Recognising, assessing, and treating delirium

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Delirium is particularly prevalent in critical care and palliative care settings, and in residential aged care facilities. It is estimated that over 40 percent of people receiving palliative care experience delirium with the prevalence increasing to over 80 per cent at the end of life. It is important you understand that delirium causes distress for the person with delirium, their families, and the treating health care providers.

Where an older adult experiences delirium, it is often associated with prolonged hospitalisation, decline in cognitive and physical functioning, rehospitalisation, placement in residential aged care, and death.

The risk of developing delirium is particularly high in end-stage diseases, and cognitive impairment can increase the risk of onset.


Delirium is an acute change in a person’s mental status characterised by fluctuating disturbances in consciousness, attention, cognition, and perception. There is commonly an exacerbation of agitation and confusion at night and when the person wakes.

“Terminal delirium' is a commonly used phrase. It indicates delirium in a person in the final days/weeks of their life.

Delirium is characterised by disorientation, reduced attention and concentration, disorganised thinking and behaviour, memory deficits and, sometimes, perceptual disturbances including hallucinations or delusional beliefs.

Behavioural changes may be noted such as agitation, sleep disturbance, depressed mood, or anxiety.
Family or carers are key in detecting early signs of delirium; they often know that the person “isn't quite right” yet they may not share their observations or concerns. Follow up on any indications given by people who know the person well.

Delirium is potentially preventable in up to two-thirds of hospitalised patients and is often treatable.
The cause of delirium can be multifactorial and includes opioid use, dehydration, and infection. Sensory impairment (difficulty in hearing or seeing), cognitive impairment and depression are risk factor in older people.

Delirium is less likely to be recognised in people with frailty or dementia.

Dementia is a risk factor for delirium. This can complicate diagnosis, as some people who present to hospital with delirium may have underlying and undiagnosed dementia.

Not recognising the symptoms of delirium as such and confusing them with an undiagnosed dementia can delay the treatment of delirium.

It is important to find and treat the cause of delirium as early as possible as it can be reversed with early detection and medical attention.

The Australian Commission on Safety and Quality in Health Care’s Delirium Clinical Care Standard (2021) describes the key components of care for people at risk of or experiencing delirium.

Asking the person's relative or friend: “Do you think (person's name) has been more confused recently?” may help with early recognition of delirium.

Check with families if the person’s behaviour is in step with usual cultural beliefs or behaviour or specific rituals and ceremonies.

There are many screening tools validated for the assessment of delirium.
Screening tools that nurses might use include the:

The CAM and MDAS have been tested and validated for use with palliative care patients.
The Confusion Assessment Method - Severity (CAM-S) can be used alongside the CAM to quantify the intensity of delirium symptoms.

Delirium is different to dementia. The acute onset and fluctuation of symptoms in delirium usually assists in differentiation, and the input from family or significant others is also important to separate a delirium from an underlying dementia.

Delirium may be reversible if it is caused by an infection, urinary retention, severe constipation, dehydration, pain, or a side effect of medication. The GP or nurse practitioner will check for any underlying and reversible causes. A medicines review may help reduce the risk of delirium.

As a nurse you can:

  • keep a calm demeanour and reassure the person if they are worried or frightened
  • communicate clearly – use short sentences and plain language, and make sure the person understands you; remind the person where they are, and what day it is
  • explain what is being done and why
  • help the person become familiar with their environment - make sure they can see a clock and a calendar; can see day light; where relevant, check that hearing aids and glasses work well and are used
  • encourage visits from people who are familiar to the person; they can bring in personal items that are familiar to the person or treasured
  • limit change where possible – staff changes and room changes can be disorienting
  • keep the person safe by making sure someone is with the person all the time if they are agitated, likely to wander or at risk of falling
  • encourage the person to eat and drink, and if they have dentures make sure they are clean and fit well.
  • support the person to avoid or manage constipation and urinary retention. Try to avoid using a catheter if possible
  • encourage a good sleep routine, limiting noise at night
  • look out for signs of infection
  • check for signs that the person is in pain and help to make sure this is well managed
  • help the person remain mobile – give them support to walk or do other exercises safely
  • if the person is taken to hospital or a care home, help to arrange for familiar objects to accompany them
  • prevent complications of delirium such as immobility, falls, pressure sores, dehydration, malnourishment, isolation.

To help the family and carer(s), nurses can

  • explain that delirium is a change in mental state that often starts suddenly but usually improves when the physical condition improves and the underlying cause is treated
  • explain the importance of visits from people who are familiar to the person and the presence of personal items that are familiar to the person or treasured
  • explain how they can help by:
    • providing a calm and reassuring presence
    • speaking gently and clearly and orienting the person to where they are
    • ensuring the person has their glasses on, hearing aids fitted or any other aids to be able to hear and communicate well
    • encouraging the person to eat and drink
    • ensuring that the person is safe and comfortable when resting
    • encouraging the person to safely mobilise
  • explain what is being done and why
  • encourage those who know the person well to tell healthcare professionals about any changes to the person's condition or behaviour.

Medicines used in the treatment of delirium include antipsychotics (used to treat mental distress) and benzodiazepines (sedatives). These tend to only be used if the non-drug treatment methods have not worked and the person is in severe distress, and/or at risk of harming themself or others.

It is important that physical causes of the delirium such as infection or loss of hearing aids are eliminated before moving to these drugs.

It may help to ask the doctor or pharmacist to review the person’s medicines.

Allied health professionals who can help

Music therapists may be able to help in the prevention and management of delirium.

This information was drawn from the following resources:


  1. Australian Commission on Safety and Quality in Health Care (ACSQHC). Delirium clinical care standard. Sydney: ACSQHC; 2021.
  2. Bush SH, Lawlor PG, Ryan K, Centeno C, Lucchesi M, Kanji S, et al. Delirium in adult cancer patients: ESMO ClinicalPractice Guidelines. Ann Oncol. 2018;29(Suppl 4):iv143-iv65.
  3. De J, Wand APF. Delirium screening: A systematic review of delirium screening tools in hospitalized patients. The Gerontologist. 2015 Dec;55(6):1079-99. doi: 10.1093/geront/gnv100. Epub 2015 Nov 5. Erratum in: Gerontologist. 2017 Apr 1;57(2):387.
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  6. Jones RN, Cizginer S, Pavlech L, Albuquerque A, Daiello LA, Dharmarajan K, et al. Assessment of instruments for measurement of delirium severity: A systematic review. JAMA Intern Med. 2019 Feb 1;179(2):231-239. doi: 10.1001/jamainternmed.2018.6975.
  7. Leonard MM, Nekolaichuk C, Meagher DJ, Barnes C, Gaudreau J-D, Watanabe S, et al. Practical assessment of delirium in palliative care. J Pain Symptom Manage. 2014 Aug;48(2):176-90. doi: 10.1016/j.jpainsymman.2013.10.024. Epub 2014 Apr 21.
  8. Scottish Intercollegiate Guidelines Network (SIGN). Risk reduction and management of delirium. Edinburgh: SIGN; 2019. (SIGN publication no. 157).
  9. The National Institute for Health and Care Excellence (NICE). Delirium: prevention, diagnosis and management [Internet]. London: NICE; 2019. (Clinical guideline CG103).
  10. Therapeutic Guidelines Limited. Delirium in palliative care [Internet]. 2016. [cited 2022 Aug 11].
  11. Varghese R, Irfan M. Delirium versus dementia: A diagnostic conundrum in clinical practice. Psychiatr Ann. 2017;47(5):239-45.
  12. Delirium. In: Watson M, Ward S, Vallath N, Wells J, Campbell R, editors. Oxford handbook of palliative care [Internet]. Oxford: Oxford University Press; 2019.

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