Serum anticholinergic activity in hospitalized older persons with delirium: a preliminary study

Potential Risk Factors for, and Clinical Implications of, Delirium during Inpatient Rehabilitation: A Matched Case-Control Study

OBJECTIVES

To investigate the association between a wide set of baseline characteristics (age, sex, rehabilitation discipline), functional scores [Functional Independence Measure (FIM), cumulative Illness Rating Scale (CIRS)], diseases, and administered drugs and incident delirium in rehabilitation inpatients and, furthermore, to assess clinical implications of developing delirium during rehabilitation.

DESIGN

Matched case-control study based on electronic health record data.

SETTING AND PARTICIPANTS

We studied rehabilitation stays of inpatients admitted between January 1, 2015, and December 31, 2018, to ZURZACH Care, Rehaklinik Bad Zurzach, an inpatient rehabilitation clinic in Switzerland.

METHODS

We conducted unconditional logistic regression analyses to estimate adjusted odds ratios (AORs) with 95% CIs of exposures that were recorded in ≥5 cases and controls.

RESULTS

Among a total of 10,503 rehabilitation stays, we identified 125 validated cases. Older age, undergoing neurologic rehabilitation, a low FIM, and a high CIRS were associated with an increased risk of incident delirium. Being diagnosed with a bacterial infection (AOR 2.62, 95% CI 1.06-6.49), a disorder of fluid, electrolyte, or acid-base balance (AOR 2.76, 95% CI 1.19-6.38), Parkinson's disease (AOR 5.68, 95% CI 2.54-12.68), and administration of antipsychotic drugs (AOR 8.06, 95% CI 4.26-15.22), antiparkinson drugs (AOR 2.86, 95% CI 1.42-5.77), drugs for constipation (AOR 2.11, 95% CI 1.25-3.58), heparins (AOR 2.04, 95% CI 1.29-3.24), or antidepressant drugs (AOR 1.88, 95% CI 1.14-3.10) during rehabilitation, or an increased anticholinergic burden (ACB ≥ 3) (AOR 2.59, 95% CI 1.41-4.73) were also associated with an increased risk of incident delirium.

CONCLUSIONS AND IMPLICATIONS

We identified a set of factors associated with an increased risk of incident delirium during inpatient rehabilitation. Our findings contribute to detect patients at risk of delirium during inpatient rehabilitation.

Effects of anti-ulcer drugs on delirium in trauma patients

OBJECTIVE

Histamine-2 receptor antagonists (H2RAs) may induce a higher risk of developing delirium than proton pump inhibitors (PPIs), but current evidence is insufficient. Therefore, this study aimed to investigate whether anti-ulcer drugs increase delirium risk.

METHOD

Data were obtained from the medical records of patients admitted to a hospital due to trauma. We compared the incidence of delirium in patients who received H2RAs and PPIs with that in patients who received no anti-ulcer drugs.

RESULTS

A total of 150, 158, and 238 patients received H2RAs, PPIs, and no anti-ulcer drugs, respectively. Delirium incidence was significantly higher in patients who received H2RAs (34.0%) and PPIs (44.9%) than in those who did not receive anti-ulcer drugs (22.3%). Even after adjustment for possible confounding factors, the association between H2RAs and delirium remained (adjusted OR 1.78; 95% CI 1.04-3.05), but that between PPIs and delirium was attenuated (adjusted OR 1.25; 95% CI 0.71-2.23).

CONCLUSIONS

Our results show that H2RAs are associated with delirium risk. We replicated findings of a previous data-driven study. Clinicians need to consider the effect of delirium in anti-ulcer drug selection.

Association of natural light exposure and delirium according to the presence or absence of windows in the intensive care unit

Background

Patients in the intensive care unit (ICU) have increased risks of delirium, which is associated with worse outcomes. As pharmacologic treatments for delirium are ineffective, prevention is important. Nonpharmacologic preventive strategies include exposure to natural light and restoring circadian rhythm. We investigated the effect of exposure to natural light through windows on delirium in the ICU.

Methods

This retrospective cohort study assessed all patients admitted to the medical ICU of a university-affiliated hospital between January and June 2020 for eligibility. The ICU included 12 isolation rooms, six with and six without windows. Patients with ICU stays of >48 hours were included and were divided into groups based on their admission to a single room with (window group) or without windows (windowless group). The primary outcome was the cumulative incidence of delirium. The secondary outcomes were the numbers of delirium- and mechanical ventilation-free days, ICU and hospital length of stay, and in-ICU and 28-day mortalities.

Results

Of the 150 included patients (window group: 83 [55.3%]; windowless group: 67 [44.7%]), the cumulative incidence of delirium was significantly lower in the window group than in the windowless group (21.7% vs. 43.3%; relative risk, 1.996; 95% confidence interval [CI], 1.220–3.265). Other secondary outcomes did not differ between groups. Admission to a room with a window was independently associated with a decreased risk of delirium (adjusted odds ratio, 0.318; 95% CI, 0.125–0.805).

Conclusions

Exposure to natural light through windows was associated with a lower incidence of delirium in the ICU.

Delirium risk of histamine-2 receptor antagonists and proton pump inhibitors: A study based on the adverse drug event reporting database in Japan

OBJECTIVE

Although histamine-2 receptor antagonists (H2RAs) have been shown to be more likely to cause delirium than proton pump inhibitors (PPIs), these results were not adjusted for potential confounding factors. Accordingly, we investigated whether H2RAs and PPIs are risk factors for delirium, even when adjusting for other risk factors by analyzing adverse drug event reports compiled in the post-marketing stages of drugs provided by the Japanese regulatory authorities.

METHOD

We analyzed 577,431 reports in the Japanese Adverse Drug Event Report database from April 2004 to July 2020.

RESULTS

Of all reports analyzed, 2532 described delirium, and 574,899 described other adverse events. Delirium was associated with H2RAs (crude reporting odds ratio, ROR, 4.17; 95% CI, 3.34-5.22) but not PPIs (crude ROR 0.62; 95% CI 0.43-0.90). Even with adjustment for age, sex, history of dementia or depression, and concomitant drugs reported as risk factors for delirium, the use of H2RAs showed a significantly higher adjusted ROR than that of PPIs (H2RAs: adjusted ROR 3.99; 95% CI 3.18-5.01 and PPIs: adjusted ROR 0.58; 95%CI 0.40-0.84).

CONCLUSIONS

These results suggest that, from a cognitive perspective, PPIs may be preferable to H2RAs for patients with or at risk for delirium.

The role of acetylcholinesterase and butyrylcholinesterase activity in the development of delirium in acute stroke

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Delirium is frequent in acute stroke.

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We tested if AchE or BChE activity could be related to the presence and intensity of delirium.

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Delirious patients had higher levels of BChE activity at discharge.

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BChE activity may be secondary to delirium related inflammatory processes.

Aim

Our study aimed to test whether plasma acetylcholinesterase and butyrylcholinesterase enzyme activity were related to the presence and intensity of delirium in acute stroke patients.

Methods

We carried out a matched (age and gender) case-control study, in a sample of consecutive patients with an acute infarct or intracerebral haemorrhage (≤7 days). We assessed delirium using the DSM-5 criteria and the Delirium Rating Scale, and we measured plasma acetylcholinesterase and butyrylcholinesterase enzyme activity after the patient's admission in the stroke unit and before hospital discharge. Mantel-Haenszel's chi-square was used to test bivariate associations between cases (delirious patients) and controls (non-delirious patients).

Results

At admission in the stroke unit, cases and controls did not present significant differences in plasma acetylcholinesterase or butyrylcholinesterase activity. At hospital discharge (18 cases and 21 controls) patients who have had delirium at admission had higher levels of butyrylcholinesterase activity. Butyrylcholinesterase activity may secondarily increase due to the inflammatory process associated with neuronal dysfunction in delirium patients.

Prevention and management of delirium in critically ill adult patients in the intensive care unit: a review based on the 2018 PADIS guidelines

Delirium is an acute, confusional state characterized by altered consciousness and a reduced ability to focus, sustain, or shift attention. It is associated with a number of complex underlying medical conditions and can be difficult to recognize. Many critically ill patients (e.g., up to 80% of patients in the intensive care unit [ICU]) experience delirium due to underlying medical or surgical health problems, recent surgical or other invasive procedures, medications, or various noxious stimuli (e.g., underlying psychological stressors, mechanical ventilation, noise, light, patient care interactions, and drug-induced sleep disruption or deprivation). Delirium is associated with a longer duration of mechanical ventilation and ICU admittance as well as an increased risk of death, disability, and long-term cognitive dysfunction. Therefore, the early recognition of delirium is important and ICU medical staff should devote careful attention to both watching for the occurrence of delirium and its prevention and management. This review presents a brief overview of delirium and an update of the literature with reference to the 2018 Society of Critical Care Medicine Clinical Practice Guidelines for the Prevention and Management of Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption in Adult Patients in the ICU.

[Non-withdrawal-related delirium : Evidence on prevention and therapy]

Delirium is a severe and common yet under-diagnosed disorder in the clinical routine. Multiple factors may contribute to the development of delirium, which is associated with increased mortality and high healthcare costs. Treatment of delirium is often provided with delay and limited to pharmacological interventions. This article summarizes the key symptoms for delirium as well as risk factors and highlights the pharmacological and non-pharmacological options for treatment and prevention.

Postoperative Delirium Following Orthognathic Surgery in a Young Patient

Delirium is an organic mental syndrome with acute onset characterized by diffuse brain dysfunction and neural activity disorganization. It is usually related to cognition and perception changes, decreased level of consciousness, and disorganization of thoughts that are unrelated to previous dementia. Occurrence is more frequent in patients with previous degenerative disease and elderly patients, especially those older than 85 years. Although the pathophysiology is not totally known, studies have shown that, among the main factors that lead to delirium, the drugs used for general anesthesia induction are the most relevant (hypnotics, anticholinergic drugs, and H₂ receptor blockers), especially those used in long surgical procedures. This report describes the case of a 24-year-old woman with a noncontributory medical and psychological history. She underwent bimaxillary orthognathic surgery with a total general anesthesia time of 7 hours. Postoperatively, she developed agitation, confusion, and delirium. After a psychiatry consult and discussion with the anesthesia team, the diagnosis of psychotic break owing to late postoperative delirium was established.

Mini Review: Anticholinergic Activity as a Behavioral Pathology of Lewy Body Disease and Proposal of the Concept of "Anticholinergic Spectrum Disorders"

Given the relationship between anticholinergic activity (AA) and Alzheimer's disease (AD), we rereview our hypothesis of the endogenous appearance of AA in AD. Briefly, because acetylcholine (ACh) regulates not only cognitive function but also the inflammatory system, when ACh downregulation reaches a critical level, inflammation increases, triggering the appearance of cytokines with AA. Moreover, based on a case report of a patient with mild AD and slightly deteriorated ACh, we also speculate that AA can appear endogenously in Lewy body disease due to the dual action of the downregulation of ACh and hyperactivity of the hypothalamic-pituitary-adrenal axis. Based on these hypotheses, we consider AA to be a behavioral pathology of Lewy body disease. We also propose the concept of “anticholinergic spectrum disorders,” which encompass a variety of conditions, including AD, Lewy body disease, and delirium. Finally, we suggest the prescription of cholinesterase inhibitors to patients in this spectrum of disorders to abolish AA by upregulating ACh.

Serum Anticholinergic Activity and Cognitive and Functional Adverse Outcomes in Older People: A Systematic Review and Meta-Analysis of the Literature

INTRODUCTION

Studies have reported associations between serum anticholinergic activity (SAA) and decline in cognitive performance, delirium, and functional impairment. The aim of this meta-analysis was to explore and quantify associations between SAA and adverse cognitive and functional outcomes in older people.

MATERIALS AND METHODS

A literature search in Ovid MEDLINE, EMBASE, PsycINFO and IPA from 1946-2014 was completed. The primary outcomes of interest were cognitive and functional adverse outcomes associated with SAA in older people aged 55 years and above. The Cochrane Risk-Bias assessment tool was used to assess bias in randomised controlled trials (RCTs). The Newcastle-Ottawa Scale was used to assess the quality of non-RCTs. Meta-analyses were conducted for RCTs and cohort studies separately. Heterogeneity was assessed using I2 tests.

RESULTS

The primary electronic literature search identified a total of 1559 records in the 4 different databases. On the basis of full-text analysis, 33 studies that met the inclusion criteria. The review included 4 RCTs, 5 prospective cohort studies, 3 longitudinal cohort studies, 17 cross-sectional studies, and 4 case-control studies. Twenty-four of the retrieved studies examined an association between SAA and cognitive outcomes, 2 studies examined an association with SAA and functional outcomes and 8 studies examined associations between SAA and both cognitive, and functional outcomes. The meta-analysis on 4 RCTs showed no association with higher SAA and cognitive performance (I2 = 89.38%, H2 = 25.53 and p-value = <0.05) however, the pooled data from 4 observational studies showed elevated SAA was associated with reduced cognitive performance (I2 = 0.00%, H2 = 3.37 and p-value = 0.34).

CONCLUSION

This systematic review summarises the limitations of the SAA on predicting cognitive and functional outcomes in older people. SAA measured by receptor bioassay is flawed and its use in older people with multimorbidity and polypharmacy is questionable.

Biomarkers of postoperative delirium and cognitive dysfunction

Elderly surgical patients frequently experience postoperative delirium (POD) and the subsequent development of postoperative cognitive dysfunction (POCD). Clinical features include deterioration in cognition, disturbance in attention and reduced awareness of the environment and result in higher morbidity, mortality and greater utilization of social financial assistance. The aging Western societies can expect an increase in the incidence of POD and POCD. The underlying pathophysiological mechanisms have been studied on the molecular level albeit with unsatisfying small research efforts given their societal burden. Here, we review the known physiological and immunological changes and genetic risk factors, identify candidates for further studies and integrate the information into a draft network for exploration on a systems level. The pathogenesis of these postoperative cognitive impairments is multifactorial; application of integrated systems biology has the potential to reconstruct the underlying network of molecular mechanisms and help in the identification of prognostic and diagnostic biomarkers.

Pain, agitation, delirium, and neuromuscular blockade: a review of basic pharmacology, assessment, and monitoring

Agitation, pain, and delirium are focal points for targeted pharmacologic therapy in the intensive care unit. Understanding how to treat these essential entities necessitates fundamental understanding of the pharmacology of sedation, analgesia, and antipsychotics. Monitoring the effectiveness of these medications is crucial to optimize therapeutic outcomes and minimize untoward effects. Agents used in the management of agitation include drugs that target γ-aminobutyric acid A such as benzodiazepines and propofol and those with other targets such as dexmedetomidine and ketamine. Analgesia in the intensive care unit is controlled primarily using intravenous opioids, which differ on the basis of their potencies and pharmacokinetics. The management of delirium involves preventing its occurrence, removing potential causes, and pharmacotherapy with antipsychotics. Finally, the introduction of paralysis with the use neuromuscular blockers is often necessary in critically ill patients in various situations. In addition to understanding pharmacologic principles associated with the treatment of agitation, pain, and delirium, familiarization with the plethora of assessment tools used to guide therapy in these critically ill patients is mandated. This review focuses on the pharmacology of therapeutic agents used for sedation, analgesia, delirium, and neuromuscular blockade. Significant focus is given to the various assessment tools often used in practice today.

Increasing anticholinergic burden and delirium in palliative care inpatients

BACKGROUND

Delirium may complicate the hospital course and adversely impact remaining quality of life for palliative care inpatients. Medications with anticholinergic properties have been linked to delirium within elderly populations via serum anticholinergic assays.

AIM

The aim of this study is to determine whether increasing anticholinergic burden, as measured using a clinical assessment tool, is associated with an increase in delirium among palliative care inpatients.

DESIGN

This study was completed as a retrospective, case-control study.

SETTING/PARTICIPANTS

Veterans admitted to the Veterans Affairs Boston Healthcare System and consulted to the palliative care service were considered for inclusion. Increase in anticholinergic burden from admission through hospital day 14 was assessed using the Anticholinergic Risk Scale. Presence of delirium was determined by use of a validated chart review instrument.

RESULTS

A total of 217 patients were analyzed, with a mean age of 72.9 (±12.8) years. The overall delirium rate was 31% (n = 67). Patients with an increase in Anticholinergic Risk Scale (n = 72 (33%)) were 40% more likely to experience delirium (odds ratio = 1.44, 95% confidence interval = 1.07-1.94) compared to those without increase (n = 145 (67%)). After adjustment for age, brain metastasis, intensive care unit admission, illness severity, opiate use, and admission Anticholinergic Risk Scale using multivariable modeling, delirium risk remained significantly higher in patients with an Anticholinergic Risk Scale increase compared to those without increase (adjusted odds ratio = 1.43, 95% confidence interval = 1.04-1.94).

CONCLUSION

An increase in Anticholinergic Risk Scale from admission was associated with delirium in palliative care inpatients. While additional study is needed, anticholinergic burden should be increased cautiously in palliative inpatients, and those with increases should be closely followed for delirium.

Serum anticholinergic activity: a possible peripheral marker of the anticholinergic burden in the central nervous system in Alzheimer's disease

We review the utility of serum anticholinergic activity (SAA) as a peripheral marker of anticholinergic activity (AA) in the central nervous system (CAA). We hypothesize that the compensatory mechanisms of the cholinergic system do not contribute to SAA if their system is intact and that if central cholinergic system deteriorates alone in conditions such as Alzheimer's disease or Lewy body dementia, CAA and SAA are caused by way of hyperactivity of inflammatory system and SAA is a marker of the anticholinergic burden in CNS. Taking into account the diurnal variations in the plasma levels of corticosteroids, which are thought to affect SAA, it should be measured at noon or just afterward.

Neuropathogenesis of delirium: review of current etiologic theories and common pathways

Delirium is a neurobehavioral syndrome caused by dysregulation of neuronal activity secondary to systemic disturbances. Over time, a number of theories have been proposed in an attempt to explain the processes leading to the development of delirium. Each proposed theory has focused on a specific mechanism or pathologic process (e.g., dopamine excess or acetylcholine deficiency theories), observational and experiential evidence (e.g., sleep deprivation, aging), or empirical data (e.g., specific pharmacologic agents' association with postoperative delirium, intraoperative hypoxia). This article represents a review of published literature and summarizes the top seven proposed theories and their interrelation. This review includes the "neuroinflammatory," "neuronal aging," "oxidative stress," "neurotransmitter deficiency," "neuroendocrine," "diurnal dysregulation," and "network disconnectivity" hypotheses. Most of these theories are complementary, rather than competing, with many areas of intersection and reciprocal influence. The literature suggests that many factors or mechanisms included in these theories lead to a final common outcome associated with an alteration in neurotransmitter synthesis, function, and/or availability that mediates the complex behavioral and cognitive changes observed in delirium. In general, the most commonly described neurotransmitter changes associated with delirium include deficiencies in acetylcholine and/or melatonin availability; excess in dopamine, norepinephrine, and/or glutamate release; and variable alterations (e.g., either a decreased or increased activity, depending on delirium presentation and cause) in serotonin, histamine, and/or γ-aminobutyric acid. In the end, it is unlikely that any one of these theories is fully capable of explaining the etiology or phenomenologic manifestations of delirium but rather that two or more of these, if not all, act together to lead to the biochemical derangement and, ultimately, to the complex cognitive and behavioral changes characteristic of delirium.

Measures of anticholinergic drug exposure, serum anticholinergic activity, and all-cause postdischarge mortality in older hospitalized patients with hip fractures

OBJECTIVES

To assess possible associations between anticholinergic drug exposure and serum anticholinergic activity (SAA) and their capacities to predict all-cause mortality in older hospitalized patients.

SETTING

Academic medical center.

PARTICIPANTS AND MEASUREMENTS

Data on clinical characteristics, full medication exposure, SAA, and 4 anticholinergic drug scoring systems (ADSSs: Anticholinergic Risk Scale [ARS], Anticholinergic Drug Scale, Anticholinergic Burden scale, and anticholinergic component of the Drug Burden Index) were collected in 71 older hospitalized patients (age 84 ± 6 years) awaiting surgical repair after hip fractures.

RESULTS

The median (range) SAA was 2.8 (1.1-4.9) pmol/mL. Age (ρ = 0.25, p = 0.03), Katz Index of Independence in Activities of Daily Living score (ρ = 0.39, p = 0.001), in-hospital delirium (ρ = 0.29, p = 0.01), preadmission cognitive impairment (ρ = 0.31, p = 0.01), and the number of nonanticholinergic drugs (n-NA, ρ = -0.27, p = 0.02) were associated with SAA. No significant associations were detected between ADSSs and SAA. Cognitive impairment (β = 2.1, 95% confidence interval [CI]: 0.7 to 2.5, p = 0.005) and n-NA (β = -0.3, 95% CI: -0.5 to -0.03, p = 0.03) were independently associated with SAA. Cognitive impairment (hazard ratio [HR]: 6.7, 95% CI: 1.1 to 40.3, p = 0.04) and higher ARS scores (HR: 2.2, 95% CI: 1.2 to 3.7, p = 0.006) independently predicted 3-month mortality whereas in-hospital delirium (HR: 3.6, 95% CI: 1.3 to 10.3, p = 0.02), living at home (HR: 0.2, 95% CI: 0.0 to 0.9, p = 0.03), and length of hospital stay (HR: 1.1, 95% CI: 1.0 to 1.2, p = 0.004) independently predicted 1-year mortality after adjustment for age, gender, and Charlson comorbidity index.

CONCLUSIONS

Cognitive impairment and n-NA, but not ADSSs, are independently associated with SAA in older hospitalized patients. The ARS score, together with cognitive impairment, in-hospital delirium, place of residence, and length of hospital stay, predicts all-cause mortality in this group.

Longitudinal assessment of serum anticholinergic activity in delirium of the elderly

BACKGROUND

Delirium, a frequently occurring, devastating disease, is often underdiagnosed, especially in dementia. Serum anticholinergic activity (SAA) was proposed as a disease marker as it may reflect delirium's important pathogenetic mechanism, cholinergic deficiency. We assessed the association of serum anticholinergic activity with delirium and its risk factors in a longitudinal study on elderly hip fracture patients.

METHOD

Consecutive elderly patients admitted for hip fracture surgery (n = 142) were assessed longitudinally for delirium, risk factors, and serum markers (IL-6, cortisol, and SAA). Using a sophisticated statistical design, we evaluated the association between SAA and delirium in general and with adjustments, but also the temporal course, including the events fracture, surgery, and potential delirium, individual confounders, and a propensity score.

RESULTS

Among elderly hip fracture patients 51% developed delirium, these showed more risk factors (p < 0.001), and complications (p < 0.05). Uncontrolled SAA levels (463 samples) were significantly higher in the delirium group (4.2 vs. 3.4 pmol/ml) and increased with delirium onset, but risk factors absorbed the effect. Using mixed-modeling we found a significant increase in SAA concentration (7.6% (95%CI 5.0-10.2, p < 0.001)) per day, which was modified by surgery and delirium, but this effect was confounded by cognitive impairment and IL-6 values. Confounder control by propensity scores resulted in a disappearance of delirium-induced SAA increase.

CONCLUSIONS

Delirium-predisposing factors are closely associated with changes in the temporal profile of serum anticholinergic activity and thus neutralize the previously documented association between higher SAA levels and delirium. An independent relationship of SAA to delirium presence is highly questionable.

Postoperative complications: delirium

Delirium is a common feature of the postoperative period, leading to increased morbidity and mortality and significant costs. Multiple factors predispose a patient to delirium in its hypoactive, hyperactive, or mixed forms. Tools have been validated for its quick and accurate identification to ensure timely and effective multidisciplinary intervention and treatment. A significant percentage of patients may require placement in skilled nursing facilities or similar care environments because of the long-lasting effects. The physician must be vigilant in the search for and identification of all forms of delirium and must effectively treat the underlying medical condition and symptoms.

Influence of anticholinergic activity in serum on clinical symptoms of Alzheimer's disease

Alzheimer's disease (AD) is well known as a disease characterized by degeneration of cholinergic neuronal activity in the brain. It follows that patients with AD would be sensitive to an 'anticholinergic burden', and also that medicine with anticholinergic properties would promote various clinical symptoms of AD. Despite the relevance of this important phenomenon to the clinical therapeutics of AD patients, few reports have been seen concerning the relationship between anticholinergic burden and clinical AD symptoms. Therefore, we wished to investigate the relationship between serum anticholinergic activity (SAA) and the severity of clinical symptoms of AD patients. Twenty-six out of 76 AD patients referred by practitioners to our hospital were positive for anticholinergic activity in their serum, and the remaining 50 patients were negative. Cognitive and psychiatric symptoms in AD patients were compared between the positive SAA (SAA+) group and the negative SAA (SAA-) group. The SAA+ group showed a significantly (p < 0.05) lower total score on the Mini-Mental State Examination, and significantly (p < 0.05) higher scores on the Functional Assessment Staging and the Behavioral Pathology in Alzheimer's Disease Rating Scale (BEHAVE-AD). In particular, certain subscales of the BEHAVE-AD, i.e. the items of paranoid and delusional ideation, hallucinations and diurnal rhythm disturbances, had higher scores in the SAA+ group. Moreover, it was shown that many more psychotropic medicines were prescribed to the SAA+ group. By means of logistic regression analysis, the items of paranoid and delusional ideation and diurnal rhythm disturbances in the BEHAVE-AD were positively correlated with SAA in patients. We hypothesized that SAA in AD patients would be associated with clinical symptoms, especially delusion and diurnal rhythm disturbances.

Delirium in Palliative Care Patients: Focus on Pharmacotherapy

Patients receiving palliative care often possess multiple risk factors and predisposing conditions for delirium. The impact of delirium on patient care in this population may also be far-reaching: affecting not only quality of remaining life but the dying process experienced by patients, caregivers, and the medical team as well. As palliative care focuses on comfort and symptom management, the approach to assessment and subsequent treatment of delirium in palliative care patients may prove difficult for providers to navigate. This article summarizes the multifactorial nature, numerous predisposing medical risk factors, neuropsychiatric adverse effects of palliative medications, pharmacokinetic changes, and challenges complicating delirium assessment and provides a systematic framework for assessment. The benefits, risks, and patient-specific considerations for treatment selection are also discussed.

Rivastigmine in the treatment of delirium in older people: a pilot study

BACKGROUND

Delirium is common in the elderly and is associated with high mortality and negative health outcomes. Reduced activity in the cholinergic system has been implicated in the pathogenesis of delirium. Cholinesterase inhibitors, which increase cholinergic activity, may therefore be beneficial in the treatment of delirium.

METHODS

This is a double-blind, placebo-controlled randomized pilot study of the treatment of delirium with a cholinesterase inhibitor of patients admitted to hospital medical wards. Patients over the age of 65 years were identified as having delirium by the Confusion Assessment Method (CAM). Patients with delirium were randomized to receive rivastigmine 1.5 mg once a day increasing to 1.5 mg twice a day after seven days or an identical placebo (two tablets after seven days).

RESULTS

Fifteen patients entered the trial; eight received rivastigmine and seven received placebo. All of the rivastigmine group, but only three of the placebo group, were negative for delirium on the CAM when they left the study and eventually discharged home. There was no significant difference in the duration of delirium between the two groups (rivastigmine group 6.3 days versus placebo group 9.9 days, p = 0.5, 95% confidence interval -15.6-8.4).

CONCLUSIONS

The numbers of patients who screened positive for delirium was very small and as a result the sample size was too small to make any meaningful inferences about treatment of delirium. Despite the small numbers included in the study, there are some indicators that rivastigmine may be safe and effective in treating delirium.

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.

The cognitive impact of anticholinergics: a clinical review

Context:

The cognitive side effects of medications with anticholinergic activity have been documented among older adults in a variety of clinical settings. However, there has been no systematic confirmation that acute or chronic prescribing of such medications lead to transient or permanent adverse cognitive outcomes.

Objective:

Evaluate the existing evidence regarding the effects of anticholinergic medications on cognition in older adults.

Data sources:

We searched the MEDLINE, OVID, and CINAHL databases from January, 1966 to January, 2008 for eligible studies.

Study selection:

Studies were included if the anticholinergic activity was systematically measured and correlated with standard measurements of cognitive performance. Studies were excluded if they reported case studies, case series, editorials, and review articles.

Data extraction:

We extracted the method used to determine anticholinergic activity of medications and its association with cognitive outcomes.

Results:

Twenty-seven studies met our inclusion criteria. Serum anticholinergic assay was the main method used to determine anticholinergic activity. All but two studies found an association between the anticholinergic activity of medications and either delirium, cognitive impairment or dementia.

Conclusions:

Medications with anticholinergic activity negatively affect the cognitive performance of older adults. Recognizing the anticholinergic activity of certain medications may represent a potential tool to improve cognition.

Changes in anticholinergic load from regular prescribed medications in palliative care as death approaches

Although there is an understandable emphasis on the side effects of individual medications, the cumulative effects of medications have received little attention in palliative care prescribing. Anticholinergic load reflects a cumulative effect of medications that may account for several symptoms and adverse health outcomes frequently encountered in palliative care. A secondary analysis of 304 participants in a randomised controlled trial had their cholinergic load calculated using the Clinician-Rated Anticholinergic Scale (modified version) longitudinally as death approached from medication data collected prospectively by study nurses on each visit. Mean time from referral to death was 107 days, and mean 4.8 visits were conducted in which data were collected. Relationships to key factors were explored. Data showed that anticholinergic load rose as death approached because of increasing use of medications for symptom control. Symptoms significantly associated with increasing anticholinergic load included dry mouth and difficulty concentrating (P < 0.05). There were also significant associations with increasing anticholinergic load and decreasing functional status (Australia-modified Karnofsky Performance Scale; and quality of life (P < 0.05). This study has documented in detail the longitudinal anticholinergic load associated with medications used in a palliative care population between referral and death, demonstrating the biggest contributor to anticholinergic load in a palliative care population is from symptom-specific medications, which increased as death approached.

Drugs with anticholinergic properties: cognitive and neuropsychiatric side-effects in elderly patients

Drug consumption in older people is usually high and many prescribed medications have unsuspected anticholinergic (ACH) (Table 1) properties. Drug induced ACH side-effects are particularly severe in aging brain and even more in demented patients. This review will focus on the association between ACH drug intake and the risk of developing central nervous system side-effects in elderly people. The threat of developing cognitive impairment, psychosis and delirium will be particularly analyzed.

Delirium in the intensive care unit

Delirium is a common manifestation of acute brain dysfunction in critically ill patients with prevalence as high as 75%. In the last years there has been a progressive increase of publications regarding intensive care (ICU) delirium, acknowledging its importance. The occurrence of delirium in ICU is related to more adverse outcomes including self-extubation and removal of catheters, prolonged hospitalization, increased costs, higher mortality, and potentially, long-term cognitive impairment. The pathophysiology explaining the processes subtending the development of delirium is still elusive, though several theories have been discussed. It is known that different risk factors are associated with delirium in the ICU. Patients in ICU frequently receive medications to treat pain and to ensure sedation, but an association between these drugs and delirium has been shown. Therefore, this pharmacological exposure should be modified to reduce the risk factors. Giving the multifactorial genesis of delirium, multicomponent interventions to prevent delirium developed in non-ICU settings can be adapted to critically ill patients with the purpose of reducing the incidence. When delirium is diagnosed the use of typical and atypical antipsychotics may be effective for its treatment. Future studies should evaluate target interventions to prevent delirium in the ICU.

Pathoetiological model of delirium: a comprehensive understanding of the neurobiology of delirium and an evidence-based approach to prevention and treatment

Delirium is the most common complication found in the general hospital setting. Yet, we know relatively little about its actual pathophysiology. This article contains a summary of what we know to date and how different proposed intrinsic and external factors may work together or by themselves to elicit the cascade of neurochemical events that leads to the development delirium. Given how devastating delirium can be, it is imperative that we better understand the causes and underlying pathophysiology. Elaborating a pathoetiology-based cohesive model to better grasp the basic mechanisms that mediate this syndrome will serve clinicians well in aspiring to find ways to correct these cascades, instituting rational treatment modalities, and developing effective preventive techniques.

Delirium and its treatment

Delirium occurs at rates ranging from 10% to 30% of all hospital admissions. It is a negative prognostic indicator, often leading to longer hospital stays and higher mortality. The aetiology of delirium is multifactorial and many causes have been suggested. The stress-diathesis model, which posits an interaction between the underlying vulnerability and the nature of the precipitating factor, is useful in understanding delirium. Preventing delirium is the most effective strategy for reducing its frequency and complications. Environmental strategies are valuable but are often underutilized, while remedial treatment is usually aimed at specific symptoms of delirium. Antipsychotics are the mainstay of pharmacological treatment and have been shown to be effective in treating symptoms of both hyperactive and hypoactive delirium, as well as generally improving cognition. Haloperidol is considered to be first-line treatment as it can be administered via many routes, has fewer active metabolites, limited anticholinergic effects and has a lower propensity for sedative or hypotensive effects compared with many other antipsychotics. Potential benefits of atypical compared with typical antipsychotics include the lower propensity to cause over-sedation and movement disorder. Of the second-generation antipsychotics investigated in delirium, most data support the use of risperidone and olanzapine. Other drugs (e.g. aripiprazole, quetiapine, donepezil and flumazenil) have been evaluated but data are limited. Benzodiazepines are the drugs of choice (in addition to antipsychotics) for delirium that is not controlled with an antipsychotic (and can be used alone for the treatment of alcohol and sedative hypnotic withdrawal-related delirium). Lorazepam is the benzodiazepine of choice as it has a rapid onset and shorter duration of action, a low risk of accumulation, no major active metabolites and its bioavailability is more predictable when it is administered both orally and intramuscularly.

Serum anticholinergic activity and cerebral cholinergic dysfunction: an EEG study in frail elderly with and without delirium

Background

Delirium increases morbidity, mortality and healthcare costs especially in the elderly. Serum anticholinergic activity (SAA) is a suggested biomarker for anticholinergic burden and delirium risk, but the association with cerebral cholinergic function remains unclear. To clarify this relationship, we prospectively assessed the correlation of SAA with quantitative electroencephalography (qEEG) power, delirium occurrence, functional and cognitive measures in a cross-sectional sample of acutely hospitalized elderly (> 80 y) with high dementia and delirium prevalence.

Methods

61 consecutively admitted patients over 80 years underwent an extensive clinical and neuropsychological evaluation. SAA was determined by using radio receptor assay as developed by Tune, and standard as well as quantitative EEGs were obtained.

Results

15 patients had dementia with additional delirium (DD) according to expert consensus using DSM-IV criteria, 31 suffered from dementia without delirium (D), 15 were cognitively unimpaired (CU). SAA was clearly detectable in all patients but one (mean 10.9 ± 7.1 pmol/ml), but was not associated with expert-panel approved delirium diagnosis or cognitive functions. Delirium-associated EEG abnormalities included occipital slowing, peak power and alpha decrease, delta and theta power increase and slow wave ratio increase during active delirious states. EEG measures correlated significantly with cognitive performance and delirium severity, but not with SAA levels.

Conclusion

In elderly with acute disease, EEG parameters reliable indicate delirium, but SAA does not seem to reflect cerebral cholinergic function as measured by EEG and is not related to delirium diagnosis.

Pathophysiology of delirium in the intensive care unit

Delirium, or acute brain dysfunction, is a life-threatening global disturbance in cognitive functioning that frequently manifests in critically ill patients. This review examines the current status of knowledge regarding the pathophysiology of delirium in the ICU, in particular, evaluating the role of iatrogenic factors such as sedatives and analgesic administration in brain dysfunction. This hypothesis is considered along with several other plausible mechanisms of ICU delirium, including sepsis, postoperative cognitive dysfunction, and changes in biomarkers and neurotransmitters. The review concludes by highlighting potential future directions in molecular genetics for the elucidation of delirium and its long-term consequences.

EEG changes and serum anticholinergic activity measured in patients with delirium in the intensive care unit

The aim of this study was to examine whether serum anticholinergic activity (SAA) is a reliable indicator of delirium in the ICU, and whether there is a significant correlation between SAA and quantitative electroencephalographic (EEG) data in delirious patients. In a prospective cohort study, we assessed ICU patients diagnosed with delirium (n = 37). EEG measurements and blood analysis including SAA were performed 48 h following ICU admission. The presence of delirium was evaluated using the Confusion Assessment Method for critically ill patients in ICU (CAM-ICU). The SAA level was measured using a competitive radioreceptor binding assay for muscarinergic receptors and quantitative EEG was measured using the CATEEM system. We found that, under comparable conditions, patients in the delirium group showed a higher relative EEG theta power and a reduced alpha power (n = 17) than did the non-delirious patients (n = 20). No difference in measured SAA levels were seen; therefore, there was no correlation between SAA and EEG measurements in delirious patients. We conclude that, in contrast to the EEG, the SAA level cannot be proposed as a tool for diagnosing delirium in ICU patients.

Significant correlation between plasma and CSF anticholinergic activity in presurgical patients

Previous studies have suggested a possible link between cognitive impairment and anticholinergic burden as reflected by high serum anticholinergic activity (SAA). Thus, we hypothesized a close relationship between anticholinergic activity in cerebral spinal fluid (CSF) and blood. However, it has never been convincingly demonstrated that peripheral anticholinergic activity correlates with central anticholinergic levels in presurgical patients. Therefore, anticholinergic activity was measured in blood and CSF from 15 patients with admission scheduled for urological surgery to compare peripheral and central anticholinergic level. Blood and CSF probes were taken after routine premedication and before spinal anesthesia. Anticholinergic activity was determined by competitive radioreceptor binding assay for muscarinergic receptors. Correlation analysis was conducted for peripheral and central anticholinergic levels. The mean anticholinergic levels were 2.4+/-1.7 in the patients' blood and 5.9+/-2.1 pmol/mL of atropine equivalents in CSF. Interestingly, the anticholinergic activity in CSF was about 2.5-fold higher than in patients' blood. A significant linear correlation was detected between blood and CSF levels. Therefore we conclude that SAA levels adequately reflect central anticholinergic activity. When patients receiving or not receiving anticholinergic medication were compared, anticholinergic activity tended to increase in blood and CSF after receiving anticholinergic medication > or =4 weeks (p>0.05).

A randomized, double-blind, placebo-controlled trial of donepezil hydrochloride (Aricept) for reducing the incidence of postoperative delirium after elective total hip replacement

OBJECTIVES

This was a pilot, phase 2a study to assess methodological feasibility and the safety and efficacy of donepezil in preventing postoperative delirium after elective total hip replacement surgery in older people without pre-existing dementia. The hypothesis was that donepezil would reduce the incidence of postoperative delirium.

METHODS

A double blind, placebo controlled, parallel group randomized trial was undertaken. Patients were block randomized pre-operatively to receive placebo or donepezil 5 mg immediately following surgery and every 24 h thereafter for a further three days. The main outcome was the incidence of delirium (using the Delirium Symptom Interview). The secondary outcome was length of hospital stay.

RESULTS

Thirty-three patients (mean age 67 years; 17 males, 16 females) completed the study (19 donepezil, 14 placebo). Donepezil was well tolerated with no serious adverse events. Postoperative delirium occurred in 21.2% of subjects. Donepezil did not significantly reduce the incidence of delirium. The unadjusted risk ratio (donepezil vs placebo) for delirium was 0.29 (95% CI = 0.06,1.30) (chi(2) ([1]) = 3.06; p = 0.08). Mean length of hospital stay was 9.9 days for the donepezil group vs 12.1 days in the placebo group; difference in means = -2.2 days (95% CI = -0.39,4.78) (t([31]) = 1.73: p = 0.09).

CONCLUSIONS

The experimental paradigm was feasible and acceptable. Donepezil did not significantly reduce the incidence of delirium or length of hospital stay, however for both outcomes there was a consistent trend suggesting possible benefit. The sample size required for a definitive trial (99% power, alpha 0.05) would be 95 subjects per arm.

Serum biomarkers for delirium

This narrative review examines serum biomarkers for the diagnosis and monitoring of delirium. Serum biomarkers for delirium fall into three major groups: 1) those that are present or elevated prior to disease onset-risk markers, 2) those that rise with onset and fall with recovery-disease markers, and 3) those that rise in proportion to the consequences of disease-end products. As risk markers, we examine serum chemistries and genetic risk markers. As disease markers, we examine serum anticholinergic activity, amino acids, melatonin, cytokines, cortisol, and gene expression. As end products of delirium, we examine markers of neuronal injury. Finally, we discuss methodological and biostatistical considerations for future biomarker studies. Identifying accurate biomarkers for delirium may shed further light into its pathophysiology and on the interrelationship between delirium and dementia.

Methods for Assessing Drug-Related Anticholinergic Activity

The geriatric population is a large consumer of both prescription and over-the-counter drugs. Positive outcomes from drugs depend on the delicate interplay between therapeutic and adverse effects. This relationship becomes tortuous with simultaneous administration of several drugs. Numerous concomitant drug therapies may be essential for providing quality patient care but may also increase the possibility of an adverse drug event. Increasing sensitivity to drug effects in the geriatric population also creates concern over adverse effects. Drugs that possess anticholinergic properties are especially worrisome, as these properties may manifest as hazardous physiologic and psychological adverse drug events. Consequently, clinicians strive to minimize total drug exposure to agents possessing anticholinergic properties in elderly patients. A review of the literature revealed four methods that might help clinicians systematically reduce or eliminate potentially offending anticholinergic drugs. Each of the four has merits and limitations, with no ideal evidence-based approach used. Three of the four methods described have research utility; however, only one of the methods is clinically useful.

Drugs with anticholinergic properties and cognitive performance in the elderly: results from the PAQUID Study

OBJECTIVES

To measure the association between the use of drugs with anticholinergic properties and cognitive performance in an elderly population, the PAQUID cohort.

METHODS

The sample studied was composed of 1780 subjects aged 70 and older, living at home in South western France. Data on socio-demographic characteristics, medical history and drug use were collected using a standardized questionnaire. Cognitive performance was assessed using the following neuropsychological tests: the Mini-Mental State Examination (MMSE) which evaluates global cognitive functioning, the Benton Visual Retention Test (BVRT) which assesses immediate visual memory, and the Isaacs' Set Test (IST) which assesses verbal fluency. For each test, scores were dichotomized between low performance and normal to high performance using the score at the 10th percentile of the study sample as the cut-off point, according to age, gender and educational level. The association between the use of drugs with anticholinergic properties and cognitive performance was examined using logistic regression models, adjusting for several potential confounding factors.

RESULTS

About 13.7% of the subjects used at least one drug with anticholinergic properties. In multivariate analyses, the use of these drugs was significantly associated with low performance in the BVRT [odds ratio (OR) = 1.6; 95% confidence interval (CI) 1.1, 2.3] and in the IST (OR = 1.9; 95% CI 1.3, 2.8). The association found with low performance in the MMSE (OR = 1.4; 95% CI 1.0, 2.1) was barely statistically significant.

CONCLUSION

These findings suggest that the use of drugs with anticholinergic properties is associated with low cognitive performance among community-dwelling elderly people.

Delirium in acute stroke: a preliminary study of the role of anticholinergic medications

The pathogenesis of delirium in acute stroke is incompletely understood. The use of medications with anticholinergic (ACH) activity is associated with an increased frequency of delirium. We hypothesized that the intake of medications with ACH activity is associated with delirium in acute stroke patients. Delirium was assessed using the DSM-IV-TR criteria and the Delirium Rating Scale, in a sample of consecutive patients with an acute (< or =4 days) cerebral infarct or intracerebral haemorrhage (ICH). We performed a gender and age matched case-control study. Twenty-two delirious stroke patients (cases) and 52 non-delirious patients (controls) were compared concerning the intake of ACH medications (i) before stroke, (ii) during hospitalization but before the assessment. The variables associated with delirium on bivariate analysis were entered in a stepwise logistic regression analysis. The final regression model (Nagelkerke R2 = 0.65) retained non-neuroleptics ACH medication during hospitalization (OR = 24.4; 95% CI = 2.18-250), medical complications (OR = 20.8; 95% CI = 3.46-125), ACH medication taken before stroke (OR = 17.5; 95% CI = 1.00-333.3) and ICH (OR = 16.9; 95% CI = 2.73-100) as independent predictors of delirium. This preliminary result indicates that drugs with subtle ACH activity play a role in the pathogeneses of delirium in acute stroke. Medication with ACH activity should be avoided in acute stroke patients.

Predicting post-surgical cognitive disturbance in older Taiwanese patients

The purpose of this study was to test a theoretical model to understand the influences of six predicting variables in post-surgical cognitive disturbance in older Taiwanese patients after elective surgery. The data were collected in a medical center in Taipei, Taiwan. Ninety-three patients were included in the final analysis. The findings showed that cognitive function at admission (beta=0.50, p<0.001), physical function at admission (beta=-0.34, p<0.001), and physiological stability (beta=-0.21, p<0.01) had direct effects on post-surgical cognitive disturbance. Physical function and cognitive function at admission also affected post-surgical cognitive disturbance indirectly through physiological stability. These variables accounted for 67% of the total variance of post-surgical cognitive disturbance. The findings from this study suggest that a careful and systematic assessment of the patient's condition at the time of admission is important. It is necessary to monitor and correct these variables at admission or before surgery to prevent or reduce the impact of post-operative delirium. It is also necessary to monitor these variables during the hospital stay to help nurses to distinguish the etiology of delirium. In each case, knowing when confusion is more likely to occur can assist in focusing more appropriate and effective efforts at detection, thereby reducing the consequences associated with confusion.

A randomized, placebo-controlled trial of paroxetine in nursing home residents with non-major depression

Depression is common across a broad spectrum of severity among nursing home residents. Previous research has demonstrated the effectiveness of antidepressants in nursing home residents with major depression, but it is not known whether antidepressants are helpful in residents with less severe forms of depression. We conducted a randomized double-blind placebo-controlled 8-week trial comparing paroxetine and placebo in very old nursing home residents with non-major depression. The main outcome measure was the primary nurse's Clinical Impression of Change (CGI-C). Additional outcome measures were improvement on the interview-derived Hamilton Depression Rating Scale (HDRS) and Cornell Scale for Depression (CS) scores. Twenty-four subjects with a mean age of 87.9 were enrolled and twenty subjects completed the trial. Placebo response was high, and when all subjects were considered, there were no differences in improvement between the paroxetine and placebo groups. Two subjects that received paroxetine developed delirium, and subjects that received paroxetine were more likely to experience a decrease in Mini Mental State Exam scores (P =.03). There were no differences in serum anticholinergic activity between groups. In a subgroup analysis of 15 subjects with higher baseline HDRS and CS scores, there was a trend toward greater improvement in the paroxetine group in an outcome measure that combined the CGI-C and interview-based measures (P =.06). Paroxetine is not clearly superior to placebo in this small study of very old nursing home residents with non-major depression, and there is a risk of adverse cognitive effects. Because of the high placebo response and the trend towards improvement in the more severely ill patients, it is possible that a larger study would have demonstrated a significant therapeutic effect for paroxetine as compared with placebo. The study also illustrates the discordance between patient and caregiver ratings, and the difficulties in studying very elderly patients with mood disorders.

The panorama of opioid-related cognitive dysfunction in patients with cancer: a critical literature appraisal

BACKGROUND

Opioids have an essential role in the management of pain in cancer patients, particularly those with advanced disease. Cognitive dysfunction is a recognized complication of opioid use. However, misconceptions and controversy surround the nature and prevalence of its occurrence. A projected increase in the aging cancer population highlights the need for a better understanding of this phenomenon.

METHODS

A critical appraisal of the literature evidence in relation to the pattern, pathophysiology, assessment, impact, and management of cognitive dysfunction due to opioid use in cancer pain management is given.

RESULTS

Studies in cancer patients with less advanced disease reveal subtle evidence of cognitive impairment, largely related to initial dosing or dose increases. In advanced cancer, opioid-induced cognitive dysfunction usually occurs in the form of delirium, a multifactorial syndrome. The presence of both cognitive impairment and delirium frequently is misdiagnosed or missed. Potential risk factors include neuropathic and incidental pain, opioid tolerance, somatization of psychologic distress, and a history of drug or alcohol abuse. Elevation of opioid metabolites with renal impairment may contribute to cognitive dysfunction. Recognition of opioid-related cognitive dysfunction is improved by objective screening. Successful management requires either dose reduction or a change of opioid, in addition to addressing other reversible precipitants such as dehydration or volume depletion.

CONCLUSIONS

Opioid-related cognitive dysfunction tends to be subtle in the earlier stages of cancer, whereas delirium, a more florid form with behavioral disturbance is likely to be present in the advanced cancer population. In patients with advanced disease, an optimal management approach requires careful clinical assessment, identification of risk factors, objective monitoring of cognition, maintenance of adequate hydration, and either dose reduction or switching to a different opioid.