Delirium and Dementia
I. Delirium
Delirium is defined by the acute onset of fluctuating cognitive impairment and a disturbance of consciousness. Delirium is a syndrome, not a disease, and it has many causes, all of which result in a similar pattern of signs and symptoms relating to the patient’s level of consciousness and cognitive impairment.
A. Epidemiology.
Delirium is a common disorder. According to text revision of the fourth edition of the Diagnostic Statistical Manual of Mental Disorders (DSM-IV-TR), the point prevalence of delirium in the general population is 0.4% for people 18 years of age and older and 1.1% for people 55 and older. Approximately 10% to 30% of medically ill patients who are hospitalized exhibit delirium. Approximately 30% of patients in surgical intensive care units and cardiac intensive care units and 40% to 50% of patients who are recovering from surgery for hip fractures have an episode of delirium. The highest rate of delirium is found in postcardiotomy patients—more than 90% in some studies. An estimated 20% of patients with severe burns and 30% to 40% of patients with acquired immunodeficiency syndrome (AIDS) have episodes of delirium while they are hospitalized.
B. Risk factors
Advanced age. A major risk factor for the development of delirium is advanced age. Approximately 30% to 40% of hospitalized patients older than age 65 years have an episode of delirium, and another 10% to 15% of elderly persons exhibit delirium on admission to the hospital.
Nursing home residents. Of residents older than age 75 years, 60% have repeated episodes of delirium.
Pre-existing brain damage. Such as dementia, cerebrovascular disease, and tumor.
Other risk factors. A history of delirium, alcohol dependence, and malnutrition.
Male gender. An independent risk factor for delirium.
C. Etiology.
The major causes of delirium are central nervous system disease (e.g., epilepsy), systemic disease (e.g., cardiac failure), and either intoxication or withdrawal from pharmacological or toxic agents. When evaluating patients with delirium, clinicians should assume that any drug that a patient has taken may be etiologically relevant to the delirium.
D. Diagnosis and clinical features.
The DSM-IV-TR gives separate diagnostic criteria for each type of delirium: (1) delirium due to a general medical condition (Table 7-1), (2) substance intoxication delirium (Table 7-2),
(3) substance withdrawal delirium (Table 7-3), (4) delirium due to multiple etiologies (Table 7-4), and (5) delirium not otherwise specified (Table 7-5) for a delirium of unknown cause or of causes not listed, such as sensory deprivation. The syndrome, however, is the same, regardless of cause.
(3) substance withdrawal delirium (Table 7-3), (4) delirium due to multiple etiologies (Table 7-4), and (5) delirium not otherwise specified (Table 7-5) for a delirium of unknown cause or of causes not listed, such as sensory deprivation. The syndrome, however, is the same, regardless of cause.
Table 7-1 DSM-IV-TR Diagnostic Criteria for Delirium Due to a General Medical Condition | ||
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The core features of delirium include
Altered consciousness. Such as decreased level of consciousness.
Altered attention. Can include diminished ability to focus, sustain, or shift attention.
Disorientation. Especially to time and space.
Decreased memory.
Rapid onset. Usually hours to days.
Brief duration. Usually days to weeks.
Fluctuations.
Sometimes worse at night (sundowning). May range from periods of lucidity to quite severe cognitive impairment and disorganization.
Disorganization of thought. Ranging from mild tangentiality to frank incoherence.
Perceptual disturbances. Such as illusions and hallucinations.
Disruption of the sleep–wake cycle. Often manifested as fragmented sleep at night, with or without daytime drowsiness.
Table 7-2 DSM-IV-TR Diagnostic Criteria for Substance Intoxication Delirium
- Disturbance of consciousness (i.e., reduced clarity of awareness of the environment) with reduced ability to focus, sustain, or shift attention.
- A change in cognition (such as memory deficit, disorientation, language disturbance) or the development of a perceptual disturbance that is not better accounted for by a pre-existing, established, or evolving dementia.
- The disturbance develops over a short period of time (usually hours to days) and tends to fluctuate during the course of the day.
- There is evidence from the history, physical examination, or laboratory findings of either (1) or (2):
- The symptoms in Criteria A and B developed during substance intoxication.
- Medication use is etiologically related to the disturbance.
- The symptoms in Criteria A and B developed during substance intoxication.
From American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Text rev. Washington, DC: American Psychiatric Association; 2000, with permission.
Table 7-3 DSM-IV-TR Diagnostic Criteria for Substance Withdrawal Delirium
- Disturbance of consciousness (i.e., reduced clarity of awareness of the environment) with reduced ability to focus, sustain, or shift attention.
- A change in cognition (such as memory deficit, disorientation, language disturbance) or the development of a perceptual disturbance that is not better accounted for by a pre-existing, established, or evolving dementia.
- The disturbance develops over a short period of time (usually hours to days) and tends to fluctuate during the course of the day.
- There is evidence from the history, physical examination, or laboratory findings that the symptoms in Criteria A and B developed during, or shortly after, a withdrawal syndrome.
Note: This diagnosis should be made instead of a diagnosis of substance withdrawal only when the cognitive symptoms are in excess of those usually associated with the withdrawal syndrome and when the symptoms are sufficiently severe to warrant independent clinical attention.
Code (Specific substance) withdrawal delirium:
(Alcohol; Sedative, hypnotic, or anxiolytic; Other [or unknown] substance)
From American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Text rev. Washington, DC: American Psychiatric Association; 2000, with permission.
Table 7-4 DSM-IV-TR Diagnostic Criteria for Delirium Due to Multiple Etiologies
- Disturbance of consciousness (i.e., reduced clarity of awareness of the environment) with reduced ability to focus, sustain, or shift attention.
- A change in cognition (such as memory deficit, disorientation, language disturbance) or the development of a perceptual disturbance that is not better accounted for by a pre-existing, established, or evolving dementia.
- The disturbance develops over a short period of time (usually hours to days) and tends to fluctuate during the course of the day.
- There is evidence from the history, physical examination, or laboratory findings that the delirium has more than one etiology (e.g., more than one etiological general medical condition, a general medical condition plus substance intoxication or medication side effect).
Coding note: Use multiple codes reflecting specific delirium and specific etiologies, e.g., Delirium due to viral encephalitis; Alcohol withdrawal delirium.
From American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Text rev. Washington, DC: American Psychiatric Association; 2000, with permission.
Table 7-5 DSM-IV-TR Diagnostic Criteria for Delirium Not Otherwise Specified
This category should be used to diagnose a delirium that does not meet criteria for any of the specific types of delirium described in this section.
Examples include
- A clinical presentation of delirium that is suspected to be due to a general medical condition or substance use but for which there is insufficient evidence to establish a specific etiology.
- Delirium due to causes not listed in this section (e.g., sensory deprivation).
From American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Text rev. Washington, DC: American Psychiatric Association; 2000, with permission.
- Disturbance of consciousness (i.e., reduced clarity of awareness of the environment) with reduced ability to focus, sustain, or shift attention.
Mood alterations. From subtle irritability to obvious dysphoria, anxiety, or even euphoria.
Altered neurological function. For example, autonomic hyperactivity or instability, myoclonic jerking, and dysarthria.
E. Physical and laboratory examinations.
Delirium is usually diagnosed at the bedside and is characterized by the sudden onset of symptoms. The physical examination often reveals clues to the cause of the delirium. The presence of a known physical illness or a history of head trauma or alcohol or other substance dependence increases the likelihood of the diagnosis.
The laboratory workup of a patient with delirium should include standard tests and additional studies indicated by the clinical situation. In delirium, the EEG characteristically shows a generalized slowing of activity and may be useful in differentiating delirium from depression or psychosis. The EEG of a delirious patient sometimes shows focal areas of hyperactivity.
F. Differential diagnosis
Delirium versus dementia. The developmental time of delirium symptoms is usually short, and, except for vascular dementia caused by stroke, it is usually gradual and insidious in dementia. A patient with dementia is usually alert; a patient with delirium has episodes of decreased consciousness. Occasionally, delirium occurs in a patient with dementia, a condition known as beclouded dementia. A dual diagnosis of delirium can be made when there is a definite history of pre-existing dementia. See Table 7-6.
Delirium versus schizophrenia or depression. The hallucinations and delusions of patients with schizophrenia are more constant and better
organized than those of patients with delirium. Patients with hypoactive symptoms of delirium may appear somewhat similar to severely depressed patients, but they can be distinguished on the basis of an EEG.
Table 7-6 Clinical Differentiation of Delirium and Dementiaa
Delirium
Dementia
History
Acute disease
Chronic disease
Onset
Rapid
Insidious (usually)
Duration
Days to weeks
Months to years
Course
Fluctuating
Chronically progressive
Level of consciousness
Fluctuating
Normal
Orientation
Impaired, at least periodically
Intact initially
Affect
Anxious, irritable
Labile but not usually anxious
Thinking
Often disordered
Decreased amount
Memory
Recent memory markedly impaired
Both recent and remote impaired
Perception
Hallucinations common (especially visual)
Hallucinations less common (except sundowning)
Psychomotor function
Retarded, agitated, or mixed
Normal
Sleep
Disrupted sleep–wake cycle
Less disruption of sleep–wake cycle
Attention and awareness
Prominently impaired
Less impaired
Reversibility
Often reversible
Majority not reversible
aDemented patients are more susceptible to delirium, and delirium superimposed on dementia is common.
Dissociative disorders. May show spotty amnesia but lack the global cognitive impairment and abnormal psychomotor and sleep patterns of delirium.
G. Course and prognosis.
The symptoms of delirium usually persist as long as the causally relevant factors are present, although delirium generally lasts less than a week. After identification and removal of the causative factors, the symptoms of delirium usually recede over a 3- to 7-day period, although some symptoms may take up to 2 weeks to resolve completely. Recall of what occurred during a delirium, once it is over, is characteristically spotty. The occurrence of delirium is associated with a high mortality rate in the ensuing year, primarily because of the serious nature of the associated medical conditions that lead to delirium. Periods of delirium are sometimes followed by depression or posttraumatic stress disorder (PTSD).
H. Treatment.
The primary goal is to treat the underlying cause. When the underlying condition is anticholinergic toxicity, the use of physostigmine salicylate (Antilirium), 1 to 2 mg intravenously or intramuscularly, with repeated doses in 15 to 30 minutes may be indicated. Physical support is necessary so that delirious patients do not get into situations in which they may have accidents. Patients with delirium should be neither sensory deprived nor overly stimulated by the environment. Delirium can sometimes occur in older patients wearing eye patches after cataract surgery (“black-patch delirium”). Such patients can be helped by placing pinholes in the patches to let in some stimuli or by occasionally removing one patch at a time during recovery.
Pharmacotherapy. The two major symptoms of delirium that may require pharmacological treatment are psychosis and insomnia. A commonly used drug for psychosis is haloperidol (Haldol), a butyrophenone antipsychotic drug. The initial dose may range from 2 to 6 mg intramuscularly, repeated in an hour if the patient remains agitated. The effective total daily dose of haloperidol may range from 5 to 40 mg for most patients with delirium. Phenothiazines should be avoided in delirious patients because these drugs are associated with significant anticholinergic activity.
Use of second-generation antipsychotics, such as risperidone (Risperdal), clozapine (Clozaril), olanzapine (Zyprexa), quetiapine (Seroquel), ziprasidone (Geodon), and aripiprazole (Abilify), may be considered for delirium management, but clinical trial experience with these agents for delirium is limited. Insomnia is best treated with benzodiazepines with short or intermediate half-lives (e.g., lorazepam [Ativan] 1 to 2 mg at bedtime). Benzodiazepines with long half-lives and barbiturates should be avoided unless they are being used as part of the treatment for the underlying disorder (e.g., alcohol withdrawal).
II. Dementia
Dementia is defined as a progressive impairment of cognitive functions occurring in clear consciousness (e.g., in the absence of delirium). Global impairment of intellect is the essential feature, manifested as difficulty with memory, attention, thinking, and comprehension. Other mental functions can often be affected, including mood, personality, judgment, and social behavior.
A. Epidemiology.
The prevalence of dementia is rising. The prevalence of moderate to severe dementia in different population groups is approximately 5% in the general population older than 65 years of age, 20% to 40% in the general population older than 85 years of age, 15% to 20% in outpatient general medical practices, and 50% in chronic care facilities. Of all patients with dementia, 50% to 60% have the most common type of dementia, dementia of the Alzheimer’s type (Alzheimer’s disease). The second most common type of dementia is vascular dementia, which is causally related to cerebrovascular diseases. Other common causes of dementia, each representing 1% to 5% of all cases, include head trauma, alcohol-related dementias, and various movement disorder–related dementias, such as Huntington’s disease and Parkinson’s disease.
B. Etiology.
The most common causes of dementia in individuals older than 65 years of age are (1) Alzheimer’s disease, (2) vascular dementia, and (3) mixed vascular and Alzheimer’s dementia. Other illnesses that account for approximately 10% include Lewy body dementia; Pick’s disease; frontotemporal dementias; normal pressure hydrocephalus (NPH); alcoholic dementia; infectious dementia, such as that due to infection with human immunodeficiency virus (HIV) or syphilis; and Parkinson’s disease (Table 7-7).
C. Diagnosis, signs, and symptoms.
The major defects in dementia involve orientation, memory, perception, intellectual functioning, and reasoning. Marked changes in personality, affect, and behavior can occur. Dementias are commonly accompanied by hallucinations (20% to 30% of patients) and delusions (30% to 40%). Symptoms of depression and anxiety are present in 40% to 50% of patients with dementia. Dementia is diagnosed according to etiology (Table 7-8).
D. Laboratory tests.
First, identify a potentially reversible cause for the dementia, and then identify other treatable medical conditions that may otherwise worsen the dementia (cognitive decline is often precipitated by other medical illness). The workup should include vital signs, complete blood cell count with differential sedimentation rate (ESR), complete blood chemistries, serum B12 and folate levels, liver and renal function tests, thyroid function tests, urinalysis, urine toxicology, ECG, chest roentgenography, computed tomography (CT) or magnetic resonance imaging (MRI) of the head, and lumbar puncture. Single photon emission computed tomography (SPECT) can be used to detect patterns of brain metabolism in certain types of dementia. See Table 7-9.
Table 7-7 Causes of Dementia | |
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