Introduction to delirium

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Delirium AcademyEducation about delirium

Introduction to delirium

Introduction to delirium

Delirium is an acute change in how the brain is working. Attention and awareness are disturbed, other aspects of cognition change, and the picture often fluctuates over hours. It usually reflects one or more physiological problems that need assessment and treatment.

About 20 minutes Adult, non-ICU care 10 formative questions Version 1.2 pilot

By the end, you should be able to

  • recognise the acute, fluctuating pattern of delirium;
  • spot hypoactive as well as agitated presentations;
  • establish whether the person has changed from their usual baseline;
  • explain the role and limits of the 4AT;
  • describe the principle of multicomponent prevention; and
  • use a practical notice, check, escalate, support, and review sequence;
  • start sensible cause-finding and supportive care; and
  • hand over and document the change clearly.
Scope: This module covers adult delirium in general hospital and long-term-care settings. It does not cover children, critical care, the recovery room immediately after surgery, delirium at the end of life, or delirium related to alcohol or drug withdrawal or intoxication. Use the relevant specialist and local pathway in those situations.

1. Recognise the pattern

Hold onto three features: acute change, inattention, and fluctuation. The change develops over hours or days, not months or years. The person may lose the thread of a conversation, struggle to follow an instruction, or drift between drowsiness and alertness. A better hour does not rule delirium out.

Delirium can occur with or without dementia. If a person with dementia becomes suddenly less attentive, less alert, or otherwise different from their usual self, consider delirium superimposed on dementia. If the distinction is difficult, NICE advises managing the delirium first.

The baseline question: Is this person different from usual, and did the change develop quickly? Ask the patient where possible, and use family, carers, familiar staff, and existing records to establish the usual baseline and recent course.

2. Do not miss the quiet presentation

Delirium is not always noisy. A person with hypoactive delirium may become quiet, withdrawn, sleepy, slow to respond, less mobile, and less interested in food. This can look like tiredness, low mood, or progression of dementia. It still needs assessment.

Other people become restless or agitated. Some move between the two patterns. Behaviour tells you that something is wrong, but it does not tell you the cause.

3. Use the 4AT appropriately

The 4AT is a brief bedside assessment that looks at alertness, orientation, attention, and acute change or fluctuation. The Months Backwards item directly tests attention. Information about acute change may come from someone who knows the person or from the clinical record.

What the total score means:
0Suggests no delirium and no moderate-to-severe cognitive impairment, but does not definitively exclude either.
1–3Suggests cognitive impairment but does not itself indicate delirium. Interpret the result with the history and clinical findings.
4 or moreSuggests possible delirium. It is not a diagnosis; final diagnosis requires clinical assessment and judgement.

Communication matters: take account of hearing impairment, dysphasia, and lack of a shared language, and use appropriate communication support.

Do not abandon the assessment as “unable to assess”. If illness, drowsiness, or severe inattention prevents the person attempting AMT4 or Months Backwards, the official 4AT permits each item to be scored as untestable and assigns 2 points. If both are untestable, their combined score is 4, suggesting possible delirium but not proving the diagnosis.

In severe dementia, cognitive items may score highly even without delirium. Acute change from baseline, collateral information, observation over time, and clinical judgement are especially important.

A health or social care practitioner who is competent to do so should complete the 4AT. NICE recommends CAM-ICU or ICDSC instead in critical care or the recovery room immediately after surgery.

Use the official 4AT resources

For the test, full scoring guidance, translations, FAQs, case examples, and further information about the 4AT and delirium, use the official website.

Open the4AT.com Read the user guide Open the 4AT form

These links open in a new tab so that your place in the module is preserved.

4. Help prevent delirium

For adults at risk in hospital or long-term care, prevention should be tailored and multicomponent. Address the factors relevant to that person—for example orientation, hydration, infection, hypoxia, pain, mobility, nutrition, constipation, sensory impairment, medication review, and sleep—and follow local guidance.

5. Act on suspected delirium

Delirium often has several contributors. Look promptly for urgent physiological threats, then identify and manage the likely causes and contributing factors. The exact assessment depends on the person and the setting.

  1. Notice the change. Look for a new or fluctuating change in attention, alertness, thinking, communication, behaviour, appetite, sleep, mobility, or ability to take part in care. Quiet withdrawal matters as much as agitation.
  2. Check promptly. Establish the usual baseline and time course. Check immediate safety and physiology within your role and competence. Use the 4AT where appropriate if competent to do so, but urgent assessment must not wait for completion of a tool.
  3. Escalate concerns. Use the local deterioration and delirium pathway. State clearly that this is an acute change from baseline, describe the exact observations, and explain any immediate safety concern.
  4. Support the person and address causes. As a team, identify and manage likely causes and address relevant factors such as pain, hydration, nutrition, constipation, mobility, sensory impairment, sleep, orientation, and the care environment.
  5. Review and communicate. Delirium fluctuates. Reassess the course, response, and remaining concerns. Document the baseline, change, assessment, findings, actions, and next review, and communicate these across shifts and transfers.
Stay within your role: only undertake assessments and interventions for which you are trained, competent, and authorised, following local policy. Students, care workers, and others who are not authorised to complete a clinical assessment still have a vital role: notice and record the change, support the person, and alert the registered or supervising practitioner promptly.

For a frightened or distressed person, look for pain, urinary retention, constipation, hunger, thirst, fear, noise, and unfamiliar surroundings. Reorientation, reassurance, a suitable environment, and verbal and non-verbal de-escalation come first. Antipsychotic medication used for delirium-related distress or risk has a restricted role: consider it only when the person is distressed or a risk to themselves or others and de-escalation is ineffective or inappropriate, using individual clinical judgement and local guidance.

Keep reorientation gentle: introduce yourself, explain where the person is and what is happening, and offer calm reassurance—for example, “You are in hospital. I am your nurse. You are safe, and I will explain what happens next.” Avoid arguing with, repeatedly testing, or confronting a frightened person.

Individual prescribing is outside this module. Prescribers should follow current local and national guidance, including MHRA safety advice for haloperidol in older people, particularly where Parkinson’s disease or dementia with Lewy bodies is present.

Fictional multidisciplinary case

6. Putting it together: the quiet change

Mrs Ahmed, aged 84, has dementia and was admitted after a fall. Her daughter and care-home staff say that she normally chats, eats independently, and walks with a frame. On the second day, the ward nurse and physiotherapist notice that she is quiet, intermittently drowsy, slow to respond, eating little, and needing much more help to stand. She is not agitated. Her daughter confirms that the change began yesterday and has fluctuated.

Notice and check

A competent practitioner completes the 4AT while Mrs Ahmed is currently alert:

  • Alertness: normal during this assessment — 0
  • AMT4: two or more mistakes — 2
  • Months Backwards: unable to start because of marked inattention — 2
  • Acute change or fluctuation: clearly present — 4

Total: 8 out of 12.

This suggests possible delirium; it does not establish the diagnosis. Dementia may influence the cognitive items, making the confirmed acute change and collateral history especially important.

Act together

The nurse checks observations within their competence and uses the local deterioration pathway when fever and newly low oxygen saturation are identified. Medical assessment considers more than one contributor, including infection, reduced intake, pain, constipation, and medicine effects. A clinician or pharmacist reviews recent medication changes. The physiotherapist delays the planned walk until immediate safety and physiology have been addressed, then supports suitable mobility when appropriate. Mrs Ahmed’s family provide her baseline, bring her hearing aids, and help with calm reassurance. The team documents and reviews the changing course.

Learning point: reduced appetite, mobility, and engagement may be early signs of hypoactive delirium. Do not dismiss an acute functional change as dementia, tiredness, or unwillingness to participate. A better hour does not rule delirium out.

Example handover

Situation: “Mrs Ahmed has had an acute, fluctuating change since yesterday. She is quieter, intermittently drowsy, and has reduced intake and mobility.”

Background: “She has dementia, but her daughter and care home confirm that she normally chats, eats independently, and walks with a frame.”

Assessment: “Her 4AT is 8 out of 12, suggesting possible delirium rather than establishing the diagnosis. Immediate physiological abnormalities have been escalated, and several possible contributors are being assessed.”

Recommendation: “Please continue the urgent clinical review, cause management, and supportive care, reassess the course, and update the family and next team.”

Document more than “confused”: record the date and time, usual baseline and its source, exact acute changes and fluctuation, 4AT item and total scores with any limitations, immediate concerns, who was informed and when, actions taken, response, next review, and family communication.

7. Recovery, transfer, and discharge

Explain to the person and their family or carers that delirium is common and usually temporary, while the course and speed of recovery vary. Invite relatives to report further changes, and give the person an opportunity to discuss their experience during recovery.

At transfer or discharge, communicate the person’s usual baseline, onset and course of the change, current cognitive and functional state, assessment findings, diagnosis or continuing concern, likely contributors, actions taken, and outstanding review or follow-up. Ensure that a confirmed delirium diagnosis is documented in the clinical record and primary care health record.

If delirium has not resolved, re-evaluate possible underlying causes and arrange appropriate follow-up, including assessment for possible dementia where indicated. Explain who the person or family should contact if sudden changes recur or worsen.

Further information to use and share

For practitioners: the official 4AT website provides the assessment, user guidance, translations, FAQs, case examples, and further information about delirium.

For patients, families, and carers: Delirium Support provides clear, plain-language information about delirium. Practitioners can share it when explaining what delirium is, what families may notice, and how they can help, alongside local advice and contact details.

Open the4AT.com Open Delirium Support

These links open in a new tab. They support education and communication but do not replace urgent clinical assessment, professional judgement, or local pathways.

Before the questions

This is a formative knowledge check. It helps you see what you have understood. It cannot assess bedside competence. A score of 8 out of 10 meets the threshold for generating a personal completion record; it is not a validated clinical pass mark. You can review the explanations and try again.

Knowledge check

Choose one answer for each question. Within this module, answers and scores are processed only in the current browser page and are not sent to or stored by Delirium Academy.

Privacy note: the site host and security services may retain standard access logs, as on ordinary websites, but the module does not put quiz answers or the completion-record name into those requests.

1. Which statement best describes delirium?
2. A patient was attentive yesterday morning, became drowsy and confused in the afternoon, and appears almost back to normal during today’s review. What is the best interpretation?
3. Which component of the 4AT directly tests attention?
4. A person with established dementia develops sudden new inattention and reduced alertness. What is the best approach?
5. Over the past day, a previously interactive patient has become quiet, sleepy, withdrawn, slow to respond, less mobile, and less interested in food. What is the best interpretation?
6. Why is information from family, carers, familiar staff, or existing records especially useful when delirium is suspected?
7. Which statement most accurately describes the role of the 4AT?
8. Which plan best reflects recommended delirium prevention for an at-risk adult?
9. In a person with delirium, what is the best immediate management priority alongside supportive care?
10. A person with delirium is frightened and distressed. What is the most appropriate initial care?

Sources

Prepared as a source-checked pilot and updated on 20 July 2026. The wider site remains under clinical and editorial review. Educational information for healthcare professionals, not individualised clinical advice.

Clinical owner: Professor Alasdair MacLullich. No adverts, sponsorship, industry involvement, or external funding. This is not an official NHS or University of Edinburgh website.

Original educational text is available under CC BY 4.0. The 4AT has separate terms at the4at.com.