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Diagnosis, prevention and management of delirium: spot it, stop it, treat it

Published online by Cambridge University Press:  04 November 2024

Isabel A. Yoon*
Affiliation:
A resident physician in the Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN, USA and a graduate of the University of Queensland Medical School–Ochsner Clinical School, New Orleans, LA, USA.
David Galarneau
Affiliation:
An associate professor at the University of Queensland Medical School–Ochsner Clinical School, New Orleans, LA, USA and vice chair in the Department of Psychiatry, Ochsner Clinic Foundation, New Orleans, LA, USA.
Marlie Winslow
Affiliation:
A resident physician in the Department of Neurology, University of North Carolina, Chapel Hill, NC, USA and a graduate of the University of Queensland Medical School–Ochsner Clinical School, New Orleans, LA, USA.
Jacob Park
Affiliation:
A family medicine resident physician at Forrest General Hospital, Hattiesburg, MS, USA and a graduate of the University of Queensland Medical School–Ochsner Clinical School, New Orleans, LA, USA.
Adam X. Mauricio
Affiliation:
An emergency medicine resident physician at Sutter Health, Roseville, CA, USA and a graduate of the University of Queensland Medical School–Ochsner Clinical School, New Orleans, LA, USA.
Michael C. Reade
Affiliation:
A professor in the Faculty of Medicine at the University of Queensland, Brisbane, Queensland, Australia and a consultant intensive care physician in the Intensive Care Unit at the Royal Brisbane and Women's Hospital, Herston, Queensland, Australia.
Andrew Teodorczuk
Affiliation:
A professor in the Faculty of Medicine at the University of Queensland, Brisbane, Queensland, Australia, consultant old age psychiatrist with Metro North Mental Health Service at The Prince Charles Hospital, Chermside, Queensland, Australia and a professor in the School of Nursing, Queensland University of Technology, Brisbane, Queensland, Australia.
*
Correspondence Isabel A. Yoon. Email: yoon.isabel@mayo.edu
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Summary

Delirium frequently occurs among hospital in-patients, with significant attributable healthcare costs. It is associated with long-term adverse outcomes, including an eightfold increased risk of subsequent dementia. The purpose of this article is to inform clinicians of the best practices for spotting, stopping and treating delirium and provide guidance on common challenging clinical dilemmas. For spotting delirium, suggested screening tools are the 4 ‘A's Test (in general medical settings) and the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU). Prevention is best achieved with multicomponent interventions and targeted strategies focusing on: (a) avoiding iatrogenic causes; (b) brain optimisation by ensuring smooth bodily functioning; (c) maintaining social interactions and normality. Non-pharmacological approaches are the first line for treatment; they largely mirror prevention strategies, but the focus of empirical evidence is on prevention. Although sufficient evidence is lacking for most pharmacological approaches, an antipsychotic at low doses for short durations may be of utility for highly distressing or high-risk situations, particularly in hyperactive delirium, but only as a last resort.

Type
Article
Creative Commons
Creative Common License - CCCreative Common License - BY
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.
Copyright
Copyright © The Author(s), 2024. Published by Cambridge University Press on behalf of Royal College of Psychiatrists

LEARNING OBJECTIVES

After reading this article you will be able to:

  • apply best practice guidelines on how to spot, stop and treat delirium in hospital in-patients, including those in the ICU

  • describe management strategies for specific diagnostic challenges with delirium, including hypoactive delirium versus depression, catatonia, Lewy body dementia and delirium tremens.

  • recognise the importance of appropriate management and treatment for each individual patient.

Delirium is commonly experienced by older adult hospital in-patients, with an estimated overall prevalence of 23% in general medical settings (Gibb Reference Gibb, Seeley and Quinn2020) and even higher, at 31.8%, among patients in the intensive care unit (ICU) (Krewulak Reference Krewulak, Stelfox and Leigh2018). It is often missed despite being one of the most common hospital complications. Several potential reasons for this oversight have been suggested, including healthcare staff's lack of education about the condition, insufficient attention given to patients with hypoactive delirium (as these patients do not pose immediate challenges for the medical staff), therapeutic nihilism and diagnostic overshadowing by other conditions, such as dementia.

Long-term sequelae: personal and financial burden

Although delirium might traditionally be considered a temporary condition, the prognosis of those who experience it is poor. Epidemiological studies are exposing the long-term cognitive trajectories of patients who have suffered an episode of delirium. One meta-analysis found greater post-discharge institutionalisation, morbidity and mortality (Witlox Reference Witlox, Eurelings and De Jonghe2010) and recent cohort studies, such as Delirium and Cognitive Impact in Dementia (DECIDE), have shown that delirium accelerates cognitive decline and increases the risk of dementia in a dose-dependent fashion, irrespective of comorbidity and baseline level of cognitive decline (Richardson Reference Richardson, Davis and Stephan2021). Compared with control groups without delirium, the odds of mortality among older persons with delirium in the emergency department setting are increased 5.5-fold (Anand Reference Anand, Cheng and Ibitoye2022) and in the ICU they are increased 7-fold (Aung Thein Reference Aung Thein, Pereira and Nitchingham2020). Unlike other conditions, there has been no improvement in mortality outcomes for patients with delirium, despite advancements in research into the condition (Aung Thein Reference Aung Thein, Pereira and Nitchingham2020). Especially vulnerable are those with delirium superimposed on dementia. The long-term cognitive sequelae of episodes of delirium include cognitive deficits that are similar to those seen with moderate traumatic brain injury (Pandharipande Reference Pandharipande, Girard and Jackson2013). Moreover, delirium in older persons has been shown to be associated with an eightfold increase in the risk of subsequent dementia (Davis Reference Davis, Muniz Terrera and Keage2012).

The financial toll is also considerable, as the healthcare costs attributable to post-operative delirium have been estimated at £25.9 billion ($32.9 billion) per year in the USA alone (Gou Reference Gou, Hshieh and Marcantonio2021). The costs continue to grow as the population ages.

Aetiological theories

The pathophysiology of delirium is still relatively unknown, although it is thought there may be a final common pathway leading to the delirium syndrome. Evidence for specific metabolic and pharmacological precipitants of delirium have been demonstrated in human studies of hypoxia, hypoglycaemia and cholinergic antagonism (Wilson Reference Wilson, Mart and Cunningham2020). The recently proposed systems integration failure hypothesis theorises that acute brain failure results from ‘a combination of neurotransmitter function and availability, variability in the integration and processing of sensory information, motor responses to both external and internal cues, and the degree of breakdown in neuronal network connectivity’ (Maldonado Reference Maldonado2018). A competing theory of inflammation is also prominent, although the precise mechanism of how it disturbs brain function is only partially understood. Some of the suspected mechanisms include neuronal dysfunction, injury or cell death resulting from microglial-derived inflammatory mediators such as interleukin 1-beta (IL-1β) and tumour necrosis factor (TNF) that can directly affect neuronal function (Feng Reference Feng, Valdearcos and Uchida2017). As a result, such indicators are currently being investigated as potential plasma biomarkers for delirium.

The landmark study by Inouye and colleagues detailed the stress vulnerability hypothesis, which is key to understanding how to manage delirium (Inouye et al Reference Inouye, Bogardus and Charpentier1999). Based on this, the Hospital Elder Life Program (HELP) in the USA demonstrated that good general practice targeted at the risk factors can prevent delirium in a third of cases (Inouye Reference Inouye, Baker and Fugal2006).

Best practice

The purpose of this article is to inform readers of the best delirium practices relating to spotting, stopping and treating delirium in hospital in-patients. In addition, we consider three special diagnostic dilemmas that clinicians might encounter and provide clues to help guide practice.

Spot it: diagnosis/identification

Clinical features

Delirium presents in a phenotypically diverse manner ranging from a hypoactive subtype (65% of cases) with a withdrawn patient with decreased motor activity, to an agitated and overexcited patient described as the hyperactive subtype (25%), or a mix of both symptoms (10%) – although the incidence of each can vary with different durations of observation (Meagher Reference Meagher and Trzepacz2000). Extreme cases can include a catatonic variant, which is not to be confused with pure catatonia (Meagher Reference Meagher and Trzepacz2000). ‘Subsyndromal’ delirium is used to describe patients who have begun to fluctuate in awareness and cognition but do not meet all criteria for delirium (van Velthuijsen Reference van Velthuijsen, Zwakhalen and Mulder2018) and evidence shows existence of ‘persistent’ delirium where many patients are discharged with ongoing delirium (Whitby Reference Whitby, Nitchingham and Caplan2022).

The starting point of delirium may be a prodrome in which increasing symptoms of restlessness, anxiety, irritability and sleep disturbances develop. As delirium progresses, impaired attention, cognition and consciousness, as well as perceptual disturbances and behavioural changes, characterise the syndrome. Of note, hallucinations that can occur in delirium are usually non-auditory and are often misinterpretations of environmental or interpersonal cues, especially in visual and tactile cases (Oldham Reference Oldham, Flanagan and Khan2018).

The clinical presentation of delirium (Box 1) may overlap with other diagnoses, such as those reviewed in the final section of this article. Diagnostic testing may help distinguish between diagnoses that cannot easily be differentiated by history and presentation alone.

BOX 1 Clinical features of delirium

Prodromal features

Anxiety, restlessness, irritability, disorientation, sleep disturbances

Cognitive disturbance

Impaired attention, awareness, arousal, orientation, concentration, organisation of thought process, immediate recall and recent memory, visuospatial function, language, speech

Perceptual disturbance and delusions

Hallucinations (usually visual or tactile), illusions

Psychomotor disturbance

Hypoactive, hyperactive, mixed (unpredictable, fluctuating features of both)

Sleep–wake cycle disturbance

Insomnia, nightmares, reversal of sleep–wake cycles, excessive daytime somnolence

Emotional disturbance

Anxiety, fear, irritability, emotional lability, euphoria, depression, apathy, withdrawal

Neurological abnormality

Asterixis, tremor, myoclonus, frontal release signs, anomic aphasia (dysnomia), dysgraphia, constructional apraxia

Timeline

Rapid development over hours to a few days. Fluctuation of severity over a 24-hour period. Lasting around 1 week in most hospital in-patients with reversible precipitating factors, although may persist for longer

(Adapted from Bush Reference Bush, Lawlor and Ryan2018)

Diagnosis

The first step in the evaluation of delirium is the history obtained from an informed observer (e.g. family member or staff), followed by a cognitive assessment to screen and confirm delirium. The Single Question in Delirium (SQiD) asks the patient's family/carers whether they feel that the patient has been more confused lately, which may be a feasible screening tool when limited time is available for interview (Sands Reference Sands, Sharma and Carpenter2021). It is crucial to define a baseline level of cognition, consciousness and attention – ideally, in at-risk or prodromal patients, but if necessary also in those who are already in the throes of an acute episode. In addition, given the fluctuating nature of this syndrome, being oriented during one evaluation does not necessarily rule out the diagnosis.

The current standard diagnostic criteria for delirium are outlined in DSM-5-TR (American Psychiatric Association 2022) and ICD-11 (World Health Organization 2022). In terms of preferred screening tools, variability is commonplace. In review of studies to date, work by MacLullich and colleagues (MacLullich Reference MacLullich, Shenkin and Goodacre2019) suggests that the 4 ‘A's Test (4AT) (Table 1) may be the screening tool of choice in the general medical setting. Based on a well-conducted head-to-head trial comparing it with the Confusion Assessment Method (CAM), 4AT showed higher sensitivity and similar specificity (Shenkin Reference Shenkin, Fox and Godfrey2019). A key benefit of the 4AT is that it is quick and simple to administer and a range of health and social care practitioners can carry out the screen without specialised training. Therefore, it is recommended that staff members who have frequent scheduled contact with the patient (e.g. nursing staff) perform the screening and that patients with positive screens are brought to the attention of the healthcare provider for further diagnostic evaluation. Modified versions of the CAM have been identified as effective tools in different settings, such as the ICU (CAM-ICU) with sedated patients or the time-constrained emergency department (Brief CAM) (Box 2).

TABLE 1 Outline of the 4 ‘A's Test (4AT) delirium assessment toola

a The full assessment tool and additional information on use are freely accessible on the website developed by the test's author, Alasdair MacLullich (www.the4at.com).

b If patient is asleep attempt to wake with speech or gentle touch on shoulder. Ask patient to state their name and address to assist rating.

c To assist initial understanding one prompt of ‘what is the month before December?’ is permitted.

BOX 2 Screening tools of choice for different medical settings

  • General medical setting (patient able to speak): 4AT

  • ICU or post-anaesthesia care unit (patient conscious): Confusion Assessment Method for the Intensive Care Unit (CAM-ICU)

  • Emergency department (with time constraints): Brief CAM (bCAM)

    (National Institute for Health and Care Excellence 2010; Han Reference Han, Wilson and Vasilevskis2013).

Workup

Delirium can be the initial signal of a medical emergency. Consequently, the next steps in evaluating delirium must include the timely evaluation of potential causes and precipitating factors. Table 2 summarises the potential routine investigations and additional methods of workup for specific indications. Of note, the selection of the appropriate workup needs to be context specific and may be varied according to local service provision and practice. Moreover, it is important to note that, according to one study, no attributable cause of delirium may be identified in up to 30% of cases in clinical settings (van Velthuijsen Reference van Velthuijsen, Zwakhalen and Mulder2018).

TABLE 2 Workup for delirium

a Delirium can result in a characteristic pattern of ‘a diffuse slowing with increased theta and delta activity and poor organization of background rhythm’ on the EEG that reflects its severity (Jenssen Reference Jenssen2005).

Stop it: prevention

Managing risk factors

Risk factors for delirium among ICU patients have been well studied (Box 3) and several risk factors can apply universally to populations in any clinical setting, such as older age, frailty, functional disabilities and high burden of coexisting conditions (including baseline cognitive impairment). Although many of these risk factors are non-modifiable, identifying high-risk patients can help improve the proactive implementation of preventive strategies such as closer monitoring, identifying the target areas for intervention, and prognostic decision-making.

BOX 3 Risk factors for delirium among intensive care unit (ICU) patients

  • Older age (>65 years):

    • frailtya

    • functional disabilitiesa

    • high burden of coexisting conditionsa

  • Dementia or baseline cognitive impairment

  • Pre-ICU emergency surgery

  • Trauma (e.g. hip fracture)

  • Higher score on the Acute Physiology and Chronic Health Evaluation II (APACHE II)

  • Mechanical ventilation

  • Metabolic acidosis

  • Prior episode of delirium

a. Predisposing factors for delirium that are associated with advanced age.

(Maldonado Reference Maldonado2017)

Non-pharmacological prevention strategies

Multicomponent approaches have the strongest evidence for the prevention of delirium, compared with any single-component interventions (Kim Reference Kim, Kim and Ryu2022). The ‘ABCDEF bundle’ (Box 4) is an example of a multicomponent approach that has been recommended for reduction of delirium risk in the ICU (Devlin Reference Devlin, Skrobik and Gélinas2018). The above-mentioned Hospital Elder Life Program is another widely disseminated and evidence-based multicomponent intervention that is less specific to the ICU setting and can be applied in the general medical setting (Inouye Reference Inouye, Baker and Fugal2006). The protocol uses non-pharmacological approaches to systematically target visual and hearing impairment, immobility, disorientation, sleep deprivation and dehydration.

BOX 4 The ABCDEF bundle

The Awakening and Breathing Coordination, Delirium monitoring/management, and Early exercise/mobility strategy (ABCDEF) focuses on:

  • Assessing, preventing and managing pain

  • Breathing – both spontaneous awakening trials and spontaneous breathing trials

  • Choice of analgesia and sedation

  • Delirium: assessment, prevention and management

  • Early mobility and exercise

  • Family engagement and empowermenta

    a. Included in the revised version of the ABCDE bundle.

    (Balas Reference Balas, Vasilevskis and Olsen2014)

Individual approaches that have shown efficacy in prevention can be grouped into the following categories: (a) avoiding iatrogenic causes; (b) ensuring smooth bodily functioning, which in turn optimises brain function; (c) regular monitoring and social interactions.

Avoiding iatrogenic causes includes medication reviews and avoidance of medications with high deliriogenic potential (e.g. benzodiazepines, meperidine) or anticholinergic load. This includes avoiding GABAergic agents (e.g. propofol, midazolam) for agitation, particularly in older persons. Table 3 summarises the medications to be reviewed for potential removal or titration based on each patient's clinical circumstances by weighing the benefits and risks associated with the medication and the condition it is treating. Consultations with a clinical pharmacist are helpful in making the relevant clinical decisions to cautiously titrate down any medications that may be contributing to delirium. Medicines reconciliation together with a pharmacist before discharge is also essential to reduce the contributory effects of these agents.

TABLE 3 Medications to review for delirium prevention

a Collectively identified as anticholinergics.

b Individual agents identified as having particularly high anticholinergic and deliriogenic potentials.

c Formally classified as ‘sedative hypnotics’ in the previous version of the AGS Beers Criteria.

d Although these may be required for conditions such as chronic obstructive pulmonary disease exacerbation, should be prescribed in the lowest effective dose for shortest possible duration.

Source: This list was created based on the findings of our literature review for this article and the American Geriatrics Society 2019 AGS Beers Criteria (American Geriatrics Society Beers Criteria® Update Expert Panel 2019).

Infection prevention during hospital admission is another important step, which can be achieved by avoiding unnecessary urinary catheterisation and implementing appropriate infection control protocols.

Although physical restraints are often employed in clinical settings for hyperactive delirium, these should be avoided as much as possible, as they actually increase the risk of delirium (Wilson Reference Wilson, Mart and Cunningham2020). Physical restraint in ICUs (as opposed to other hospital areas) may be justified by the perceived requirement to prevent the removal of life-sustaining devices such as endotracheal tubes and vascular access catheters; however, there is little evidence that restraint alone effectively achieves this goal (Smithard Reference Smithard and Randhawa2022).

The second category – ensuring brain optimisation – is achieved by ensuring smooth bodily functioning (Box 5). Regular monitoring of at-risk patients can be achieved through the routine use of delirium screening scales (e.g. by each shift up to post-operative day 5) and diagnostic interviews by properly trained staff. Staff education focused on recognition, screening, risk factors, prevention and management has also been shown to be effective, as it allows for a concerted effort by all members of the treatment team (Rudolph Reference Rudolph, Boustani and Kamholz2011). Assessing for pain, including non-verbal signs in patients with communication difficulties (e.g. people with intellectual disability or dementia, or those unable to speak owing to the presence of an endotracheal or tracheostomy tube) is also crucial to ensure adequate pain management, which is associated with a reduction in delirium risk (Peden Reference Peden, Miller and Deiner2021).

BOX 5 Specific components of brain optimisation

  • Adequate oxygenation, hydration and nutrition

  • Prevention of constipation and urinary retention

  • Improvement in sleep and restoration of circadian rhythm (e.g. ensure natural lighting during the day, noise and light reduction with earplugs and eye covers at night, relaxation techniques to promote sleep, avoid medical/nursing procedures and unnecessary scheduled medications at night)

  • Early post-operative mobilisation (i.e. physical therapy at least once or twice daily, at least daily passive range of motion in bedbound patients)

  • Adaptations for visual and hearing impairment

    (Maldonado Reference Maldonado2017; Oh Reference Oh, Fong and Hshieh2017; Devlin Reference Devlin, Skrobik and Gélinas2018)

Social interactions are also integral to reducing delirium risk and can be facilitated by family and visitors as well as the hospital staff. Some specific examples include daily awakening protocols for ICU patients (i.e. ‘sedation holidays’), cognitive stimulation (e.g. books, puzzles, games) and reorientation (e.g. introducing self, role and location at every patient encounter; using an orientation board).

Pharmacological prevention strategies

In terms of preventing delirium in critical care patients, use of anaesthetics such as dexmedetomidine (an alpha-2 agonist) as adjuncts to GABAergic agents (e.g. propofol, midazolam) has been supported by evidence (Burry Reference Burry, Hutton and Williamson2019). For pain management, multimodal analgesia should be utilised while seeking to avoid or at least minimise use of opioids (Aldecoa Reference Aldecoa, Bettelli and Bilotta2017).

Acetylcholinesterase inhibitors (e.g. rivastigmine or donepezil) should be continued for patients with dementia who are already on the medication at home (Maldonado Reference Maldonado2017). They should not be newly prescribed peri-operatively for delirium prevention or treatment, however, as clinical trials have shown that agents such as rivastigmine resulted in higher delirium duration and mortality compared with placebo (van Eijk Reference van Eijk, Roes and Honing2010).

Melatonin may reduce the incidence of post-operative delirium by allowing for improved sleep (Maneeton Reference Maneeton, Kongsaengdao and Maneeton2022). Ramelteon (a melatonin receptor agonist) has not shown efficacy in preventing delirium, however, and neither melatonin nor ramelteon individually have shown efficacy in preventing delirium in older persons (Maneeton Reference Maneeton, Kongsaengdao and Maneeton2022). Additional studies are needed for a stronger recommendation and to determine the optimal dosage, duration and formulation of melatonin.

Treat it: management

Non-pharmacological management

When encountering a patient experiencing delirium, the first step to take is verbal and non-verbal de-escalation, such as adopting a respectful, non-confrontational and empathetic tone and posture while talking calmly and slowly to the patient (Box 6). It is important to understand how distressing the experience of delirium may be to a patient: one individual describes feeling that they experienced ‘7 years worth of torture’ during 3 weeks with delirium in an ICU (Hudson Reference Hudson2022).

BOX 6 How to implement non-pharmacological management of delirium

  • Engage in verbal and non-verbal de-escalation

  • Correct malnutrition, dehydration and electrolyte abnormalities as quickly and safely as possible

  • Review the inventory of all prescribed and over-the-counter pharmacological agents, discontinuing any, if feasible, known to cause delirium (e.g. GABAergic agents, opioids) or that have high anticholinergic potential

  • Promptly restore circadian rhythms and reduce noise and light affecting sleep

  • Remove unnecessary immobilising lines and devices (e.g. chest tubes, intravenous lines, urinary catheters) and physical restraints as early as possible

  • Correct sensory deficits (e.g. glasses, hearing aids)

  • Minimise environmental isolation by providing reorientation and cognitive stimulation at the level adjusted to the individual patient (i.e. provide more stimulation for hypoactive delirium but reduce stimulation for hyperactive delirium)

  • Empower family members and loved ones to assist in the process

  • Increase mobility and physical activity (including physical and occupational therapy)

    (National Institute for Health and Care Excellence 2010; American Geriatrics Society Expert Panel on Postoperative Delirium in Older Adults 2015; Australian Commission on Safety and Quality in Health Care 2021)

Another immediate step after the identification of delirium should be medical evaluation, appropriate diagnostic tests and clinical consultations to look for identifiable causes. A caveat to note is that in clinical settings, causes of delirium are often multifactorial. In fact, numerous causes of smaller effect can sometimes cumulatively lead to an episode of delirium, which makes it more challenging to identify the causes in vulnerable patients.

As family members can also be distressed when encountering a relative in a state of delirium, family education about the condition and their role in providing interpersonal stimulation and therapeutic presence is vital.

It is also important to note that the management of delirium does not necessarily end on discharge – arranging follow-up services for patients who experienced delirium while in hospital can help manage any complications and ensure rehabilitation to minimise any prolonged negative consequences of delirium.

Pharmacological management

Antipsychotics

Although non-pharmacological approaches remain first line, an antipsychotic at the lowest effective dose for the shortest possible duration may be used as a last resort in cases of severe agitation that pose a risk of substantial harm to the patient or others if behavioural interventions have failed or are not possible. A single dose can be sufficient in managing severe agitation in hyperactive delirium, and ongoing use needs to be evaluated daily with an in-person examination (American Geriatrics Society Expert Panel on Postoperative Delirium in Older Adults 2015).

It is important to highlight the limitations of the recommendation for use of antipsychotics in the management of severe agitation in delirium, as evidence does not support their routine use in treating delirium. For example, a Cochrane review found no reported data on improvements in the duration of delirium, length of hospital stays, discharge disposition or health-related quality of life with antipsychotic treatment (Burry Reference Burry, Mehta and Perreault2018). Moreover, older patients (>75 years) were found to be less likely to respond to antipsychotics, particularly to olanzapine (Yoon Reference Yoon, Park and Choi2013). Low-dose haloperidol, risperidone and several second-generation antipsychotics are used in clinical practice without any particular agent shown to be universally more effective (Nikooie Reference Nikooie, Neufeld and Oh2019). As a result, the side-effects profile must be considered when selecting the right agent for the individual patient when required. For example, owing to its antihistamine effect quetiapine is a particularly sedating option among the atypical antipsychotics, so it is indicated for patients with predominantly hyperactive delirium. Moreover, antipsychotics are not indicated for hypoactive delirium.

Before and during the use of antipsychotics, ideally a 12-lead electrocardiogram (ECG) should be obtained for evaluation of the QTc interval, and electrolyte abnormalities should be screened and corrected, particularly potassium and magnesium (Maldonado Reference Maldonado2017). Of note, guidelines recommend discontinuing antipsychotic use if the QTc increases by more than 25% of baseline or more than 500 ms, to avoid the rare but potentially fatal arrhythmia of torsade de pointes (Maldonado Reference Maldonado2017). Moreover, the patient's family must be involved in the decisions to prescribe.

If antipsychotics are prescribed during an admission, providers must be cautious to prevent patients from inadvertently continuing the medication post-discharge without a clear indication.

Dexmedetomidine

Dexmedetomidine has been suggested for the management of delirium in the ICU, in addition to prevention (Lewis Reference Lewis, Alshamsi and Carayannopoulos2022). As it has been shown to decrease the duration of mechanical ventilation, dexmedetomidine is recommended for delirium in mechanically ventilated adults with severe agitation that precludes weaning or extubation (Reade Reference Reade, Eastwood and Bellomo2016). Although dexmedetomidine is licensed for continued use following extubation in a critical care environment because of the unique nature of its sedative effects in preserving airway reflexes and respiratory drive, the evidence for the safety and effectiveness of dexmedetomidine as a delirium treatment for ward patients is not yet sufficient, as only a small effect in shortening delirium duration was found in a single study (Reade Reference Reade, Eastwood and Bellomo2016).

Special cases in liaison psychiatry: challenging clinical dilemmas

In clinical practice, it is sometimes challenging to distinguish depression from hypoactive delirium, given their overlap in clinical presentation. For example, one might mistake hypoactivity for psychomotor retardation or misdiagnose features of depressive agitation as hyperactive delirium. Table 4 describes the key distinguishing factors between delirium and depression on clinical presentation.

TABLE 4 Key factors distinguishing hypoactive delirium from depression

It is important to note that early delirium may sometimes present initially with mood lability in the absence of other sentinel symptoms. Therefore, we recommend providers perform a delirium screen for all patients presenting with symptoms of depression in the hospital setting. Accurate diagnosis and appropriate management are crucial to reduce symptom duration and severity, as well as to decrease the risk of exacerbating the delirium with inappropriate pharmacological agents such as antidepressants. For example, initiating antidepressants with high anticholinergic potential, such as tricyclics and paroxetine, should be avoided in patients with delirium. First-line treatment for major depressive disorder in any setting includes psychotherapy and antidepressant therapy tailored to patient comorbidities, typically beginning with a selective serotonin reuptake inhibitor.

Similarly, clinical entities such as catatonia, delirium tremens secondary to alcohol withdrawal, and Lewy body dementia may pose diagnostic challenges because of features that overlap with delirium (Table 5).

TABLE 5 Challenges in liaison psychiatry: conditions with features that overlap with delirium

CIWA-Ar, Clinical Institute Withdrawal Assessment for Alcohol; ECT, electrocardiogram; EEG, electroencephalogram; GI, gastrointestinal; IV, intravenous; OT, occupational therapy; PT, physical therapy; REM, rapid eye movement; SLP, speech/language therapy.

Lewy body dementia stands out from other common types of dementia, such as Alzheimer's disease, as the cognitive deterioration typically manifests in fluctuating levels of alertness and attention rather than as gradual and progressive change. Delirium may also be superimposed onto pre-existing dementia, which poses a further challenge in diagnosis.

As regards delirium tremens, it is important to note that the patient may not be able to give an accurate drinking history – or may be disinclined to do. Delirium tremens may also appear in a mixed state such as with hepatic encephalopathy. It is also important to note that even in mixed states treatment should start with benzodiazepines at least until withdrawal symptoms have lessened.

Important commonality among these conditions is that their management differs from the typical pharmacological approaches for managing delirium (Table 5). Misdiagnosis can potentially exacerbate the corresponding condition owing to inappropriate management. It is also important to highlight that other medical teams can consult psychiatry and other relevant experts to provide a second opinion when facing such challenging clinical scenarios.

Conclusion

As we reviewed how to best to spot, stop and treat delirium we hope this three-stage approach filters into clinical practice, given the limited accurate knowledge about the condition held within textbooks. This is especially important as some argue that incidence of delirium during hospitalisation provides ‘a window to hospital care', affording a wider glimpse of how hospitals are managing their patients and the possibility of change (Inouye Reference Inouye, Schlesinger and Lydon1999). Patients with delirium are vulnerable and often fall through the cracks in hospital systems.

In terms of implications for clinicians, issues that hinder the implementation of best practice recommendations must be considered. For example, multicomponent approaches for prevention can be labour-intensive and may not be feasible with the available medical and nursing staff in certain settings. Consistently implementing non-pharmacological approaches may also be difficult owing to contextual variations in busy ward environments. Educating families and carers to assist with care is critical. Furthermore, complex clinical situations often force clinicians to balance competing and conflicting demands, posing a challenge to following the outlined strategies. For example, opioid medications should be avoided but insufficiently managed pain is itself a risk factor for delirium. Therefore, we must weigh the pros and cons of each intervention for the individual patient, factoring in their comorbidities and current required treatment needs, in order to maximise benefit and minimise harm.

A final but important consideration is that treatment approaches call on us as practitioners to draw on the humanity that we have in our care processes. Compassion, kindness and the understanding that education is at the core of good delirium practice are central to effective approaches. All too often, in the busyness of clinical practice, humane approaches in medicine have gone adrift; perhaps a refocus on improving delirium management can help inject a much-needed dose of humanity into an increasingly technical and super-specialised medical world. As Wes Ely claimed, what is important is to unlearn the depersonalising aspects of care and think about magnifying dignity (Ely Reference Ely2022).

Data availability

Data availability is not applicable to this article as no new data were created or analysed in this study.

Author contributions

I.A.Y.: write-up and revision of manuscript, data acquisition and synthesis, edits to sections from co-authors; D.G.: critical review and revision of manuscript; M.W.: write-up of subsections (clinical features, workup, hypoactive delirium vs depression, catatonia); J.P.: write-up of delirium tremens section, assistance with data synthesis; A.X.M.: write-up of Lewy body dementia section, assistance with data synthesis; M.C.R.: critical review of manuscript, expert opinion on delirium management in ICU; A.T.: conception, write-up of subsections (introduction, discussion, conclusion), critical review of manuscript.

Funding

This research received no specific grant from any funding agency, commercial or not-for-profit sectors.

Declaration of interest

None.

MCQs

Select the single best option for each question stem

  1. 1 Which of the following is not correct regarding clinical features of delirium?

    1. a Prodromal features can include anxiety, restlessness, irritability and sleep disturbance.

    2. b Emotional disturbance such as fear, lability, depression and apathy can occur.

    3. c Hallucinations and delusions are rare in delirium.

    4. d Symptoms are not better explained by another preexisting, established, or evolving neurocognitive disorder.

    5. e The disturbance is a direct physiological consequence of another medical condition, substance intoxication or withdrawal, or exposure to a toxin, or has multiple aetiologies.

  2. 2 Which medication class should generally be avoided in the treatment of delirium, owing to their potential to worsen confusion?

    1. a Antidepressants

    2. b Anticholinergics

    3. c Antihypertensives

    4. d Anticonvulsants

    5. e None of the above.

  3. 3 Which of the following strategies is not recommended for preventing delirium in hospital in-patients?

    1. a Early mobilisation and physical therapy

    2. b Regular use of benzodiazepines for sleep

    3. c Adequate hydration and nutrition

    4. d Minimising use of physical restraints

    5. e Appropriate family involvement in education.

  4. 4 Which the following statements about the 4AT screening tool is not correct?

    1. a The tool assesses for alertness, rating mild sleepiness for <10 s after waking as normal.

    2. b Attention is assessed by asking the person to list the months of the year backwards.

    3. c Assessment should be deferred if the person appears to be asleep.

    4. d The timeline of acute change or fluctuating course of alertness, cognition or other mental function is determined as being within the past 2 weeks, with changes still evident in the past 24 h.

    5. e It includes orientation items asking the person to give their age, date of birth, current location and the current year.

  5. 5 Which of the following factors is not an established risk factor for delirium?

    1. a High APACHE-II score

    2. b Advanced age

    3. c Use of sedatives

    4. d Family history of delirium

    5. e Morphine use.

MCQ answers

1 c 2 b 3 b 4 c 5 d

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Figure 0

TABLE 1 Outline of the 4 ‘A's Test (4AT) delirium assessment toola

Figure 1

TABLE 2 Workup for delirium

Figure 2

TABLE 3 Medications to review for delirium prevention

Figure 3

TABLE 4 Key factors distinguishing hypoactive delirium from depression

Figure 4

TABLE 5 Challenges in liaison psychiatry: conditions with features that overlap with delirium

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