Delirium is characterised by confusion and/or altered conscious level associated with a physical cause. It is acute in onset, coming on quickly over hours or days. Symptoms fluctuate, with symptoms often worse in the evenings or overnight. It is a potentially life-threatening disorder characterised by high morbidity and mortality, and is a risk factor for subsequent cognitive impairment. Most delirium has a duration of a small number of days, but in around 20% of cases it can persist for weeks or months.
Delirium has been known by different terms in the past such as acute confusional state, acute confusion, and acute on chronic confusion. It is recommended that HCPs use the term Delirium rather than alternatives to promote more consistent communication among professionals, more accurate provision of information to patients and carers, and more consistent use of detection tools and management strategies.
Treatment should focus on identifying and treating the precipitant cause(s).
Features of delirium can include:
- Impairment of consciousness (disorientation, poor concentration)
- Change in behaviour (hyper or hypoactive)
- Irritability and disturbed sleep / reversal of sleep-wake cycle
- Changes in thinking and perception, including paranoia, hallucinations
- Impaired memory recall/retention during delirium, and amnesia of events after delirium
Causes of delirium are numerous and there are often multiple contributing factors. Common causes include:
- Infection
- Medications (including abrupt withdrawal from psychoactive medications)
- Alcohol (consumption and withdrawal)
- Metabolic failure
- Neurological (space occupying lesion, post ictal, normal pressure hydrocephalus)
Risk factors for delirium include: Acute illness; sensory impairment; recent discharge from hospital; Cognitive Impairment; constipation; polypharmacy; use of opioids, anticholinergics, and benzodiazepines; Depression; age over 70 years; recent anaesthetic / surgery; having a catheter; acute or chronic pain; history of alcohol misuse.
A.C & J.B – 6-7-26
Who to refer:
- Patients with delirium require urgent assessment and treatment of the cause. This may be clear and in these cases treatment can often be initiated by primary care.
- Refer patients to Hospital at Home who would otherwise require admission to hospital, or where the cause of delirium is not clear. Hospital at Home is the preferred choice for patients with Delirium as changes in environment will usually make delirium worse. If in doubt, all Hospital at Home services are happy to discuss referrals by telephone.
Who not to refer:
Patients with a history suggestive of longer-term cognitive decline rather than delirium should be referred to Older Peoples Mental Health for appropriate assessment.
How to refer:
If acutely unwell and Hospital at Home admission is appropriate, please refer to locality Hospital at Home (H@H) Locality Team
In all patients with delirium, consideration needs to be given to the likely causes – remember there may be more than one. If admission to hospital is being considered, please give careful consideration to a Hospital at Home referral instead; changes in environment will usually make delirium worse. If in doubt, all Hospital at Home services are happy to discuss referrals by telephone.
Assessment
- Consider other associated symptoms precipitating delirium (i.e. suggesting intercurrent illness)
- Collateral history essential (partner, family, carers)
- Cardiovascular, respiratory, abdominal, and neurological examinations as appropriate to identify intercurrent illness.
- Full medication review (in particular considering anticholinergic burden and consider any recent changes e.g. medication that may have been suddenly stopped)
- Alcohol history
- FBC, U&E, LFT, Calcium, TFT, CRP, B12/folate, Blood glucose
- MSU (do not use dipstick in >65 to assess for infection)
- Assessment of risk of staying at home vs. hospital admission – this will include falls risk, family’s ability to support and their understanding of delirium, existing care arrangements, risk, and appropriateness of acute admission, etc.
- Please provide patients and families with a diagnosis of delirium and information about delirium; explanation and reassurance goes a long way to alleviating patients’ and families’ concerns
Polypharmacy guidance including information about anticholinergic burden
NHS Lothian Guidance on Capacity and Consent (Intranet Link)
SIGN Guideline: Risk reduction and management of delirium
Assessment of delirium – Differential diagnosis of symptoms | BMJ Best Practice
