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CHAPTER 13: MEMORY AND THINKING: DEMENTIA, DELIRIUM, AND AMNESIA

Overview

Classifying Dementias

Dementia Management

Delirium (Sudden Confusion)

Amnesia


Overview

Memory problems, or dementia, represent an acquired loss of intellectual ability that occurs over a long period of time and affects many areas of cognitive functioning. Problems in thinking and memory may be caused by a variety of diseases, including Alzheimer's disease, Pick's disease, and vascular causes. Although memory loss is one feature of dementing illness, it is usually accompanied by an impairment in at least one of the following areas: language; recognizing spatial relationships; other areas of thinking (such as calculating numbers or abstract thinking); executive functions such as making lists or planning; or a change in personality. The degree of intellectual loss is generally severe enough to interfere with social and occupational functioning. Dementia is differentiated from sudden memory problems by its long time course. While sudden states of confusion (called delirium) progress in hours to days, dementia progresses over months to years. In addition, dementia does not usually affect the person's level of consciousness, but sudden confusion generally does. Other features that distinguish dementing illness from acute confusional states are listed in Table 11.

Epidemiology

Dementia affects less than 10 percent of people who are older than 65, but increases to approximately 15 to 20 percent for people at the age of 85. A much higher prevalence of Alzheimer's disease may occur in older age groups.

Table 11. Clinical Characteristics of Dementia Compared with Delirium

CHARACTERISTIC DEMENTIA DELIRIUM
History
      Onset Insidious Sudden
      Duration Months to years Hours to days
Motor Signs None (until late) Muscle shakes or tremors
      Speech Normal Slurred
Mental Status
      Attention Normal Fluctuating, inattention, easily distracted
      Memory Impaired recent memory Impaired by poor attention
      Language Difficulty finding the right word Normal; misnaming may be prominent; writing difficulty often prominent
      Perception Abnormalities not prominent Visual, auditory, and/or tactile hallucinations may be clear
      Mood/effect Apathetic and/or loss of impulse control Fear and suspiciousness may often be prominent
      Other systems No involvement of other organ systems Systemic illness (fever, chills, weight loss, poor appetite) or toxic exposure may be present
Source: Cummings JL, Benson DF. Dementia: A Clinical Approach. Boston: Butterworth; 1983:13. Reprinted with permission.

Evaluation

If you are having problems with memory or other cognitive abilities, you should have an interview and complete physical examination by a physician trained in geriatric medicine. Memory assessments can also be performed by neurologists, psychiatrists, or primary care physicians with appropriate training. By paying close attention to memory, language, visual and spatial function, and additional skills, the physician can usually tell if you have a dementing illness and define the type of dementia and whether any other neurologic abnormalities are present.

    Formal, detailed neuropsychological testing that involves such activities as interpreting stories, drawing objects, remembering words, and so on may be helpful in some circumstances. Such testing is especially useful for those people who, despite a history of functional decline, have very mild dementing illnesses or who have such a high intelligence that the extent of their dementing illness remains unclear on examination. Further testing can also be helpful in establishing a reference point for people with uncertain diagnoses and in determining if depression is a contributing factor to any cognitive or functional decline.

    The diagnostic use of neuroimaging studies that show the brain structures such as computed tomography (CT) scans or magnetic resonance imaging (MRI) remains controversial. The vast majority of these examinations do not identify potentially treatable lesions; however, they may detect characteristic patterns of atrophy, in some of the less common dementias. For example, both Huntington's and Pick's diseases can be identified by the location of atrophy in the brain. (These conditions are discussed later in this chapter.) Imaging studies may also detect structural abnormalities such as tumors, strokes, hydrocephalus, subdural hematomas (bleeding beneath the membrane tissue covering the skull), and other conditions. Imaging studies are not necessarily needed for people who begin to show signs of dementia. When dementia results from one of these structural abnormalities, it may be partially reversible. Other potentially reversible causes of dementia are sometimes detectable through a complete blood count and a routine set of blood tests. These include tests of kidney and liver function, thyroid function, vitamin B12 and folic acid levels, and a test for syphilis. Sometimes an electroencephalogram (EEG) can be helpful. Its use is restricted to situations where there is a high suspicion of a condition that produces EEG abnormalities, such as Pick's disease or Creutzfeldt-Jakob disease. In general, the usefulness of examining the spinal fluid in the evaluation of dementia is limited and a spinal tap is only recommended in certain circumstances: when dementia begins in a relatively young person; when the disease progresses very rapidly; in people who have a positive blood test for syphilis; for very unusual symptoms; for signs and symptoms of meningitis; or other underlying diseases that may involve the nervous system.

Table 12. Causes of Dementing Illness

CAUSE EXAMPLES
Degenerative Alzheimer's disease
Pick's disease
Depression Depression
Infectious AIDS
Neurosyphilis
Metabolic Thyroid disease
Vitamin B12 deficiency
Toxins Alcohol
Heavy metal exposure
Drugs
Vascular Multiple strokes
Others Trauma (head injuries)
Cancer
Subdural hematoma

Classifying Dementias

Dementing illnesses are usually categorized according to their suspected cause as degenerative, vascular, infectious, toxic, or metabolic. There are also a variety of miscellaneous conditions (see Table 12). Autopsy series suggest that about 50 percent of all cases of dementia are due to Alzheimer's disease, the predominant degenerative dementia. Between 10 and 15 percent are due to vascular causes such as small strokes, and an additional 10 to 20 percent to a combination of Alzheimer's disease and multiple small strokes. A smaller percentage of dementias is due to alcoholism, trauma, brain tumors, and miscellaneous causes. There is now an increased awareness and recognition of the AIDS-dementia complex.

Alzheimer's Disease

Over two million Americans have Alzheimer's disease, a type of dementing illness named after the German physician who first described its pathologic features.

    With Alzheimer's disease, nerve loss is usually seen in a number of important brain regions. In particular, there appears to be a marked reduction in those structures that use acetylcholine as their primary neurotransmitter (neurotransmitters enable nerve cells to communicate with each other).

Causes of Alzheimer's Disease. Increasing age and a history of the illness in other family members are risk factors for the development of Alzheimer's disease. Women are more prone to develop the disease, and proposed risk factors that have not been proven include prior head trauma, age of mother at time of delivery, and the aluminum and other trace metal content in drinking water. Various subtypes of Alzheimer's disease have been proposed based on age of onset, family history, the presence of shaking or movement disorders, and particular neuropsychological profiles.

    One of the two characteristics of Alzheimer's disease on microscopic examination of the brain at autopsy is the presence of dying nerves called neuritic plaques. At the core of these nerves are amyloid deposits. Amyloid is a poorly soluble material (resembling silk) that is sometimes deposited in blood vessels. A specific type of protein appears to be the primary building block of amyloid, and deposits of this protein have recently been found in people with Alzheimer's disease and Down syndrome. These deposits may be seen in parts of the brain that are not associated with the neuritic plaques and are thought to represent an earlier change in brain structure in people who have Alzheimer's disease. The other characteristic feature of Alzheimer's disease seen under the microscope are neurofibrillary tangles, which are thought to contain abnormal microtubular proteins. Normally these microtubules are used as scaffolding within the cells, providing structure. Despite these hallmarks, however, both neuritic plaques and neurofibrillary tangles are found in the brains of many elderly people who had no evidence of Alzheimer's disease.

    Considerable interest has been focused recently on the genetics of Alzheimer's disease. It seems that there is a variety of Alzheimer's disease that is primarily familial (genetic). At present, the prevalence of the disease and the lack of complete family medical histories make it difficult to distinguish between genetic and nongenetic cases. Extensive research is under way to determine the causes of the entity we call Alzheimer's disease and whether it is actually one or several diseases.

Symptoms of Alzheimer's Disease. People with Alzheimer's disease usually show a subtle and progressive worsening of their memory; in contrast to people with other forms of dementia or age-associated memory impairment, they respond very poorly to cues (or "reminders"). Language difficulties are also a consistent feature of Alzheimer's disease. Early in the course of Alzheimer's disease, affected individuals may have difficulty finding the right word. This can later progress to more severe difficulties in understanding language and in speaking. The content of language in Alzheimer's disease is sometimes characterized as empty or impoverished; it carries very little meaning. While the ability to repeat words is relatively well preserved, naming and comprehension abilities are impaired as the disease progresses.

    People with Alzheimer's disease may have difficulty in recognizing objects, drawing simple designs, and locating objects. A common complaint of caregivers is that the demented person gets lost, even in the immediate neighborhood. Executive functions such as the ability to organize and plan and to think abstractly are frequently impaired. These disabilities usually interfere with the capacity to make appropriate social and occupational judgments.

    Behavioral and psychiatric symptoms are also common features of Alzheimer's disease. These include wandering, aggressive behaviors, visual hallucinations, and delusions. These delusions may often involve concern that others are stealing objects from them or being unreasonably suspicious of other people's intentions. Misidentification of familiar people or locations may also occur, and irritability and anxiety may develop as well as features of depression. Despite these significant deteriorations in cognitive function, the ability to perform physical activity is remarkably preserved until late in the course of the disease. Very late in the illness some people develop stiffness in their arms and legs.

Table 13. Criteria for Clinical Diagnosis of Alzheimer's Disease

1.

 

 

 

 

 

 

 

 

 

 


2.

 

 

 

 

 

 

 

 

 

3.

The criteria for the clinical diagnosis of probable Alzheimer's disease include:

dementia established by clinical examination and documented by the Mini-Mental State Examination, Blessed Dementia Scale, or some similar examination, and confirmed by neuropsychologic tests;

deficits in two or more areas of cognition;

progressive worsening of memory and other cognitive functions;

no disturbance of consciousness;

onset between ages 40 and 90, most often after age 65; and

absence of systemic disorders or other brain diseases that in and of themselves could account for the progressive deficits in memory and cognition.

The diagnosis of probable Alzheimer's disease is supported by:

progressive deterioration of specific cognitive functions such as language (aphasia), motor skills (apraxia), and perception (agnosia);

impaired activities of daily living and altered patterns of behavior;

family history of similar disorders, particularly if confirmed neuropathologically; and

laboratory results of normal lumbar puncture as evaluated by standard techniques, normal pattern or nonspecific changes in EEG such as increased slow-wave activity, and evidence of cerebral atrophy on CT with progression documented by serial observation.

Other clinical features consistent with the diagnosis of probable Alzheimer's disease, after exclusion of causes of dementia other than Alzheimer's disease, include:

plateaus in the course of progression of the illness;

associated symptoms of depression, insomnia, incontinence, delusions, illusions, hallucinations, catastrophic verbal, emotional, or physical outbursts, sexual disorders, and weight loss;

other neurologic abnormalities in some patients, especially with more advanced disease and including

 

 

 


4.

 

 

 

 

 

5.

 

 

 

 

 

 

 


6.

 

 


7.

motor signs such as increased muscle tone, myoclonus, or gait disorder;

seizures in advanced disease; and

CT normal for age.

Features that make the diagnosis of probable Alzheimer's disease uncertain or unlikely include:

sudden, apoplectic onset;

focal neurologic findings such as hemiparesis, sensory loss, visual field deficits, and incoordination early in the course of the illness; and

seizures or gait disturbances at the onset or very early in the course of the illness.

Clinical diagnosis of possible Alzheimer's disease:

may be made on the basis of the dementia syndrome, in the absence of other neurologic, psychiatric, or systemic disorders sufficient to cause dementia, and in the presence of variations in the onset, in the presentation, or in the clinical course;

may be made in the presence of a second systemic or brain disorder sufficient to produce dementia, which is not considered to be the cause of the dementia; and

should be used in research studies when a single, gradually progressive, severe cognitive deficit is identified in the absence of other identifiable cause.

Criteria for diagnosis of definite Alzheimer's disease are:

the clinical criteria for probable Alzheimer's disease and histopathologic evidence obtained from a biopsy or autopsy.

Classification of Alzheimer's disease for research purposes should specify features that may differentiate subtypes of the disorder, such as:

familial occurrence;

onset before age of 65;

presence of trisomy 21; and

coexistence of other relevant conditions such as Parkinson's disease.

EEG, electroencephalogram; CT, computed tomography.
Source: Stadlan EM. Clinical diagnosis of Alzheimer's disease. In: McKhann G, Drachman D, Folstein M, et al, eds. Report of the NINCDS-ADRDA Work Group under the auspices of Department of Health and Human Services Task Force on Alzheimer's disease. Neurology. 1984;34:940. Reprinted with permission.

    Generally, people with Alzheimer's disease have little insight into their own disabilities and as the disease progresses, they may require increasing help with very basic daily activities. Even with the marked individual variation in the rate of disease progression, most people experience severe disability within 8 to 12 years of onset. The severity of the dementia is strongly related to survival. Wandering, falling, urinary incontinence, and behavioral problems such as suspiciousness or paranoia, agitation, and hallucinations are also associated with a poor outlook.

Evaluation of Alzheimer's Disease. The diagnosis of Alzheimer's disease is based on a complete evaluation by a very skilled interviewer and diagnostician. The clinical criteria for Alzheimer's disease are shown in Table 13. If established by these criteria, the diagnosis of probable Alzheimer's disease has an 85 to 95 percent correlation with autopsy studies (which are the only way to make a diagnosis with certainty). Nonetheless, the differentiation of Alzheimer's disease from other dementing illnesses is usually difficult.

Treatment of Alzheimer's Disease. There is presently no cure for Alzheimer's disease. Useful management approaches are given later in this section.

Pick's Disease

Pick's disease, named after the 19th-century neurologist Arnold Pick, is a rare disease that usually afflicts people who are between the ages of 40 and 60, although it can occur in a person as old as 80 or as young as 21.

Cause of Pick's Disease. The cause of Pick's disease is unknown, although about 20 percent of affected individuals have a family history of it. Pick's disease and Alzheimer's disease may initially appear to be similar, but the brain degeneration is different in these two dementing illnesses. Localized atrophy of particular sections of the brain, especially the frontal and temporal lobes, is characteristic. In addition, when brain tissue is examined under the microscope at autopsy, there are two abnormalities that are unique to Pick's disease: "balloon cells," which are swollen nerve cells, and "inclusion bodies." Other degenerative changes in the brain include loss of nerve networks and atrophy of the areas involved with language, memory storage, and thought processing.

Symptoms of Pick's Disease. The first symptoms of Pick's disease are personality changes, emotional disturbances, impaired judgment and insight, and socially inappropriate behavior. Speech disturbances are common. People sometimes have a cluster of three symptoms called the Kluver-Bucy syndrome: blunted emotional responses including lack of fear, inappropriate sexual behavior, and unusual oral behavior, such as putting objects into their mouths. Curiously, people tend to retain their memory function and the ability to calculate numbers until the disease is advanced.

    Pick's disease often progresses rapidly and as the disease progresses, loss of memory and speech difficulties increase; ultimately, the person eventually becomes mute. Death usually occurs from between 2 and 15 years after symptoms begin.

Treatment for Pick's Disease. There is no known cure for Pick's disease, although some of the behavior abnormalities do respond to selectively appropriate treatment as outlined in the management section.

Dementias Caused by Vascular Disease

The precise definition of dementia caused by blood vessel diseases is not well established even though vascular disease is the second most common cause of dementia after Alzheimer's disease. Cognitive ability is damaged, it appears, by multiple small strokes that decrease blood supply to various parts of the brain. In vascular dementia there is sometimes a sudden onset of difficulty followed by abrupt deterioration of function. The location of the vascular damage is an important factor in whether or not stroke patients develop dementia; dementing illness is most likely when a blood vessel at the back of the brain is damaged.

    Cortical multi-infarct dementia refers to a syndrome of multiple small strokes caused by vascular disease or the migration of blood clots arising in the large feeding arteries to the brain. A person with this condition may have several neurological difficulties that, depending on their location, may include loss of the use of one-half of the body, sensory loss, speaking difficulties, difficulty organizing things, difficulty naming objects, and other specific difficulties.

    Multi-infarct dementias of deeper brain structures are caused by lack of blood flow in medium to small vessels. These blood vessel problems form little holes in the brain, called lacunae (from the Latin, meaning "pit" or "gap"), that are most often found deep in the brain. People with this situation have difficulty swallowing, difficulty speaking, fluctuating emotions, slow movements, urinary incontinence, and a small-step gait.

Dementias Caused by Infections

While much less common than Alzheimer's or vascular disease, infections can also be the cause of dementing illness. One infectious disease called Creutzfeldt-Jakob disease (named for two German psychiatrists) is a rare disorder occurring in about one in one million demented individuals. The infection is thought to be due to a very slow growing virus, which, unlike other viruses, does not provoke an inflammatory response from the body. This virus is resistant to conventional treatments. As a result of these differences from true viruses, physicians hypothesize that the cause is really an infectious protein particle called a prion.

    The onset of Creutzfeldt-Jakob disease usually occurs in people aged 50 to 70 and is marked initially by subtle changes in behavior such as fatigue, difficulty concentrating, and depression. Eventually, multiple cognitive difficulties develop. Muscle jerks are common, and the person may develop difficulty with coordination. This illness proceeds rapidly to a state where the person cannot move. The final stages are characterized by seizures.

    In a significant percentage of the patients with AIDS, the human immunodeficiency virus (HIV) may infect the brain directly and cause a slowly progressive dementia. Most people affected in this way are forgetful and demonstrate inattention and slowing of their thought processes. They may appear to be withdrawn, apathetic, or depressed, and psychiatric symptoms may be present. Within the brain, the white matter below the brain surface and basal ganglia are the structures most severely affected. Cognitive dysfunction in people with the HIV virus can also be due to additional infections with a number of other organisms.

Reversible Dementias

Of all people with dementing illness, about 5 to 10 percent may have partially reversible dementia and 3 percent have totally reversible dementia. Drug toxicity heads the list of partially and completely reversible causes of dementia. (Adverse drug reactions are discussed in Chapter 9.)

Alcohol-Associated Dementias. A chronic dementia can also be associated with alcoholism. People with alcohol problems experience acute confusion and memory disorders. This dementia usually occurs after more than ten years of alcohol abuse. Difficulty with the memory alone and not in other areas suggests this disorder. Cognitive problems may vary but nonverbal skills are usually more affected than verbal skills.

Depression. Sometimes called pseudodementia, depression that is associated with intellectual decline is a potentially reversible cause of dementing illness in older people. Forgetfulness, slowness to respond, poor attention, and disorientation are common characteristics, as are a depressed mood and feelings of worthlessness or guilt. A clinical evaluation characteristically reveals no language difficulties, word-finding difficulties, or poor coordination. Usually there is an overall slowing down of movement, although some people may have restlessness and agitation. Clues to depression usually include sleep disturbances, problems with appetite, and a lowered sexual drive.

    It is important to recognize that depression and dementia may exist together and that some people who initially respond to antidepressant medication may subsequently develop the symptoms of an irreversible dementia. (Depression is covered more extensively in Chapter 15.)

Thyroid Disease. Both overactive and underactive thyroid glands can cause dementia. The neurologic signs of an overactive thyroid gland include tremors, muscle weakness, seizures, and eye problems. A dementia caused by thyroid disease is usually characterized by anxiety, restlessness, irritability, and poor attention and memory; there may also be depression, apathy, and other psychiatric symptoms. Hypothyroidism, or an underactive thyroid, may result in muscle weakness, clumsiness, and seizures. Mental difficulties include lack of attention, lethargy, and impaired ability to think abstractly. With appropriate treatment to restore the thyroid hormone level to normal, the changes in mental function caused by both overactive and underactive thyroid conditions may improve, sometimes dramatically.

Vitamin B12 Deficiency. The neurologic signs of vitamin B12 deficiency include dementia, atrophy of the nerves in the eye, and changes in the nerves in the arms and legs. The dementia is characterized by slowness, apathy, irritability, and confusion. The mental status changes may fluctuate, and agitation and depression may also be present. Within the brain, there is degeneration and a swelling of the lining around the nerves. Treatment with intramuscular vitamin B12, if started early, can reverse the changes in the nervous system and can stop the progression of dementia in long-standing cases.

Normal-Pressure Hydrocephalus. Normal-pressure hydrocepalus is the condition caused by an increased fluid pressure inside the brain causing a gait disturbance, dementia, and urinary incontinence. The problem seems to be due to difficulty in reabsorbing spinal fluid generated by past trauma or inflammations at the base of the brain. Stiffness of the legs and difficulty in starting to walk contribute to the gait disturbance. The gait problem has been described as a "magnetic gait." The person seems to have feet that are stuck to the floor as if wearing magnetic shoes on a metal floor. There is also difficulty in standing straight, and falls are frequent. The degree of mental change ranges from minor inattention, decreased spontaneity, and generalized slowing, to more significant memory disturbances, apathy, withdrawal, and poor judgment. Brain imaging shows very large fluid spaces in the brain without shrinkage of the tissue. Treatment consists of placement of a neurosurgical shunt, a catheter or tube that goes from the brain to the abdomen to help divert the accumulation of spinal fluid. Drainage of spinal fluid through this tube sometimes improves the cognitive problems.

Neurosyphilis. Neurosyphilis occurs about 15 years after the primary infection with syphilis. Prior to the introduction of penicillin, this accounted for 15 to 30 percent of admissions to mental institutions. Psychiatric features of neurosyphilis are common and include grandiose delusions, a hyperactive state, depression, and hallucinations. In addition, there are many cognitive defects including disorders of memory, attention, language, and organizing and sequencing tasks. There is brain shrinkage, especially in the frontal and temporal areas. At autopsy, the lining of the brain looks thick and dulled. Although it is a rare disorder today, cases of neurosyphilis are increasing particularly in people who also have the AIDS virus.

Dementias Caused by Poisons. In addition to alcohol, a number of other toxic substances may cause cognitive dysfunction especially with exposure over long periods of time. Examples include arsenic and heavy metals such as lead, thallium, manganese, and mercury. A number of industrial solvents and insecticides have also been found to cause dementia.

Dementia Management

When a dementing illness has a potentially reversible cause, treatment of the underlying disease is undertaken to attempt to halt progression of the illness and possibly reverse the decline of mental function. It is also important to review carefully any medications that may contribute to mental dysfunctions. If possible, visual and hearing difficulties should be corrected since sensory difficulties can contribute to cognitive problems. Early in the illness, memory-helping techniques such as note taking can be useful. Speech and physical therapy can help.

    Caregivers concerned with management of people suffering dementia should keep in mind that people do better with ongoing sensory and social stimulation tailored to their skills and that regularity of daily routines provides security for most people with dementia. Stimulants in the evening such as coffee are not recommended since they can produce or aggravate sleep disturbances. Additional helpful strategies include simplifying the environment, removing clutter, and providing better lighting. Sessions where people can reminisce about any life events they still remember can emphasize cognitive abilities and help maintain self-esteem.

    Because people with Alzheimer's disease have complex mental dysfunction and because they have a high rate of motor vehicle accidents, they should not be allowed to drive under any circumstances. The general principle is to preserve a person's autonomy as much as possible without compromising anyone's safety.

    There is currently no treatment that consistently improves memory in people with Alzheimer's disease. While a number of compounds have been studied, there is no evidence that any of them has a lasting effect. The drug tacrine, which increases the concentration of one of the brain's neurotransmitters, may set back the clock of cognitive decline by six months in some people with Alzheimer's disease, but decline is at the same rate. The drug is very expensive and causes substantial liver toxicity, requiring frequent blood tests.

    In Alzheimer's disease and other dementing illnesses, caregivers need to consider the best methods for managing the patient's mood and behavior. Characteristically, Alzheimer's victims suffer from depression, anxiety, hallucinations, or aggressive behavior. They can wander and get lost and become very agitated at night. The first challenge for caregivers is to identify which, if any, of these problems is significant enough to warrant intervention. Then it is important to develop a treatment plan for each specific problem while realizing that other difficulties may not improve. One helpful way to think about these problems is to determine how aware the person is of his surroundings and the consequences of his actions; the capacity for controlling impulses; the amount of arousal exhibited; and the outlets for self-expression. Categorizing the difficulties in this way can lead to creative solutions.

    Another principle of treatment is for caregivers to learn about behavior patterns that can be anticipated and environmental modifications that might be beneficial. For example, it may become important to take the knobs off of the stove to prevent cooking accidents or to lock doors to prevent wandering and getting lost. In addition, caregivers should look out for and, if possible, reduce any factors that might aggravate or produce a behavior problem, such as stress in the household or medical problems in addition to Alzheimer's disease. In some cases, drug treatment may be necessary to modify discomforting or difficult behavior. Because individuals suffering from dementia may not be able to verbalize the side effects they are experiencing, caregivers should obtain information about possible adverse drug effects (pharmacists are an excellent source) and should be on the alert for their manifestations.

    Wandering, a common complication that affects up to one-half of people with severe dementia, can have one or more causes. A demented person may get lost, especially if she has recently moved to an unfamiliar location. Agitation, depression, hallucinations, boredom, the need for more frequent toileting, or pain can also cause the demented individual to wander, and sometimes no specific cause for wandering is evident. Regular exercise is often helpful. Provide the person with an armband or a nonremovable identification bracelet so she can be promptly identified and returned if she becomes lost. Drug treatments and physical restraints do not cure wandering and usually increase agitation and irritability, but in very rare circumstances they may be necessary to maintain a person's safety.

    The psychiatric complications of dementia, such as paranoid or accusatory beliefs, delusions, and hallucinations, need not be treated if they are mild. If, however, these conditions are disruptive to the person or cause very agitated, aggressive, or hostile behavior, medication may be necessary. Aggressive behavior can take many forms and range from cursing and spitting to direct physical attack. Maintaining composure, using distraction, and modifying the environment all can be helpful. For example, soothing music can sometimes help to relieve stress. In addition, spending more time completing a potentially disruptive task, such as bathing, may help reduce this sort of behavior.

    Confusion or agitation that occurs in the early evening or night is referred to as "sundowning." Dementia clearly predisposes a person to sundowning but the extent of this problem is unknown. The primary management involves establishing soothing environmental conditions such as a quiet room with reduced (but not absent) sensory input--lighting, music, television. Special cues such as talking quietly to the agitated person can be helpful. Although it is occasionally necessary to administer sedative medications, it is important to appreciate that such medications also have the potential to increase a person's confusion.

    In caring for a person with a dementing illness, a caregiver undergoes a tremendous amount of stress and is vulnerable to depression, drug and alcohol abuse, and stress-related problems. These consequences appear to be more closely related to the characteristics of the caregivers, such as their level of morale, health, and coping mechanisms, than they are to the cognitive or functional status of the older people for whom they are caring. It is important for caregivers to know about the patient's illness and its likely course, the type of therapy that may be required, and any difficulties in function and behavior that may be encountered because it helps caregivers not to place unrealistic demands upon the demented person. Education and informed and effective assistance improve the quality of care and help reduce caregiver stress and burnout. The Alzheimer's Association, with chapters throughout the United States, is a useful source of information and support groups.

    Finally, in caring for people with dementia it is important for families and other caregivers to know of all of the available community services that might provide assistance, including caregivers' relief opportunities. Obviously, all decisions regarding management can become very difficult, especially those regarding possible placement in nursing homes. It is also important to discuss the issues of power of attorney, guardianship, and end-of-life issues, such as advanced directives for treatment options and life-sustaining measures (see Chapter 11 for a more detailed discussion) and, if feasible, information about arrangements for an autopsy. An examination of the brain after death may be important to help understand the cause of the dementing illness and to provide useful information for family members.

Delirium (Sudden Confusion)

A sudden change in mental function, or acute confusion, is the most common complication of hospitalization in older people. In the past, this condition was known by a variety of names including sundowning, toxic psychosis, and metabolic encephalopathy. The preferred medical term is delirium. Table 14 lists the medical criteria for the diagnosis of delirium.

What Causes Delirium?

Delirium is often caused by changes in the chemical transmitter between nerves--acetylcholine. Relatively small reductions of oxygen or glucose in the brain can significantly reduce the amount of acetylcholine made in the brain. Medications that block acetylcholine can produce delirium. People who have Alzheimer's disease can experience delirium in addition to dementias and appear to lose the cells in the brain that make acetylcholine.

Table 14. Clinical Criteria for Delirium

A. Reduced ability to maintain attention to external stimuli and to appropriately shift attention to new external stimuli
B. Disorganized thinking, as indicated by rambling, irrelevant, or incoherent speech
C. At least two of the following:
1. Reduced level of consciousness
2. Perceptual disturbances: misinterpretations, illusions, or hallucinations
3. Disturbance of sleep-wake cycle, with insomnia or daytime sleepiness
4. Increased or decreased psychomotor activity
5. Disorientation of time, place, or person
6. Memory impairment
D. Development of clinical features over a short period of time; tendency for them to fluctuate over the course of a day
E. Either (1) or (2):
1. Evidence from the history, physical examination, or laboratory tests of a specific organic factor (or factors) judged to cause the disturbance
2. In the absence of such evidence, a causative factor can be presumed if the disturbance cannot be accounted for by any other mental disorder
   Source: American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 3d ed (rev). Washington, D.C.: American Psychiatric Association, 1987. Reprinted with permission.

    While an interruption of these nerve signals via acetylcholine cannot explain all episodes of delirium, it is important to remember this chemical transmitter because a number of medications can affect its functioning. For example, medications given to nearly 60 percent of nursing home residents and about 25 percent of people living in the community are potentially capable of blocking at least some acetylcholine transmission.

    Other substances, such as cortisol, endorphins, and small proteins have also been considered as potential causes of delirium. Information concerning these substances and their relation to delirium is very limited.

Conditions That Produce Delirium

Virtually any medical condition is a potential cause of delirium. For example, delirium may be the initial presentation of a serious life-threatening illness such as a heart attack. Often there is more than one potential cause identified in a given person with delirium. The most common causes in people who are in the hospital include problems in body chemistry, drug toxicities, infections, low blood pressure, and reduced oxygen in the blood (hypoxemia). In only a small number of people is delirium due to a sudden change in the nervous system such as a stroke, brain tumor, or an infection in the nervous system.

    Delirium can also result from sensory deprivation. In one study, delirium after an operation occurred twice as often in intensive care units without windows as compared with those with windows. In addition, a form of delirium that occurs at night (sundowning) may, in part, be due to sensory deprivation. Problems with vision and hearing may make it more likely for the person to misperceive stimuli and increase their susceptibility to delusions or hallucinations.

    Drugs are a leading cause of delirium in the hospital. Common drugs causing this condition include narcotics (and other pain relievers), sedatives, corticosteroids, and drugs that affect acetylcholine in the brain.

    Alcohol abuse is frequently overlooked as a cause of delirium in older people. Delirium can be produced by either intoxication or an abrupt withdrawal from alcohol. Alcohol-withdrawal delirium appears to be as common in elderly people with alcoholism as in their younger counterparts. Alcohol withdrawal has an increased mortality rate in elderly people, about 25 percent in one study. Another underappreciated cause of delirium is withdrawal from sedatives.

Delirium After Surgery

Delirium after an operation is one of the most frequent conditions seen in the surgical setting, and it can be mistaken for depression. This postoperative delirium in older people leads to longer hospital stays, a higher death rate, and a greater need for nursing home care after discharge. The type of operation determines the risk for delirium. Five to 15 percent of people have delirium after cataract surgery, and over 50 percent of older people who undergo hip surgery will have delirium. Trends in surgical practice also affect one's chances of having delirium. For example, a decrease in the rates of delirium after heart surgery has been attributed to shorter time spent on the heart bypass machine and improved monitoring during surgery.

    If a person has dementing illness or depression before surgery, they are at higher risk for postoperative onset of delirium. Delirium may be the initial observable manifestation of a number of medical complications that can arise after surgery, such as infection, heart difficulties, or drug toxicities.

Symptoms of Delirium

A diagnosis of delirium is based on careful observation, awareness of changes in the person's usual mental state, and knowledge of the current physical problems. An attempt at conversation with the person reveals wandering attention, poor ability to follow directions, and easy distraction. The content of the person's speech itself may reflect disorganized thoughts and problems with perception. The person may appear restless and move a lot, and the level of consciousness may change frequently. Various disturbances may occur at night. Sometimes the muscles jerk and twitch and there can be a flapping movement of the hands, called asterixis, which is known to occur only in delirium. While asterixis is characteristic of delirium, it is a relatively uncommon occurrence.

    The person's difficulty in thinking may not be obvious to a casual observer, and sometimes physicians ask a series of simple standardized questions to try to evaluate mental function. The use of standardized questions makes it possible to monitor subsequent progress, to a certain extent. However, these verbal tests do not identify the key symptoms of the delirium, which usually include a lack of attention, a rapid onset, and a fluctuating course. Sometimes more sophisticated testing is recommended in order to determine and monitor these features.

    The electroencephalogram (EEG) observes brain waves through electrodes placed on the scalp. It is a useful test if delirium is suspected because test results are always abnormal in this disorder. The reason for the delirium cannot always be determined from the EEG, but if the EEG is normal, then the person does not have delirium.

Differentiating Delirium from Look-alike Conditions

Delirium can be mistaken for dementing illness or for psychiatric diseases such as schizophrenia. While much less common than delirium, certain forms of epilepsy can also closely resemble delirium.

    Generally, psychiatric conditions occur in early adult life before the age of 40. Any sudden and acute change in a person's behavior after that age should initially be considered as delirium until examination or testing proves otherwise.

    Other features that may help separate psychiatric diseases from delirium are the character of any hallucinations the person may have. Psychotic patients typically hallucinate that they are hearing voices or sounds. People with delirium usually experience visual hallucinations. In addition, the physical characteristics that are typical of delirium, such as the hand flapping, asterixis, EEG changes, and the evidence of an acute medical illness, are generally absent in psychiatric disorders.

    Like delirium, dementing illness may produce memory and thinking problems. One key difference is that dementia has a much longer onset and generally fluctuates over a period of weeks to months. In addition, demented individuals generally remain aware of their environment until very late in the illness.

    The two conditions can occur together, however, and delirium occurs more frequently in demented than in nondemented individuals. Up to half of demented people manifest evidence of delirium during a hospitalization for medical illness. Whenever there is a sudden deterioration in behavior or thinking in a demented person, particularly when the person is hospitalized, the cause is likely to be delirium. Sudden confusion may be due to epilepsy rather than delirium. Most of the time, when this is the case, the person is known to have a seizure disorder but in the case of some older people, sudden and acute confusion may be the initial manifestation of epilepsy.

Treatment of Delirium

Delirium is a true medical emergency and immediate medical evaluation and treatment should be obtained. The cornerstones of medical management include prompt recognition of the condition, identifying the specific cause, managing any agitation or disruptive behavior, and providing general supportive care. Because delirium can be caused by so many different things, no simple strategy for this evaluation can be given here.

    Generally, the physician looks for any underlying conditions. Unless they are absolutely necessary, all drugs are generally stopped and specific laboratory tests are ordered to check for any underlying conditions.

    People with delirium may have brain abnormalities that will show up on brain-imaging studies such as computed tomography or magnetic resonance imaging. However, the imaging frequently uncovers a preexisting condition that may have predisposed the person to delirium. A comprehensive medical evaluation is still needed to identify any precipitating illness, which is usually apart from the nervous system.

    At times, people with delirium can be so agitated or disruptive that their behaviors must be controlled promptly to prevent them from harming themselves or others. Regretfully, there is no ideal solution to this problem.

    Because sedatives do not reverse the underlying abnormalities that cause delirium, they are never to be used in people who are drowsy or not easily aroused. Furthermore, these drugs can bring on delirium. Because of this, they are usually only given for short periods of time, and their use is limited only to those people whose agitation seriously interferes with their care.

    Supportive care for people with delirium includes careful attention to medical, environmental, and social situations. Medical complications include disorders of body chemistry, aspiration, malnutrition, pressure ulcers, joint stiffness, and any other conditions that might result from immobility and a reduced state of consciousness. Management of the environment involves continually helping the person feel oriented, avoiding unnecessary moves from one room or space to another, and leaving on dim lights at night to decrease delusions or hallucinations. Eyeglasses or hearing aids can help to diminish sensory isolation. Family members, close friends, or even paid assistants can participate as sitters to reduce the fear and anxiety that accompanies delirium. Professionals in social work and nursing are often quite skillful in helping the person with delirium. Decisions about nursing home care should be made cautiously because the person's hospital behavior may not accurately reflect the capacity to function in a stable, familiar environment. In addition, the delirium may be slow in resolving.

    There is no evidence that using physical restraints on people with delirium is effective in reducing falls or other accidents. Furthermore, restraints increase immobility and thus the risk of contracting pneumonia, developing pressure ulcers, and even accidental strangling. Unfortunately, the harsh realities of personnel shortages in the hospital or in nursing homes (especially at night) and concerns about institutional liability in the event that residents injure themselves often make the use of physical restraints seem appealing.

    Finally, treatment may be complicated by medical and legal issues. The use of restraints and strong medications constitutes a common form of involuntary treatment of an agitated person. Furthermore, civil commitment procedures are generally followed in the involuntary treatment of behaviorally disturbed people; they are not considered necessary or appropriate in treating people with delirium.

The Outlook for People with Delirium

Approximately 25 percent of people aged 70 or more who are admitted to a general medical hospital have delirium. For most of these people delirium was one of the symptoms of their medical illness. The risk of delirium is influenced by a number of factors and increases in people who are demented, dehydrated, taking drugs known to affect the nervous system, or who are judged to be severely ill by their doctor. In these older people, the delirium is not typically characterized by disruptive features (the person may be quiet and withdrawn) and may be missed by doctors or else mistaken for dementing illness.

    Delirium is an underappreciated source of disability and death. Death rates are significantly higher; the relative risks for death are from 2 to 20 times greater for people with delirium than for those without it. The short-term death rate appears to be higher because of the presence of significant underlying medical problems; the longer-term death rate probably reflects the underlying frailty that predisposes a person to delirium.

Amnesia

Amnesia is a relatively rare memory disorder in older people that is characterized by the inability to learn or recall any new information, even though there is normal attention, memory for past events, and generally good intellectual function.

Causes of Amnesia

All conditions that produce amnesia share a common underlying change in the brain: a disorder located in deep brain structures. In most cases, the abnormalities must be on both sides of the brain to produce a permanent amnesia. The most common causes of amnesia include the Wernicke-Korsakoff syndrome (named for the 19th-century German professor Carl Wernicke and for Sergiei Korsakoff, a Russian neurologist), rare forms of stroke, head trauma, brain infections with the herpes virus, a period of very low blood sugar, brain tumors, and prolonged cardiac arrest that impairs blood supply to the brain. The Wernicke-Korsakoff syndrome results from thiamine depletion and is most commonly observed in patients with alcoholism. It can occur in other settings, especially with other causes of chronic nutritional depletion.

Symptoms of Amnesia

People with amnesia fail to learn dates and locations and are sometimes disoriented as to time and space. They cannot learn word lists for later recall. The amnesia may extend back from a few minutes to at most a few years from the onset of the memory disturbance. It is interesting that people generally do not lose their identity or forget their names. A complete loss of personal identity, such as the complete amnesiac portrayed in the movies, almost never occurs and usually indicates the presence of a severe psychiatric condition. People with amnesia do not benefit from cues to help them remember such as multiple-choice lists. Making up farfetched stories is common in the sudden onset periods of amnesic disorders. People with this condition can supply sensible and often seemingly autobiographical but totally inaccurate information in response to questions that they cannot answer accurately.

Treatment of Amnesia

Although there is no specific therapy for amnesia, most amnesic individuals experience some degree of spontaneous recovery. Those who recover completely are never able to remember that period during which no learning occurred. Those who make a partial recovery may experience some ongoing degree of difficulty in learning. The severity of brain damage is reflected in the length of the amnesic interval of which the person remembers nothing. This may serve as a useful guide to the likelihood of recovery of function.




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