This site is intended for UK healthcare professionals
Medscape UK Univadis Logo
Medscape UK Univadis Logo

Welcome to the new home of Guidelines in Practice

For Primary Care| Implementing guidelines

Be Vigilant for Delirium in Primary Care Settings

  • Dr Emma Nash Considers Relevant Guidance and The Care Home Element of the PCN Contract to Review the Assessment and Care of People With, or at Risk of, Delirium
  • Read This Article to Learn More About:
    • the symptoms, risk factors, and precipitants of delirium
    • the role of primary care in the identification, management, and prevention of the condition
    • using the Comprehensive Geriatric Assessment framework to assess and develop care plans for people in long-term care.
    Key points and implementation actions for integrated care systems can be found at the end of this article.

    Reflect on your learning and download our Reflection Record.

    Delirium is a neurological condition characterised by ‘a disturbance of attention, orientation, and awareness that develops within a short period of time’.1 It is a frequent cause of hospital admission. Although the data around prevalence in the community are scarce, it is estimated that delirium affects as many as 10% of people over the age of 85 years, and even more of those with dementia.2 Delirium is preventable in approximately 30–40% of cases.3

    This article reviews delirium in the context of primary care, discussing the diagnosis, assessment, and management of the condition in relation to recently updated NICE guidance.

    Diagnosing Delirium

    Patients with delirium often experience disturbances in behaviour and emotion, impairment of multiple cognitive dimensions, and altered sleep patterns involving excessive drowsiness or total loss of sleep followed by reversal of the sleep–wake cycle.1 Despite these seemingly obvious criteria, the subtleties and fluctuations in presentations of delirium make it easy to miss, particularly as observers tend to underappreciate any changes in behaviour.4,5

    Key Symptoms

    When a person has delirium, their cognitive function is worsened, with diminished concentration, slow responses, and confusion.1,6,7 They may experience perceptual disturbances, such as visual or auditory hallucinations, and their physical function may be altered, either through reduced movement and mobility or restlessness and agitation.7 Changes to a person’s appetite or sleep pattern may occur, and their social behaviour may change: this could present as an unprecedented difficulty following requests or instructions, altered or withdrawn communication, or changes in mood and attitude.7

    There are three different subtypes of delirium: hyperactive, hypoactive, and mixed.6,7 It is important that carers are alert to the possibility of hypoactive delirium, in which people tend to be withdrawn, quiet, and sleepy, as this type of delirium is easier to miss than hyperactive delirium, which is instead characterised by restlessness, agitation, and aggression.6,7

    The key diagnostic criteria from the 11th revision of the International Classification of Diseases are shown in Box 1. 

    Box 1: ICD-11 Essential (Required) Features of Delirium1
    • A disturbance of attention, orientation, and awareness developing within a short period of time (e.g., within hours or days), typically presenting as significant confusion or global neurocognitive impairment with transient symptoms that may fluctuate depending on the underlying causal condition or etiology.
    • The disturbance represents a change from the individual’s baseline functioning.
    • Delirium may be caused by the direct physiological effects of a medical condition not classified under Mental, Behavioural or Neurodevelopmental Disorders, by the direct physiological effects of a substance or medication, including withdrawal, or by multiple or unknown etiological factors.
    • The symptoms are not better accounted for by a pre-existing or evolving Neurocognitive Disorder (i.e., Amnestic Disorder, Mild Neurocognitive Disorder, or Dementia) or by another mental disorder (e.g., Schizophrenia or Other Primary Psychotic Disorder, a Mood Disorder, Post-Traumatic Stress Disorder, a Dissociative Disorder).
    • The symptoms are not better accounted for by a typical syndrome of Substance Intoxication or Substance Withdrawal for a substance or medication that is known to be present, although Delirium can occur as a complication of intoxication or withdrawal states.
    ICD-11=International Classification of Diseases 11th revision

    © World Health Organization. International Classification of Diseases eleventh revision (ICD-11). Geneva: World Health Organization, 2022. License: CC BY-ND 3.0 IGO.

    NICE Guidance and the PCN DES Specification

    In January 2023, NICE published an update to its guideline on delirium.7 Although the management of delirium is usually the remit of secondary care, the guideline’s recommendations on delirium in long-term care settings are pertinent for general practice.7 This is particularly true in consideration of the Enhanced Health in Care Homes (EHCH) component of the Primary Care Network (PCN) Directed Enhanced Service (DES) specification, which requires care homes to be aligned with—and supported by—PCNs as part of a multidisciplinary approach to care planning and review.8

    The DES specification states that a person’s risk factors for delirium should be assessed within 24 hours of admission to long-term care, in line with NICE guidance, and that subsequent interventions should be informed by this assessment.7,8 The specification also requires that PCNs aim to develop a personalised care and support plan for each resident within a target time of 7 days after admission to a care home or readmission following a hospital episode.8 These care plans offer an excellent opportunity to appraise and address the risk of delirium, and to enable its early recognition. The supplementary resources accompanying the NICE guidance may facilitate the development of such plans, as they include both educational materials for care home staff and resources for audit and quality improvement.9,10

    Comprehensive Geriatric Assessment

    The EHCH specification encourages the use of the principles and domains of a Comprehensive Geriatric Assessment (CGA) when formulating care plans.8,11 Such assessments may be done by a GP, but they can be time-consuming, so the domains may be completed by a variety of professionals, as well as by an informal carer if appropriate. The information in each of these domains will accumulate over time.

    The four domains are:8,11

    • physical assessment
    • functional, social, and environmental assessment
    • psychological components
    • medication review.
    Viewing these frameworks through a ‘delirium lens’—as NICE suggests when recommending that clinicians ‘think delirium’7—could be useful when assessing a person’s risk of future issues, adopting or developing preventative strategies, and facilitating early detection. Figure 1 shows how assessment can be approached for people in long-term care.11

    Figure 1: The Comprehensive Geriatric Assessment Framework for People in Long-term Care11

    photo of
    © British Geriatrics Society. Comprehensive geriatric assessment toolkit for primary care practitioners. London: BGS, 2019. Available at:
    Reproduced with permission.

    Risk Factors for Delirium

    An awareness of the risk factors for delirium is essential, as preventative interventions rely on addressing and mitigating these risks as far as possible. When people are first admitted to long-term care, they should be assessed for key risk factors for delirium.7 In addition, there should be ongoing observation for any development or changes relating to these risk factors.7

    The risk factors for delirium are cumulative, and those relevant to primary care are shown in Box 2. A structured approach to identifying and addressing risk factors could follow the framework shown in Figure 1.

    Box 2: Risk Factors for Delirium Relevant to Primary Care7,12–14

    NICE-Highlighted Risk Factors7

    • Age ≥65 years
    • Past or present cognitive impairment
    • Dementia
    • Severe illness, defined as ‘a clinical condition that is deteriorating or is at risk of deterioration’.
    Other Important Risk Factors to Consider12–14
    • Visual or hearing impairment
    • Functional impairment or significant injury
    • History of delirium
    • Polypharmacy
    • Multimorbidity
    • Frailty
    • Excessive alcohol intake (past or present)
    • Poor nutrition
    • Lack of stimulation
    • Cardiovascular disease.

    Precipitants of Delirium

    When assessing a patient and developing a care plan that takes delirium into account, an understanding of the key precipitating factors is useful. This focuses the plan on what everyone involved in a person’s care needs to know about their usual state—to both identify and reduce risk of future delirium and to facilitate early detection of small changes in behaviour. It is recognised that, in people who are at high risk, something as seemingly benign as a single dose of a benzodiazepine can precipitate delirium.3

    Some key precipitating factors are outlined in Box 3. Although separating these factors into categories can be helpful for a structured assessment, the aetiology behind delirium is usually multifactorial.7,11,15

    Box 3: Precipitating Factors for Delirium15
    • Infection such as urinary tract infection, infected pressure sore, or pneumonia.
    • Metabolic disturbance such as hypoglycaemia, hyperglycaemia (including advanced carcinomatosis), or electrolyte abnormalities (including dehydration).
    • Cardiovascular disorders such as myocardial infarction or heart failure.
    • Respiratory disorders such as pulmonary embolism or exacerbation of chronic obstructive pulmonary disease.
    • Neurological disorders such as stroke, encephalitis, or subdural haematoma.
    • Endocrine disorders such as thyroid dysfunction or Cushing's syndrome.
    • Urological disorders such as urinary retention.
    • Gastrointestinal disorders such as hepatic failure, constipation (including faecal impaction), or malnutrition.
    • Severe uncontrolled pain.
    • Alcohol intoxication or withdrawal.
    • Medication
    • Psychosocial factors such as depression, sleep deprivation, visual or hearing impairment, emotional stress, or change of environment.
    © NICE 2023. Delirium: what factors can precipitate delirium? NICE Clinical Knowledge Summary. (accessed 1 August 2023). 

    All rights reserved. Subject to Notice of rights. NICE guidance is prepared for the National Health Service in England. All NICE guidance is subject to regular review and may be updated or withdrawn. NICE accepts no responsibility for the use of its content in this product/publication. See for further details.

    Baseline Assessment and Preventative Measures

    At the time of admission (or readmission) to social care, it is important to consider a person’s physical and psychological state, as well as their level of functioning,7 because having a clear understanding of what is normal for the person makes it easier to identify subtle changes that may indicate delirium. A baseline assessment will also offer more information on the person’s risk of delirium, and will help to facilitate preventative measures. This assessment can effectively be separated into the four domains of the CGA.11 

    1. Physical Health

    A person admitted to long-term care is likely to have at least one pre-existing health condition. Compiling a comprehensive history can therefore be challenging, as quality issues with medical notes and information transfer can cause important information to be missed. Using information from relatives or previous carers, as well as conducting a medication review, can help a clinician to identify any conditions and medications that are not clearly coded in an individual’s medical records.

    Table 1 outlines some key baseline physical parameters that could be assessed at this stage, and why they are important in relation to delirium. 

    Table 1: Physical Parameters and Their Relevance for Detecting Delirium11,15–19

    ParameterInterpretation and Relevance
    Blood pressure

    Sitting BP: provides a baseline measurement against which to compare readings during acute illness, such as sepsis or dehydration.

    Lying and standing BP: assesses for postural hypotension (a systolic drop of more than 20 mmHg is considered significant). In suspected delirium, a new postural drop associated with neurocognitive disturbance gives information about a person’s fluid status, the effects of their medication, and any potential causes of dizziness or falls.

    Falls are often a warning sign of delirium and should prompt assessment of postural drop. 

    Heart rate and pulse

    Identifying the presence of CVD and managing it appropriately can reduce the risk of delirium. For example, arrhythmias such as AF can cause decompensation in cardiac function and precipitate or contribute to delirium. 

    A baseline pulse is also helpful for comparison; tachycardia may be a sign of a severe illness such as sepsis, which is a particularly strong risk factor for delirium.


    Documented measurements of weight are useful for comparison—weight may change in acute illness or increase noticeably in fluid overload. 

    Loss of appetite is often a warning sign for delirium.

    Neurological functionDocumenting the baseline neurological function is helpful in identifying the new onset of cerebrovascular signs, such as those that may occur with a stroke or intracranial haematoma.
    Pain and the musculoskeletal systemIt is important to assess for and address pain, which often relates to joint function, because uncontrolled pain is a cause of delirium. In those with communication difficulties, nonverbal signs may be the only indication of pain. 
    ContinenceDocumentation of urinary and faecal continence, as well as usual bowel habit, helps with the identification of new changes when they develop. These changes may indicate urinary infections or constipation, both of which are important causes of delirium. 

    Understanding the usual electrolyte status of a person can contextualise any changes or abnormalities that may be precipitating factors for delirium. 

    A low level of sodium (below 125 mmol/l) can be a cause of confusion, especially when change is rapid, and levels below 115 mmol/l can cause coma and death. However, some people may have an asymptomatic level of chronically low sodium, so having this baseline comparison would contextualise a finding of low sodium during an episode of delirium. 

    Usual calcium levels are also helpful to know, as hypercalcaemia is a recognised cause of confusion and delirium.

    Urea is a helpful indicator of fluid status, but it is important to remember that a middle-range result can still represent severe dehydration in older patients. Comparative data are therefore invaluable.

    LFTs may be helpful, especially in those with a history of alcohol excess. Encephalopathy is one cause of delirium, and liver function testing can contribute to the assessment of risk. 

    BP=blood pressure; CVD=cardiovascular disease; AF=atrial fibrillation; LFT=liver function test

    2. Functional Ability

    Transition to Long-Term Care

    As a result of the change in routine, there may be transient alteration to a person’s functioning when they move to long-term care from another setting; this can, in itself, precipitate an episode of delirium.15 Simple measures, such as preserving aspects of the person’s routine or retaining familiar belongings, may be beneficial.7 It is essential to ask the person, or a family member or carer, what they like to be called. Their given name may not be the name they use, and this could lead to an assumed lack of response that is actually a result of them never being known by that name! Reorientation can also be supported by reinforcing where the person is and what the role of their carers is.7 Facilitation of regular visits from family and friends is to be encouraged.7

    Establishing a Baseline and Resolving Key Issues

    Functional assessment can include a wide variety of parameters, and it may take time to determine what is normal for the person. At baseline, the emphasis is on ascertaining what the person can do at present.11 This may include consideration of mobility, self-care, and the person’s ability to interact with people and items around them. 

    Hearing and vision are critical elements of a functional assessment, as sensory impairment is a significant risk factor for delirium and affects other precipitating factors, such as cognitive impairment and disorientation.7,11,12 Sensory impairment can be addressed by ensuring that the person’s visual and hearing aids are available and worn, and by examining for—and resolving—issues such as earwax obstructing the auditory canal.7 This optimisation of vision and hearing can help to preserve cognitive stimulation, enabling participation in activities that provoke thought or reminiscence.7 Good lighting, clear signage, and easy-read or speaking clocks have a similar effect, helping to preserve orientation.7

    Some people at risk of delirium are less able to eat or drink, and are therefore at increased risk of dehydration or malnutrition. Care planning to mitigate against this, such as with tailored meals or frequent reminders to drink, may help with this issue.7 Simple interventions, including making sure that the person has suitable dentures, can also make a significant difference to oral intake.7,11

    3. Psychological Health

    Alternative Psychological Diagnoses

    An assessment of psychological health incorporates mental wellbeing as well as neurocognitive status. Certain symptoms of depression overlap with those of delirium, particularly changes in sleep pattern, appetite, and psychomotor function.20,21 These symptoms should prompt consideration of depression, especially in people with other indications or a history of mood disorders.21 However, such changes can also be seen in delirium, so false attribution needs to be avoided. Ascertaining current or previous alcohol excess is also important—delirium tremens may occur if there is abrupt withdrawal from alcohol, and history of alcohol excess is a risk factor for delirium.12,22

    Cognitive Assessment and the 4AT Assessment Tool

    Accurately ascertaining cognitive status in people entering into long-term care is critical for the detection and prevention of delirium, and it is recommended that all clinicians formally assess a patient’s cognitive function when any level of cognitive impairment—even if small—is suspected.7,11 Cognitive assessment of patients in long-term care is no different from that carried out in other primary care settings, and there are several different assessment tools available. These include the General Practitioner Assessment of Cognition23 and the Montreal Cognitive Assessment24, both of which are validated for use in primary care.  

    Guidelines on delirium from both NICE and the Scottish Intercollegiate Guidelines Network recommend the use of the 4AT rapid clinical test for suspected delirium and cognitive impairment.7,25,26 This is a quick assessment tool that can easily be completed by various members of staff, including nurses and care assistants, to gain an indication of the likelihood of delirium.26 The result can inform the need for further assessment by a GP or another member of the primary care team; the final diagnosis should be made by a healthcare professional with the relevant expertise.7,25 Sometimes, it may be unclear whether the patient has delirium, dementia, or a combination of the two—under these circumstances, the delirium should be treated first.7

    4. Medication Review

    Following admission to long-term care, a review of a person’s medication is essential, taking into account both the type and number of medications.7,11,25 A clinical pharmacist may be qualified to do this review, but it is important that they are working within the multidisciplinary team and are not conducting an isolated evaluation.11,27 In these medication reviews, a pragmatic, individualised approach is required:11,27 patients with multimorbidity may be on a variety of medications that, individually, have a sound evidence base, but may no longer be appropriate—for example, medications intended for risk reduction in the context of a limited life expectancy. Combinations of medications can also present an increased risk of harm, as side effects are compounded.11

    A structured approach, such as that of the Screening Tool of Older People's Prescriptions (STOPP)/Screening Tool to Alert to Right Treatment (START) criteria,28–30 can be helpful for weighing up the risks and benefits of each medication a person is taking, as well as identifying any potentially beneficial treatments that they are not taking, or are not taking optimally. In relation to neurocognition, the STOPP criteria specifically mention scrutiny of benzodiazepines, anticholinergics, antimuscarinics, and neuroleptics.30,31 On the other hand, potential medicines to add or optimise include analgesics for people with significant pain and suitable anticipatory medicines for people receiving end-of-life care.30,32

    Box 4 lists medications that are associated with the development of delirium. However, there is some uncertainty around the strength of this association in medications other than benzodiazepines or opioids, and clinicians should note that any change in medication—initiation, dose change, or abrupt withdrawal—can lead to delirium.25,33 Benzodiazepines in particular markedly increase the risk of delirium, so should be avoided wherever possible.25,33 Opioids also increase the risk of delirium, but are vital medications in controlling pain, so should ideally be used at the minimum effective dose, with steps taken to avoid consequent constipation (which can in itself cause delirium).25,33 Current evidence suggests that oxycodone is the opioid with the lowest probability of causing delirium.25,33

    Box 4: Medications Associated With the Development of Delirium15,25,33
    • Benzodiazepines (use and withdrawal)
    • Opioids
    • Dihydropyridines (a type of CCB)
    • Histamine-1 receptor antagonists (antihistamines)
    • Anti-parkinsonian medications
    • Tricyclic antidepressants
    • Anticholinergics
    • Corticosteroids.
    CCB=calcium-channel blocker

    Care Planning

    The outcome of any assessment of this kind should then be summarised into a ‘problem list’, as laid out in the CGA,11 which considers the risk of delirium. Interventions to reduce the risk of delirium can thus be structured around the four domains of the CGA in a comprehensive risk-management plan. 

    In addition to guiding risk minimisation, care planning should both support the prompt identification of delirium and inform a strategy for initial management. A clearly defined picture of a person’s normal state is extremely helpful here (see Box 3)—it allows for comparison when required, and is especially useful when the person is being cared for by people who do not know them well. The input of family, friends, and previous caregivers may help to make this picture even more comprehensive, as would including the details of any previous experiences of delirium. This could allow for the identification of any early markers of deterioration following a similar pattern.


    Most people with delirium will need to be admitted to hospital for same-day investigation, monitoring, and treatment of precipitating factors.32 However, if admission is not appropriate, a full physical assessment and targeted investigations must be carried out to ascertain and address any potential causes.32 NICE emphasises that management in primary care is only appropriate if all the following criteria are met:32

    • the person is well enough to stay at home, or the benefits of hospital admission are outweighed by those of primary care management
    • the person can be managed safely in primary care, and their symptoms are not harmful to them or others
    • primary care clinicians are aware of, and able to treat, the cause of the delirium
    • the person can receive constant supervision and care from a healthcare professional who is trained in managing delirium, in order to minimise complications
    • close clinical follow up can be arranged.
    It is important to manage the patient’s presentation, as well as addressing the underlying cause. This includes facilitating their orientation, maintaining safe mobility, and normalising their sleep–wake cycle, all of which is in the remit of care home staff.32 The care home is responsible for ensuring that staff are suitably trained to manage people with delirium, cope with challenging behaviour, identify potential causes (such as discomfort, thirst, or need for the toilet), and move the person to a safe, low-stimulation environment. With the advent of the EHCH requirements in the PCN DES contract, and the need for regular care planning, it may be fruitful to signpost the care home manager to educational support and self-assessment resources9,10 early in a relationship with a PCN, so that they can support care staff to develop essential skills before they are needed. 


    Delirium is a common yet preventable cause of admission to hospital that is associated with significant mortality and morbidity. Identifying risk factors for delirium—and modifying them where possible—is an essential way to reduce the likelihood of its development. However, despite its prevalence, delirium is easily overlooked and its significance is often underappreciated. If clinicians and carers undertake a clear baseline assessment of a person’s health and function, as well as adopting a ‘think delirium’ approach, they can significantly improve detection and outcomes.

    Key Points
    • Delirium is characterised by a disturbance of attention, orientation, and awareness, developing within a short period of time
    • People aged over 85 years, and those with dementia, are at greatest risk of developing delirium
    • Care planning is part of the EHCH component of the PCN DES, and is a good opportunity to build into practice a risk assessment and intervention plan for the avoidance, detection, and management of delirium
    • Risk assessment can be structured around the four domains of the CGA (physical, functional, psychological, medicine), which is clinically useful and meets the EHCH requirements
    • There are many potential precipitants of delirium, but its cause is usually multifactorial—infection, metabolic abnormalities, and medication are among the most common precipitating factors
    • Benzodiazepines, opioids, and anticholinergics are particularly common pharmacological precipitants of delirium
    • The 4AT assessment test is recommended by NICE and SIGN for assessing an individual’s cognitive function and facilitating the detection of delirium
    • Same-day hospital admission is usually indicated for people with delirium
    • When primary care management is deemed appropriate, physical assessment and targeted investigations are required to facilitate the identification and treatment of any precipitating causes.
    EHCH=Enhanced Health in Care Homes; PCN=Primary Care Network; DES=Directed Enhanced Service; CGA=Comprehensive Geriatric Assessment; SIGN=Scottish Intercollegiate Guidelines Network
    Implementation Actions for ICSs

    written by Dr David Jenner, GP, Cullompton, Devon

    The following implementation actions are designed to support ICSs with the challenges involved in implementing new guidance at a system level. Our aim is to help you to consider how to deliver improvements to healthcare within the available resources.

    • In contracts with health and social care providers, specify which baseline assessments for delirium should be conducted on admission to their services

    • Decide what tools and methods will be used to assess patients admitted to care homes
    • Agree who is responsible for conducting and coordinating baseline assessments, and which members of the multidisciplinary teams will be involved (including their respective roles)
    • Ensure that specific time and human resource is provided to allow this often-complex assessment process to be conducted adequately.

    ICS=integrated care system