Delirium

Oct 21, 2024
6 min read

Updated: Jun 29

Recognising, symptoms, screening, preventing, managing delirium

This information is drawn from two sources:

An article by Edwards et al. (2026) suggesting delirium is an urgent health priority in Australian hosptals
A self-paced course available on the Dementia Training Australia website: https://dta.com.au . Search for Decoding Delirium

Delirium: Health Priority in Australian Hospitals

Edwards, L. M., Mudge, A., Montgomery, A. & Agar, M. R. (2026). Delirium: An urgent health priority in Australian hospitals. Public Health Research and Practice 36, PU25159. doi:10.1071/PU25159

The science

Delirium is a clinical condition involving an acute change in mental status that is observed in one-in-four hospitalised older people and approximately two-thirds of intensive care unit admissions. It is characterised by a sudden change in attention, awareness and cognition that fluctuates in severity over time. People with delirium can experience distressing symptoms, such as hallucinations, delusions and mood changes, and their family carers also frequently experience distress.

Delirium can be understood as the complex interaction between pre-disposing factors, such as age (>70 years), frailty, cognitive and sensory impairment, and existing comorbidity burden; and precipitating factors, such as severe illness, metabolic imbalances, immobility, sleep disturbances, dehydration and the use of sedative medication. This interaction reflects a systemic, multiple organ response across several physiological pathways, although the underlying neurobiology remains poorly understood. Delirium can be present on hospital admission (especially common in acute medical and geriatric unit patients) or develop during hospitalisation (e.g. postoperative delirium and critical care delirium).

Delirium is associated with shorter life expectancy and poorer future health, with serious implications for patients and health systems. In hospital, delirium significantly increases length of stay, hospital-acquired conditions (e.g. infections and falls), adverse clinical outcomes (including, but not limited to, sepsis, pneumonia, heart failure), nursing care needs, and need for sub-acute and residential aged care. Many people experience lasting impact on cognitive, physical and emotional health, which impacts their own quality of life and also their caregivers, due to increased need for formal and informal care. Prevention of delirium has the potential to reduce (or delay) dementia incidence, and its physical, cognitive and financial impact.

Currently, there is no effective treatment for delirium, making prevention a critical priority. Fortunately, there is strong evidence that delirium during hospitalisation can be prevented through non-pharmacological, multi-component interventions that address and mitigate modifiable factors.

The art

Although studies have estimated the incidence, impact and financial burden of delirium (in theory), delirium remains under-detected, inadequately prevented, poorly managed and under-funded in practice. All levels of the healthcare ecosystem (policy, institutional, community, interpersonal and individual) intersect to compromise delirium prioritisation despite its undeniable impact on patents, families and the hospital and healthcare system.

Policy level

Delirium is under-documented in administrative datasets, making it invisible at the policy level.
Policy focus and funding goes to traditionally recognised high-visibility conditions (e.g. cancer, cardiovascular disease).
Lack of integrated care models for older adults means delirium prevention and care isn’t coordinated across hospital, community, and aged care settings.

Community level (Cultural and societal norms)

Cognitive decline in older adults is often seen as inevitable, reducing the perceived urgency of delirium prevention.
Limited public awareness of delirium leading to low public pressure on the system.
Hospitals are oriented towards treatment rather than prevention.

Institutional level (Healthcare settings)

Financial and resource constraints (i.e. the time and skilled multidisciplinary staff needed to effectively screen and implement delirium prevention protocols).
Lack of standardised delirium education and training of health professionals.
Inconsistent use of delirium screening tools and pathways across and within hospitals.

Interpersonal (Social networks)

Multidisciplinary health professionals may have unclear roles in delirium screening and management.
Hospitals are often characterised by inflexible ward routines and poorly designed environments.
Lack or disempowerment of family carers to advocate.

Individual level

People at-risk of delirium are often frail and/or cognitively impaired and may be unable to advocate for themselves.
Delirium mistakenly diagnosed as dementia, depression, or considered ‘normal ageing’.
Competing clinical priorities.

The need for organised efforts

Effective public health outcomes require organised, coordinated actions rather than relying on individual efforts. These coordinated actions include standardised delirium screening, investigation and monitoring, communicating with patients, families and community partners, safe prescribing, and universal adoption of effective prevention interventions (the science); while also ensuring that all multidisciplinary healthcare professionals are trained to prevent, detect, discuss and manage delirium across varied patient populations and settings in genuine collaboration with families, who know the person best (the art).

Recognising Delirium

A delirium is a serious medical condition producing sudden and often severe changes in a person’s mental function, which are different to their usual function. While changes are acute, they also fluctuate - they vary and may come and go. The person typically has difficulty thinking clearly, maintaining focus or attention, and may appear confused or disorientated. They may also display changes in their usual behaviour and sleep patterns. Delirium occurs quickly, over a period of hours or days, and may signal serious underlying illness, injury, or infection. Medical conditions such as pain, constipation and dehydration can also trigger delirium.

Older people are at a higher risk of developing delirium, but it can occur at any age including in children. Delirium is often seen in older people in hospitals (e.g. up to one-third of older people (aged 65 and older) have delirium when they are admitted to hospital) . Delirium is also common in people living in aged care (prevalence of 10% to 30% in Australia) and can occur in people living at home in the community, especially those older than 85 years and/or with dementia.

Key features of delirium

Cognition:

· worsened concentration

· slow responses

· confusion

· reduced awareness

· difficulty recalling words

Perception:

· visual or auditory hallucinations

· delusions

Physical function:

· reduced mobility

· reduced movement

· restlessness

· agitation

· changes in appetite

· sleep disturbance

Social Behaviour:

· lack of co-operation with reasonable requests

· withdrawal

· alterations in communication, mood, or attitude

paranoia, anxiety

Symptoms

Sudden changes in behaviour and new psychological symptoms may be a sign that the person is experiencing delirium. Symptoms of delirium involve abnormal changes in the person’s mental state and always involve changes in their level of consciousness and thinking, such as being unable to maintain focus or pay attention.

The person may appear agitated or restless (hyperactive delirium) due to increased psychomotor activity or they may appear sleepy, lethargic, and withdrawn (hypoactive delirium).

Common delirium symptoms

False beliefs or delusions, e.g. thinking staff are poisoning you
Appears confused and forgetful, e.g. don’t know what has happened and what is going on
Visual hallucinations, e.g. see spiders on the bedsheets and scary figures in the room
Hypo-alert / changed sleeping patterns, e.g. drowsy, speech is irregular
Disoriented to time or place, e.g. don’t know where he is
Hyper-alert, upset, irritable, afraid, angry, e.g. so aggressive staff have to call security

Screening for delirium

In hospitals, all people aged 65 or older and Indigenous people aged 45 and over should be routinely screened to detect cognitive impairment - including delirium - on presentation to hospital using a validated tool, such as the 4AT. The 4AT measures the following attributes of a person.

Alertness – whether the person is drowsy or agitated
Awareness – whether the person is aware of, for example, the current year and where they are
Attention – whether the person has the attention to, for example name the months of the year backwards from December
Acute change or fluctuating course – whether the person’s symptoms started suddenly or are now coming and going

Detailed information about the 4AT is available at https://www.the4at.com/.

Preventing Delirium

Hospital and residential aged care staff should assess people at risk for delirium within 24 hours of admission. Based on the results of this assessment, staff may need to provide clinical management, environmental changes and psychosocial interventions.

Clinical management

Reducing the use of psychoactive drugs
Appropriate pain management
Maintaining adequate hydration and nutrition
Maintaining bladder and bowel function
Avoiding the use of physical restraints (e.g., bed rails, catheters)

Environmental changes

Re-orientating to time, place and person (e.g., clocks and calendars, signage)
Limiting room changes
Providing a calm environment with reduced noise
Providing familiar and reassuring objects and pictures (e.g. personal possessions, family photos)

Psychosocial interventions

Providing access to working hearing aids and clean glasses
Promoting good sleep hygiene
Encouraging mobility
Providing consistent routines
Involving families and friends in care

Managing Delirium

If a person is diagnosed with delirium, the responsible staff need to identify, treat, and manage the possible underlying cause or combination of causes. For example, if a chest infection is causing delirium, antibiotics will be commenced; if dehydration is a cause, additional fluids will be given. It is important to:

identify the underlying causes by examining or obtaining (e.g. from family) the patient’s history
address the underlying causes and/or precipitating factors using the preventative measures above.
manage symptoms of delirium and perform a risk assessment. Use PITCHED to help prevent, find and treat common delirium causes.

o P - Pain

o I - Infection

o T - Thirst

o C - Constipation

o H - Hunger/Hypoxia

o E - Environment

o D – Drugs

o See Appendix A for a more detailed outline of the PITCHED process