Delirium in the Older Emergency Department Patient: A Quiet Epidemic

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Definition of delirium

Delirium is defined as an acute change in cognition that cannot be better accounted for by preexisting or evolving dementia.20 This change in cognition is rapid, occurring over a period of hours or days, and is classically described as reversible. Patients with delirium typically have inattention, disorganized thinking, altered level of consciousness (somnolent or agitated), and perceptual disturbances.20

Delirium is classified into 3 psychomotor subtypes: hypoactive, hyperactive, and mixed.21

The distinction between delirium and dementia

Delirium and dementia both cause cognitive impairment, and health care providers often confuse these 2 distinct clinical entities. This confusion is exacerbated by the high frequency in which delirium is superimposed on dementia,34 which is why delirium is often missed in these patients.35 However, there are several key distinguishing features between delirium and dementia (Table 2), and most delirium assessments capitalize on these differences. Unlike delirium, dementia is characterized by a

Cause of delirium

Delirium is often the initial manifestation of an underlying acute illness and can be present before fever, tachypnea, tachycardia, or hypoxia.39 The cause of delirium is multifactorial and involves a complex interrelationship between patient vulnerability and precipitating factors (Fig. 1).40, 41 Patients who are highly vulnerable may be older, have severe dementia, and have multiple comorbidities. In these patients, a relatively benign insult, such as a small dose of narcotic medication, can

Psychoactive medications as risk factors for delirium

Medications with anticholinergic properties, benzodiazepines, and narcotics are notorious for precipitating and exacerbating delirium. Such medication risk factors are particularly relevant to the older patient population because polypharmacy is highly prevalent.49 Medications with anticholinergic properties are more frequently associated with delirium than any other drug class.65, 66, 67 More than 600 medications with anticholinergic properties exist, and of these, 11% are commonly prescribed

The negative consequences of delirium

An abundance of hospital-based studies have investigated the deleterious effects of delirium. From these studies, delirium is a powerful prognostic marker and has been associated with in-hospital and long-term mortality.4, 5, 77, 78, 79 Although some have argued that delirium is simply a surrogate for severity of illness and comorbidity burden,80 the relationship between delirium and death has been shown to be independent of these factors.4, 5

Delirium also has a profound effect on the older

Unrecognized delirium in the emergency department

Despite the negative consequences of delirium, emergency physicians miss 57% to 83% of cases because of lack of appropriate and routine screening.1, 2, 3, 88, 91, 92, 93 This quality-of-care issue extends beyond the ED as similar miss rates have been observed in the hospital setting.32, 94, 95, 96, 97 Delirium is more commonly missed in patients with hypoactive symptomatology, who are aged 80 years and older, have visual impairment, or have dementia.32, 35

The consequences of missing delirium in

Diagnosing delirium in the ED

Several delirium assessments exist, but the Confusion Assessment Method (CAM) is probably the most widely accepted by clinicians. The CAM was developed for nonpsychiatrists and is based on the Diagnostic and Statistical Manual of Mental Disorders, Revised 3rd Edition (DSM-IIIR) criteria.101 It consists of 4 features: (1) acute onset of mental status changes and a fluctuating course, (2) inattention, (3) disorganized thinking, and (4) altered level consciousness.101 A patient must have features

Diagnostic evaluation for ED Patients with Delirium

Once delirium is detected in the ED, the diagnostic evaluation should be focused on uncovering the underlying cause. Although infection is one of the most common causes of delirium in the older ED patient, life-threatening causes should initially be considered and can be recalled using the mnemonic “WHHHHIMPS” (Box 1).123 After these life-threatening causes have been considered, the ED evaluation can focus on ruling out other causes of delirium listed in Table 3.

The ED evaluation of the

Disposition

There is little evidence-based guidance regarding the disposition of older ED patients with delirium. However, admission of delirious patients is likely warranted in most cases. Older delirious patients who are discharged from the ED have higher death rates compared with nondelirious patients, and this effect is magnified when delirium is unrecognized by the emergency physician.88 In addition, delirious patients may be more likely to return to the ED and be hospitalized.1 For a small minority,

Pharmacologic management of delirium

The single most effective treatment of delirium is to diagnose and treat the underlying cause. Adjunct pharmacologic treatments have been investigated for delirium, but most studies are limited by their nonblinded trial design, poor randomization, or inadequate power. The American Psychiatry Association recommends avoiding benzodiazepines as monotherapy in delirious patients, except in the setting of alcohol and benzodiazepine withdrawal.45 As mentioned earlier, benzodiazepines can precipitate

Nonpharmacologic management of delirium

Several nonpharmacologic delirium interventions have been developed for the in-hospital setting and may be tailored for the ED. Most of these nonpharmacologic interventions contain multiple components and involve a multidisciplinary team of physicians, nurses, and social workers or case managers.140, 141 Moreover, geriatricians or geriatric psychiatrists are commonly consulted for these interventions.140, 141, 142

These interventions usually emphasize decreased use of psychoactive medications,

Summary

Delirium is common in older ED patients and its cause is multifactorial, involving a complex interplay between patient vulnerability and precipitating factors. Based on numerous hospital studies and a limited number of ED studies, delirium has devastating effects on the patient's well-being. As a result, delirium surveillance should be routinely performed in older ED patients, especially those at high risk. The CAM is the only delirium assessment validated for the ED and it has excellent

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    Jin H. Han and Amanda Wilson were supported in part by the Emergency Medicine Foundation Grant Career Development Award. Dr Wes Ely was supported in part by the National Institutes of Health AG01023 and the Veterans Affairs Tennessee Valley Geriatric Research, Education, and Clinical Center (GRECC).

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