A clinical syndrome that affects the functioning of the brain in which there are disturbances of consciousness with reduced ability to focus, sustain or shift attention; changes in cognition; and the development of a perceptual disturbance not accounted for by a preexisting or developing dementia. Also known as encephalopathy, intensive care unit (ICU) psychosis, sundowning (American Psychiatric Association, 1994).

A. Medications and especially polypharmacy (eg, opiates, benzodiazepines, anticholinergics, steroids, antifungals, chemotherapy agents)

B. Metabolic encephalopathies (eg, hypoxia; electrolyte imbalances; renal, hepatic, pancreatic, pulmonary insufficiencies)

C. Infections (eg, urinary tract infection [UTI], pneumonia)

D. Head trauma

E. Epilepsy

F. Neoplasms: especially intracranial or central nervous system (CNS) lesions

G. Vascular disorders

H. Hematologic disorders

I. Allergic responses

J. Withdrawal syndromes

A. Frequently missed or misdiagnosed by doctors and nurses

1. Lack of knowledge.

2. Symptoms may be mild and not noticed, especially in hypoalerthypoactive delirium.

3. The fluctuation of symptoms and limited time spent with a patient contribute to missing diagnosis.

4. Many of the symptoms of delirium appear to be symptoms of other disorders such as major depression, mania, and psychosis, and lead to incorrect diagnosis.

B. Widely reported to frequently occur in the medically ill elderly, cancer patients, patients entering palliative care, the terminally ill, and patients in the ICU.

1. 25% to 40% of patients with cancer at some point during the illness.

2. Increases to 85% of cancer patients when terminal (Anderson & Holmes, 1993).

3. Over 80% of ICU patients experience delirium (Ely, Siegel & Inouye, 2001).

C. Patients with delirium have increased medical complications, higher morbidity and mortality rates, and longer lengths of stay.

1. 17.5 million in-patient days and over $4 billion in Medicare expenditures for elderly patients in the United States (U.S. Bureau of the Census, 1996).

D. It is important that delirium is recognized early in patients.

1. Protected from the effects of inactivity, fearfulness, and agitation.

2. Causes are detected and, if possible, eliminated or minimized.

A. May last a few hours, days, weeks, or months.

B. Develops acutely over hours to days and resolves if causes are removed unlike dementia, which evolves slowly over time and there is no disturbance of consciousness.

C. Sleep-wake cycle is disturbed.

D. Often begins and is worse at night.

E. Symptoms tend to wax and wane but become sustained as delirium worsens.

A. Hypoalert-Hypoactive (depending on the severity)

1. Is often drowsy, has difficulty staying awake, falls asleep during interactions.

2. Can become stuporous or comatose.

3. Quiet and withdrawn.

4. Apathetic.

5. Lacks spontaneous speech and conversation and, as delirium worsens, may become incoherent or mute.

6. Becomes disoriented to time → place → person.

7. Has difficulty finding words or naming objects.

8. Has poor concentration.

9. Has difficulty shifting or sustaining attention. May perseverate.

10. Has impaired memory (especially short term) and recall.

11. Lacks ability to think abstractly or understand multiple directions.

12. Impaired written language.

B. Hyperalert-Hyperactive (depending on the severity)

1. Exhibits same difficulties of sustaining and focusing attention, poor concentration, language disturbances, disorientation, and memory difficulties as seen in hypoalert-hypoactive.

2. Restless and agitated.

3. May become aggressive and violent.

4. Uncooperative, argumentative, and unable to be reasoned with.

5. Is talkative, but speech is often rapid and disorganized.

6. Easily distracted.

C. Mixed

1. Patient fluctuates between periods of being hypoalert-hypoactive to being hyperalert-hyperactive.

D. Perceptual Disturbances and Delusions

1. More common in hyperalert-hyperactive and mixed delirium.

2. More likely to occur at night.

3. Illusions—Perception in which actual external stimuli are misinterpreted or misperceived (eg, intravenous [IV] pole appears to be a person standing by the bed).