Delirium clinical motor subtypes: a narrative review of the literature and insights from neurobiology

Predisposing and Precipitating Factors Associated With Delirium: A Systematic Review

IMPORTANCE

Despite discrete etiologies leading to delirium, it is treated as a common end point in hospital and in clinical trials, and delirium research may be hampered by the attempt to treat all instances of delirium similarly, leaving delirium management as an unmet need. An individualized approach based on unique patterns of delirium pathophysiology, as reflected in predisposing factors and precipitants, may be necessary, but there exists no accepted method of grouping delirium into distinct etiologic subgroups.

OBJECTIVE

To conduct a systematic review to identify potential predisposing and precipitating factors associated with delirium in adult patients agnostic to setting.

EVIDENCE REVIEW

A literature search was performed of PubMed, Embase, Web of Science, and PsycINFO from database inception to December 2021 using search Medical Subject Headings (MeSH) terms consciousness disorders, confusion, causality, and disease susceptibility, with constraints of cohort or case-control studies. Two reviewers selected studies that met the following criteria for inclusion: published in English, prospective cohort or case-control study, at least 50 participants, delirium assessment in person by a physician or trained research personnel using a reference standard, and results including a multivariable model to identify independent factors associated with delirium.

FINDINGS

A total of 315 studies were included with a mean (SD) Newcastle-Ottawa Scale score of 8.3 (0.8) out of 9. Across 101 144 patients (50 006 [50.0%] male and 49 766 [49.1%] female patients) represented (24 015 with delirium), studies reported 33 predisposing and 112 precipitating factors associated with delirium. There was a diversity of factors associated with delirium, with substantial physiological heterogeneity.

CONCLUSIONS AND RELEVANCE

In this systematic review, a comprehensive list of potential predisposing and precipitating factors associated with delirium was found across all clinical settings. These findings may be used to inform more precise study of delirium's heterogeneous pathophysiology and treatment.

Delirium in a surgical context from a nursing perspective: A hybrid concept analysis

Background

The term delirium has been defined in medical diagnosis criteria as a multidimensional disorder, and the term acute confusion is included in nursing classifications. Delirium can be a serious complication assessed in a patient after a surgical procedure. Still, the patient's delirium frequently remains unrecognised. Care of patients with delirium after surgical procedure is complex, and it challenges nursing expertise. From the nurses' viewpoint, delirium is associated with ambiguity of concepts and lack of knowledge. Therefore, reseach on how nurses perceive patients with delirium in a surgical context is needed.

Objective

The aim of this study was to describe the concepts of delirium and acute confusion, as well as the associated dimensions, in adult patients in a surgical context from the nursing perspective.

Design

The study used Schwartz and Barcott's hybrid concept analysis with theoretical, fieldwork, and final analytical phases.

Settings

Surgical wards, surgical intensive care units, and post-anaesthesia care units.

Data sources

A systematic literature search was performed through Pubmed (Medline), Cinahl, PsycInfo, and Embase.

Participants

Registered nurses and licensed practical nurses (n = 105) participated in the fieldwork phase.

Methods

In the theoretical phase, the concepts' working definitions were formulated based on a systematic literature search with the year limitations from 2000 until February 2021. At the fieldwork phase, the nurses' descriptions of patients with delirium were analysed using the deductive content analysis method. At the final analytical phase, findings were combined and reported.

Results

The concepts of delirium, subsyndromal delirium, and acute confusion are well defined in the literature. From the perspective of the nurses in the study, concepts were seen as a continuum not as individual diagnoses. Nurses described the continuum of delirium as a process with acute onset, duration, and recovery with the associated dimensions of symptoms, symptom severity, risk factors, and early signs. The acute phase of delirium was emphasised, and preoperative or prolonged disturbance did not seem to be relevant in the surgical care context. Patients' compliance with care may be decreased with the continuum of delirium, which might challenge both patients' recovery from surgery and the quality of nursing care.

Conclusions

In clinical practice the nurses used term confusion inaccurately. The term acute confusion might be used when illustrating an early stage of delirium. Nurses could benefit from further education where the theoretical knowledge is combined with the clinical practice. The discussion about the delirium, which covers the time both before surgery and after the acute phase should be increased.

A scientometric study of publications on delirium from 2001 to 2020

AIM

This study aims to evaluate the publications on delirium by using bibliometric analysis.

METHODOLOGY

The Scopus database was evaluated for publications on delirium, during the period of 2001-20. The search results were analyzed for the origin of country, origin of institution, authorship, collaborations, type of article, source of funding, and number of citations.

RESULTS

The searches of Scopus database yielded 22,941 publications, originating from 139 countries. Compared to the decade of 2001-2010, the number of publications on delirium doubled in the decade of 2011-2020. The majority of the papers were research articles (58.26%), and the papers were cited for mean number of 20.53 times. Only a small proportion of the papers were based on funding (13.14%). Maximum number of papers emerged from United States of America. In terms of institutional affiliations, among the authors from top 20 institutes, 15 were from United States, 2 from Netherlands and 1 each from Canada, Germany and United Kingdom. In terms of authors, the research productivity of the top 20 most productive authors varied from 172 to 612 publications with 12 authors belonging to United States, 2 from Italy and 1 each from Canada, Greece, India, Ireland, Netherland and the United Kingdom. The maximum number of papers were published in Journal of the American Geriatric Society and based on the number of citations the New England Journal of Medicine was the most impactful journal.

CONCLUSION

Over the years number of publications on delirium have increased, majority of the publications have emerged from United States.

Understanding Disorders of Consciousness: Opportunities for Critical Care Nurses

BACKGROUND

Disorders of consciousness are powerful predictors of outcomes including mortality among critically ill patients. Encephalopathy, delirium, and coma are disorders of consciousness frequently encountered by critical care nurses but often classified incorrectly.

OBJECTIVE

To provide a greater understanding of disorders of consciousness and to provide standardized assessments and nursing interventions for these disorders.

METHODS

A literature search was conducted by using the terms consciousness, mental status, awareness, arousal, wakefulness, assessment, disorders of consciousness, delirium, encephalopathy, coma, vegetative state, and minimal consciousness. Articles were published in the past 10 years in CINAHL and PubMed. Articles were excluded if they were not in English or directly related to caring for patients with a disorder of consciousness. The remaining 142 articles were evaluated for inclusion; 81 articles received full review.

RESULTS

A disorder of consciousness signifies that the threshold for compensation has been surpassed with potentially irreversible damage. Altered thalamocortical interactions and reduced cortical activity impair communication networks across the various parts of the brain, causing a disturbance in consciousness.

DISCUSSION

The cue-response theory is a model that describes the process and impact of nursing care on recovery from acute brain injury. Appropriate standardized assessments and interventions must be used to manage altered levels of consciousness in critically ill patients.

CONCLUSIONS

Paying close attention to neurological changes and monitoring them with standardized assessments are critical to implementing early measures to prevent complications.

Subtypes of delirium after ischaemic stroke-predisposing factors and outcomes: a prospective observational study (PROPOLIS)

BACKGROUND AND PURPOSE

Delirium is a serious complication after stroke. It remains unclear whether different motor subtypes of delirium are associated with diverse risk factors and outcomes. The aim was to investigate if delirium subtypes differ in predisposing factors, clinical characteristics and outcomes.

METHODS

In all, 698 patients with ischaemic stroke or transient ischaemic attack (median age 73 years; 53.7% female) were prospectively included. Core features of delirium during the first 7 days after admission were examined. The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria for delirium were used. Pre-stroke characteristics were compared between different delirium subtypes and logistic regression and Cox proportional hazard models were used to explore the association between delirium, functional outcome and death.

RESULTS

Hyperactive, hypoactive and mixed delirium were diagnosed in 28, 75 and 66 patients, respectively. Patients with hyperactive delirium had less severe neurological deficit on admission and more often had transient ischaemic attack compared with patients with hypoactive and mixed delirium. Compared with patients with hypoactive delirium, those with hyperactive delirium more often suffered from irritability/lability prior to stroke. Hyperactive and hypoactive delirium did not differ in age, sex, comorbidities, pre-stroke dependency, cognitive decline and severity of delirium. Hyperactive, hypoactive and mixed delirium were associated with an increased risk of poor 3- and 12-month functional outcome compared with patients without delirium. Moreover, patients with hypoactive and mixed delirium had an elevated risk of death.

CONCLUSIONS

Hyperactive delirium is associated with less severe stroke and higher scores of pre-existing irritability/lability. All three motor subtypes of delirium are associated with poor outcome, although hyperactive delirium seems to have a less unfavourable prognosis.

Delirium in older adults

This narrative review provides a broad examination of the most current concepts on the etiopathogenesis, diagnosis, prevention, and treatment of delirium, an acute neuropsychiatric syndrome characterized by fluctuating changes in cognition and consciousness. With the interaction of underlying vulnerability and severity of acute insults, delirium can occur at any age but is particularly frequent in hospitalized older adults. Delirium is also associated with numerous adverse outcomes, including functional impairment, cognitive decline, increased healthcare costs, and death. Its diagnosis is based on clinical and cognitive assessments, preferably following systematized detection instruments, such as the Confusion Assessment Method (CAM). Delirium and its consequences are most effectively fought using multicomponent preventive interventions, like those proposed by the Hospital Elder Life Program (HELP). When prevention fails, delirium management is primarily based on the identification and reversal of precipitating factors and the non-pharmacological control of delirium symptoms. Pharmacological interventions in delirium should be restricted to cases of dangerous agitation or severe psychotic symptoms.

Delirium in the acute hospital setting: the role of psychiatry

In this overview we discuss the role of psychiatry in managing delirium in acute hospital admissions. We briefly discuss the role psychiatry can offer in four main domains: (a) assessment; (b) management; (c) recovery; and (d) paradigm, education and research. In the assessment section we discuss accurately detecting delirium in the context of comorbid mixed neuropsychiatric syndromes, including depression and dementia, and the clinical importance of delirium subtyping. The management section briefly outlines pharmacological and non-pharmacological approaches to delirium and their evidence-based rationale. The recovery section focuses on the effect delirium can have on cognitive decline, mental health and long-term health, including functional outcome and need for institutional care after hospital discharge. Finally, we outline the role of psychiatry in delirium research and education. We hope that this article will encourage clinicians to reflect on their current practice and consider holistic and evidence-based care for this vulnerable population in the acute hospital setting.

The occurrence and timing of delirium in acute care hospitalizations in the last year of life: A population-based retrospective cohort study

BACKGROUND

Delirium is a distressing neurocognitive disorder that is common among terminally ill individuals, although few studies have described its occurrence in the acute care setting among this population.

AIM

To describe the prevalence of delirium in patients admitted to acute care hospitals in Ontario, Canada, in their last year of life and identify factors associated with delirium.

DESIGN

Population-based retrospective cohort study using linked health administrative data. Delirium was identified through diagnosis codes on hospitalization records.

SETTING/PARTICIPANTS

Ontario decedents (1 January 2014 to 31 December 2016) admitted to an acute care hospital in their last year of life, excluding individuals age of <18 years or >105 years at admission, those not eligible for the provincial health insurance plan between their hospitalization and death dates, and non-Ontario residents.

RESULTS

Delirium was recorded as a diagnosis in 8.2% of hospitalizations. The frequency of delirium-related hospitalizations increased as death approached. Delirium prevalence was higher in patients with dementia (prevalence ratio: 1.43; 95% confidence interval: 1.36-1.50), frailty (prevalence ratio: 1.67; 95% confidence interval: 1.56-1.80), or organ failure-related cause of death (prevalence ratio: 1.23; 95% confidence interval: 1.16-1.31) and an opioid prescription (prevalence ratio: 1.17; 95% confidence interval: 1.12-1.21). Prevalence also varied by age, sex, chronic conditions, antipsychotic use, receipt of long-term care or home care, and hospitalization characteristics.

CONCLUSION

This study described the occurrence and timing of delirium in acute care hospitals in the last year of life and identified factors associated with delirium. These findings can be used to support delirium prevention and early detection in the hospital setting.

Delirium Post-Stroke-Influence on Post-Stroke Dementia (Research Study-Part of the PROPOLIS Study)

BACKGROUND

Previous research confirmed association between delirium and subsequent dementia in different clinical settings, but the impact of post-stroke delirium on cognitive functioning is still under-investigated. Therefore, we aimed to assess the risk of dementia among patients with stroke and in-hospital delirium.

METHODS

A total of 750 consecutive patients admitted to the stroke unit with acute stroke or transient ischemic attacks were screened for delirium, during the first seven days after admission. At the three- and twelve-month follow-up, patients underwent cognitive evaluation. The DSM-5 definition for dementia was used. Cases with pre-stroke dementia were excluded from the analysis.

RESULTS

Out of 691 included cases, 423 (61.22%) and 451 (65.27%) underwent cognitive evaluation, three and twelve months after stroke; 121 (28.61%) and 151 (33.48%) patients were diagnosed with dementia, respectively. Six (4.96%) patients with dementia, three months post-stroke did not meet the diagnostic criteria for dementia nine months later. After twelve months, 37 (24.50%) patients were diagnosed with dementia, first time after stroke. Delirium in hospital was an independent risk factor for dementia after three months (OR = 7.267, 95%CI 2.182-24.207, p = 0.001) but not twelve months after the stroke.

CONCLUSIONS

Patients with stroke complicated by in-hospital delirium are at a higher risk for dementia at three but not twelve months post-stroke.

Drug therapy for delirium in terminally ill adults

BACKGROUND

Delirium is a syndrome characterised by an acute disturbance of attention and awareness which develops over a short time period and fluctuates in severity over the course of the day. It is commonly experienced during inpatient admission in the terminal phase of illness. It can cause symptoms such as agitation and hallucinations and is distressing for terminally ill people, their families and staff. Delirium may arise from any number of causes and treatment should aim to address these causes. When this is not possible, or treatment is unsuccessful, drug therapy to manage the symptoms may become necessary. This is the second update of the review first published in 2004.

OBJECTIVES

To evaluate the effectiveness and safety of drug therapies to manage delirium symptoms in terminally ill adults.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL and PsycINFO from inception to July 2019, reference lists of retrieved papers, and online trial registries.

SELECTION CRITERIA

We included randomised controlled trials of drug therapies in any dose by any route, compared to another drug therapy, a non-pharmacological approach, placebo, standard care or wait-list control, for the management of delirium symptoms in terminally ill adults (18 years or older).

DATA COLLECTION AND ANALYSIS

We independently screened citations, extracted data and assessed risk of bias. Primary outcomes were delirium symptoms; agitation score; adverse events. Secondary outcomes were: use of rescue medication; cognitive status; survival. We applied the GRADE approach to assess the overall quality of the evidence for each outcome and we include eight 'Summary of findings' tables.

MAIN RESULTS

We included four studies (three new to this update), with 399 participants. Most participants had advanced cancer or advanced AIDS, and mild- to moderate-severity delirium. Meta-analysis was not possible because no two studies examined the same comparison. Each study was at high risk of bias for at least one criterion. Most evidence was low to very low quality, downgraded due to very serious study limitations, imprecision or because there were so few data. Most studies reported delirium symptoms; two reported agitation scores; three reported adverse events with data on extrapyramidal effects; and none reported serious adverse events. 1. Haloperidol versus placebo There may be little to no difference between placebo and haloperidol in delirium symptoms within 24 hours (mean difference (MD) 0.34, 95% confidence interval (CI) -0.07 to 0.75; 133 participants). Haloperidol may slightly worsen delirium symptoms compared with placebo at 48 hours (MD 0.49, 95% CI 0.10 to 0.88; 123 participants with mild- to moderate-severity delirium). Haloperidol may reduce agitation slightly compared with placebo between 24 and 48 hours (MD -0.14, 95% -0.28 to -0.00; 123 participants with mild- to moderate-severity delirium). Haloperidol probably increases extrapyramidal adverse effects compared with placebo (MD 0.79, 95% CI 0.17 to 1.41; 123 participants with mild- to moderate-severity delirium). 2. Haloperidol versus risperidone There may be little to no difference in delirium symptoms with haloperidol compared with risperidone within 24 hours (MD -0.42, 95% CI -0.90 to 0.06; 126 participants) or 48 hours (MD -0.36, 95% CI -0.92 to 0.20; 106 participants with mild- to moderate-severity delirium). Agitation scores and adverse events were not reported for this comparison. 3. Haloperidol versus olanzapine We are uncertain whether haloperidol reduces delirium symptoms compared with olanzapine within 24 hours (MD 2.36, 95% CI -0.75 to 5.47; 28 participants) or 48 hours (MD 1.90, 95% CI -1.50 to 5.30, 24 participants). Agitation scores and adverse events were not reported for this comparison. 4. Risperidone versus placebo Risperidone may slightly worsen delirium symptoms compared with placebo within 24 hours (MD 0.76, 95% CI 0.30 to 1.22; 129 participants); and at 48 hours (MD 0.85, 95% CI 0.32 to 1.38; 111 participants with mild- to moderate-severity delirium). There may be little to no difference in agitation with risperidone compared with placebo between 24 and 48 hours (MD -0.05, 95% CI -0.19 to 0.09; 111 participants with mild- to moderate-severity delirium). Risperidone may increase extrapyramidal adverse effects compared with placebo (MD 0.73 95% CI 0.09 to 1.37; 111 participants with mild- to moderate-severity delirium). 5. Lorazepam plus haloperidol versus placebo plus haloperidol We are uncertain whether lorazepam plus haloperidol compared with placebo plus haloperidol improves delirium symptoms within 24 hours (MD 2.10, 95% CI -1.00 to 5.20; 50 participants with moderate to severe delirium), reduces agitation within 24 hours (MD 1.90, 95% CI 0.90 to 2.80; 52 participants), or increases adverse events (RR 0.70, 95% CI -0.19 to 2.63; 31 participants with moderate to severe delirium). 6. Haloperidol versus chlorpromazine We are uncertain whether haloperidol reduces delirium symptoms compared with chlorpromazine at 48 hours (MD 0.37, 95% CI -4.58 to 5.32; 24 participants). Agitation scores were not reported. We are uncertain whether haloperidol increases adverse events compared with chlorpromazine (MD 0.46, 95% CI -4.22 to 5.14; 24 participants). 7. Haloperidol versus lorazepam We are uncertain whether haloperidol reduces delirium symptoms compared with lorazepam at 48 hours (MD -4.88, 95% CI -9.70 to 0.06; 17 participants). Agitation scores were not reported. We are uncertain whether haloperidol increases adverse events compared with lorazepam (MD -6.66, 95% CI -14.85 to 1.53; 17 participants). 8. Lorazepam versus chlorpromazine We are uncertain whether lorazepam reduces delirium symptoms compared with chlorpromazine at 48 hours (MD 5.25, 95% CI 0.38 to 10.12; 19 participants), or increases adverse events (MD 7.12, 95% CI 1.08 to 15.32; 18 participants). Agitation scores were not reported.

SECONDARY OUTCOMES

use of rescue medication, cognitive impairment, survival There were insufficient data to draw conclusions or assess GRADE.

AUTHORS' CONCLUSIONS

We found no high-quality evidence to support or refute the use of drug therapy for delirium symptoms in terminally ill adults. We found low-quality evidence that risperidone or haloperidol may slightly worsen delirium symptoms of mild to moderate severity for terminally ill people compared with placebo. We found moderate- to low-quality evidence that haloperidol and risperidone may slightly increase extrapyramidal adverse events for people with mild- to moderate-severity delirium. Given the small number of studies and participants on which current evidence is based, further research is essential.