Delirium

Definition

Description

Demographics

Causes and symptoms

Diagnosis

Treatment

Prognosis

Resources

Definition

Delirium is a medical condition characterized by a general disorientation accompanied by cognitive impairment, mood shift, self-awareness, and inability to attend (the inability to focus and maintain attention). The change occurs over a short period of time—hours to days—and the disturbance in consciousness fluctuates throughout the day.

Description

The word delirium comes from the Latin delirare. In its Latin form, the word means to become crazy or to rave. A phrase often used to describe delirium is “clouding of consciousness,” meaning the person has a diminished awareness of their surroundings. In the Diagnostic and Statistical Manual of Mental Disorders IV, Text Revision, also known as the DSM-IV-TR, delirium is classified according to its assumed causes; for example, “Substance-Induced Delirium” is one classification. These disorders involving delirium are listed in the same section as those involving dementia, but the two manifestations of illness differ in several characteristics. Dementia, for example, may exhibit a longer developmental process and is typically accompanied by multiple cognitive deficits.

While the delirium is active, the person tends to fade into and out of lucidity, meaning that he or she will sometimes appear to know what’s going on, and at other times, may show disorientation to time, place, person, or situation. It appears that the longer the delirium goes untreated, the more progressive the disorientation becomes. It usually begins with disorientation to time, during which a patient will declare it to be morning, even though it may be late night. Later, the person may state that he or she is in a different place rather than at home or in a hospital bed. Still later, the patient may not recognize loved ones, close friends, or relatives, or may insist that a visitor is someone else altogether. Finally, the patient may not recognize the reason for his/her hospitalization and might accuse staff or others of some covert reason for his/her hospitalization. In fact, this waxing and waning of consciousness is often worse at the end of a day, a phenomenon known as “sundowning.”

A delirious patient will have a difficult time with most mental operations. Because the patient cannot attend consistently to the environment, disorientation can result. Nevertheless, disorientation and memory loss are not essential to the diagnosis of delirium; the inability to focus and maintain attention, however, is essential to rendering a correct diagnosis. Left un-checked, delirium tends to transition from inattention to increased levels of lethargy, leading to torpor, stupor, and coma. In its other form, delirious patients become agitated and almost hypervigilant, with their sleep-wake cycle dramatically altered, fluctuating between great guardedness and hypersomnia (excessive drowsiness) during the day and wakefulness during the night. Delirious patients can also experience hallucinations of the visual, auditory, or tactile type. In such cases, the patient will see things others cannot see, hear things others cannot hear, and/or feel things that others cannot, such as feeling as though his or her skin is crawling. In short, the extremes of delirium range from the appearance of simple confusion and apathy to the anxious, agitated, and hyperactive type, with some patients experiencing both ends of the spectrum during a single episode. It is imperative that a quick evaluation occur if delirium is suspected because the condition can lead to death.

Demographics

Children, possibly because of their immature brain development and physiological differences from adults, can be particularly susceptible to delirium. This susceptibility is most common in association with fevers or some kinds of medications (such as anticholinergics, medications used for motor control problems). A child in a state of delirium may exhibit behavior that can be mistaken for willful lack of cooperation.

The elderly are also particularly sensitivity to delirium, also probably because of differences in physiology as we age. Being male and elderly enhances this risk.

Causes and symptoms

Causes

While the symptoms of delirium are numerous and varied, the causes of delirium fall into four basic categories: metabolic, toxic, structural, and infectious. Stated another way, the bases of delirium may be medical, chemical, surgical, or neurological. The DSM-IV lists four classifications of delirium: delirium due to a general medical condition; substance-induced delirium, which includes delirium resulting as a side effect of medication; delirium due to multiple etiologies, meaning it has many different causes; and delirium not otherwise specified, a category applied when the symptom does not fit into any of the other groups. Delirium is often associated with factors that result in a disturbance of the normal sleep-wake cycle.

METABOLIC CAUSES

Many metabolic disorders, such as hypothyroidism, hyperthyroidism, hypokalemia, and anoxia can cause delirium. For example, hypothyroidism (the thyroid gland emits reduced levels of thyroid hormones) brings about a change in emotional responsiveness, which can appear similar to depressive symptoms and cause a state of delirium. Other metabolic sources of delirium involve the dysfunction of the pituitary gland, pancreas, adrenal glands, and parathyroid glands. It should be noted that when a metabolic imbalance goes unattended, the brain may suffer irreparable damage.

DELIRIUM AND MEDICATION

One of the most frequent causes of delirium in the elderly is overmedication. The use of medications such as tricyclic antidepressants and antiparkinsonian medications can bring about an anticholinergic toxicity and subsequent delirium. In addition to the anticholinergic drugs, other drugs that can be the source of a delirium are:

• anticonvulsants, used to treat epilepsy
• antihypertensives, used to treat high blood pressure
• cardiac glycosides, such as Digoxin, used to treat heart failure
• cimetidine, used to reduce the production of stomach acid
• disulfiram, used in the treatment of alcoholism
• insulin, used to treat diabetes
• opiates, used to treat pain
• phencyclidine (PCP), used originally as an anesthetic, but later removed from the market, now only produced and used illicitly
• salicylates, basically found in aspirin
• steroids, sometimes used to prevent muscle wasting in bedridden or other immobile patients

Additionally, systemic poisoning by chemicals or compounds such as carbon monoxide, lead, mercury, or other industrial chemicals can be the source of delirium.

DELIRIUM AND OTHER SUBSTANCES

Just as the ingestion of certain drugs may cause delirium in some patients, the withdrawal of drugs can also cause it. Alcohol is the most widely used and most well known of these drugs whose withdrawal symptoms may include delirium. Delirium onset from the abstinence of alcohol in a chronic user can begin within three days of cessation of drinking. The term delirium tremens is used to describe this form of delirium. The resulting symptoms of this delirium are similar in nature to other delirious states but may be preceded by clear-headed auditory hallucinations. In other words, the delirium has not begun, but the patient may experience auditory hallucinations. Delirium tremens follow and can have ominous consequences with as many as 15% of those affected dying.

OTHER CAUSES OF DELIRIUM

Some of the structural causes of delirium include vascular blockage, subdural hematoma, and brain tumors. Any of these can damage the brain, through oxygen deprivation or direct insult, and cause delirium. Some patients become delirious following surgery. This can be due to any of several factors, such as effects of anesthesia, infections, or a metabolic imbalance.

Infectious diseases can also cause delirium. Commonly diagnosed diseases such as urinary tract infections, pneumonia, or fever from a viral infection can induce delirium. Additionally, diseases of the liver, kidney, lungs, and cardiovascular system can cause delirium. Finally, an infection, specific to the brain, can cause delirium. Even a deficiency of thiamine (vitamin B₁) can be a trigger for delirium.

Symptoms

Symptoms of delirium are often those associated with the disturbed sleep-wake cycle and include a confused state of mind accompanied by poor attention, impaired recent memory, irritability, inappropriate behavior (e.g., use of vulgar language, despite lack of a history of such behavior), and anxiety and fearfulness. In some cases, the person can appear to be psychotic, fostering illusions, delusions, hallucinations, and/or paranoia. In other cases, the patient may simply appear to be withdrawn and apathetic. In still other cases, the patient may become agitated and restless, unable to remain in bed, and feel a strong need to pace the floor. This restlessness and hyperactivity can alternate with periods of apparent stupor.

A few examples of people affected by delirium follow:

• One man, who had already been in the hospital for three days, when asked if he knew where he was, stated the correct city and hospital. He immediately followed this by saying, “but I started out in Dallas, Texas, this morning.” The hospital location was some 1,800 miles from Dallas, Texas, and as previously indicated, he had been in the same hospital for three days.
• In another case, an elderly man was placed in a private room that had a wonderful large mural on one wall. The mural was that of a forest scene—no animals or people, only trees and sunlight. His chief complaint at various points during the day was that evil people were watching him from behind the trees in the forest scene.
• An elderly woman had to be subdued while attempting to flee from the hospital because she was convinced that she had been brought there so surgeons could harvest her organs. Despite the lack of surgical scars or incisions, she insisted that she had been taken to the basement of the hospital the previous night and that a surgeon had removed one of her kidneys.

Diagnosis

The diagnosis of delirium relies on a distinction of its occurrence from dementia. It should be determined not to arise from previously existing dementia. Other features include identifying it as a loss of clarity about the environment (inattention), sudden changes in cognition (e.g., disorientation), and a relatively sudden onset (compared to dementia).

Diagnosis of some cases of delirium may not occur at all; whether or not delirium is diagnosed in a patient depends on how it is manifested. If the person is an elderly, postoperative patient who appears quiet and apathetic, the condition may go undiagnosed. However, if the patient presents with the agitated, uncooperative type of delirium, it will certainly be noticed. In any case, where there is sudden onset of a confused state accompanied by a behavioral change, delirium should be considered. This is not intended to imply that such a diagnosis will be made easily.

Frequent mental status examinations, at various times throughout the day, may be required to render a diagnosis of delirium. This assessment is generally done using the Mini-Mental State Examination (MMSE). This abbreviated form of mental status examination begins by first assessing the patient’s ability to attend. If the patient is inattentive or in a stuporous state, further examination of mental status cannot be done. However, assuming the patient can respond to questions asked, the examination can proceed. The Mini-Mental State Exam assesses the areas of orientation, registration, attention and concentration, recall, language, and spatial perception. Another tool for use in diagnosing delirium is the Delirium Rating Scale-Revised-98, although studies regarding its ability to differentiate different types of delirium have not been undertaken. Yet another diagnostic tool is the Memorial Delirium Assessment Scale, or MDAS. One tool that does not require patient participation is the Confusion Assessment Method, or CAM.

At times, the untrained observer may mistake psychotic features of delirium for another primary mental illness such as schizophrenia or a manic episode such as that associated with bipolar disorder. However, it should be noted that there are major differences between these diagnoses and delirium. In people who have schizophrenia, their odd behavior, stereotyped motor activity, or abnormal speech persists in the absence of disorientation like that seen with delirium. The schizophrenic appears alert and although his/her delusions and/or hallucinations persist, he/she could be formally tested. In contrast, the delirious patient appears hapless and disoriented between episodes of lucidity. The delirious patient may not be testable. A manic episode could be misconstrued for agitated delirium, but consistency of elevated mood would contrast sharply to the less consistent mood of the delirious patient. Once again, delirium should always be considered when there is a rapid onset and especially when there is waxing and waning of the ability to attend and the confusion state.

Because delirium can be superimposed into a preexisting dementia, the most often posed question, when diagnosing delirium, is whether the person might have dementia instead. Both cause disturbances of memory, but a person with dementia does not reflect the disturbance of consciousness depicted by someone with delirium. Expert history taking is a must in differentiating dementia from delirium. Dementia is insidious in nature and thus progresses slowly, while delirium begins with a sudden onset and acute symptoms. A person with dementia can appear clear-headed, but can harbor delusions not elicited during an interview. One does not see the typical fluctuation of consciousness in dementia that manifests itself in delirium. It has been stated that, as a general rule, delirium comes and goes, but dementia comes and stays. Delirium rarely lasts more than a month. As a final caution, the clinician must be prepared to rule out factitious disorder and malingering as possible causes for the delirium.

When a state of delirium is confirmed, the clinician is faced with the task of making the diagnosis in appropriate context to its cause. The delirium may be caused by a general medical condition. In such a case, the clinician must identify the source of the delirium within the diagnosis. For example, if the delirium is caused by liver dysfunction, in which the liver cannot rid the system of toxins and allows them to enter the system and thus the brain, the diagnosis would be delirium due to hepatic encephalopathy. The delirium might also be caused by a substance such as alcohol. To render a diagnosis of alcohol intoxication delirium, the cognitive symptoms should be more exaggerated than those found in intoxication syndrome. The delirium could also be caused by withdrawal from a substance. Continuing the alcohol theme, the diagnosis would be alcohol withdrawal delirium (delirium tremens could be a feature of this diagnosis).

There may be instances in which delirium has multiple causes, such as when a patient has a head trauma and liver failure, or viral encephalitis and alcohol withdrawal. When delirium comes from multiple sources, a diagnosis of delirium precedes each medical condition that contributes.

Treatment

Treating delirium means treating the underlying illness that is its basis. This could include correcting any chemical disparities within the body, such as electrolyte imbalances, treating an infection, reducing a fever, or removing or discontinuing a medication or toxin. A review of anticholinergic effects of medications administered to the patient should take place. It is suggested that sedatives and hypnotic-type medications not be used; however, despite the fact that they can sometimes contribute to delirium, in cases of agitated delirium, the use of these may be necessary. Medications that are often used to treat agitated delirium include haloperidol, thioridazine, and risperidone. These can reduce the psychotic features and

KEY TERMS

Anoxia —Lack of oxygen.

Anticholinergic toxicity —A poisonous effect brought about by ingestion of medications or other toxins that block acetylcholine receptors. When these receptors are blocked, the person taking the medication may find that he or she gets overheated, has dry mouth, has blurry vision, and his or her body may retain urine.

Coma —Unconsciousness.

Hyperthyroidism —Condition resulting from the thyroid glands secreting excessive thyroid hormone, causing increased basal metabolic rate, and causing an increased need for food to meet the demand of the metabolic activity; generally, however, weight loss results.

Hypervigilant —Extreme attention and focus to both internal and external stimuli.

Hypokalemia —Abnormally low levels of potassium in the blood. Hypokalemia is a potential medical emergency, as it can lead to disturbances in of the heart rhythm.

Stupor —A trance-like state that causes a person to appear numb to their environment.

Subdural hematoma —Active bleeding or a blood clot inside the dura (leathery covering of the brain). This bleeding or clot causes swelling of the brain, and, untreated, the condition can cause death.

Torpor —Sluggishness or inactivity.

Tricyclic antidepressants —Antidepressant medications that have the common characteristic of a three-ring nucleus in their chemical structure. Imipramine and amitriptyline are examples of tricyclic antidepressants.

Vascular —Pertaining to the bloodstream (arteries, veins, and blood vessels).

curb some of the volatility of the patient, but they are only treating symptoms of the delirium and not the source. Benzodiazepines (medications that slow the central nervous system to relax the patient) can also assist in controlling agitated patients, but since they can contribute to delirium, they should be used in the lowest therapeutic doses possible. The reduction and discontinuance of all psychotropic drugs should be the goal of treatment and occur as soon as possible to permit recovery and viable assessment of the patient.

Prognosis

If a quick diagnosis and treatment of delirium occur, the condition is frequently reversible. However, if the condition goes unchecked or is treated too late, there is a high incidence of mortality or permanent brain damage associated with it. The underlying illness may respond quickly to a treatment regimen, but improvement in mental functioning may lag behind, especially in the elderly. Moreover, one study disclosed that one group of elderly survivors of delirium, at three years following hospital discharge, had a 33% higher rate of death than other patients. As a final note, delirium is a medical emergency, requiring prompt attention to avoid the potential for permanent brain damage or even death.

Resources

BOOKS

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th edition, text revised. Washington, DC: American Psychiatric Association, 2000.

Kaplan, Harold and Benjamin Sadock. Synopsis of Psychiatry. 8th edition. New York: Lippincott, Williams and Wilkins, 1997.

The Merck Manual. 17th edition. Whitehouse Station, N.J.: Merck Research Laboratories, 1999.

PERIODICALS

Chan, Daniel. “Delirium: Making the Diagnosis, Improving the Prognosis.” Geriatrics 54 (1999): 28–42.

Curyto, Kim J., Jerry Johnson, Thomas TenHave, Jana Mossey, Kathryn Knott, and Ira R. Katz. “Survival of Hospitalized Elderly Patients With Delirium: A Prospective Study.” American Journal of Geriatric Psychiatry 9 (2001): 141–147.

de Rooij, S.E., Schuurmans, M.J., van der Mast, R.C., and Levi, M. “Clinical subtypes of delirium and their relevance for daily clinical practice.” International Journal of Geriatric Psychiatry 20 (2005): 60-615.

Katz, Ira R., Kim J. Curyto, Thomas TenHave, Jana Mossey, Laura Sands, and Michael Kallan. “Validating the Diagnosis of Delirium and Evaluating its Association With Deterioration Over a One-Year Period.” American Journal of Geriatric Psychiatry 9 (2001): 148–159.

Trzepacz, Paula T. “The Delirium Rating Scale: Its Use in Consultation-Liaison Research.” Psychosomatics 40 (1999): 193–204.

Trzepacz, Paula T., Dinesh Mittal, Rafael Torres, Kim Kanary, John Norton, and Nita Jimerson. “Validation of The Delirium Rating Scale-Revised-98: Comparison with the delirium rating scale and the cognitive test for delirium.” Journal of Neuropsychiatry and Clinical Neuroscience 13 (2001): 229–242.

Webster, Robert and Suzanne Holroyd. “Prevalence of Psychotic Symptoms in Delirium.” Psychosomatics 41 (2000): 519–522.

OTHER

National Guideline Clearinghouse. “Management of alcohol-based delirium tremens.” <www.guideline.gov/sum mary/summary.aspx?ss=15&doc_id=6543&nbr=4109 > (accessed January 20, 2007).

National Cancer Center.“Cognitive disorders and delirium.”http:\\www.cancer.gov/cancertopics/pdq/sup portivecare/delirium/healthprofessional/allpages> (accessed January 20, 2007).

Jack H. Booth, Psy.D.

DELIRIUM

Delirium is a derangement of mental function characterized by disturbance of consciousness and impairment of cognition. In contrast to dementia, delirium usually develops over a short period of time, it tends to fluctuate in severity over the course of the day, and it usually resolves with treatment of the underlying causes. This disturbance of consciousness results in reduced awareness of the external environment, and a reduction of the ability to focus, sustain, and shift attention. Cognitive impairments in delirium include disorientation in time and place, memory deficits, and language disturbances. Sensory perception, particularly vision, may also be disturbed, resulting in misinterpretations, illusions, and hallucinations. There may be disruption of the normal sleep-wake cycle, with individuals being drowsy during the day and active at night. The acute mental disturbances of delirium can be very frightening and upsetting for patients, who may respond with agitated and aggressive behavior. In younger adults, an episode of delirium is usually quite dramatic and florid (hyperactive delirium), and its detection and diagnosis is relatively straightforward. By contrast, the mental disturbances in elderly individuals with delirium are often much less obvious, particularly if there is a pre-existing dementia (hypoactive delirium). As a result, it is quite common for delirium in an elderly person to be overlooked by their families, by other carers, and by medical and nursing staff. This is unfortunate because, like pain and fever, delirium is an important nonspecific sign that the patient is physically ill, and requires further investigation to identify the cause. If the individual is very demented or very ill, they may be unable to complain of other symptoms, and delirium may be the first or only sign that something significant is amiss.

Age and delirium

Delirium occurs when the brain receives an external insult powerful enough to disrupt its normal functioning. It can occur at any age, but it is most commonly seen in children and elderly people. In childhood, the brain is vulnerable because it is still developing. In old age, increased vulnerability to delirium is due to factors such as dementia and sensory impairment, which become more common with increasing age. As well as being more vulnerable, elderly people are also more liable to be exposed to the external insults, such as physical illness and medication, that commonly cause delirium. The more vulnerable the individual, the less severe such insults need to be in order to precipitate a delirium. Consequently, the highest rates of delirium are to be found in high-risk populations such as elderly medical, surgical, and psychiatric inpatients. Some elderly patient groups, such as those with hip fractures, appear to be particularly prone to developing delirium. In elderly patients, it is important to distinguish delirium from other mental disorders that occur in old age. This can be difficult, not least because disorders such as dementia and depression are themselves risk factors for delirium, and may be co-morbid with it. A useful rule of thumb is that any sudden worsening of cognitive functioning, particularly if alertness and attention are impaired, should be investigated as delirium until proved otherwise.

Causes

Physical illnesses cause delirium by acutely disrupting the normal metabolism of the nerve cells in the brain. This can come about by reducing the oxygen supply (e.g., cardiac failure, a fall in blood pressure, anemia), by physiological disturbances (e.g., fever, liver or kidney failure, endocrine disorders), by the action of drugs and toxins, and by direct damage (e.g., stroke, head injury). The most common causes of delirium in elderly patients are acute infections (particularly of the chest and urinary tract), and the prescribed drugs that they are taking. Almost any drug can cause delirium in an elderly patient, but some are particularly associated with this problem, either because they act directly on the brain (e.g., tranquilizers, anticonvulsants), or because they are broken down and eliminated less efficiently by the elderly body and so accumulate, or because they have particular modes of action. Drugs with anticholinergic activity are particularly liable to cause delirium, which has led to the suggestion that disturbance of the cholinergic nerve systems in the brain is an important feature of the pathology of delirium. In practice, elderly patients are often taking many drugs, and delirium may occur as a cumulative effect of this polypharmacy rather than it being due to one drug acting alone. It is important to bear in mind that delirium can also be caused by the sudden withdrawal of a drug upon which the patient is physically dependent. The most common drug in this respect is alcohol, although in elderly patients other possibilities, such as opiate analgesics and benzodiazepines, should be considered. Although delirium usually has a physical cause, it is recognized that, in particularly vulnerable individuals, a severe psychological stress such as bereavement, relocation, or extreme sensory deprivation may be sufficient to precipitate it.

Outcome

Traditionally, delirium has been regarded as a transient disorder that terminates with either recovery or death. In the majority of cases, the delirious episode is relatively short, but about one-third of patients have prolonged or recurrent episodes. Delirium is associated with increased short-term mortality in elderly patients, due mainly to the underlying physical illness. However, delirious patients also tend to have longer hospital stays, higher rates of functional decline, and higher rates of discharge to nursing homes. Other complications of delirium include falls and fractures if the patient is hyperactive, and pressure sores if they are hypoactive. Prospective studies show that the prognosis in terms of persistent or recurrent symptoms of delirium is relatively poor in elderly patients. This is probably because those who experience delirium are a vulnerable group more likely to develop the condition whenever they become physically ill. A proportion will also be suffering from a form of dementia, which will increase their vulnerability to delirium as it progresses. It is not known if delirium is itself a risk factor for the development or exacerbation of dementia. The family and other carers should be advised of the risk of future delirium, and educated about the symptoms so that they can recognize it if and when it occurs again.

Clinical management

The most important aspect of the clinical management of delirium is prompt diagnosis and treatment of the underlying cause or (more usually) causes. Sometimes the symptoms and behaviors of the delirium itself may need to be treated. The evidence base for this aspect of management is still very limited, and current approaches are based mainly on accumulated clinical experience. These strategies involve both pharmacological and nonpharmacological approaches. Regarding use of medication, there is always a risk that giving a powerful psychoactive drug to a delirious patient will make the problem worse, so this course of action should only be considered if the associated symptoms and behaviors are distressing or potentially dangerous to the patient and/or others. The drug treatment of delirium in elderly patients is similar to that of younger adults, although it is necessary to start with much lower doses. The drugs most commonly used in the management of delirium are neuroleptics (usually haloperidol), or benzodiazepines (e.g., diazepam, lorazepam, alprazolam) if the patient cannot tolerate a neuroleptic. The effects of the drug and its dosage need to be frequently reviewed, to ensure that it is not having any adverse effects. Once the delirium has resolved, the medication should be reduced and, if possible, discontinued over a period of a few days.

Nonpharmacological interventions in delirium are aimed at reducing the confusing, frightening, and disorienting aspects of the hospital or nursing home environment that aggravate the disorder. There is little evidence to inform the use of these strategies, but features such as good lighting, low noise levels, a visible clock, a window on the outside world, and, in particular, the reassuring presence of personal possessions and familiar individuals such as relatives are all thought to be beneficial. Any invasive intervention, including personal care tasks, should be explained simply, slowly, clearly, and repeatedly before it is carried out. Holding the patient's hand while talking helps to focus their attention, and provides reassurance.

Prevention

Regarding prevention, the aim should be to minimize exposure to the various patient- and hospital-related factors that are known to predispose to delirium in elderly inpatients. The ward environment and routines should aim to avoid unnecessary sensory impairment and sleep deprivation, and support a normal sleep-wake cycle. Nonpharmacological sleep-promotion strategies should be used in preference to hypnotic drugs. It is important to ensure adequate food and fluid intake, and patients should be encouraged to be mobile whenever possible. Careful prescribing is important, avoiding where possible any drugs with known potential to cause delirium, particularly in at-risk individuals such as those with dementia. The drug chart should be regularly reviewed, with the aim of keeping the burden of medication as low as possible. In surgical patients, good pre-, peri-, and postoperative care (especially with regard to blood pressure, oxygenation, pain relief, and infection control) will reduce the risk of postoperative delirium.

James Lindesay

See also Dementia; Disease Presentation; Psychiatric Disease in Relation to Physical Illness; Surgery in Elderly People.

BIBLIOGRAPHY

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 4th ed. Washington, D.C.: American Psychiatric Association, 1994.

American Psychiatric Association. Practice Guideline for the Treatment of Patients with Delirium. Washington, D.C.: American Psychiatric Association, 1999.

Byrne, E. J. Confusional States in Older People. London: Edward Arnold, 1994.

Carlson, A.; Gottfries, C.; Winblad, B.; and Robertsson, B., eds. "Delirium in the Elderly: Epidemiological, Pathogenetic, Diagnostic and Treatment Aspects." Dementia and Geriatric Cognitive Disorders 10 (1999): 305–430.

Francis, J., and Kapoor, W. N. "Prognosis after Hospital Discharge of Older Medical Patients with Delirium." Journal of the American Geriatrics Society 40 (1992): 601–606.

Inouye, S. K., and Charpentier, P. A. "Precipitating Factors for Delirium in Hospitalized Elderly Persons. Predictive Model and Interrelationship with Baseline Vulnerability." Journal of the American Medical Association 275 (1996): 852–857.

Levkoff, S.; Evans, D.; Liptzin, B.; et al. "Delirium, the Occurrence and Persistence of Symptoms among Elderly Hospitalised Patients." Archives of Internal Medicine 152 (1992): 334–340.

Lindesay, J.; Macdonald, A.; and Starke, I. Delirium in the Elderly. Oxford: Oxford University Press, 1990.

Lipowski, Z. J. Delirium: Acute Confusional States. New York: Oxford University Press, 1990.

Rockwood, K.; Cosway, S.; Carver, D.; et al. "The Risk of Dementia and Death Following Delirium." Age and Ageing 28 (1999): 551–556.

Rudberg, M. A.; Pompei, P.; Foreman, M. D.; Ross, R. E.; and Cassel, C. K. "The Natural History of Delirium in Older Hospitalized Patients: A Syndrome of Heterogeneity." Age and Ageing 26 (1997): 169–174.

Delirium

Definition

Delirium is a medical condition characterized by a vascillating general disorientation, which is accompanied by cognitive impairment, mood shift, self-awareness, and inability to attend (the inability to focus and maintain attention). The change occurs over a short period of time— hours to days— and the disturbance in consciousness fluctuates throughout the day.

Description

The word delirium comes from the Latin delirare. In its Latin form, the word means to become crazy or to rave. A phrase often used to describe delirium is "clouding of consciousness," meaning the person has a diminished awareness of their surroundings. While the delirium is active, the person tends to fade into and out of lucidity, meaning that he or she will sometimes appear to know what's going on, and at other times, may show disorientation to time, place, person, or situation. It appears that the longer the delirium goes untreated, the more progressive the disorientation becomes. It usually begins with disorientation to time, during which a patient will declare it to be morning, even though it may be late night. Later, the person may state that he or she is in a different place rather than at home or in a hospital bed. Still later, the patient may not recognize loved ones, close friends, or relatives, or may insist that a visitor is someone else altogether. Finally, the patient may not recognize the reason for his/her hospitalization and might accuse staff or others of some covert reason for his/her hospitalization (see example below). In fact, this waxing and waning of consciousness is often worse at the end of a day, a phenomenon known as "sundowning."

A delirious patient will have a difficult time with most mental operations. Due to the fact that the patient is unable to attend consistently to his environment, he/she can become disoriented. Nevertheless, disorientation and memory loss are not essential to the diagnosis of delirium; the inability to focus and maintain attention, however, is essential to rendering a correct diagnosis. Left unchecked, delirium tends to transition from inattention to increased levels of lethargy, leading to torpor, stupor, and coma. In its other form, delirious patients become agitated and almost hypervigilant, with their sleep-wake cycle dramatically altered, fluctuating between great guardedness and hypersomnia (excessive drowsiness) during the day and wakefulness during the night. Delirious patients can also experience hallucinations of the visual, auditory, or tactile type. In such cases, the patient will see things others cannot see, hear things others cannot hear, and/or feel things that others cannot, such as feeling as though his or her skin is crawling. In short, the extremes of delirium range from the appearance of simple confusion and apathy to the anxious, agitated, and hyperactive type, with some patients experiencing both ends of the spectrum during a single episode. It is imperative that a quick evaluation occur if delirium is suspected, because it can lead to death.

Causes and symptoms

Causes

While the symptoms of delirium are numerous and varied, the causes of delirium fall into four basic categories: metabolic, toxic, structural, and infectious. Stated another way, the bases of delirium may be medical, chemical, surgical, or neurological. Many metabolic disorders, such as hypothyroidism, hyperthyroidism, hypokalemia, anoxia, etc. can cause delirium. For example, hypothyroidism (the thyroid gland emits reduced levels of thyroid hormones) brings about a change in emotional responsiveness, which can appear similar to depressive symptoms and cause a state of delirium. Other metabolic sources of delirium involve the dysfunction of the pituitary gland, pancreas, adrenal glands, and parathyroid glands. It should be noted that when a metabolic imbalance goes unattended, the brain may suffer irreparable damage.

One of the most frequent causes of delirium in the elderly is overmedication. The use of medications such as tricyclic antidepressants and antiparkinsonian medications can bring about an anticholinergic toxicity and subsequent delirium. In addition to the anticholinergic drugs, other drugs that can be the source of a delirium are:

• anticonvulsants, used to treat epilepsy
• antihypertensives, used to treat high blood pressure
• cardiac glycosides, such as Digoxin, used to treat heart failure
• cimetidine, used to reduce the production of stomach aciddisulfiram , used in the treatment of alcoholism
• insulin, used to treat diabetes
• opiates, used to treat pain
• phencyclidine (PCP), used originally as an anesthetic, but later removed from the market, now only produced and used illicitly
• salicylates, basically found in aspirin
• steroids, sometimes used to prevent muscle wasting in bedridden or other immobile patients

Additionally, systemic poisoning by chemicals or compounds such as carbon monoxide, lead, mercury, or other industrial chemicals can be the source of delirium.

Just as the ingestion of certain drugs may cause delirium in some patients, the withdrawal of drugs can also cause it. Alcohol is the most widely used and most well known of these drugs whose withdrawal symptoms may include delirium. Delirium onset from the abstinence of alcohol in a chronic user can begin within three days of cessation of drinking. The term delirium tremens is used to describe this form of delirium. The resulting symptoms of this delirium are similar in nature to other delirious states, but may be preceded by clear-headed auditory hallucinations. In other words, the delirium has not begun, but the patient may experience auditory hallucinations. Delirium tremens follow and can have ominous consequences with as many as 15% dying.

Some of the structural causes of delirium include vascular blockage, subdural hematoma, and brain tumors. Any of these can damage the brain, through oxygen deprivation or direct insult, and cause delirium. Some patients become delirious following surgery. This can be due to any of several factors, such as: effects of anesthesia, infections, or a metabolic imbalance.

Infectious diseases can also cause delirium. Commonly diagnosed diseases such as urinary tract infections, pneumonia, or fever from a viral infection can induce delirium. Additionally, diseases of the liver, kidney, lungs, and cardiovascular system can cause delirium. Finally, an infection, specific to the brain, can cause delirium. Even a deficiency of thiamin (vitamin B1) can be a trigger for delirium.

Symptoms

Symptoms of delirium include a confused state of mind accompanied by poor attention, impaired recent memory, irritability, inappropriate behavior (such as the use of vulgar language, despite lack of a history of such behavior), and anxiety and fearfulness. In some cases, the person can appear to be psychotic, fostering illusions, delusions , hallucinations, and/or paranoia . In other cases, the patient may simply appear to be withdrawn and apathetic. In still other cases, the patient may become agitated and restless, unable to remain in bed, and feel a strong need to pace the floor.

A few examples of people affected by delirium follow:

• One gentleman, who had already been in the hospital for three days, when asked if he knew where he was, stated the correct city and hospital. He immediately followed this by saying, "but I started out in Dallas, Texas this morning." The hospital location was some 1,800 miles from Dallas, Texas, and as previously indicated, he had been in the same hospital for three days.
• In another case, an elderly gentleman was placed in a private room that had a wonderful large mural on one wall. The mural was that of a forest scene—no animals or people, only trees and sunlight. His chief complaint at various points during the day was that evil people were watching him from behind the trees in the forest scene.
• An elderly woman had to be subdued while attempting to flee from the hospital, because she was convinced that she had been brought there so surgeons could harvest her organs. Despite the lack of surgical scars or incisions, she insisted that she had been taken to the basement of the hospital the previous night and a surgeon had removed one of her kidneys.

Demographics

Delirium occurs most frequently in the elderly and the young, but can occur in anyone at any age. Of persons over 65 who are brought to the hospital for a general medical condition, roughly 10% show signs of delirium at admission. It is suspected that another 10%-15% may develop delirium while in the hospital. There appears to be no gender difference—delirium seems to affect males and females equally.

Diagnosis

Whether or not delirium is diagnosed in a patient depends on the type manifest. If the case is an elderly, postoperative patient who appears quiet and apathetic, the condition may go undiagnosed. However, if the patient presents with the agitated, uncooperative type of delirium, it will certainly be noticed. In any case, where there is sudden onset of a confused state accompanied by a behavioral change, delirium should be considered. This is not intended to imply that such a diagnosis will be made easily.

Frequent mental status examinations, at various times throughout the day, may be required to render a diagnosis of delirium. This is generally done using the Mini-Mental State Examination (MMSE). This abbreviated form of mental status examination begins by first assessing the patient's ability to attend. If the patient is inattentive or in a stuporous state, further examination of mental status cannot be done. However, assuming the patient is able to respond to questions asked, the examination can proceed. The Mini-Mental State Exam assesses the areas of orientation, registration, attention and concentration, recall, language, and spatial perception. Another recently evaluated and recommended tool for use in diagnosing delirium is the Delirium Rating Scale-Revised-98. This clinician-rated, 16-item scale allows for the assessment of 13 severity items and three diagnostic items. This test has been reported as more sensitive than the MMSE at detecting delirium.

At times, the untrained observer may mistake psychotic features of delirium for another primary mental illness such as schizophrenia or a manic episode such as that associated with bipolar disorder . However, it should be noted that there are major differences between these diagnoses and delirium. In people who have schizophrenia, their odd behavior, stereotyped motor activity, or abnormal speech persists in the absence of disorientation like that seen with delirium. The schizophrenic appears alert and although his/her delusions and/or hallucinations persist, he/she could be formally tested. In contrast, the delirious patient appears hapless and disoriented, between episodes of lucidity. The delirious patient may not be testable. A manic episode could be misconstrued for agitated delirium, but consistency of elevated mood would contrast sharply to the less consistent mood of the delirious patient. Once again, delirium should always be considered when there is a rapid onset and especially when there is waxing and waning of the ability to attend and the confusion state.

Since delirium can be superimposed into a pre-existing dementia , the most often posed question, when diagnosing delirium, is whether the person might have dementia instead. Both cause disturbances of memory, but a person with dementia does not reflect the disturbance of consciousness depicted by someone with delirium. Expert history taking is a must in differentiating dementia from delirium. Dementia is insidious in nature and thus progresses slowly, while delirium begins with a sudden onset and acute symptoms. A person with dementia can appear clear-headed, but can harbor delusions not elicited during an interview. One does not see the typical fluctuation of consciousness in dementia that manifests itself in delirium. It has been stated that, as a general rule, delirium comes and goes, but dementia comes and stays. Delirium rarely lasts more than a month. Usually, by the end of that period, a patient with dementia has full-blown dementia or has died. As a final caution, the clinician must be prepared to rule out factitious disorder and malingering as possible causes for the delirium.

When a state of delirium is confirmed, the clinician is faced with the task of making the diagnosis in appropriate context to its cause. The delirium may be caused by a general medical condition. In such a case, the clinician must identify the source of the delirium within the diagnosis. For example, if the delirium is caused by liver dysfunction, wherein the liver is unable to clean the system of toxins, thereby allowing them to enter the system and so the brain, the diagnosis would be Delirium Due to Hepatic Encephalopathy. The delirium might also be caused by a substance such as alcohol. To render a diagnosis of Alcohol Intoxication Delirium, the cognitive symptoms should be more exaggerated than those found in intoxication syndrome. The delirium could also be caused by withdrawal from a substance. Continuing the alcohol theme, the diagnosis would be Alcohol Withdrawal Delirium (delirium tremens could be a feature of this diagnosis).

There may be instances in which delirium has multiple causes, such as when a patient has a head trauma and liver failure, or viral encephalitis and alcohol withdrawal. When delirium comes from multiple sources, a diagnosis of delirium precedes each medical condition that contributes. As an example, the multiple causes would be reflected as Delirium Due to Head Trauma and Delirium Due to Hepatic Encephalopathy. Finally, when delirium is the focus of clinical attention, but insufficient evidence exists to identify a specific causal factor, a diagnosis of Delirium Not Otherwise Specified is rendered. An example of this can occur in people who are exposed to sensory deprivation, such as might occur in Intensive Care Units or Cardiac Care Units where the patient is allowed no stimulation save that of the occasional member of the hospital staff.

In summary, delirium develops rapidly, has a fluctuating course involving waxing and waning lucidity, severely affects attention, must receive immediate medical attention, and is reversible in most cases.

Treatment

Treating delirium means treating the underlying illness that is its basis. This could include correcting any chemical disparities within the body, such as electrolyte imbalances, the treatment of an infection, reduction of a fever, or removal of a medication or toxin. A review of anticholinergic effects of medications administered to the patient should take place. It is suggested that sedatives and hypnotic-type medications not be used; however, despite the fact that they can sometimes contribute to delirium, in cases of agitated delirium, the use of these may be necessary. Medications that are often used to treat agitated delirium include haloperidol , thioridazine and risperidone . These can reduce the psychotic features and curb some of the volatility of the patient, but they are only treating symptoms of the delirium and not the source. Benzodiazepines (medications that slow the central nervous system to relax the patient) can also assist in controlling agitated patients, but since they can contribute to delirium, they should be used in the lowest therapeutic doses possible. The reduction and discontinuance of all psychotropic drugs should be the goal of treatment and occur as soon as possible to permit recovery and viable assessment of the patient.

Prognosis

If a quick diagnosis and treatment of delirium occurs, the condition is frequently reversible. However, if the condition goes unchecked or is treated too late, there is a high incidence of mortality or permanent brain damage associated with it. The underlying illness may respond quickly to a treatment regimen, but improvement in mental functioning may lag behind, especially in the elderly. Moreover, one study disclosed that one group of elderly survivors of delirium, at three years following hospital discharge, had a 33% higher rate of death than other patients. As a final note, delirium is a medical emergency, requiring prompt attention to avoid the potential for permanent brain damage or even death.

Resources

BOOKS

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th edition, text revised. Washington, DC: American Psychiatric Association, 2000.

Kaplan, Harold and Benjamin Sadock. Synopsis of Psychiatry. 8th edition. New York: Lippincott, Williams and Wilkins, 1997.

The Merck Manual. 17th edition. Whitehouse Station, N.J.: Merck Research Laboratories, 1999.

PERIODICALS

Chan, Daniel. "Delirium: Making the diagnosis, improving the prognosis." Geriatrics 54 (1999): 28-42.

Curyto, Kim J., Jerry Johnson, Thomas TenHave, Jana Mossey, Kathryn Knott, and Ira R. Katz. "Survival of Hospitalized Elderly Patients With Delirium: A Prospective Study." American Journal of Geriatric Psychiatry 9 (2001): 141-147.

Katz, Ira R., Kim J. Curyto, Thomas TenHave, Jana Mossey, Laura Sands, and Michael Kallan. "Validating the Diagnosis of Delirium and Evaluating its Association With Deterioration Over a One-Year Period." American Journal of Geriatric Psychiatry 9 (2001): 148-159.

Trzepacz, Paula T. "The Delirium Rating Scale: Its Use in Consultation-Liaison Research." Psychosomatics 40 (1999): 193-204.

Trzepacz, Paula T., Dinesh Mittal, Rafael Torres, Kim Kanary, John Norton, and Nita Jimerson. "Validation of The Delirium Rating Scale-Revised-98: Comparison with the delirium rating scale and the cognitive test for delirium." Journal of Neuropsychiatry and Clinical Neuroscience 13 (2001): 229-242.

Webster, Robert and Suzanne Holroyd. "Prevalence of Psychotic Symptoms in Delirium." Psychosomatics 41 (2000): 519-522.

Jack H. Booth, Psy.D.

Delirium

Definition

Delirium is a syndrome caused by many different diseases or disorders. It is characterized by acute disturbances in thinking processes, changes in mental states, altered levels of consciousness, and inability to focus attention. Some doctors use the phrase acute confusional state as a synonym for delirium.

Description

Delirium has the following characteristics:

• Disturbance of the patient's consciousness. Individuals are less aware of their environment and have less ability to focus, sustain, or shift attention.
• A change in cognition. This change may involve loss of memory, disorientation, or language difficulties. It may also involve the development of a perceptual disturbance that cannot be accounted for by a preexisting, established, or evolving dementia.
• The disturbance develops over a short period of time (usually hours to days) and tends to fluctuate (go up and down) during the course of a day.
• Evidence from the medical history, physical examination, or laboratory findings indicate that the disturbance is related to a general medical condition.

There are three major categories of delirium:

• Hyperactive. Patients may be agitated (excitable), delusional, hallucinating, or disoriented. This type of delirium affects about 25% of elderly patients diagnosed with delirium. It is often misdiagnosed as dementia, schizophrenia, or another psychotic disorder. Hyperactive delirium can occur in alcohol withdrawal.
• Hypoactive. Patients may be disoriented but are also quiet, withdrawn, and subdued. About 25% of cases of delirium in seniors fall into this category. Hypoactive delirium may be mistaken for depression or go undiagnosed.
• Mixed. Patients exhibit delirium that varies between hypoactive and hyperactive forms. About 50% of seniors with delirium have the mixed type.

Demographics

Delirium is a common disorder among patients in general hospitals and among the elderly. Some studies have reported that between 10 and 30% of hospitalized patients experience delirium, and as many as 40 to 60% of hospitalized elderly patients do. Delirium adds significantly to healthcare costs in the United States; a study published in 2008 estimated that the annual cost of treating delirium ranges from $38 billion to $152 billion.

Delirium appears with equal frequency in both sexes and all racial and ethnic groups; however, there is some evidence as of 2006 that delirium is more likely to develop in seniors with low levels of education than in those who completed college.

A major risk factor for delirium in the elderly is a surgical operation. Between 15 and 25% of patients over 70 develop delirium after an elective procedure; between 35 and 65% develop delirium after an emergency operation.

Other risk factors for delirium in seniors include:

• medication/overmedication, perhaps the leading cause of delirium and a risk that increases with age and debility
• age over 75
• underlying dementia
• a coexisting medical disorder and the medications used to treat it
• functional impairment

Causes and symptoms

Causes

The underlying cause of delirium is incompletely understood but is thought to involve abnormalities in the production of neurotransmitters, which are chemicals produced by the body that transmit nerve impulses across the gaps (synapses) between nerve cells. As of 2008, research focused on a specific neurotransmitter—acetylcholine—and genetic risk factors in order to identify causes of delirium.

Certain conditions or treatments are known to be common triggers of delirium. Doctors sometimes use a checklist:

• infection (particularly infection of the urinary or respiratory tract)
• drug use (particularly when the drug is first prescribed or the dosage is changed)
• electrolyte imbalance
• lack of drugs (withdrawal)
• reduced and/or altered input from the senses (deafness, blindness)
• change in the patient's surroundings, especially when the living situation has changed (e.g., with the death of spouse, change of home, admittance to hospital/care facility)
• intracranial (inside the skull) problems, such as stroke, bleeding into brain tissue, or seizures
• urinary retention (inability to empty the bladder completely) and fecal impaction
• myocardial disorders (heart attack, heart failure, or irregular heart rhythm)

Symptoms

Although the specific symptoms of delirium in a given patient often depend on the cause of the delirium and its subtype, the following are the symptoms most commonly encountered in seniors:

• Loss of memory and disorientation (not knowing the date, time, or one's present location).
• Emotional lability (instability). An emotionally labile patient is one whose feelings change rapidly. A senior with delirium may be alternately tearful, anxious, giggly, or enraged.
• Agitation. Agitation is a condition in which the patient is excitable and easily stirred up emotionally.
• Sleep disturbances. Seniors with delirium may sleep during the day and be awake all night.
• Disturbances of perception. These include visual or auditory hallucinations (seeing objects or hearing voices that are not real) or delusions (persistent false beliefs about the self or other people that the patient maintains despite proof to the contrary).
• Neurologic signs and symptoms. These may include tremor, unsteadiness when trying to walk, difficulty writing or reading, difficulty finding the right word for a person or object, or involuntary twitching or contraction of muscles.

Diagnosis

A careful process of diagnosis is essential in evaluating a senior for delirium, as the condition is so often mistaken for a mental disorder or a disease of the central nervous system. Delirium is often underdiagnosed in patients with Alzheimer's disease or other disorders that cause dementia, as it is possible for a person to have both delirium and dementia at the same time.

Physical diagnosis

The first step in diagnosing delirium is a careful and complete physical examination, with particular attention paid to vital signs (temperature, pulse rate, blood pressure , and respiration). A review of the patient's medical history, along with the results of laboratory tests and a record of the patient's medications, is also essential. The medication review should include over-the-counter products, herbal medicines, or illicit drugs that the patient has been using, as well as information about his or her alcohol consumption. The patient may also be given an electroencephalogram (EEG) to rule out epilepsy or certain types of psychiatric disorders; a chest x ray to rule out a lung disease; or an electrocardiogram (EKG) to rule out heart disease .

Psychiatric screening and evaluation

Delirium is usually distinguished from dementia by its rapid onset (in most cases) and its tendency to fluctuate during the day; however, the two conditions can be difficult to differentiate when the patient has been previously diagnosed with dementia. The doctor may talk to friends or family members to determine when the patient's symptoms started, what medications the patient has been taking, and the patient's typical or average level of mental functioning.

QUESTIONS TO ASK YOUR DOCTOR

• What type of delirium does my family member have?
• Do you know what might be causing or triggering the delirium?
• Is the delirium reversible?
• Is there any way to tell how long it might last?
• What is the long-term prognosis?

The most common test used to evaluate a senior's mental functioning is the Mini-Mental State Examination (MMSE), which is a set of questions and requests that measure the senior's memory, orientation, attentiveness, ability to use and understand language, and ability to perform simple tasks (such as drawing a circle on a piece of paper). It can be given by a nurse or other healthcare professional trained in its use as well as by a physician. Other measures used are the Confusion Assessment Method (CAM) and the Telephone Interview for Cognitive Status (TICS; can be used when the examiner is in a different location from the patient). If the senior's delirium is of the hypoactive type, the senior may be given the Hamilton Depression Rating Scale to rule out depression.

Treatment

Treatment for delirium involves combining immediate treatment of the symptoms of delirium itself with treatment of the underlying disorder. The second aspect may be complex because many seniors suffer from more than one condition associated with delirium.

Nutrition/Dietetic concerns

Close attention to the patient's diet is necessary during an episode of delirium in order to avoid the risk of malnutrition . Observation is also important in order to reduce the risk choking or having food and drink get into the lungs. Dietary care is particularly important if the patient's behavior requires social or physical restraint; if the patient has hypoactive delirium and has lost his or her appetite; or if the delirium was triggered by a urinary tract infection , urinary retention, or fecal impaction.

KEY TERMS

Acute confusional state —A term that some doctors use as a synonym for delirium.

Agitation —An emotional condition in which the patient is highly excitable and often physically restless.

Cognitive —Pertaining to the mental functions of thinking, learning, or memory.

Delirium —A disturbance of consciousness marked by confusion, difficulty paying attention, delusions, hallucinations, or restlessness, distinguished from dementia by its relatively sudden onset and variation in the severity of the symptoms.

Delusion —A persistent false belief about the self or other people that the person maintains in spite of proof to the contrary.

Dementia —A progressive decline in a person's intellectual skills, particularly memory, attention, problem-solving ability, and use of language, leading to a loss of the ability to perform activities of daily living.

Disorientation —Losing one's sense of time, place, and personal identity.

Hallucination —A sensory perception that occurs in the absence of a real stimulus. Hallucinations can affect any of the body's senses; however, the most common hallucinations in delirium are visual (seeing things) or auditory (hearing voices).

Neurotransmitter —Any of several chemicals produced by the body that serve to relay signals between nerve cells or between a nerve cell and another type of body cell. Delirium is thought to be related to abnormalities in the level of neurotransmitters in the central nervous system.

Psychosis —A general psychiatric term for a mental state in which the patient has lost contact with reality. It is marked by delusions, hallucinations, and disorganized thinking.

Social restraint —A technique for restraining a patient with delirium or dementia by placing the person close to a nursing station or by having relatives or healthcare professionals stay with the patient to monitor the person's behavior. Social restraint is preferred to physical restraints or medications.

Syndrome —A group or cluster of symptoms that often occur together, such that the presence of one often alerts the doctor to the existence of the others. Delirium is a syndrome rather than a disease.

Therapy

Therapy for delirium is guided by treatment of the underlying disease or disorder. While the patient is receiving treatment for this condition, however, the delirium is typically managed by a combination of approaches: medications (to control hallucinations and restore normal sensory perception and orientation); keeping the patient physically active when possible; and modifying the patient's environment:

• Medications. To control hallucinations and delusions, the senior may be given low doses of haloperidol (Haldol) or risperidone (Risperdal), which are antipsychotic medications. Drugs that the senior is taking for other conditions may be discontinued or have their dosages adjusted if they are thought to be contributing to the delirium.
• Physical activity. Patients with delirium frequently lose muscle strength or develop bedsores, constipation, or bladder incontinence if they are confined to bed. Encouraging the patient to walk or practice range-of-motion exercises is often recommended.
• Environmental changes. Agitated patients may require behavioral control of some kind. Although physical or chemical restraints are discouraged, they may be necessary for a short period of time if individuals seem likely to injure themselves or others. Social restraints (placing patients near the nurses' station or having a friend or relative stay with them) are preferred whenever possible. Other environmental changes to manage delirium include: keeping a clock and calendar near patients to reduce disorientation; giving patients familiar items from home; keeping lighting adequate and reducing unnecessary lights especially at night, and keeping the temperature comfortable to reduce perceptual disturbances; lowering the noise level near patients' rooms; making sure that patients are using their eyeglasses or hearing aid; and giving medical treatments while patients are awake so their sleep is not interrupted.

Prognosis

The prognosis of delirium depends on its cause. The condition may clear up in a matter of hours or last for several months. In most cases, delirium in seniors is reversible when the underlying disorder is treated; however, the patient's family should be advised that it may take weeks to months for the patient's memory and other cognitive functions to return to normal.

Delirium does, however, increase the risk of death in hospitalized elderly patients; the mortality rate is estimated by various sources to range between 22 and 76%. Seniors who are admitted to the hospital with delirium have a mortality rate of 10 to 26%.

Prevention

There is no known way to prevent delirium.

Caregiver concerns

Caregivers should do the following:

• If there is sudden onset or progressive delirium, have medical evaluation for infection.
• Look for signs of malnutrition or inadequate exercise (e.g., constipation, bedsores, weight loss). The caregiver may need to feed the senior if the senior is not eating independently.
• Recognize that the delirium may last for some time and that the patient may never recover completely if the individual is very old. In some cases the delirium may progress to dementia.
• Make sure that the senior is taking medications or following other treatment recommendations for any disorder related to the delirium.

Resources

BOOKS

Beers, Mark H., and Thomas V. Jones. Merck Manual of Geriatrics, 3rd ed., Chapter 39, “Delirium.” White-house Station, NJ: Merck, 2005.

Mace, Nancy L., and Peter V. Rabins. The 36-Hour Day: A Family Guide to Caring for People with Alzheimer Disease, Other Dementias, and Memory Loss in Later Life, 4th ed. Baltimore, MD: Johns Hopkins University Press, 2006.

PERIODICALS

Jones, Richard N., Frances M. Yang, Ying Zhang, et al. “Does Educational Attainment Contribute to Risk for Delirium? A Possible Role for Cognitive Reserve.” Journals of Gerontology Series A: Biological Sciences and Medical Sciences 61 (2006): 1307–1311.

Leentjens, A. F., J. N. Schieveld, M. Leonard, et al. “A Comparison of the Phenomenology of Pediatric, Adult, and Geriatric Delirium.” Journal of Psychosomatic Research 64 (February 2008): 219–223.

Leslie, D. L., E. R. Marcantonio, Y. Zhang, et al. “One-year Health Care Costs Associated with Delirium in the Elderly Population.” Archives of Internal Medicine 168 (January 14, 2008): 27–32.

OTHER

Alagiakrishnan, Kannayiram. “Delirium.” eMedicine, August 27, 2007 [cited February 11, 2008]. http://www.emedicine.com/med/topic3006.htm

ORGANIZATIONS

American Psychiatric Association, 1000 Wilson Blvd., Suite 1825, Arlington, VA, 22209, (703) 907-7300, apa@psych.org, http://www.psych.org/.

National Institutes of Health (NIH) Neurological Institute, PO Box 5801, Bethesda, MD, 20824, (301) 496-5751, (800) 352-9424, http://www.ninds.nih.gov/index.htm.

Rebecca J. Frey Ph.D.

Delirium

Definition

Delirium is a transient, abrupt, usually reversible syndrome characterized by a disturbance that impairs consciousness, cognition (ability to think), and perception.

Description

The word delirium is derived from the Latin delirare which literally translates "to go out of the furrow." Delirium is typically an acute change in thinking with a disturbance in consciousness. Delirium is not a disease, but a syndrome that can occur as a result of many different underlying conditions. Typically, there is a broad range of accompanying symptoms. Delirium is also called acute confusional state. Delirium is a medical emergency and affects 10–30% of hospitalized patients with medical illness. It is a widespread condition that affects more than 50% of persons in certain high-risk population. Often the condition can be reversed, but delirium is associated with increased morbidity and mortality rates.

Demographics

Patients who develop delirium during hospitalization have a mortality rate of 22–76% and a high death rate months after discharge. Approximately 80% of patients develop delirium near death, and 40% of patients in the intensive care units have symptoms of delirium. The prevalence of postoperative delirium following general surgery is 5–10%, and 42% following orthopedic surgery. Delirium is very common in nursing homes. The exact incidence of delirium in emergency departments is unknown. Delirium is present in approximately 20% of medical patients at the time of hospital admission. The prevalence in hospitalized patients is approximately 10% on a general medical service, 8–12% on a psychiatric service, 35–80% on a geriatric unit, and 40% on a neurologic service. In the elderly and postoperative patients, delirium may result in long-term disability, increased complications, and prolonged hospital stay. Geriatric patients have the highest risk for developing delirium. The incidence is higher among young children, females, and Caucasians. Medications are the most common cause of delirium in the elderly, which accounts for 22–39% of cases. Medications are the most common reversible causes of delirium. Approximately 25% of hospitalized patients with cancer and 30–40% of patients with HIV (AIDS ) infection develop delirium during hospitalizations.

Abnormal mechanisms causing delirium

There are three types of delirium based on the state of arousal. They include hyperactive delirium, hypoactive delirium, and mixed delirium. The hyperactive delirium is associated with drug intake such as alcohol withdrawal (or intoxication), amphetamine, phencyclidine (PCP), and lysergic acid diethylamide (LSD), a psychedelic compound. Hypoactive delirium is observed in patients with hypercapnia and hepatic encephalopathy . Patients who exhibit mixed delirium often exhibit nocturnal agitation, behavioral problems, and daytime sedation. The exact pathophysiological mechanisms that elicit delirium are not fully understood. Research that primarily studied subjects with alcohol withdrawal and hepatic encephalopathy indicated that delirium is caused by a reversible impairment of cerebral oxidative metabolism and multiple neurotransmitter abnormalities.

Neurotransmitter abnormality

Acetylcholine is an excitatory chemical in the central nervous system (CNS). Anticholinergic medications, which disrupt release of acetylcholine, typically cause acute confusional states (delirium). Additionally, patients with diseases such as Alzheimer's disease with impaired cholinergic transmission and decreased acetylcholine are susceptible to delirium. Patients who develop postoperative delirium have an increase in serum anticholinergic activity.

Another neurotransmitter in the brain called dopamine causes delirium if there is an excess of dopaminergic activity. Dopaminergic and cholinergic activity in the brain exhibit a reciprocal relationship (i.e., a decrease in cholinergic activity leads to delirium, while an increase in dopaminergic activity leads to delirium). Studies have demonstrated that serotonin levels are increased in patients with septic delirium and encephalopathy. Serotoninergic agents, which are medications that may have unwanted side effects, leading to impaired serotonin release, can also cause delirium. Gama-aminobutyric acid (GABA) is an inhibitory neurochemical in the central nervous system. GABA is increased in patients with hepatic encephalopathy; this is probably caused by increases in ammonia levels.

Inflammatory mechanisms

Recent research indicates that there is a role for specific chemical mediators such as interleukin-1 (IL-1) and interleukin-6 (IL-6). These chemical mediators are released from cells after a broad range of infectious and toxic insults. Head trauma and ischemia, which are frequently associated with delirium, cause brain responses that are mediated by IL-1 and IL-6. Abnormal release can cause damage to nerve cells.

Structural mechanisms

Specific objective nerve pathways in the brain that induce delirium are unknown. Neuroimaging studies in patients with traumatic brain injury (TBI), stroke , and hepatic encephalopathy indicate that certain anatomical nerve pathways may contribute to a delirious state more than others. A specific pathway called the dorsal tegmental is also involved in delirium.

Summary of causes

In general, the causes of delirium fall within 11 categories: infectious, withdrawal, acute metabolic, trauma, CNS disease, hypoxic, deficiencies, environmental, acute vascular, toxins/drugs, and heavy metals. Examples of diseases or disorders in each category include:

• infectious: sepsis (infections that spread in blood and cause infections in the brain), encephalitis, meningitis, syphilis, CNS abscess
• withdrawal: as a result of drug withdrawal from alcohol or sedatives
• acute metabolic: acidosis, electrolyte disturbance, liver and kidney failure, other metabolic disturbances (glucose, Mg++, Ca++, conditions that affect the body's regulation of acid and electrolyte balance)
• trauma: head trauma, burns (delirium can occur secondary to traumatic events or severe burns)
• CNS disease such as stroke, bleeding in the brain, or seizures
• hypoxia : as a result of hypoxia (lack of oxygen), chronic obstructive lung disease (e.g., emphysema, bronchitis), or low blood pressure
• deficiencies of vitamins, especially B-complex vitamins
• environmental: severe changes in body temperature, either a decrease (hypothermia) or an increase (hyperthermia); hormonal imbalance (diabetes and thyroid problems)
• acute vascular: conditions affecting blood vessels in the brain, such as hemorrhage or blockage of a blood vessel from a clot
• toxins/drugs: chemical toxins such as street drugs, alcohol, pesticides, industrial poisons, carbon monoxide, cyanide, and solvents
• heavy metals: exposure to certain metals such as lead or mercury Other common causes of delirium include hypoglycemia and hyperthermia.

Diagnostic criteria for delirium

The diagnosis of delirium is clinical, requiring physical examination and the analysis of symptoms because there is no single test that can successfully measure this condition. A careful history is essential to establish the diagnosis. Delirium is clinically characterized by an acutely transient alteration in mental status. Patients can have problems in orientation and short-term memory, difficulty sustaining attention, poor insight, and impaired judgment. In the hyperactive subtype of delirium, patients have an increased state of arousal, hypervigilance, and psychomotor abnormalities. Conversely, patients with the hypoactive subtype are typically withdrawn, less active, and sleepy. The mixed subtype category often presents with delirium as the primary symptom of an underlying illness. Mental status can be checked quickly and should include assessment of memory, attention, concentration, orientation, constructional tasks, spatial discrimination, writing, and arithmetic ability. Two of the most sensitive indicators for delirium are dysgraphia (impaired writing ability) and dysnomia (inability to name objects correctly).

Psychological deficit

The psychological diagnostic criteria for delirium include:

• change in cognition (i.e., disorientation, language disturbance, perceptual disturbance): this alteration cannot be accounted for by a preexisting, established, or evolving dementia
• disturbance of consciousness (i.e., reduced clarity of awareness of the environment) occurs with a reduction in ability to focus, maintain, or shift (change) attention
• the alterations develop over a short period (hours to days) and exhibit fluctuation during the day
• evidence exists from history, medical and/or laboratory findings, which indicates that the delirium is caused by a general medical condition, substance intoxication, substance withdrawal, medication use, or more than one cause (multiple etiologies)

Diagnostic instruments

There are several instruments that help establish the diagnosis of delirium. They include the Confusion Assessment Method (CAM), the Delirium Symptom Interview (DSI), and the Folstein Mini-Mental State Examination (MMSE). Delirium symptom severity can be assessed utilizing the Memorial Delirium Assessment Scale (MDAS) and the Delirium Rating Scale (DRS).

Lab studies

Glucose levels can help diagnose delirium causes by hypoglycemia or uncontrolled diabetes. A complete blood count with differential cell analysis can help to diagnose infection and anemia. Electrolyte analysis can diagnose high or low levels. Renal (kidney) and liver function test (LFTs) can diagnose liver and/or kidney failure. Other tests that can assist with identifying the underlying cause of delirium include urine analysis (urinary tract infections), urine/blood drug screen (to diagnose the presence of toxic substance), thyroid function tests (to diagnose an underfunctioning thyroid gland, a condition called hypothyroidism), and special tests to diagnose bacterial and viral causes of infection.

Neuroimaging studies such as computerized axial tomography (CAT) and magnetic resonance imaging (MRI) can be helpful to establish a diagnosis due to structural lesions or hemorrhage. Electroencephalogram (EEG), a special test that records brain activity in waves can be helpful to establish a diagnosis, especially in patients with hepatic encephalopathy (diffuse slow waves) and alcohol/sedative withdrawal (faster wave pattern).

Treatment

Clinicians must be vigilant to aggressively identify the underlying etiology of delirium, since the condition is a medical emergency. Symptomatic treatment for delirium may include the use of antipsychotic drugs. These medications help to control hallucinations, agitation, and help to improve the level of orientation and attention abilities (sensorium). Haloperidol (Haldol) is a highly researched medication and is often administered in the symptomatic management of delirium. The typical dose for patients with delirium of moderate severity is 1–2 mg twice daily and repeated every four hours as needed. Haldol can be administered orally, intravenously, or by intramuscular injection. Elderly patients should start with lower doses of Haldol, typically 0.25–1.0 mg twice daily and repeated every four hours as needed.

Environmental interventions

Treatment of delirium can be worsened by over stimulation or under stimulation in the environment. It is important to provide support and orientation to the patient. Additionally, providing the patients an environment with few distractions such as removing unnecessary objects in the room, use of clear language when talking to them, and avoidance of sensory extremes can be conducive to treatment planning.

Clinical trials

Information concerning clinical trials and research on delirium can be obtained from the National Institutes of Health (NIH). Research related to delirium is active at the Mayo Clinic Foundation, including research on Alzhiemer's disease, postoperative delirium in orthopedic surgical patients, and pharmacological treatment of Parkinson's disease .

Resources

BOOKS

Marx, John A., et al. (eds). Rosen's Emergency Medicine: Concepts and Clinical Practice, 5th ed. St. Louis: Mosby, Inc., 2002.

PERIODICALS

Chan, D., and N. Brennan. "Delirium: Making the Diagnosis, Improving the Prognosis." Geriatrics 54, no. 3 (March 1999).

Francis, J. "Three Millennia of Delirium Research: Moving Beyond Echoes of the Past." Journal of the American Geriatrics Society 47, no. 11 (1999).

Gleason, O. "Delirium." American Family Physician (March 2003).

Samuels, S., and M. M. Evers. "Delirium: Pragmatic Guidance for Managing a Common, Confounding, and Sometimes Lethal Condition." Geriatrics 57, no. 6 (June 2002).

WEBSITES

Delirium. (May 20, 2004) <http://omni.ac.uk>.

National Cancer Institute. (May 20, 2004) <http://www.cancer.gov>.

Association of Cancer Online Resources. (May 20, 2004) <http://www.acor.org>.

ORGANIZATIONS

National Institute of Neurological Disorders and Stroke (NINDS) Neurological Institute. P.O. Box 5801, Bethesda, MD 20824.

Laith Farid Gulli, MD

Nicole Mallory, MS, PA-C

Robert Ramirez, DO