Delirium in the Elderly

Delirium in the Elderly By Sue Fosnight, BSPharm, BCPS, CGP Reviewed by Christine M. Ruby, Pharm.D., BCPS; and Jeffrey T. Sherer, Pharm.D., MPH, BCPS Learning Objectives quickly (hours to days) and fluctuates with time. In addi- tion to fluctuating cognition, it is characterized by inat- 1. Explain theories of the pathogenesis of delirium. tention and either disorganized thinking or an altered 2. Assess patient risk factors for delirium. level of consciousness. Delirium differs fromdementia 3. Analyze patient drug regimens to determine the like- because delirium has a sudden onset, fluctuates, and is lihood that delirium or delirium-like symptoms are characterized by inattention and disorganized thoughts drug related. and speech. Dementia has an insidious onset, does not 4. Adjust a patient’s drugs to prevent delirium. fluctuate, and is not normally characterized by inatten- 5. Prepare a patient care plan that includes patient-spe- tion or speech disturbances. Delirium is usually (but not cific pharmacologic and nonpharmacologic meth- always) reversible, whereas dementia is not. ods to prevent delirium. Delirium is categorized further on the basis of psy- 6. Compare and contrast differences in screening tools chomotor symptoms. Hyperactive delirium refers to the to detect delirium. restless or agitated patient. In contrast, a patient with 7. Apply the best available evidence to manage delirium. hypoactive delirium will be lethargic and apathetic. The patient with a mixed delirium will have periods of Introduction both hyperactivity and hypoactivity. Older age is a sig- nificant independent predictor for hypoactive delirium. Delirium can have devastating outcomes that burden Hypoactive delirium is often missed and is associated patients, family members, and the health care system. with a poorer prognosis than hyperactive delirium. Delirium has been associated with increased health care costs, long-term cognition deficits, and increased Prevalence mortality. However, there is often a delay in recognition Delirium is common, occurring in as many as 56% of delirium symptoms. This chapter will describe out- of hospitalized patients. Delirium occurs in 20% to 79% comes that have been associated with delirium, discuss of hospitalized older patients. It is also common in ICU strategies to prevent and detect delirium, and outline patients, occurring in 20% to 50% of non-mechanically the benefits and risks of treatment options. ventilated ICU patients and in 60% to 80% of mechan- Delirium has been described by many terms in the lit- ically ventilated ICU patients. Postoperative delirium erature, including an acute confusional state, septic enceph- and end-of-life delirium are also common. alopathy, acute brain failure, and intensive care unit (ICU) psychosis. The Diagnostic and Statistical Manual of Men- Outcomes tal Disorders IV (DSM-IV) definesdelirium as a distur- Patients who have had delirium are more likely to bance of consciousness and cognition that develops have longer hospital stays (an average of 5–10 additional Baseline Review Resources The goal of PSAP is to provide only the most recent (past 3–5 years) information on topics. Chapters do not provide an overall review. Suggested resources for background information on this topic include: • Inouye SK. Delirium in older persons. N Engl J Med 2006;354:1157–65. • Tropea J, Slee J, Brand CA, Gray L, Snell T. Clinical practice guidelines for the management of delirium in older people in Australia. Australas J Ageing 2008;27:150–6. PSAP-VII • Geriatrics 73 Delirium in the Elderly institutionalization, and dementia in elderly patients. Abbreviations in This Chapter All qualified studies were required to adequately adjust CAM Confusion Assessment Method outcomes by statistical analysis for age, sex, comorbid CAM-ICU Confusion Assessment Method illness, illness severity, and baseline dementia. A sig- for the Intensive Care Unit nificant relationship between delirium diagnosis and DSM-IV Diagnostic and Statistical Man- need for institutionalization, dementia diagnosis, and ual of Mental Disorders IV mortality was found, suggesting that in elderly patients, ICDSC Intensive Care Delirium Screen- a relationship between delirium and increased risk of ing Checklist death, institutionalization, and dementia exists that is MDAS Memorial Delirium Assessment independent of age, sex, comorbid illness, illness sever- Scale ity, and baseline dementia. NICE National Institute for Health and Clinical Excellence Pathogenesis Nu-DESC Nursing Delirium Screening The pathology of delirium is not fully understood; it Scale may result from acute illness (Figure 1-1). A disturbance in the production, release, or inactivation of neurotransmitters controlling cognitive function (γ-aminobutyric acid [GABA], glutamate, acetylcholine, serotonin, nor- days) and are more likely to be discharged to a nursing epinephrine, dopamine, and tryptophan) has been pro- facility than to home (16% vs. 3%). Patients with delir- posed to occur at the same time as delirium. ium are more likely to be reintubated if they are in an An excess of dopamine and a depletion of acetylcho- ICU. Each day spent in delirium in the ICU is associated line occurs in patients with delirium. A study showed with a 20% increased risk of prolonged hospitalization that high serum anticholinergic activity has a 100% pre- and a 10% increased risk of death. dictive value for delirium (defined as a positive Confu- Negative financial outcomes accompany these neg- sion Assessment Method [CAM] score). The CAM is a ative clinical outcomes. More than $100 billion was widely used, validated tool to recognize delirium. When spent in the United States because of delirium in 2005. dividing the values for serum anticholinergic activity into Delirium cases have higher ICU costs (median $22,346 five quintiles ranging from very low to very high serum vs. $13,332 for non-delirium cases) and hospital costs anticholinergic activity, each increase in quintile is asso- (median $41,836 vs. $27,106 for non-delirium cases). ciated with a 2.38 times increased risk of delirium. Studies have also shown that patients with delirium There are other related pathogenic theories for delir- are more likely to die while in the hospital or within 1 ium. One theory postulates that a decrease in oxygen- year of hospital discharge. In-hospital mortality rates for ation of the brain (possibly caused by decreased neu- patients with delirium range from 22% to 76%, similar rotransmitter concentrations) leads to delirium symp- to mortality rates for acute myocardial infarction or sep- toms. An inflammatory hypothesis suggests that vari- sis. Patients older than 70 years who experienced delir- able stresses cause an increase in cytokines that then ium during hospitalization have a 62% increased risk of affect the neurotransmitters. Disturbances in cellular death at 1 year. Intensive care unit mechanically venti- signaling are also suggested as a possible cause. Neuro- lated patients with delirium have a significantly higher imaging studies show that extensive cerebral hypoper- 6-month mortality rate than ICU mechanically venti- fusion occurs in patients with delirium. A recent theory lated patients without delirium (34% vs. 15%). Patients proposes that disturbances in tryptophan metabolim admitted to a postacute care unit with persistent delir- lead to delirium. Patients with dementia are known to be ium are significantly more likely to die in 1 year than at increased risk of delirium, and a recent study reported those who do not have persistent delirium. a longer duration of delirium in patients with the apoli- Long-term studies have found that a significantly poprotein E4 phenotype, suggesting that patients with higher percentage of patients who experienced delir- underlying dementia are unable to recover from delirium will eventually be given a diagnosis of demen- ium as quickly as others. tia. Although no clear cause-and-effect relationship between delirium and subsequent dementia exists, a delirium episode may increase the progression of an Risk Factors for Delirium unrecognized early dementia. Risk factors for delirium include those the patient Some investigators have questioned whether these arrives with (predisposing) and those that are iatro- negative outcomes are because of delirium or whether, genic (precipitating) (Table 1-1, Table 1-2). Patients instead, delirium is a marker for more serious illness with many risk factors will be vulnerable to a low-level that leads to worse outcomes. A meta-analysis assessed precipitating insult, whereas those without risk fac- the association between delirium and mortality, tors may only become delirious after a high-level insult. Delirium in the Elderly 74 PSAP-VII • Geriatrics Medications Medications Medical illness Alcohol withdrawal Surgical illness Medications Stroke Cholineric Cholinergic Hepatic failure activation inhibition Benzodiazepine and alcohol withdrawal Dopamine activation GABA activation Cytokine excess Glutamate Serotonin activation activation Delirium Hepatic failure Alcohol withdrawal Medications Serotonin Cortisol Substance withdrawal deciency excess Tryptophan depletion Phenalanine elevation Glucocorticoids Cushing syndrome Surgery Surgical Illness Stroke Medical Illness Figure 1-1. Neurotransmitters and biomarkers of delirium. Reprinted with permission from: Flacker JM, Lipsitz LA. Neural mechanisms of delirium: current hypotheses and evolving concepts. J Gerontol Biol Sci Med Sci 1999;54A:B243. Alcoholism and

Load more