US Pharm.
2007;32(9):20-25.
Dementia can devastate the
lives of patients and their families. While it is not a specific disease,
dementia is a chronic and usually irreversible deterioration of cognition.
1 It is often difficult for families and caregivers to grasp the global
nature of this condition. With the loss of intellectual capacity, activities
of daily living and social and occupational functions are no longer carried
out with ease or reliability, if at all. A patient's impaired communicative
ability poses misunderstandings, misinterpretations, frustration, and
embarrassment for family members and caregivers. Affecting four to five
million individuals in the United States, dementia strikes approximately 5% of
individuals age 65 to 74 and 40% of those older than 85.2
Diagnosis and Differential
Diagnosis
The diagnosis of
dementia is clinical and based on the development of multiple cognitive
deficits manifested by bothmemory impairment (an impaired ability to recall
learned information or learn new information) and at least one of the
following: aphasia (language disturbance), apraxia (impaired ability to
perform motor activities despite intact motor function), agnosia (inability to
recognize or identify objects despite intact sensory function), or a
disturbance in executive functioning (planning, organizing, initiating,
sequencing, or abstracting).3 The loss of executive
ability renders the individual unable to think abstractly and function through
volitional activities.3,4 Distinguishing the causes and type of
dementia (TABLE 1) is difficult since a definitive diagnosis usually
requires a pathological examination of brain tissue at autopsy. Other
conditions have been identified as potential causes of dementia or
dementia-like symptoms. These include metabolic problems (e.g.,
hypercalcemia), endocrine abnormalities (e.g., hypothyroidism), some
structural brain disorders (e.g., normal pressure hydrocephalus, subdural
hematoma), nutritional deficiencies (e.g., vitamin B12, folic
acid), infections (e.g., HIV, Lyme disease, syphilis), poisoning (e.g., lead),
brain tumors, anoxia or hypoxia, and cardiac and pulmonary problems.1-3,5
Adverse reactions to medications, such as anticholinergic agents,
antihistamines, and sedative hypnotics, can cause confusion and cognitive
impairment, mimicking dementia, and may even cause acute delirium, requiring
immediate medical attention. The deterioration of cognition associated with
these situations may resolve with appropriate treatment and/or the removal of
the offending agent.1
The most common differential
diagnoses in the assessment of dementia are delirium and depression.2
Acute delirium may indicate a medication-induced condition or the development
of an acute medical condition, such as those outlined above. Delirium is a
common and usually reversible syndrome which may be precipitated by almost any
organ system–related acute illness or may be an exacerbation of an existing
chronic illness; drugs are the most common reversible cause of delirium.
6-8 Although difficult, it is crucial to distinguish between delirium
and dementia since delirium is usually reversible when treatment is prompt.
1 Assessment of attention is recommended as inattention likely indicates
delirium.1 A thorough history, physical examination, and
testing (e.g., complete blood count, thyroid-stimulating hormone, vitamin B
12, CT, or MRI) would determine other features suggesting delirium.
1,2
Depression can present
comorbidly with dementia but can also occur separately and precipitate
significant cognitive changes. The depressed elderly may be irritable, have a
decrease or loss of interest in activities, and experience weight gain or loss
and daily insomnia or hypersomnia.2 When a major life change
occurs in a senior female patient, such as a recent stroke or myocardial
infarction, screening for depression should be considered.2 Women
of advanced age are more likely to suffer from depression than their male
counterparts, even though their risk of suicide is lower.9,10 This
holds true regardless of economic status, ethnicity, or race.2
Furthermore, because complaints of pain are common in elderly patients with
depression, and since depression is common in those with pain, pain can signal
depression that might be otherwise overlooked in this population.11
Normal Aging and Cognitive
Functioning
Clearly, there are variations in
aging, and while dementia is common in very elderly individuals, dementia is
not part of the normal aging process. The cognitive effects of normal aging
encompass both preserved and declining cognitive functions. For example, in
normal aging, under the cognitive domain of memory, preserved functions would
include remote memory, procedural memory, and semantic memory, while learning
and recall of new information would show decline.12 Dementia
would be distinguishable from age-associated memory impairment, which presents
as deficient recall relative to a senior's previous youthful ability; this
decline is not progressive, nor does it affect daily function.1 In
fact, changes in memory may be the most common cognitive complaint
self-reported by seniors.
Mild Cognitive Impairment
When there is
cognitive impairment in an aging individual that does not meet the diagnostic
criteria for dementia and is not attributable to a medical condition, it is
often referred to as mild cognitive impairment(MCI).12
MCI involves a subjective memory complaint, and while there is memory
impairment (as compared with that of age-matched controls) other cognitive
domains (e.g., reasoning, judgment, writing) and daily function are not
impaired.1 While knowledge about factors that predict the
development of MCI is limited, it is often a precursor to Alzheimer's disease
(AD).13 While longitudinal research has suggested that 80% of
individuals with MCI will progress to develop AD within five to eight years,
other authors note that up to 50% of patients with MCI develop dementia within
three years.1,12
A recent study found that
among community-dwelling older persons without manifest cognitive impairment,
difficulty in identifying odors predicts subsequent development of MCI.13
A longitudinal cohort study examined motor function in persons with
MCI and its relation to risk of AD.14 At baseline, persons
with MCI had impaired motor function relative to those without cognitive
impairment and superior motor function compared with the individuals with
dementia. Among those with MCI, baseline levels of lower extremity motor
performance, parkinsonian gait, and bradykinesia were inversely related to
risk of AD, even after controlling for clinical stroke. Findings revealed that
a person with impaired lower limb performance or parkinsonian gait was two to
three times more likely to develop AD than a person with good lower limb
function. The researchers concluded that individuals with MCI also have
impaired motor function, and the degree of impairment in lower extremity
function is related to the risk of AD.14
Screening for Dementia
The prevalence of
dementia is high in advanced age, so screening for dementia is recommended
particularly for women older than 75, since the life expectancy of women is
greater than that of men at every age and older women are more likely than
their male counterparts to reside without a spouse and live alone.15
In attempting to maximize independent functioning and avoid accidents and
injuries, assessment of physical and cognitive function is recommended in the
overall care of older females to establish current ability and determine areas
where assistance may be necessary.
The Folstein Mini-Mental State
Examination (MMSE) is considered the most widely used single test for
evaluating mental status in the elderly.16-18 This
neuropsychological instrument has been widely translated and can be reliably
administered by any practitioner trained to do so (e.g., physician,
psychologist, pharmacist, nurse, social worker) as a screening test for
dementia.
The Aging, Demographics, and
Memory Study, part of the Health and Retirement Study (HRS) and sponsored by
the National Institute on Aging (NIA), is primarily conducting in-depth
investigations related to the impact of dementia on formal health care
utilization, informal caregiving, and the total societal costs of this care.
19 Secondarily, the study will examine the validity of the HRS cognitive
functioning measures as a screening tool for cognitive impairment or dementia.
Medication Therapy
Through a
medication regimen review, the avoidance or restriction of anticholinergic and
sedating agents in seniors can minimize and avoid medication-induced cognitive
impairment that may worsen dementia and cause delirium. Avoiding central
nervous system–depressant medications eliminates drug-induced functional
impairment. Medications approved for the treatment of AD do not halt the
disease or reverse brain damage; however, they can improve symptoms and slow
progression of the disease, which may improve quality of life, ease the burden
on caregivers, or delay admission to a nursing home.5 Studies are
looking at whether these cognition-enhancing agents may be useful in the
treatment of other types of dementia. For AD, the cholinesterase inhibitors
modestly improve cognitive function and memory in some individuals; donepezil,
galantamine, and rivastigmine are generally equally effective, while tacrine
is rarely chosen due to hepatotoxicity.1 The most recent agent
approved for AD is the N-methyl-D-aspartate receptor antagonist
memantine, which appears to slow the progression of the disease.1
Estrogen does not appear to be useful in the prevention or treatment of AD,
and the efficacy of nonsteroidal anti-inflammatory drugs, high-dose vitamin E,
selegiline, Ginkgo biloba extracts, and cholesterol-lowering statins is
unclear.1
While the efficacy of
cognition-enhancing agents in vascular dementia is unclear, prevention of this
condition is recommended through a variety of measures (TABLE 1). The
Journal of the American Geriatrics Society reported a recent study that
looked at trends in blood pressure control and cognition across a spectrum of
older ages focusing on blood pressure changes before onset of dementia.20
The researchers reported that high systolic blood pressure was associated
with greater risk of dementia in the young elderly (<75 years) but not in
older individuals. They suggested that adequate control of hypertension in
early old age may reduce the risk for dementia.20
For Lewy body dementia,
treatment is generally supportive, although cholinesterase inhibitors may
improve cognition. Extrapyramidal symptoms, appearing in half of these
patients, respond to antiparkinsonian agents, with the risk of worsening
psychiatric symptoms.1,21 HIV-associated dementia is
primarily treated with highly active antiretroviral therapy to increase CD4
+ counts and improve cognitive function; even with immune restoration,
there is no specific treatment for HIV-induced cognitive dysfunction.1
Similar supportive measures, as with the other dementias, would also apply.
While antipsychotic agents can help to reduce paranoia, they may worsen
confusion, cause extrapyramidal effects, and tardive dyskinesia or tardive
dystonia (which may not resolve upon reduction of dose or discontinuation).
Antipsychotic efficacy has been shown only in psychotic patients. Furthermore,
a U.S. Black Box Warning states, "Elderly patients with dementia-related
behavioral disorders treated with atypical antipsychotics are at an increased
risk of cerebrovascular adverse effects and death compared to placebo."
21 Nonanticholinergic antidepressants, preferably SSRIs, are
recommended for dementia patients with signs of depression.1
Nonpharmacologic
Intervention
According to the
National Institutes of Health, many people with dementia, especially during
the early stages, may benefit from practicing tasks designed to improve
performance in specific aspects of cognitive functioning.5 For
example, seniors may be able to learn to use memory aids, such as mnemonics,
computerized recall devices, or note taking.5 A prospective study
found women with higher levels of baseline physical activity such as walking
and stair climbing were less likely to develop cognitive decline.22
Although this association was not explained by differences in baseline
function or health status, the finding supported the hypothesis that physical
activity prevents cognitive decline in older community-dwelling women.
22
Role of the Pharmacist
Pharmacists may
take an active role in the care of the dementia patient through medication
regimen review for appropriate therapy and avoidance of potentially
inappropriate medications. Screening for dementia and assisting in the
prevention of vascular dementia through monitoring and educating in the areas
of blood pressure control, cholesterol-lowering therapy, blood glucose
regulation, and smoking cessation is recommended. Providing caregiver guidance
with regard to education, patient referral, and recommendations for
appropriate treatment of dementia, pain, and depression may maximize the
cognitive and functional ability in these vulnerable individuals.
References
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