Do delirium and Alzheimer's dementia share specific pathogenetic mechanisms?

Evaluating Nutritional Risk Factors for Delirium in Intensive-Care-Unit Patients: Present Insights and Prospects for Future Research

Malnutrition, hypercatabolism, and metabolic changes are well-established risk factors for delirium in critically ill patients. Although the exact mechanisms are not fully understood, there is mounting evidence suggesting that malnutrition can cause a variety of changes that contribute to delirium, such as electrolyte imbalances, immune dysfunction, and alterations in drug metabolism. Therefore, a comprehensive metabolic and malnutrition assessment, along with appropriate nutritional support, may help to prevent or ameliorate malnutrition, reduce hypercatabolism, and improve overall physiological function, ultimately lowering the risk of delirium. For this aim, bioelectrical impedance analysis can represent a valuable strategy. Further research into the underlying mechanisms and nutritional risk factors for delirium is crucial to developing more effective prevention strategies. Understanding these processes will allow clinicians to personalize treatment plans for individual patients, leading to improved outcomes and quality of life in the intensive-care-unit survivors.

Delirium risk factors in hospitalized patient: a comprehensive evaluation of underlying diseases and medications in different wards of a large Urban Hospital Center in Iran

BACKGROUND

Delirium is a neurobehavioral syndrome, which is characterized by a fluctuation of mental status, disorientation, confusion and inappropriate behavior, and it is prevalent among hospitalized patients. Recognizing modifiable risk factors of delirium is the key point for improving our preventive strategies and restraining its devastating consequences. This study aimed to identify and investigate various factors predisposing hospitalized patients to develop delirium, focusing mostly on underlying diseases and medications.

METHOD

In a prospective, observational trial, we investigated 220 patients who had been admitted to the internal, emergency, surgery and hematology-oncology departments. We employed the Confusion Assessment Method (CAM) questionnaire, The Richmond Agitation Sedation Scale (RASS), the General Practitioner Assessment of Cognition (GPCOG), demographic questionnaire, patient interviews and medical records. Multivariate logistic regression models were used to analyze the predictive value of medications and underlying diseases for daily transition to delirium.; demographics were analyzed using univariate analysis to identify those independently associated with delirium.

RESULTS

Two hundred twenty patients were enrolled; the emergency department had the most incident delirium (31.3%), and the surgery section had the least (2.4%); delirium was significantly correlated with older ages and sleep disturbance. Among multiple underlying diseases and the medications evaluated in this study, we found that a history of dementia, neurological diseases and malignancies increases the odds of transition to delirium and the use of anticoagulants decreases the incident delirium.

CONCLUSION

Approximately 1 out of 10 overall patients developed delirium; It is important to evaluate underlying diseases and medications more thoroughly in hospitalized patients to assess the risk of delirium.

Impact of delirium on mortality in patients hospitalized for heart failure

OBJECTIVE

Heart Failure (HF) is one of the leading causes of hospitalization in the United States accounting for ≈800,000 hospital discharges and $11 billion in annual costs. Delirium occurs in approximately 30% of elderly hospitalized patients and its incidence is significantly higher among those admitted to the critical care units. Despite this, there has been limited exploration of the clinical and economic impact of delirium in patients hospitalized with acute HF. We hypothesized that delirium in HF is associated with excess mortality and hospital costs.

METHODS

We queried the 2001-2014 Nationwide Inpatient Sample to identify hospitalizations that included a primary discharge diagnosis of HF (ICD-9-CM: 428.xx) and stratified them by presence or absence of delirium (ICD-9-CM: 239.0, 290.41, 293.0, 293.1, 348.31). Differences in in-hospital mortality, length of stay (LOS), and hospital costs were assessed using propensity-score matched cohorts.

RESULTS

Major predictors of delirium included advanced age, Caucasian race, underlying dementia or psychiatric diagnoses, higher Elixhauser Comorbidity Index, renal failure, cardiogenic shock, and coronary artery bypass surgery. In the propensity-score matched analysis of 76,411 hospitalization with delirium compared to 76,612 without delirium, in-hospital mortality (odds ratio: 1.67, 95% CI: 1.51-1.77), LOS (rate ratio [RR]: 1.47, 95% CI: 1.45-1.51), and hospital costs (RR: 1.44, 95% CI: 1.41-1.48) were all statistically higher in the presence of delirium (all p < 0.001).

CONCLUSION

In patients hospitalized with HF, delirium is an independent predictor of increased in-hospital mortality, longer LOS, and excess hospital costs despite adjustment for baseline characteristics.

Management of Delirium in the Intensive Care Unit

In the intensive care unit, delirium is a major contributor to morbidity and mortality in adult patients. Patients with delirium have been shown to have increased length of stay, decreased functional outcomes, and increased risk for requiring placement at the time of discharge. In addition, decreased cognitive function and dementia have been shown to be long-term complications from delirium. The mainstay of treatment and prevention include therapy- and behavioral-based interventions, including frequent orientation, cognitive stimulation, mobilization, sleep restoration, and providing hearing and visual aids. Refractory delirium may require pharmacologic intervention with antipsychotics or alpha-2 agonists.

Blood-Based Biomarkers of Neuroinflammation in Alzheimer's Disease: A Central Role for Periphery?

Neuroinflammation represents a central feature in the development of Alzheimer’s disease (AD). The resident innate immune cells of the brain are the principal players in neuroinflammation, and their activation leads to a defensive response aimed at promoting β-amyloid (Aβ) clearance. However, it is now widely accepted that the peripheral immune system—by virtue of a dysfunctional blood–brain barrier (BBB)—is involved in the pathogenesis and progression of AD; microglial and astrocytic activation leads to the release of chemokines able to recruit peripheral immune cells into the central nervous system (CNS); at the same time, cytokines released by peripheral cells are able to cross the BBB and act upon glial cells, modifying their phenotype. To successfully fight this neurodegenerative disorder, accurate and sensitive biomarkers are required to be used for implementing an early diagnosis, monitoring the disease progression and treatment effectiveness. Interestingly, as a result of the bidirectional communication between the brain and the periphery, the blood compartment ends up reflecting several pathological changes occurring in the AD brain and can represent an accessible source for such biomarkers. In this review, we provide an overview on some of the most promising peripheral biomarkers of neuroinflammation, discussing their pathogenic role in AD.

Brain FDG PET for the Etiological Diagnosis of Clinically Uncertain Cognitive Impairment During Delirium in Remission

BACKGROUND

Positron emission tomography (PET) of the brain with 2-[F-18]-fluoro-2-deoxy-D-glucose (FDG) is widely used for the etiological diagnosis of clinically uncertain cognitive impairment (CUCI). Acute full-blown delirium can cause reversible alterations of FDG uptake that mimic neurodegenerative disease.

OBJECTIVE

This study tested whether delirium in remission affects the performance of FDG PET for differentiation between neurodegenerative and non-neurodegenerative etiology of CUCI.

METHODS

The study included 88 patients (82.0±5.7 y) with newly detected CUCI during hospitalization in a geriatric unit. Twenty-seven (31%) of the patients were diagnosed with delirium during their current hospital stay, which, however, at time of enrollment was in remission so that delirium was not considered the primary cause of the CUCI. Cases were categorized as neurodegenerative or non-neurodegenerative etiology based on visual inspection of FDG PET. The diagnosis at clinical follow-up after ≥12 months served as ground truth to evaluate the diagnostic performance of FDG PET.

RESULTS

FDG PET was categorized as neurodegenerative in 51 (58%) of the patients. Follow-up after 16±3 months was obtained in 68 (77%) of the patients. The clinical follow-up diagnosis confirmed the FDG PET-based categorization in 60 patients (88%, 4 false negative and 4 false positive cases with respect to detection of neurodegeneration). The fraction of correct PET-based categorization did not differ between patients with delirium in remission and patients without delirium (86% versus 89%, p = 0.666).

CONCLUSION

Brain FDG PET is useful for the etiological diagnosis of CUCI in hospitalized geriatric patients, as well as in patients with delirium in remission.

Neuropsychological functioning in severe acute respiratory disorders caused by the coronavirus: Implications for the current COVID-19 pandemic

Objective: The coronavirus class of respiratory viruses - including Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19) - has been associated with central nervous system (CNS) disease. In fact, multiple mechanisms of CNS involvement have been proposed, making it difficult to identify a unitary syndrome that can be the focus of clinical work and research. Neuropsychologists need to understand the potential cognitive and psychological sequelae of COVID-19 and the impact of the interventions (e.g., ICU, ventilation) that have been used in treating patients with severe forms of the illness.Method: We briefly review the literature regarding the neurological and neuropsychological effects of similar coronaviruses, the limited information that has been published to date on COVID-19, and the literature regarding the long-term cognitive and psychological effects of undergoing treatment in the intensive care unit (ICU).Results: We discuss the roles that neuropsychologists can play in assessing and treating the cognitive difficulties and psychiatric symptoms described.Conclusions: At this time, the mechanisms, correlates, and effects of COVID-19 are poorly understood, but information gleaned from the literature on similar viruses and utilized interventions should help inform neuropsychologists as they begin to work with this population.

Deciphering delirium through semantics: a selective synopsis

During the course of the more than 2000 years of its recorded history, delirium has been given a very large number of different names, including phrenitis and paraphrenitis, mania and délire maniaque, (febrile, agitated, asthenic, lethargic, reversible toxic, symptomatic, exogenous) psychosis, inattention, acute and reversible dementia and insanity, amentia and sensorial phrenosis, reversible cognitive dysfunction, paralepsia, confusion and mental confusion, disorientation, dysergasia, and incoherence. Such a wide range of names with related definitions and pathogenic hypotheses not only bears witness to the interest that delirium has aroused in clinical investigators, but also reflects the difficulties in scientifically investigating its intrinsic nature. Furthermore, these difficulties have raised doubts about making a diagnosis that may explain why its incidence is reported to be under-estimated.

Association Between Critical Care Admissions and Cognitive Trajectories in Older Adults

OBJECTIVES

Patients requiring admission to an ICU may subsequently experience cognitive decline. Our objective was to investigate longitudinal cognitive trajectories in older adults hospitalized in ICUs. We hypothesized that individuals hospitalized for critical illness develop greater cognitive decline compared with those who do not require ICU admission.

DESIGN

A retrospective cohort study using prospectively collected cognitive scores of participants enrolled in the Mayo Clinic Study of Aging and ICU admissions retrospectively ascertained from electronic medical records. A covariate-adjusted linear mixed effects model with random intercepts and slopes assessed the relationship between ICU admissions and the slope of global cognitive z scores and domains scores (memory, attention/executive, visuospatial, and language).

SETTING

ICU admissions and cognitive scores in the Mayo Clinic Study of Aging from October 1, 2004, to September 11, 2017.

PATIENTS

Nondemented participants age 50 through 91 at enrollment in the Mayo Clinic Study of Aging with an initial cognitive assessment and at least one follow-up visit.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 3,673 participants, 372 had at least one ICU admission with median (25-75th percentile) follow-up after first ICU admission of 2.5 years (1.2-4.4 yr). For global cognitive z score, admission to an ICU was associated with greater decline in scores over time compared with participants not requiring ICU admission (difference in annual slope = -0.028; 95% CI, -0.044 to -0.012; p < 0.001). ICU admission was associated with greater declines in memory (-0.029; 95% CI, -0.047 to -0.011; p = 0.002), attention/executive (-0.020; 95% CI, -0.037 to -0.004; p = 0.016), and visuospatial (-0.013; 95% CI, -0.026 to -0.001; p = 0.041) domains. ICU admissions with delirium were associated with greater declines in memory (interaction p = 0.006) and language (interaction p = 0.002) domains than ICU admissions without delirium.

CONCLUSIONS

In older adults, ICU admission was associated with greater long-term cognitive decline compared with patients without ICU admission. These findings were more pronounced in those who develop delirium while in the ICU.

Effectiveness of multicomponent interventions on incidence of delirium in hospitalized older patients with hip fracture: a systematic review

ABSTRACTBackground:Delirium is the most frequent complication among the hospitalized elderly with hip fracture. Although, delirium is associated with longer hospital stay, higher mortality rates, worse functional outcomes, and higher institutionalization rates yet health service planners have hugely ignored its existence. This review aims to identify the effectiveness of multicomponent interventions to prevent delirium in hospitalized elderly patients with hip fracture.

METHODS

This review includes experimental, non-experimental, and observational studies. Electronic searches were conducted in MEDLINE, CINAHL, PsycINFO, Cochrane Central Register of Controlled Trials, Embase, and Web of science.

RESULTS

After inclusion and exclusion criteria were applied, nine full text articles were included in the review. The studies reported the following effect on delirium: We pooled data regarding incidence of delirium from the three RCTs. The effect was in favor of the intervention group (odds ratio 0.64, 95% CI 0.46-0.87). All three RCTs reported that duration of delirium was shorter in the intervention group than in the usual care group (mean 2.9 vs. 3.1 days, median 3 vs. 4 days, median 5.0 vs. 10.2 days). Four other studies reported on the duration of delirium with Milisen and colleagues reported shorter duration of delirium within the intervention group. Four studies reported on severity of delirium with two research groups reporting significant results.

CONCLUSION

Early engagement of multidisciplinary staff who addresses the risk factors of delirium as soon as the patient presents to the acute care environment is the key element of a successful delirium prevention program. Once delirium had developed, the multicomponent interventions did not appear to make a difference to the duration or severity of delirium.

Underdiagnosis of delirium on admission and prediction of patients who will develop delirium during their inpatient stay: a pilot study

INTRODUCTION

The study aimed to determine the prevalence and documentation of delirium among the elderly and if the Clock Drawing Test (CDT) can be used to predict which patients had delirium on admission and those who may develop delirium during their stay in acute medical wards.

METHODS

A single researcher performed the Mini-Mental State Examination (MMSE) and CDT on admission and discharge of 57 elderly adults at the National University Hospital, Singapore. Delirium was defined as a ≥ 3-point improvement or ≥ 2-point decline in MMSE scores from admission to discharge, where a fall denotes development of delirium and a rise denotes resolution. The case notes of the same patients were reviewed for documentation of delirium. All inpatients from two acute medical wards were examined. One CDT score and a pair of MMSE scores were collected from each patient.

RESULTS

A total of 57 patients (28 male, 29 female) were involved in the study. Their mean age was 76.0 ± 8.7 years. The prevalence of delirium based on MMSE scores was 40.4%; 16 patients had delirium on admission while seven developed delirium during their inpatient stay. However, delirium was documented in the case notes of only 7 (30%) of the 23 patients. CDT score was better than baseline MMSE score at predicting a decline in MMSE score.

CONCLUSION

The prevalence of delirium in the acute medical setting is high but underdiagnosed. The CDT may be a good screening tool to identify patients at risk of delirium during their inpatient stay. Baseline cognition screening should be performed in every elderly patient admitted to hospital.

Cognitive functioning, mental health, and quality of life in ICU survivors: an overview

Critical illness can and often does lead to significant cognitive impairment and to the development of psychological disorders. These conditions are persistent and, although they improve with time, often fail to completely abate. Although the functional correlates of cognitive and psychological morbidity (depression, anxiety, and posttraumatic stress disorder) have been studied, they may include poor quality of life, inability to return to work or to work at previously established levels, and inability to function effectively in emotional and interpersonal domains. The potential etiologies of cognitive impairment and psychological morbidity in ICU survivors are particularly poorly understood and may vary widely across patients. Potential contributors may include the potentially toxic effects of sedatives and narcotics, delirium, hypoxia, glucose dysregulation, metabolic derangements, and inflammation. Patients with preexisting vulnerabilities, including predisposing genetic factors, and frail elderly populations may be at particular risk for emergence of acceleration of conditions such as mild cognitive impairment.

Delirium superimposed on dementia and mild cognitive impairment

Dementia is an illness that progressively affects cognition, emotion, and functional status. It can be complicated by delirium, an acute disturbance of consciousness and cognition that develops over a short course with fluctuating symptoms. Patients with dementia who experience delirium tend to have slower resolution of symptoms, more adverse events, and poorer outcomes. There are significant health care expenditures associated with delirium. Many health care providers fail to recognize and diagnose delirium. The confusion assessment method is a suggested tool for diagnosing delirium. Delirium is multifactorial, occurring in an individual who has a predisposing factor (dementia is the number 1 risk factor) and is exposed to further precipitating risk factors that are often preventable. The main focus of treatment and management of delirium should be on prevention, which can be achieved through assessing patients for predisposing and precipitating factors. If a patient does develop delirium, a reassessment of precipitating factors is the first step in treatment, and then nonpharmacologic or pharmacologic treatment can be considered. The use of antipsychotics or melatonin to treat delirium in dementia is considered off-label.

Using the Mini-Mental State Examination to screen for delirium in elderly patients with hip fracture

BACKGROUND

The main aim of this paper was to examine the usefulness of the Mini-Mental State Examination (MMSE) for screening delirium in elderly patients with hip fracture.

METHODS

The sample included 364 elderly patients with hip fracture admitted to two hospitals in Oslo. Delirium was assessed by the Confusion Assessment Method (CAM) as an approximation of the gold standard, DSM-IV. To evaluate the psychometric properties of the MMSE scale, we used the Mokken nonparametric latent trait model for unidimensional scaling.

RESULTS

In total, 76 (21%) patients were diagnosed with delirium based on the CAM, and 141 (43%) had preexisting cognitive impairment. As a screening tool, the recommended MMSE cut-point of 24 showed an acceptable sensitivity of 88% with a specificity of 54%. The prediction of delirium, based on logistic regression on the MMSE total score and on the 5 items selected by the stepwise logistic regression procedure, gave clearly less acceptable results.

CONCLUSIONS

Our study indicates that the MMSE may be useful in screening for delirium, but the high percentage of false positives shows that it does not have diagnostic potential in patients with hip fracture.

Cognitive functioning, mental health, and quality of life in ICU survivors: an overview

The significant and sometimes permanent effects of critical illness on wide-ranging aspects of functioning are increasingly recognized. Among the areas affected are acute and long-term cognitive functioning, depression, anxiety, PTSD, and quality of life. These and other areas are increasingly being studied and indeed are increasingly the focus of clinical attention and investigations. These conditions have been a focus of attention for more than a dozen years, with much improvement occurring in the ability to characterize these phenomena. For instance, in intervening years, it has been learned that cognitive impairment is highly prevalent and functionally disruptive and that it occurs in wide-ranging domains. Key questions remain unanswered with regard to vital questions such as determining causes, risk factors, and mechanisms as well as the degree to which brain injuries associated with critical illness are amenable to rehabilitation. Little remains known about the effects of critical illness on elderly ICU cohorts and on the neurologic functioning of individuals with preexisting impairment versus those who are normal. Few data exist regarding the development of strategies designed to prevent the emergence of neuropsychological deficits after critical illness. Although great progress has been made and is ongoing, a pressing need exists for additional investigation of cognitive impairment and other conditions,such as PTSD and quality of life after critical illness, that will seek to untangle the many pertinent questions related to this condition and that will ultimately offer help and hope to the thousands of survivors affected by this condition.

The role of inflammation in the pathogenesis of delirium and dementia in older adults: a review

AIMS

To review recent evidence that suggests inflammation plays a similar role in the pathogenesis of delirium and dementia.

METHODS

We performed a literature search of original research and review articles in PubMed using the keywords: delirium, dementia, and inflammation. We summarized the evidence linking inflammation to the pathogenesis of delirium and dementia.

DISCUSSION

Delirium and dementia share similarities in clinical and pathogenic features, leading to the speculation that instead of being distinct clinical entities, the two age-related conditions may be linked by a common pathogenic mechanism. Inflammatory markers have been shown to be elevated in both delirium and dementia, thereby implicating inflammation as a possible mediating factor in their genesis. There is evidence in both basic science and clinical research literature that elevated cytokines play a crucial role in the development of cognitive dysfunction observed in both dementia and delirium.

CONCLUSION

Mounting evidence supports the role of inflammation in the development of both dementia and delirium. Further studies are needed to elucidate the mechanisms underlying these relationships.

Serum S100B in elderly patients with and without delirium

OBJECTIVE

Elevation of S100B has been shown after various neurologic diseases with cognitive dysfunction. The aim of this study was to compare the serum level of S100B of patients with and without delirium and investigate the possible associations with different subtypes of delirium.

METHODS

Acutely admitted medical patients aged 65 years or more were included from 2005 through 2008. Delirium was diagnosed by Confusion Assessment Method, delirium subtype by Delirium Symptom Interview and preexistent global cognitive function by the 'Informant Questionnaire on Cognitive Decline-short form'. S100B levels were determined in serum by electrochemiluminescence immunoassay.

RESULTS

Samples of 412 patients were included, 91 during delirium, 35 after delirium and 286 of patients without delirium. Patients with delirium (31%) were significantly older, 81.5 versus 76.6 years (p < 0.001) and experienced significantly more often preexistent cognitive and functional impairment (p < 0.001). S100B level differed significantly (p = 0.004) between the three groups: median 0.07 microg/L (inter-quartile ranges: 0.05-0.14 microg/L) during delirium, 0.12 microg/L (0.05-0.29 microg/L) after delirium and 0.06 microg/L (0.03-0.10 microg/L) in patients without delirium. Combining the impact of cognitive impairment, infection and age on S100B, highest S100B was observed in the oldest patients after delirium with preexistent cognitive impaired and infection. Delirium subtype and S100B level were not significantly correlated.

CONCLUSION

Higher S100B levels were found in patients with delirium than in patients without delirium, with highest levels of S100B in samples taken after delirium. Future studies are needed to elucidate the mechanism responsible for the increase of S100B and the possible association with long term cognitive impairment.

Strategies for promoting early activity in critically ill mechanically ventilated patients

Prolonged immobilization plays a significant role in neuromuscular abnormalities and complicates the clinical course of a majority of critically ill patients. Immobilization in critically ill patients is associated with significant morbidity and impaired physical function. Overuse of sedation, sleep deprivation, immobility, and the development of delirium are all intensive care unit (ICU) factors that may negatively impact patient outcomes. Ambulation of critically ill patients is difficult with risk for adverse events. However, with a dedicated and trained team and culture change, early ICU mobility can be a feasible and safe process. Early mobility has potential as a therapy to prevent or treat the neuromuscular complications of critical illness. ICU culture can be transformed in a way that leads to improved and more reliable treatments and care, including early activity and mobility.

Cognitive functioning, mental health, and quality of life in ICU survivors: an overview

Critical illness can and often does lead to significant cognitive impairment and to the development of psychological disorders. These conditions are persistent and, although they improve with time, often fail to completely abate. Although the functional correlates of cognitive and psychological morbidity (depression, anxiety, and posttraumatic stress disorder) have been studied, they may include poor quality of life, inability to return to work or to work at previously established levels, and inability to function effectively in emotional and interpersonal domains. The potential etiologies of cognitive impairment and psychological morbidity in ICU survivors are particularly poorly understood and may vary widely across patients. Potential contributors may include the potentially toxic effects of sedatives and narcotics, delirium, hypoxia, glucose dysregulation, metabolic derangements, and inflammation. Patients with preexisting vulnerabilities, including predisposing genetic factors, and frail elderly populations may be at particular risk for emergence of acceleration of conditions such as mild cognitive impairment.

The association between delirium and the apolipoprotein E epsilon 4 allele: new study results and a meta-analysis

OBJECTIVES

To determine a possible association between Apolipoprotein E (APOE)sigma4-allele and delirium in a large cohort and combining these current data with former studies in a meta-analysis.

DESIGN

Combination of a new prospective cohort study and meta-analysis.

SETTING

Medical department and orthopedic/traumatology department of University hospital from 2003 to 2007.

PARTICIPANTS

A total of 656 patients aged 65 years and older acutely admitted with a medical diagnosis or after hip fracture.

MEASUREMENTS

Confusion Assessment Method for delirium, Informant Questionnaire on Cognitive Decline-short form for predelirium global cognitive impairment, and Katz Index of Activities of Daily Living for functionality. APOE was genotyped by mass spectrometer. A meta-analysis was performed combining the current data with published studies analyzing the association between the APOE sigma4-allele and the delirium.

RESULTS

: The 49% of the 76 surgical patients and 35% of the 580 medical patients experienced delirium. Delirious patients were significantly older (82 versus 77 years) and had more frequently functional (66% versus 26%) and cognitive impairment (86% versus 29%) than nondelirious patients. The odds ratio (OR) for delirium adjusted for age, cognitive, and functional impairment of sigma4 carriers compared with non-sigma4 carriers was 1.7 (95% confidence interval [CI]: 1.1-2.6). Four studies were added to the meta-analysis, which included 1,099 patients in total. The OR for delirium in the meta-analysis was 1.6 (95% CI: 0.9-2.7) of sigma4 carriers compared with non-sigma4 carriers.

CONCLUSIONS

This study and meta-analysis suggest an association between delirium and the APOE sigma4 allele.

Delirium in elderly adults: diagnosis, prevention and treatment

Delirium is a common and serious acute neuropsychiatric syndrome with core features of inattention and global cognitive dysfunction. The etiologies of delirium are diverse and multifactorial and often reflect the pathophysiological consequences of an acute medical illness, medical complication or drug intoxication. Delirium can have a widely variable presentation, and is often missed and underdiagnosed as a result. At present, the diagnosis of delirium is clinically based and depends on the presence or absence of certain features. Management strategies for delirium are focused on prevention and symptom management. This article reviews current clinical practice in delirium in elderly individuals, including the diagnosis, treatment, outcomes and economic impact of this syndrome. Areas of future research are also discussed.

Delirium in elderly adults: diagnosis, prevention and treatment

Delirium is a common and serious acute neuropsychiatric syndrome with core features of inattention and global cognitive dysfunction. The etiologies of delirium are diverse and multifactorial and often reflect the pathophysiological consequences of an acute medical illness, medical complication or drug intoxication. Delirium can have a widely variable presentation, and is often missed and underdiagnosed as a result. At present, the diagnosis of delirium is clinically based and depends on the presence or absence of certain features. Management strategies for delirium are focused on prevention and symptom management. This article reviews current clinical practice in delirium in elderly individuals, including the diagnosis, treatment, outcomes and economic impact of this syndrome. Areas of future research are also discussed.

Markers of cerebral damage during delirium in elderly patients with hip fracture

Background

S100B protein and Neuron Specific Enolase (NSE) can increase due to brain cell damage and/or increased permeability of the blood-brain-barrier. Elevation of these proteins has been shown after various neurological diseases with cognitive dysfunction. Delirium is characterized by temporal cognitive deficits and is an important risk factor for dementia. The aim of this study was to compare the level of S100B and NSE of patients before, during and after delirium with patients without delirium and investigate the possible associations with different subtypes of delirium.

Methods

The study population were patients aged 65 years or more acutely admitted after hip fracture. Delirium was diagnosed by the Confusion Assessment Method and the subtype by Delirium Symptom interview. In maximal four serum samples per patient S100B and NSE levels were determined by electrochemiluminescence immunoassay.

Results

Of 120 included patients with mean age 83.9 years, 62 experienced delirium. Delirious patients had more frequently pre-existing cognitive impairment (67% vs. 18%, p < 0.001). Comparing the first samples during delirium to samples of non-delirious patients, a difference was observed in S100B (median 0.16 versus 0.10 μg/L, p = < 0.001), but not in NSE (median 11.7 versus 11.7 ng/L, p = 0.97). Delirious state (before, during, after) (p < 0.001), day of blood withdrawal (p < 0.001), pre- or postoperative status (p = 0.001) and type of fracture (p = 0.036) were all associated with S100B level. The highest S100B levels were found 'during' delirium. S100B levels 'before' and 'after' delirium were still higher than those from 'non-delirious' patients. No significant difference in S100B (p = 0.43) or NSE levels (p = 0.41) was seen between the hyperactive, hypoactive and mixed subtype of delirium.

Conclusion

Delirium was associated with increased level of S100B which could indicate cerebral damage either due to delirium or leading to delirium. The possible association between higher levels of S100B during delirium and the higher risk of developing dementia after delirium is an interesting field for future research. More studies are needed to elucidate the role of S100B proteins in the pathophysiological pathway leading to delirium and to investigate its possibility as biomarker for delirium.

Cholinergic deficiency hypothesis in delirium: a synthesis of current evidence

Deficits in cholinergic function have been postulated to cause delirium and cognitive decline. This review examines current understanding of the cholinergic deficiency hypothesis in delirium by synthesizing evidence on potential pathophysiological pathways. Acetylcholine synthesis involves various precursors, enzymes, and receptors, and dysfunction in these components can lead to delirium. Insults to the brain, like ischemia and immunological stressors, can precipitously alter acetylcholine levels. Imbalances between cholinergic and other neurotransmitter pathways may result in delirium. Furthermore, genetic, enzymatic, and immunological overlaps exist between delirium and dementia related to the cholinergic pathway. Important areas for future research include identifying biomarkers, determining genetic contributions, and evaluating response to cholinergic drugs in delirium. Understanding how the cholinergic pathway relates to delirium may yield innovative approaches in the diagnosis, prevention, and treatment of this common, costly, and morbid condition.

Unravelling the pathophysiology of delirium: a focus on the role of aberrant stress responses

Delirium is a common and serious acute neuropsychiatric syndrome with core features of inattention and cognitive impairment, and associated features including changes in arousal, altered sleep-wake cycle, and other changes in mental status. The main risk factors are old age, cognitive impairment, and other comorbidities. Though delirium has consistent core clinical features, it has a very wide range of precipitating factors, including acute illness, surgery, trauma, and drugs. The molecular mechanisms by which these precipitating factors lead to delirium are largely obscure. In this article, we attempt to narrow down some specific causal pathways. We propose a basic classification for the etiological factors: (a) direct brain insults and (b) aberrant stress responses. Direct brain insults are largely indiscriminate and include general and regional energy deprivation (e.g., hypoxia, hypoglycaemia, stroke), metabolic abnormalities (e.g., hyponatraemia, hypercalcaemia), and the effects of drugs. Aberrant stress responses are conceptually and mechanistically distinct in that they constitute adverse effects of stress-response pathways, which, in health, are adaptive. Ageing and central nervous system disease, two major predisposing factors for delirium, are associated with alterations in the magnitude or duration of stress and sickness behavior responses and increased vulnerability to the effects of these responses. We discuss in detail two stress response systems that are likely to be involved in the pathophysiology of delirium: inflammation and the sickness behavior response, and activity of the limbic-hypothalamic-pituitary-adrenal axis. We conclude by discussing the implications for future research and the development of new therapies for delirium.

Rapid restoration of cognition in Alzheimer's transgenic mice with 8-hydroxy quinoline analogs is associated with decreased interstitial Abeta

As a disease-modifying approach for Alzheimer's disease (AD), clioquinol (CQ) targets beta-amyloid (Abeta) reactions with synaptic Zn and Cu yet promotes metal uptake. Here we characterize the second-generation 8-hydroxy quinoline analog PBT2, which also targets metal-induced aggregation of Abeta, but is more effective as a Zn/Cu ionophore and has greater blood-brain barrier permeability. Given orally to two types of amyloid-bearing transgenic mouse models of AD, PBT2 outperformed CQ by markedly decreasing soluble interstitial brain Abeta within hours and improving cognitive performance to exceed that of normal littermate controls within days. Nontransgenic mice were unaffected by PBT2. The current data demonstrate that ionophore activity, inhibition of in vitro metal-mediated Abeta reactions, and blood-brain barrier permeability are indices that predict a potential disease-modifying drug for AD. The speed of recovery of the animals underscores the acutely reversible nature of the cognitive deficits associated with transgenic models of AD.

Participation in activity and risk for incident delirium

OBJECTIVES

To examine the mediating role between educational attainment and risk for incidence delirium of activity participation and to examine the contribution of participation in specific activities to the development of delirium.

DESIGN

Prospective cohort study.

SETTING

Urban teaching hospital in New Haven, Connecticut.

PARTICIPANTS

Participants were drawn from two prospective cohort studies of 779 newly hospitalized patients aged 70 and older without dementia.

MEASUREMENTS

The main outcome was delirium, measured using the full Confusion Assessment Method (CAM) algorithm, which consisted of acute onset and fluctuating course, inattention, and disorganized thinking or altered level of consciousness, as rated by trained clinical interviewers.

RESULTS

Bivariable results indicated a significant relationship between education and the development of delirium (odds ratio (OR)=0.92, 95% confidence interval (CI)=0.88-0.97) and between activity and delirium (OR= 0.60, 95% CI=0.46-0.79). In multivariable analysis, activity mediated the relationship between education and risk for delirium. Considering each activity separately, multivariable logistic regression analysis showed that regular exercise significantly lowered the risk for developing delirium (OR=0.76, 95% CI=0.60-0.96).

CONCLUSION

In older persons without dementia, activity participation before hospitalization is a mediator between education and incidence of delirium. Specifically, it was found that participation in regular exercise was found to be significantly protective against delirium.

The cognitive consequences of critical illness: practical recommendations for screening and assessment

Critically ill patients are at risk for several secondary complications, including delirium and long-term cognitive impairment. The exact mechanisms of delirium and ICU-related cognitive decline are not fully understood; however, the authors review several recent investigations that have proposed plausible explanations. This article also includes several practical guidelines for the identification and management of delirium to aid in the development and implementation of clinical procedures that will lower the risk for ICU delirium and cognitive decline.

Delirium superimposed on dementia predicts 12-month survival in elderly patients discharged from a postacute rehabilitation facility

BACKGROUND

Delirium superimposed on dementia (DSD) is highly prevalent and associated with high mortality among hospitalized elderly patients, yet little is known about the effect of DSD on midterm mortality. The purpose of this study was to assess 12-month survival in patients with DSD and matched groups with dementia alone, delirium alone, or neither delirium nor dementia.

METHODS

Among 1278 consecutively admitted elderly participants (aged > or =65 years) to our Rehabilitation Unit between January 2002 and May 2005, four matched samples of 47 participants each (DSD, dementia alone, delirium alone, or neither delirium nor dementia) were selected. Matching was based on age, gender, and reason for admission. Postdischarge 12-month survival was assessed in the four groups with Kaplan-Meyer analysis and compared with Cox proportional hazard regression models adjusted for confounders.

RESULTS

Survival was significantly lower for DSD patients than for the other three groups. After adjustment for comorbidity and Barthel Index score before admission, patients with DSD had significantly higher mortality (hazard ratio, 2.3; 95% confidence interval, 1.1-5.5; p =.04) than did patients with neither delirium nor dementia.

CONCLUSIONS

Demented patients who experienced delirium during hospitalization had a more than twofold increased risk of mortality in the 12 months following discharge than did patients with dementia alone, with delirium alone, or with neither dementia nor delirium.

The association between delirium and the apolipoprotein E epsilon4 allele in the elderly

OBJECTIVE

As not all patients with similar risk factors and eliciting conditions develop delirium; it may be hypothesized that genetic variation may play a role in the risk of delirium. On the basis of the relationship between dementia, respectively reduced cholinergic activity, and the APOE epsilon4-allele, and the similarities between dementia and delirium in reduced cholinergic activity, the APOE epsilon4-allele is a rational candidate-gene for delirium. This study examined the association between APOE epsilon4-allele and delirium in elderly patients.

METHODS

Acutely admitted patients to the Department of Medicine of 65 years and over were included during a 27-month time period. Delirium was scored by the confusion assessment method. Cognitive impairment was diagnosed by Mini Mental State Examination and informant questionnaire on cognitive decline. Genotyping was done with matrix-assisted laser-desorption/ionization time-of flight mass spectrometry.

RESULTS

Of 415 included patients, a random sample of 264 patients was genotyped for APOE. The patients who met the criteria for delirium (35%) were significantly older and more frequently had preexisting functional and cognitive impairment. APOE genotype was borderline significantly associated with cognitive impairment in patients below 75 years (P=0.057). The odds ratio for carriers of an APOE epsilon4-allele compared with patients without an APOE epsilon4-allele for developing delirium was 1.17 (95% confidence interval (CI): 0.49-2.78) in the cognitively intact patients and 0.42 (95% CI: 0.14-1.30) in the cognitively impaired patients. No relation existed between the total number of APOE epsilon4-alleles and the different delirium subtypes (P=0.12).

CONCLUSIONS

We found no convincing evidence that carriers of the APOE epsilon4-allele have a higher risk of delirium.

Factors associated with delirium severity among older patients

AIM

The goal of this study was to determine whether the factors associated with delirium varied according to the severity of the delirium experienced by the older patients.

BACKGROUND

Delirium among older patients is prevalent and leads to numerous detrimental effects. The negative consequences of delirium are worse among older adults with severe delirium compared with patients with mild delirium. There has been no study identifying those factors associated with delirium severity among long-term care older patients newly admitted to an acute care hospital.

DESIGN

This is a descriptive study.

METHODS

This is a secondary analysis study of institutionalized older patients newly admitted to an acute care hospital (n = 104). Upon admission, patients were screened for delirium with the Confusion Assessment Method and severity of delirium symptoms were determined by using the Delirium Index.

RESULTS

Of the 71 delirious older patients, 32 (45.1%) had moderate-severe delirium while 39 (54.9%) presented mild delirium. In univariate analyses, a significant positive relationship was observed between the level of prior cognitive impairment and the severity of delirium (p = 0.0058). Low mini-mental state examination (MMSE) scores (p < 0.0001), the presence of severe illness at the time of hospitalization (p = 0.0016) and low functional autonomy (BI: p = 0.0017; instrumental activities of daily living: p = 0.0003) were significantly associated with moderate-severe delirium. Older patients suffering from mild delirium used significantly more drugs (p = 0.0056), notably narcotics (p = 0.0017), than those with moderate-severe delirium. Results from the stepwise regression indicated that MMSE score at admission and narcotic medication use are the factors most strongly associated with the severity of delirium symptoms.

CONCLUSIONS

This present study indicates that factors associated with moderate-severe delirium are different from those associated with mild delirium. Given the result concerning the role of narcotics, future studies should evaluate the role of pain management in the context of delirium severity.

RELEVANCE TO CLINICAL PRACTICE

As moderate-severe delirium is associated with poorer outcomes than is mild delirium, early risk factor identification for moderate-severe delirium by nurses may prove to be of value in preventing further deterioration of those older patients afflicted with delirium.

Managing delirium in hospitalized elderly patients

This review highlights the key elements of guidelines developed for the management of delirium. Experts and expert panels in several countries have presented their own guidelines, which have similarities but also differences in their emphases. The essential elements in the management of delirium are appropriate detection and diagnosis, assessment and treatment of underlying conditions, symptom management, environmental and supportive interventions, post-delirium care and follow-up, and paying attention to risk factors and prevention. The level of evidence behind each recommendation of the guidelines is discussed, as well as some of the typical pitfalls in the care of patients with delirium. Although rigorous randomized intervention trials on full-blown delirium are still scarce, we have some trials suggesting how to manage each dimension of the care of delirium.

Cytokines and acute phase response in delirium

OBJECTIVE

This study aimed to examine the expression patterns of pro- and anti-inflammatory cytokines in elderly patients with and without delirium who were acutely admitted to the hospital.

METHODS

All consecutive patients aged 65 years and older, who were acutely admitted to the Department of Internal Medicine of the Academic Medical Center, Amsterdam, a tertiary university teaching hospital, were invited. Members of the geriatric consultation team completed a multidisciplinary evaluation for all study participants within 48 h after admission, including cognitive and functional examination by validated measures of delirium, memory, and executive function. C-reactive protein and cytokines (IL-1beta, IL-6, TNF-alpha, IL-8, and IL-10) were determined within 3 days after admission.

RESULTS

In total, 185 patients were included; mean age was 79 years; 42% were male; and 34.6% developed delirium within 48 h after admission. Compared to patients without delirium, patients with delirium were older and had experienced preexistent cognitive impairment more often. In patients with delirium, significantly more IL-6 levels (53% vs. 31%) and IL-8 levels (45% vs. 22%) were above the detection limit as compared with patients who did not have delirium. After adjusting for infection, age, and cognitive impairment, these differences were still significant.

CONCLUSIONS

Proinflammatory cytokines may contribute to the pathogenesis of delirium in acutely admitted elderly patients.

Impact of delirium on cognition, distress, and health-related quality of life after hematopoietic stem-cell transplantation

PURPOSE

To determine the impact of delirium during the acute phase of myeloablative hematopoietic stem-cell transplantation (HSCT) on health-related quality of life (HRQOL), distress, and neurocognitive functioning 30 and 80 days after transplantation.

PATIENTS AND METHODS

Ninety patients completed a battery assessing HRQOL, distress, and neuropsychological functioning before receiving their first HSCT. Delirium was assessed three times per week using the Delirium Rating Scale and the Memorial Delirium Assessment Scale from 7 days before transplantation through 30 days after transplantation. At 30 days after transplantation, distress and neurocognitive functioning were assessed. At 80 days after transplantation, HRQOL, distress, and neuropsychological functioning were re-evaluated.

RESULTS

After adjusting for confounding factors, patients who experienced a delirium episode, versus patients who did not, reported significantly worse depression, anxiety, and fatigue symptoms at 30 days (linear regression beta(s) = 0.2, 0.3, and 0.5, respectively; P < .04). At 80 days, patients with a delirium episode had significantly worse executive functioning (beta = -1.1; P < .02), attention and processing speed (beta(s) = -4.7 and -5.4, respectively; P < .03), mental health on the Medical Outcomes Study Health Survey, 12-item short form (beta = -6.5; P < .02), and anxiety, fatigue, and cancer and treatment distress symptoms (beta(s) = 0.4, 0.6, and 0.3, respectively; P < .03).

CONCLUSION

Patients with a malignancy who experience delirium during myeloablative HSCT showed impaired neurocognitive abilities and persistent distress 80 days after transplantation. Effective prevention or treatment of delirium during HSCT may improve both cognitive and psychological outcomes.

Isoflurane-induced apoptosis: a potential pathogenic link between delirium and dementia

BACKGROUND

Dementia and delirium have been postulated to share common pathophysiologic mechanisms; however, identification of these unifying mechanisms has remained elusive. The inhalation anesthetic isoflurane has been shown to enhance beta-amyloid protein (Abeta) oligomerization and generation, to potentiate the cytotoxicity of Abeta, and to induce apoptosis. To address the molecular mechanisms of dementia and delirium associated with anesthesia and surgery, we assessed whether the Abeta fibrillar aggregation inhibitor Congo red can attenuate isoflurane-induced caspase-3 activation in H4 human neuroglioma cells overexpressing human beta-amyloid precursor protein (APP).

METHODS

H4 human neuroglioma cells stably transfected to express human full-length wild-type APP were exposed to 2% isoflurane for 6 hours. The cells were harvested at the end of the treatment. Caspase-3 activation was measured with quantitative Western blotting.

RESULTS

We found that isoflurane induces cellular apoptosis in a dose-dependent manner, and that Congo red inhibits isoflurane-induced apoptosis in H4 human neuroglioma cells overexpressing APP. Interestingly, Congo red also inhibits staurosporine-induced apoptosis.

CONCLUSION

The demonstration that isoflurane contributes to well-described mechanisms of Alzheimer's neuropathogenesis provides a plausible link between the acute effects of anesthesia, a well-described risk factor for delirium, and the more long-term sequelae of dementia. These findings suggest that isoflurane-induced Abeta oligomerization and apoptosis may contribute to the risk of postoperative cognitive dysfunction and provide a potential pathogenic link between delirium and dementia.

Assessing neurocognitive outcomes after critical illness: are delirium and long-term cognitive impairments related?

PURPOSE OF REVIEW

Critically ill patients have a high risk of developing neurologic dysfunction including delirium and long-term cognitive impairment. In this paper we examine possible relationships between delirium and long-term cognitive impairments and explore this in the context of critical illness.

RECENT FINDINGS

Critical illness and its treatment can lead to neurologic morbidity including neuropathological abnormalities, delirium, and cognitive impairments. The association between delirium and long-term cognitive impairments has been shown in a number of populations. Among intensive care unit cohorts, delirium appears to be one of many possible causes of cognitive impairments and may be a leading modifiable cause. The mechanisms of both delirium and intensive care unit related cognitive impairment remain unclear, although a variety of common mechanisms have been proposed.

SUMMARY

Potential neurologic consequences of critical illness include delirium and long-term cognitive impairments. Defining the extent of their association in intensive care unit cohorts is an important research priority due to the high prevalence of delirium and persistent cognitive impairments in critically ill patients. Future research should focus on strategies for the early identification of delirium and cognitive impairments, elucidating mechanisms of brain injury, and the development and implementation of therapeutic modalities designed to prevent or decrease delirium and cognitive morbidity.

The role of oxidative stress in postoperative delirium

AIM

This study aimed to determine a marker that predicts delirium using preoperative oxidative processes in patients undergoing cardiopulmonary bypass surgery.

METHOD

Twelve of the 50 patients included in the study showed signs of delirium during postoperative follow-up. The Delirium Rating Scale was used in patients with delirium according to DSM-IV-TR in the postoperative period. Venous blood samples were obtained from the patients the day before and the day after the surgery to determine plasma antioxidant enzyme levels.

RESULTS

While there were no differences in preoperative superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) levels in both groups, catalase (CAT) levels were significantly lower in the delirium group. Postoperative SOD and MDA levels were also higher in the delirium group, while the GSH-Px levels were found to be lower when compared with those during the preoperative period. In the nondelirium group, the postoperative MDA and GSH-Px levels were found to be lower than preoperative levels, and postoperative SOD levels were found to be higher than preoperative levels. CAT levels were lower in the delirium group when the pre- and postoperative levels were compared in both groups. The postoperative levels of SOD, GSH-Px and CAT in the nondelirium group and MDA in the delirium group were significantly higher than preoperative levels.

CONCLUSION

Patients with low preoperative CAT levels appeared to be more susceptible to delirium than patients with higher CAT levels.

Drugs of anesthesia acting on central cholinergic system may cause post-operative cognitive dysfunction and delirium

Given the progressive and constant increase of average life expectancy, an increasing number of elderly patients undergo surgery. After surgery, elderly patients often exhibit a transient reversible state of cerebral cognitive alterations. Among these cognitive dysfunctions, a state of delirium may develop. Delirium is an aetiologically non-specific syndrome characterised by concurrent disturbances of consciousness and attention, perception, thinking, memory, psychomotor behaviour and the sleep-wake cycle. Delirium appears to occur in 10-26% of general medical patients over 65, and is frequently associated with a significant increase in morbidity and mortality. During hospitalization, mortality rates have been estimated to be 10-26% of patients who developed post-operative delirium, and 22-76% during the following months. Over the last few decades, post-operative delirium has been associated with several pre-operative predictor factors, as well as age (50 years and older), alcohol abuse, poor cognitive and functional status, electrolyses or glucose abnormalities, and type of surgery. The uncertain pathogenesis of post-operative cognitive dysfunctions and delirium has not permitted a causal approach to developing an effective treatment. General anesthesia affects brain function at all levels, including neuronal membranes, receptors, ion channels, neurotransmitters, cerebral blood flow and metabolism. The functional equivalents of these impairments involve mood, memory, and motor function behavioural changes. These dysfunctions are much more evident in the occurrence of stress-regulating transmission and in the alteration of intra-cellular signal transduction systems. In addition, more essential cellular processes, that play an important role in neurotransmitter synthesis and release, such as intra-neuronal signal transduction and second messenger system, may be altered. Keeping in mind the functions of the central muscarinic cholinergic system and its multiple interactions with drugs of anesthesia, it seems possible to hypothesize that the inhibition of muscarinic cholinergic receptors could have a pivotal role in the pathogenesis not only of post-operative delirium but also the more complex phenomena of post-operative cognitive dysfunction.

Risk factors for delirium in acutely admitted elderly patients: a prospective cohort study

Background

Delirium is a neuropsychiatric syndrome frequently observed in elderly hospitalised patients and can be found in any medical condition. Due to the severe consequences, early recognition of delirium is important in order to start treatment in time. Despite the high incidence rate, the occurrence of delirium is not always identified as such. Knowledge of potential risk factors is important. The aim of the current study is to determine factors associated with the occurrence of a prevalent delirium among elderly patients acutely admitted to an internal medicine ward.

Methods

All consecutive patients of 65 years and over acutely admitted to the Department of Internal Medicine of the Academic Medical Centre, Amsterdam, a university hospital, were asked to participate. The presence of delirium was determined within 48 hrs after admission by an experienced geriatrician.

Results

In total, 126 patients were included, 29% had a prevalent delirium after acute admission. Compared to patients without delirium, patients with delirium were older, more often were cognitively and physically impaired, more often were admitted due to water and electrolyte disturbances, and were less often admitted due to malignancy or gastrointestinal bleeding. Independent risk factors for having a prevalent delirium after acute admission were premorbid cognitive impairment, functional impairment, an elevated urea nitrogen level, and the number of leucocytes.

Conclusions

In this study, the most important independent risk factors for a prevalent delirium after acute admission were cognitive and physical impairment, and a high serum urea nitrogen concentration. These observations might contribute to an earlier identification and treatment of delirium in acutely admitted elderly patients.