Delirium: detection, risk reduction and management

Use the 4AT to identify probable delirium in emergency departments and on acute hospital wards.

Strong recommendationSection 3.1

For anyone at risk, consider a multicomponent package of care: reorientation with glasses and hearing aids in use, sleep hygiene, early mobilisation, pain control, prevention and early treatment of postoperative complications, adequate hydration and nutrition, attention to bladder and bowel function, and oxygen where appropriate.

Conditional recommendationSection 4.2

Everyone at risk of delirium should have their medicines reviewed by an experienced healthcare professional.

Strong recommendationSection 5.1

Manage established delirium along a recognised pathway of good care: deal first with life-threatening causes, then look systematically for every contributing cause, since several often act together.

Strong recommendationSection 6

Record and code the diagnosis so that it travels with the person in handovers, referrals and discharge letters.

Good-practice pointSection 3.1

Delirium is an acute deterioration in mental function that develops over hours or days, mainly triggered by acute illness, surgery, trauma or drugs. It may show as cognitive change, drowsiness to the point of not speaking, agitation, or hallucinations and delusions, and is described as hyperactive, hypoactive or mixed.

Sections 1.1 and 1.2.3

A positive screening test must be followed by a formal assessment and diagnosis (against ICD or DSM criteria) by a suitably trained clinician.

Good-practice pointSection 3.1

In intensive care, consider the CAM-ICU or the ICDSC to identify probable delirium. The 4AT can also be considered in the community and other settings.

Conditional recommendationSection 3.1

Delirium fluctuates, so one negative test does not rule it out. When it is unclear whether a change is delirium, dementia or both, assume delirium unless the notes or the family confirm that this is the person's usual mental state.

Section 3.1

Take a collateral history from family or carers as early as possible: usual cognition and function, recent medicine changes, alcohol, falls, eating and drinking.

Annex 2; Annex 4

Assess capacity to make decisions about treatment and personal care, and complete the documentation your local law requires if the person lacks capacity.

Section 3.1

Check vital signs, oxygen saturation and capillary glucose straight away, and consider medicine intoxication in every case.

Annex 2

Tests commonly done, guided by history and examination: urea and electrolytes, full blood count, CRP, liver function, calcium, thyroid function, B12 and folate when indicated, blood cultures if infection is suspected, an ECG, and a chest X-ray if there are chest symptoms or signs. A bladder scan detects retention, and pain should be assessed.

Annex 2

Interpret urine dipsticks with care: a negative result makes infection less likely, but a positive one does not prove it, as asymptomatic bacteriuria is common in older people. Treat suspected urinary infection on clinical grounds.

Annex 2

Do not request a CT brain scan routinely. Consider one in people presenting to hospital with delirium plus new focal neurological signs, reduced consciousness not explained by another cause, recent falls, a head injury, or anticoagulant treatment.

Conditional recommendationSection 3.4.1

Consider imaging when delirium does not resolve and no clear cause has been found, or when features suggest primary brain disease.

Good-practice pointSection 3.4.1

Consider an EEG when epileptic activity or non-convulsive status epilepticus is suspected as the cause.

Conditional recommendationSection 3.4.2

Do not perform lumbar puncture routinely in delirium.

Good-practice pointSection 3.4.3

Optimise physiology, other conditions, medicines, the environment (including less noise) and natural sleep to help the brain recover.

Strong recommendationSection 6

Look for and treat the causes of agitation or distress, using non-drug measures wherever possible.

Strong recommendationSection 6

Prevent complications such as immobility, falls, pressure injury, dehydration, malnutrition and isolation, and promote cognitive engagement, mobilisation and rehabilitation.

Section 6

Evidence for treating delirium with antipsychotics is inconclusive. If one is started, review it daily and stop it as soon as the situation allows, usually within one to two days. If it has to continue after discharge or transfer, agree a plan for early review.

Section 7.1

Medicines are reserved for specific situations, such as intractable distress or when the safety of the person or others is at risk.

Section 7.5

There is not enough evidence to recommend antipsychotics or dexmedetomidine to prevent delirium, or cholinesterase inhibitors to treat it.

Sections 5.2, 5.3 and 7.3

In people over 60 having general anaesthesia for surgery expected to last more than an hour, monitor the depth of anaesthesia to avoid excessively deep anaesthesia.

Strong recommendationSection 4.2.1

In intensive care, consider earplugs as part of a sleep-promotion strategy.

Conditional recommendationSection 4.3

Risk rises with older age, dementia, frailty, multimorbidity, male sex, sensory impairment, depression, previous delirium and alcohol misuse. It affects up to half of people with hip fracture.

Section 1.1

Hypoactive delirium is common in older people, and delirium of any kind is frequently undetected.

Section 3.1; Annex 4

Benzodiazepines markedly increase the risk of delirium; avoid them except in specific situations such as alcohol withdrawal or seizures. Pain itself can precipitate delirium, so treat it, titrating opioids to the lowest effective dose and prescribing a laxative.

Section 5.1

Medicines to avoid, stop or reduce where possible include tricyclic antidepressants, anticholinergics, benzodiazepines, antihistamines and tramadol. Avoid stopping drugs with dependence potential abruptly.

Section 5.1; Annex 4

Avoid ward moves for people at risk, involve relatives and carers in care, and tell people having surgery (and their carers) about the risk of delirium beforehand.

Good-practice pointSection 4.2

Older people may have cognitive impairment that was never detected, or that delirium has made worse. Consider cognitive and functional assessment, timed with any persistent delirium in mind.

Strong recommendationSection 8

Only if symptoms threaten the safety of the person or others: use one drug at a low dose and review every 24 hours. Haloperidol 0.5–1 mg by mouth, or 0.5 mg intramuscularly, to a maximum of 2 mg in 24 hours. Haloperidol is contraindicated with other QTc-prolonging drugs.

Annex 4 (Scottish Delirium Association pathway)

Alternatively a low-dose atypical antipsychotic, for example risperidone 0.25 mg daily (maximum 1 mg in 24 hours). Do not use antipsychotics if there are signs of parkinsonism or Lewy body dementia.

Annex 4 (Scottish Delirium Association pathway)

If antipsychotics are contraindicated: lorazepam 0.5–1 mg by mouth (maximum 2 mg in 24 hours) or midazolam 2.5 mg intramuscularly (maximum 7.5 mg in 24 hours).

Annex 4 (Scottish Delirium Association pathway)

Refer to the appropriate local specialist if delirium is not improving after one week, or sooner if it is severe.

Annex 4 (Scottish Delirium Association pathway)

Involve liaison psychiatry for severe agitation or distress that does not respond to standard measures, doubt about the diagnosis, or when detention under mental health law is being considered.

Annex 4 (Scottish Delirium Association pathway)

After delirium in intensive care, consider follow-up for psychological after-effects, including cognitive impairment.

Conditional recommendationSection 8

Note the delirium in the discharge letter. Everyone who has had delirium should be reviewed by the primary care team, and their record coded to flag the higher risk if they are admitted again.

Good-practice pointSection 8

Act first on acute, severe causes: sepsis, hypoxia, hypoglycaemia, low blood pressure, and drug intoxication or withdrawal.

Section 6; Annex 4

Delirium with new focal neurological signs, reduced consciousness, a head injury, a recent fall or anticoagulant treatment: consider brain imaging, urgently if the person is anticoagulated.

Section 3.4.1; Annex 4

Sudden unexplained confusion (onset within 24 hours) with poor response to simple commands may be non-convulsive status epilepticus.

Section 3.4.2

Where meningitis, encephalitis or sepsis is suspected as the cause, manage it as the emergency it is.

Section 3.4

SIGN 157 was published in March 2019 and revalidated in 2022. SIGN planned to consider it for review in 2025.

SIGN guideline page