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Because delirium can arise from many sources, there is no uniform
presentation. Very often there is a prodrome of irritability, restlessness,
sleep disturbance (insomnia and daytime sleeping), and some difficulty
in thinking.
This may go on for 1 or 2 days before the development of overt behavioral
disturbances. Fluctuations in functional ability, often with relative lucid
intervals, are common early in the course. Some variability in the degree
of cognitive dysfunction may continue throughout the illness.
syndrome. Failure to recognize and manage delirium can lead to longer
hospital stays and increased morbidity and mortality, especially among the
REVIEW SUMMARY- This article reviews definitions and diagnosis. The
Diagnostic and Statistical Manual of Mental Disorders, 4th edition, and the
International Statistical Classification of Diseases and Related Health Problems,
10th edition, criteria are quite similar in their diagnostic criteria. Risk factors
include advanced age, preexisting brain disease or cognitive impairment,
can be more subtle and recovery more prolonged.
Diagnosis is more complex if there is already an underlying dementia. An
organized approach should be used to discover etiology and in ordering
appropriate laboratory studies. At the cellular level, delirium is considered
a selective vulnerability of certain populations of neurons and neurotransmitter
dysfunction. Practical treatment Issues are reviewed.
CONCLUSIONS- Despite advances, delirium is usually still diagnosed at
the bedside. Having an organized approach to diagnosis and understanding
the underlying pathophysiology should help with overall evaluation and treatment.
metabolic encephalopathy
The Neurologist 2001 November;7(6):327-340 Psychiatric Disorders Symposium: Delirium
Delirium Quick recognition, careful evaluation, and appropriate treatment
David A. Casey, MD; John V. DeFazio Jr, MD; Kaycia Vansickle, MD;
Steven B. Lippmann, MD VOL 100 /
This is the fourth of four articles on psychiatric disorders Preview : Delirium
should be suspected when a patient rather suddenly shows evidence of
intermittent confusion, perceptual changes, short-term memory loss, and
sleep disturbance.
Clinical features Delirium typically develops over hours to days and is provoked by certain
medical illnesses, metabolic derangements, intoxications, or withdrawal
states (3) (table 1). A prodromal period of subtle confusion, irritability, or
psychomotor behavioral change may precede the advent of the full
syndrome. Common causes of delirium
Exogenous exposures
Prescription drugs, including but not limited to psychotropic medications, narcotics, antiparkinson agents, anticholinergics, anesthetics, and cardiovascular medications Over-the-counter medicines Illegal substances Other pharmaceuticals Poisoning Drug withdrawal Alcohol Sedatives Systemic disorders Metabolic Infectious Nutritional deficiencies Cardiopulmonary Endocrine Neoplastic Central nervous system diseases Cerebrovascular Infectious Traumatic Neoplastic Confusion, intermittent clouding of sensorium or consciousness, and
alterations in perception commonly occur, as do psychotic symptoms
such as paranoia. Marked disturbances of the sleep cycle contribute to
"sundowning," in which patients become more confused, agitated,
or psychotic at night.
Autonomic changes such as tachycardia and hypertension can also occur,
particularly in the hyperactive form of delirium. Patients with this form
often have increased irritability and startle responses and may be acutely
sensitive to light and sound.
In addition, the delirious patient may experience profound shifts in mood
and use rambling, illogical language while still having lucid intervals of
relatively normal mental functioning. Although short-term memory may be
disturbed, long-term memory is typically preserved.
The syndrome usually runs a course of several days. However, the duration
of illness is largely controlled by the course of the underlying condition that
provoked the delirious episode. Predisposing factors
Delirium occurs more commonly among patients with certain predisposing
features (4). Old age is probably the most important of these, although
very young children are also at increased risk. Preexisting neurologic
conditions (eg, dementia, Parkinson's disease, cerebrovascular disease)
and medical conditions such as pneumonia, urinary tract infection, congestive
heart failure, and myocardial infarction can cause delirium, especially in
the frail elderly.
Nutritional deficiencies (eg, low levels of thiamine or cyanocobalamin) may
play a permissive role. Frail patients who have multisystem disease or who
take multiple medications are at increased risk for delirium. Drug or alcohol
abusers also are at increased risk, as are persons who have had a previous
delirious episode.
The setting in which a patient receives care may also play a role. Delirium
often develops in patients with severe illnesses who are in an intensive care
unit, with its high noise levels and lack of a normal day-night cycle.
Patients with delirium sometimes manifest psychotic symptoms such as
delusions or hallucinations, which can lead to the syndrome's being mistaken
for other psychiatric illnesses (eg, schizophrenia). However, psychotic
disorders such as schizophrenia typically do not include severely disordered
orientation or memory and daily fluctuation of symptoms. Schizophrenic
delusional systems are often sustained and elaborate, with hallucinations
that are most commonly auditory.
In contrast, the delusions of delirious patients tend to be fleeting and
poorly systematized, and their hallucinations are usually visual and sometimes
olfactory or tactile. Delirious patients are also subject to illusions, which are
sensory distortions or misperceptions (eg, when a cane is taken to be a snake). Evaluation
A high index of suspicion is required when evaluating changes in
mental status among patients at risk for delirium, particularly
medically ill elders who are in hospitals or nursing homes. The
hyperactive, agitated form of delirium is likely to be recognized
because of the obvious problems in managing patients' behavior.
Patients with withdrawal from alcohol or sedative-hypnotics usually
manifest this form of delirium, which is accompanied by prominent
autonomic disturbances with hyperadrenergic signs.
The diagnosis of delirium may easily be missed, however, particularly
if patients manifest the quiet, or hypoactive, form. In such situations,
it may be family members who draw attention to subtle alterations in
a patient's mental status.
Assessment of the delirious patient includes several crucial components
(6) (table 3). The first step is evaluation of the underlying medical illness,
along with any other predisposing factors, such as poor nutrition,
substance abuse, or overmedication.
In the majority of cases, delirium is caused by an illness outside the
central nervous system. Assessment includes thorough history taking
and physical examination.
Laboratory tests including complete blood cell count, urinalysis, and
blood chemistry profile are indicated. In most cases a chest radiograph
should be obtained to rule out pneumonia or other pulmonary processes.
Thyroid profile, electrocardiogram, toxic drug screening, vitamin B12 levels,
and magnesium concentrations may also be useful. Treatment
Prompt treatment of the underlying medical condition is
essential, along with correction of any remediable pre-
disposing factors and elimination of all drugs that might
cause delirium. Symptoms usually remit following resolution
of the underlying cause.
Supportive measures designed to calm, reassure, and protect
the patient are also important. It is helpful to "normalize" the
environment by having family members present and placing a
clock, a calendar, and familiar objects in the room.
Alterations in activity schedules and lighting can help restore
a normal sleep cycle. The main room lights should be dimmed
at night, but a night-light should be left on so the patient can
reorient if he or she awakes in darkness. Daytime exposure to
natural lighting through a window may also be helpful (7).
Supportive therapy should aim to calm anxiety or agitation and
ensure protection from harm for the patient and others. The
patient may be at risk because of suicidal ideation, confusion, or
psychosis, so it is helpful for the physician to exhibit a calm,
reassuring manner. Use of physical restraints may occasionally
be necessary for the patient's protection. However, this may
further agitate some patients. Restraints should be used only
when less intrusive measures have been inadequate.
Psychotropic medications are prescribed if necessary to treat
significant anxiety, agitation, or psychosis (8). The most useful
medications for anxious or agitated patients are short-acting
benzodiazepines, such as lorazepam (Ativan) and oxazepam
(Serax). High-potency antipsychotic agents such as haloperidol
(Haldol), which can be administered orally, intramuscularly, or
intravenously, can be given to patients with psychotic symptoms.
With all of these agents, doses must be individualized, but a
small amount of medication often suffices. The need for such
drugs usually abates when the delirium resolves.
Pharmaceuticals with a high degree of anticholinergic effect,
such as chlorpromazine hydrochloride (Ormazine, Thorazine),
may exacerbate confusion and should be avoided. Patients with
preexisting psychiatric disorders (eg, schizophrenia) sometimes
present special treatment challenges and may require psychiatric
consultation.
Treatment of patients whose delirium stems from alcohol or
sedative-hypnotic withdrawal merits special consideration (9).
Mild withdrawal states are generally self-limiting, requiring only
supportive care for the patient. Multivitamins, thiamine hydrochloride
(Biamine), and magnesium are often useful.
However, when patients have irritability and autonomic signs
along with confusion and perceptual distortions, more aggressive
treatment is required, usually therapy with a cross-tolerant sedative
-hypnotic and supportive measures. Benzodiazepines are appropriate
in most cases, but views about the best choice of pharmacotherapy
differ. Once a choice is made, dosage is adjusted to provide
coverage for withdrawal symptoms, then gradually decreased.
The exact withdrawal schedule depends on the particular clinical
situation, including the patient's degree of dependence and overa
medical and psychological state.
Although withdrawal over a few days is appropriate for many patients,
others require prolonged tapering to prevent the reemergence of
significant withdrawal symptoms. Severe alcohol or sedative-hypnotic
withdrawal can be complicated by life-threatening fever, autonomic
dysregulation, and seizures, which require aggressive management.
Fortunately, the great majority of patients experience mild syndromes. Sequelae
Traditionally, delirium has been viewed as a transient condition
that fully resolves when the precipitating problem is alleviated.
However, recent reports challenge this view (10). Some patients
experience serious sequelae after a delirious episode.
Long-term effects may include a decline in functional abilities
(activities of daily living) as well as persistent cognitive deficits,
particularly in elderly patients. In addition, the long-term mortality
rate after an episode of delirium is elevated (10).
The explanations for these observed effects are not clear. In some
situations, the delirium may unmask an evolving, previously un-
recognized dementia. In other cases, vulnerability to delirium may
be a marker for a compromised biological system. Although the
explanations may be uncertain, it is important for physicians to be
aware that severe or prolonged delirious episodes may induce
long-term negative effects on mental functioning (10). Summary
Delirium is a common medical condition, especially in elderly
hospitalized patients. The syndrome is characterized by a short
course of confusion and changes in perception and behavior.
Early detection can be enhanced by routine assessment of
cognitive functioning in hospitalized patients, especially those
at risk for delirium.
Prompt recognition and aggressive treatment of the underlying
cause are essential for a positive outcome. Supportive measures
are designed to calm and protect the patient and provide
symptomatic relief until the precipitating condition is corrected.
Also see this article Postgraduate Medicine: The many faces of confusion (apathy)
URL: http://www.postgradmed.com/issues/1996/07_96/casey2.htm Recognition of a patient's state of confusion is only the beginning of a clinical odyssey that can implicate a huge spectrum of diagnostic
possibilities. Among these are delirium, depression, dementia, and
sensory deprivation. However, with appropriate physical examination
and laboratory studies, collateral history, and clarification of time
course for the symptom complex, the cause of confusion need not
remain confusing.
Internet Mental Health (www.mentalhealth.com)Diagnostic Criteria
Associated Features
Mental Status Examination
Treatment
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