter; blocked by drugs like ketamine and memantine.
- Dopamine: Affected by antipsychotics and Parkinson's drugs.
- Acetylcholine: Affected by anticholinesterases and antimuscarinics.
- Serotonin: Affected by SSRIs and triptans.
7. Which benzodiazepine forms long-acting active metabolites?
Answer: Diazepam. Diazepam is metabolised in the liver to active metabolites such as desmethyldiazepam, which have very long half-lives, so effects last days and accumulate in the elderly and in liver disease. Lorazepam, oxazepam and temazepam are directly glucuronidated with no active metabolites, so they are safer in liver disease.
- Lorazepam: No active metabolites.
- Oxazepam: No active metabolites.
- Temazepam: No active metabolites.
- Midazolam: Short-acting; minor metabolites.
References and dose sources
- NICE CG103: Delirium
- The 4AT rapid assessment test for delirium
- Lorazepam dosing: Drugs.com: Lorazepam dosage (see also our lorazepam dose page)
- Thiamine (vitamin B1) dosing: Drugs.com: Thiamine dosage (see also our thiamine (vitamin b1) dose page)
International guidance is linked where it reflects good practice. Where your hospital’s protocol differs, follow your hospital.