15.2 Delirium

Mrs. B.’s cognitive difficulties emerged gradually over time. Although she forgot appointments, she never forgot—and was never confused about—who and where she was. Moreover, she did not experience unusual or rapid changes in consciousness or in the ability to focus her attention. If she had, these symptoms might have indicated that she was delirious, as are many residents of nursing homes who are 85 years old or older (American Psychiatric Association, 2013).

What Is Delirium?

Delirium A neurocognitive disorder characterized by a relatively sudden disturbance in attention and awareness as well as disruption of at least one other aspect of cognitive functioning.

Delirium is characterized by a disturbance in attention and awareness as well as disruption of at least one other aspect of cognitive functioning (American Psychiatric Association, 2013). These symptoms develop rapidly—over hours to days—and fluctuate within a 24-hour period. The disturbance in attention is evidenced by difficulty directing, focusing, sustaining, and shifting attention, as well as a decreased awareness of the external environment; the person may appear “stoned” or seem to be focusing on internally generated stimuli, such as mental images. A delirious patient may have a hard time understanding a question, or may have trouble shifting attention to a new question and remain focused on the previous one. Alternatively, he or she may be distracted and unable to pay attention to any question. The DSM-5 diagnostic criteria are summarized in TABLE 15.2.

Table : TABLE 15.2 • DSM-5 General Diagnostic Criteria for Delirium
  1. A disturbance in attention (i.e., reduced ability to direct, focus, sustain, and shift attention) and awareness (reduced orientation to the environment).
  2. The disturbance develops over a short period of time (usually hours to a few days), represents a change from baseline attention and awareness, and tends to fluctuate in severity during the course of a day.
  3. An additional disturbance in cognition (e.g., memory deficit, disorientation, language, visuospatial ability, or perception).
  4. The disturbances in Criteria A and C are not better explained by another preexisting, established, or evolving neurocognitive disorder and do not occur in the context of a severely reduced level of arousal, such as coma.
  5. There is evidence from the history, physical examination, or laboratory findings that the disturbance is a direct physiological consequence of another medical condition, substance intoxication or withdrawal (i.e., due to a drug of abuse or to a medication), or exposure to a toxin, or is due to multiple etiologies.
Reprinted with permission from the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, (Copyright ©2013). American Psychiatric Association. All Rights Reserved.

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These attentional problems can make it difficult for a clinician to interview the delirious patient; the clinician must infer the patient’s mental state from his or her behavior and unusual responses and then seek information from family members or friends. Case 15.2 describes one woman’s experience with delirium.

CASE 15.2 • FROM THE OUTSIDE: Delirium

A 74-year-old African American woman, Ms. Richardson, was brought to a city hospital emergency room by the police. She is unkempt, dirty, and foul-smelling. She does not look at the interviewer and is apparently confused and unresponsive to most of his questions. She knows her name and address, but not the day or the month. She is unable to describe the events that led to her admission.

The police reported that they were called by neighbors because Ms. Richardson had been wandering around the neighborhood and not taking care of herself. The medical center mobile crisis unit went to her house twice but could not get in…they broke into the apartment…and then found Ms. Richardson hiding in the corner, wearing nothing but a bra. The apartment was filthy….

[Ms. Richardson was diabetic, and her diabetes was out of control when she was admitted to the hospital. They begin to stabilize her medically and decided to transfer her the next day to a medical unit. Her mental state improved when the diabetes was treated.]

(Spitzer et al., 2002, pp. 13–14)

When delirious, people may also be disoriented, not knowing where they are or what the time, day, or year is; this was the case with Ms. Richardson in Case 15.2. Less frequently, when delirious, people may not know who they are. In addition, they may have difficulty speaking clearly, naming objects, or writing. The content of their speech may resemble that of someone in a manic episode: pressured and nonsensical, or flitting from topic to topic.

Delirious people may also experience perceptual alterations, including:

The perceptual disturbances are most frequently visual. Delirious people may believe that their perceptual experiences are real and behave accordingly. Hallucinations that are threatening may make them afraid, and they may respond by attacking others. Sometimes people in a delirious state are injured while responding to their altered perceptions, and their behavior can appear bizarre. Because of the perceptual difficulties, such patients may not consent to appropriate treatment.

Delirium is most common among the elderly and terminally ill, as well as patients who have just had surgery; it is not yet known why delirium is more likely among these groups, but neurological changes related to aging may make the elderly more vulnerable to developing delirium. TABLE 15.3 provides additional information about delirium.

Table : TABLE 15.3 • Delirium Facts at a Glance
Prevalence
  • Older adults are more likely than others to develop delirium.
  • Between 14% and 24% of patients admitted to a hospital are delirious.
  • Approximately 70–87% of people in intensive care may become delirious.
  • Delirium occurs in up to 60% of nursing home residents.
  • Up to 80% of terminally ill patients will become delirious at the end of life (Brown & Boyle, 2002).
Comorbidity
  • Delirium may occur along with another neurocognitive disorder or as a result of a substance-related disorder.
Onset
  • When delirium arises after head trauma, symptoms often develop immediately.
Course
  • Delirium typically resolves, and does so sooner, when the underlying problem is treated.
  • Symptoms of delirium typically fluctuate over the course of the day.
  • For most people, symptoms completely subside within a few hours or days; for others, especially the elderly, symptoms may persist for months or longer.
  • People who had relatively good health and cognitive functioning before their delirium began are likely to make a better recovery than those with poor health and cognitive functioning.
  • People with previous episodes of delirium are vulnerable to subsequent episodes.
Gender Differences
  • Among elderly people, men are more likely than women to become delirious.
Cultural Differences
  • Countries have different guidelines for diagnosing delirium, which can prohibit making meaningful comparisons across countries (Leentjens & Diefenbacher, 2006).
Source: Unless otherwise noted, the source for information is American Psychiatric Association, 2013.

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Symptoms that appear similar to delirium can occur with other disorders, which may make it difficult to provide a definitive—or even a tentative—diagnosis. The following symptoms may appear similar to those of delirium:

If a clinician has reason to suspect that the symptoms arise because of a medical condition (such as untreated diabetes, infection, or substance use), delirium is a tentative diagnosis, pending physical or laboratory tests.

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Understanding Delirium: A Side Effect?

Delirium can be a side effect of prescribed medication, substance use or exposure, or can result from a medical condition.

Delirium Caused by Substance Use

Delirium can arise from the effects of a psychoactive substance such as alcohol or a medication, or from withdrawal from such a substance. Intoxication and withdrawal are considered to give rise to delirium only when the symptoms are severe enough to require more than the usual clinical attention and treatment provided to someone who used the substance in question. If the symptoms are not severe enough to reach the level needed for a diagnosis of delirium, the appropriate diagnosis is a substance-related disorder, either intoxication or withdrawal (see Chapter 9).

Delirium Caused by a General Medical Condition

Delirium can arise from a variety of medical problems, including dehydration, or after receiving anesthesia. Some surgery patients—particularly elderly ones—become temporarily delirious in response to anesthesia.
LA LOUVIERE/ASTIER/BSIP/SuperStock

Like a fever, delirium can arise for a variety of medical reasons:

Some of these causes, such as dehydration, can be fatal if not treated (Brown & Boyle, 2002).

Clinicians determine the underlying cause of a person’s delirium in several ways: from a physical examination, a consultation with someone who knows the patient and may know something about what led to the symptoms, results of laboratory tests, and a review of the patient’s medical history.

Treating Delirium: Rectify the Cause

Treatment for delirium usually targets neurological factors—treating the underlying medical condition or substance use that affects the brain and causes the delirium. In most cases, as the medical condition improves or the substance intoxication or withdrawal resolves, the delirium ends. In some cases, however, treatment for the underlying medical problem—for example, administering antibiotics to treat bacterial pneumonia—can take days to affect the delirium; in other cases, such as when people are close to death, doctors may not be able to treat the underlying cause of the delirium. For temporary relief, the patient may be given antipsychotic medication, usually haloperidol or risperidone (Leentjens & van der Mast, 2005). In fact, studies find that giving haloperidol preventatively to elderly patients about to undergo surgery can decrease the severity and duration of postoperative delirium (Kalisvaart et al., 2005).

Treatment may also target psychological and social factors. Such interventions for people with delirium include (Brown & Boyle, 2002):

Thinking Like A Clinician

Drew is on his college’s football team and had to have surgery on his knee. For the procedure, he had general anesthesia. His mom was with him right after the surgery, and Drew was delirious and remained so for hours. What can you assume, and what should you not assume, about Drew’s emotions and his cognitive functions? What might be a likely cause of his delirium? What should be done, if anything, to help Drew?