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 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

Delirium

Definition

Delirium is a state of mental confusion that develops quickly and usually fluctuates in intensity.

Description

Delirium is a syndrome, or group of symptoms, caused by a disturbance in the normal functioning of the brain. The delirious patient has a reduced awareness of and responsiveness to the environment, which may be manifested as disorientation, incoherence, and memory disturbance. Delirium is often marked by hallucinations, delusions, and a dream-like state.

Delirium affects at least one in 10 hospitalized patients, and is a common part of many terminal illnesses. Delirium is more common in the elderly than in the general population. While it is not a specific disease itself, patients with delirium usually fare worse than those with the same illness who do not have delirium.

Causes and symptoms

Causes

There are a large number of possible causes of delirium. Metabolic disorders are the single most common cause, accounting for 20-40% of all cases. This type of delirium, termed "metabolic encephalopathy," may result from organ failure, including liver or kidney failure. Other metabolic causes include diabetes mellitus, hyperthyroidism and hypothyroidism, vitamin deficiencies, and imbalances of fluids and electrolytes in the blood. Severe dehydration can also cause delirium.

Drug intoxication ("intoxication confusional state") is responsible for up to 20% of delirium cases, either from side effects, overdose, or deliberate ingestion of a mind-altering substance. Medicinal drugs with delirium as a possible side effect or result of overdose include:

• anticholinergics, including atropine, scopolamine, chlorpromazine (an antipsychotic), and diphenhydramine (an antihistamine)
• sedatives, including barbiturates, benzodiazepines, and ethanol (drinking alcohol)
• antidepressant drugs
• anticonvulsant drugs
• nonsteroidal anti-inflammatory drugs (NSAIDs), including ibuprofen and acetaminophen
• corticosteroids, including prednisone
• anticancer drugs, including methotrexate and procarbazine
• lithium
• cimetidine
• antibiotics
• L-dopa

Delirium may result from ingestion of legal or illegal psychoactive drugs, including:

• ethanol (drinking alcohol)
• marijuana
• LSD (lysergic acid diethylamide ) and other hallucinogens
• amphetamines
• cocaine
• opiates, including heroin and morphine
• PCP (phencyclidine)
• inhalants

Drug withdrawal may also cause delirium. Delirium tremens, or "DTs," may occur during alcohol withdrawal after prolonged or intense consumption. Withdrawal symptoms are also possible from many of the psychoactive prescription drugs.

Poisons may cause delirium ("toxic encephalopathy"), including:

• solvents, such as gasoline, kerosene, turpentine, benzene, and alcohols
• carbon monoxide
• refrigerants (Freon)
• heavy metals, such as lead, mercury, and arsenic
• insecticides, such as Parathion and Sevin
• mushrooms, such as Amanita species
• plants such as jimsonweed (Datura stramonium ) and morning glory (Ipomoea spp.)
• animal venoms

Other causes of delirium include:

• infection
• fever
• head trauma
• epilepsy
• brain hemorrhage or infarction
• brain tumor
• low blood oxygen (hypoxemia)
• high blood carbon dioxide (hypercapnia)
• post-surgical complication

Symptoms

The symptoms of delirium come on quickly, in hours or days, in contrast to those of dementia, which develop much more slowly. Delirium symptoms typically fluctuate through the day, with periods of relative calm and lucidity alternating with periods of florid delirium. The hallmark of delirium is a fluctuating level of consciousness. Symptoms may include:

• decreased awareness of the environment
• confusion or disorientation, especially of time
• memory impairment, especially of recent events

• hallucinations
• illusions and misinterpreted stimuli
• increased or decreased activity level
• mood disturbance, possibly including anxiety, euphoria or depression
• language or speech impairment

Diagnosis

Delirium is diagnosed through the medical history and recognition of symptoms during mental status examination. The most important part of diagnosis is determining the cause of the delirium. Tests may include blood and urine analysis for levels of drugs, fluids, electrolytes, and blood gases, and to test for infection; lumbar puncture ("spinal tap") to test for central nervous system infection; x ray, computed tomography scans (CT), or magnetic resonance imaging (MRI) scans to look for tumors, hemorrhage, or other brain abnormality; thyroid tests; electroencephalography (EEG); electrocardiography (ECG); and possibly others as dictated by the likely cause.

Treatment

Treatment of delirium begins with recognizing and treating the underlying cause. Delirium itself is managed by reducing disturbing stimuli, or providing soothing ones; use of simple, clear language in communication; and reassurance, especially from family members. Physical restraints may be needed if the patient is a danger to himself or others, or if he insists on removing necessary medical equipment such as intravenous lines or monitors. Sedatives or antipsychotic drugs may be used to reduce anxiety, hallucinations, and delusions.

Prognosis

Persons with delirium usually have a worse prognosis for the underlying disease than the person without delirium. Nonetheless, those without terminal illness usually recover from delirium. They may not, however, regain all their original cognitive abilities, and may be left with some permanent impairments, including fatigue, irritability, difficulty concentrating, or mood changes.

Prevention

Prevention of delirium is focused on treating or avoiding its underlying causes. The most preventable forms are those induced by drugs. Strategies for reducing delirium include following prescriptions, consulting the prescribing physician immediately if symptoms occur, and consulting the physician before discontinuing the drug, even if it has been ineffective; avoiding intoxication with legal or illegal drugs, and seeking professional assistance before suddenly discontinuing an addictive drug such as alcohol or heroin; maintaining good nutrition, which promotes general health and can minimize the likelihood of delirium from alcohol intoxication and withdrawal; and avoiding exposure to solvents, insecticides, heavy metals, or biological poisons in the home or workplace.

Resources

BOOKS

Guze, Samuel, editor. Adult Psychiatry. Mosby Year Book, 1997.

KEY TERMS

Dementia— A loss of mental ability severe enough to interfere with functioning. While dementia and delirium have some of the same symptoms, dementia has a much slower onset.

Electroencephalogram (EEG)— A chart of the brain wave patterns picked up by electrodes placed on the scalp. This is useful for diagnosing central nervous system disorders.

Encephalopathy— A brain dysfunction or disorder.

delirium is a widely-used diagnostic category used to denote a confused and excited state. It has been recognized ever since antiquity. Plato stated that there were four kinds of delirium; that of the prophets sent by Apollo, that of the ‘initiated’ sent by Dionysus, that of the poets due to the Muses, and that of lovers caused by Aphrodite and Eros.

The core symptoms are disturbances of consciousness accompanied by a change in cognition. The disturbance develops over a period of hours or days, and tends to fluctuate. A patient may be coherent and co-operative in the morning but at night insist on leaving hospital and going home to long-dead parents. Maniacal excitement often sets in, sometimes accompanied by violence. Other physical manifestations include muscular tremors and sweats.

The disturbance in consciousness is marked by a muddled awareness. Attention is impaired, and a delirious person is difficult to engage in conversation and easily distracted by irrelevant stimuli. There is an accompanying change in cognition — memory impairment, disorientation, or language disturbance — and sometimes the emergence of perceptual disturbance, usually manifested in disorientation with respect to time or place. In some cases, speech is rambling or incoherent. Language disturbance may be evident, as in dysnomia (impaired ability to name objects) or dysgraphia (reduced ability to write). Perceptual disturbances are common. A banging door may be mistaken for a gunshot (misinterpretation); bedclothes may turn into terrifying animals (illusion); or the person may ‘see’ enemies when no one is actually there (hallucination).

The debates over delirium as a diagnostic label concern its relationship to mental disease and, hence, more broadly, to the mind-body problem. Until the nineteenth century, disorientation with memory loss, and loss of the sense of time and place, was routinely considered a sign of mental disease. Since then, it has become accepted that many types of mental disorder occur without delirium (manie sans délire in the formulation developed by Pinel and Esquirol in France). There has, by consequence, been a growing tendency to stress the organic aetiology of delirium.

In modern medical thinking it is axiomatic that delirium is primarily an organic condition. From the patient's history, physical examination, or laboratory tests it will be apparent whether it arises as a physiological consequence of some medical condition (e.g. fever), or through injury to the head, or through substance intoxication or withdrawal, or through use of a medication (for instance, bromides or barbiturates), or by exposure to poison.

Substance-induced delirium has achieved considerable prominence nowadays. This includes the diagnosis of delirium tremens — a state of confusion, agitation, and tremulousness, associated with alcohol or its withdrawal, first identified as a separate clinical entity in 1813 by Thomas Sutton, who coined the term. Alcoholic delirium is a product not merely of excessive alcohol consumption but of accompanying exhaustion, lack of food, and dehydration. The patient has usually been deteriorating physically because of vomiting and restlessness. Vitamin B deficiency is also implicated.

Roy Porter

Bibliography

Berrios, G. E. (1996). The history of mental symptoms: descriptive psychopathology since the nineteenth century. Cambridge University Press.

Delirium

A mental condition characterized by disorientation, confusion, uncontrolled imagination, reduced ability to focus or to maintain attention, and general inability to correctly comprehend immediate reality; often accompanied by illusions, delusions, and hallucinations.

Delirious behavior ranges from mildly inappropriate to maniacal, and is a symptom of a number of disorders. Delirium has been classified into several varieties, based primarily on causal factors. As an example, alcohol-withdrawal delirium, which is also called delirium tremens or D.T.s (because of the characteristic tremor), is an acute delirium related to physical deterioration and the abrupt lowering of blood alcohol levels upon cessation of alcohol intake after a period of abuse.

Delirium is believed to be caused by a chemical imbalance in the brain , which, in turn, may be caused by fever, drugs, head injury, disease, malnutrition, or other factors. The onset of delirium is usually fairly rapid, although the condition sometimes develops slowly, especially if a metabolic disorder is involved. Typically, delirium disappears soon after the underlying cause is successfully treated. Occasionally, however, recovery from delirium is limited by neurological or other damage.

de·lir·i·um / diˈli(ə)rēəm/ • n. an acutely disturbed state of mind that occurs in fever, intoxication, and other disorders and is characterized by restlessness, illusions, and incoherence of thought and speech. ∎  wild excitement or ecstasy. ORIGIN: mid 16th cent.: from Latin, from delirare ‘deviate, be deranged’ (literally ‘deviate from the furrow’), from de- ‘away’ + lira ‘ridge between furrows.’

delirium (di-li-ri-ŭm) n. an acute disorder of the mental processes accompanying organic brain disease. It may be manifested by delusions, disorientation, hallucinations, or extreme excitement and occurs in metabolic disorders, intoxication, deficiency diseases, and infections. d. tremens an acute confusional state often seen as a withdrawal syndrome in chronic alcoholics and caused by sudden cessation of drinking alcohol. Features include anxiety, tremor, sweating, and vivid hallucinations.

delirium State of confusion in which a person becomes agitated and incoherent and loses touch with reality; often associated with delusions or hallucinations. It may be seen in various disorders, brain disease, fever, and drug or alcohol intoxication.

delirium XVI. — L. dēlīrium, f. dēlīrāre deviate from a straight line, be deranged, f. DE- 2 + līra ridge between furrows.
Hence delirious XVIII.

Delirium

of debutantes: an excited company of girls who are coming out into Society—Lipton, 1970.

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