Alzheimer's Disease
A chronic,
progressive, neurologic disorder characterized by degeneration of the neurons
in the cerebral cortex and subcortical structures, resulting in irreversible
impairment of intellect and memory.
Causes and
Incidence The cause is unknown, although theories involving genetic links,
neurotransmitter deficiencies, viruses, aluminum poisoning, autoimmune disease,
and viruses have been advanced. Alzheimer's disease is the fourth leading cause
of death among the elderly in the United States. Approximately 3% of
individuals over 65 years of age show signs of the disease; the proportion
climbs to 20% in those over 80 years of age. The incidence is higher in women.
Disease Process
Selective neuronal cells, primarily those involved in the transmission and
reception of acetylcholine, degenerate in the cerebral cortex and basal
forebrain, resulting in cerebral atrophy of the frontal and temporal lobes,
with wide sulci and dilated ventricles. Senile plaques and neurofibrillary
tangles are present. The basic pathophysiologic processes accompanying the
brain damage are unknown.
Symptoms
Early
Short-term memory
loss, impaired insight/judgment, momentary disorientation, emotional lability,
anxiety, depression, decline in ability to perform activities of daily living
(ADLS)
Midcourse
Apraxia, ataxia,
alexia, astereognosis, auditory agnosia, agraphia, prolonged disorientation,
progressive memory loss (longand shortterm), aphasia, lack of comprehension,
decline in care abilities, insomnia, loss of appetite, repetitive behavior,
socially unacceptable behavior, hallucinations, delusions, paranoia
Late
Total dependence
in ADLs, bowel and bladder incontinence, loss of speech, loss of individuation,
myoclonic jerking, seizure activity, loss of consciousness
Potential
Complications
The end stage of
Alzheimer's disease invites complications commonly associated with comatose
conditions (e.g., skin breakdown, joint contractures, fractures, emaciation,
aspiration pneumonia, infections).
Diagnostic Tests
Definitive
diagnosis can be made only through autopsy.
Clinical
evaluation
Any of the above
manifestations after depression,
delirium, and other dementia disorders (e.g., head injury, brain tumor,
alcoholism, drug toxicity, arteriosclerosis) have been ruled out; family
history
Mental status
examination
Decreased
orientation, impaired memory,
impaired insight/ judgment, loss of abstraction/ calculation abilities, altered
mood
CT/MRI
Brain atrophy;
symmetric, bilateral, ventricular enlargement
Electroencephalogram
Slowed brain wave
activity, reduced voltage
Drugs
Medications for
treating specific symptoms or behavioral manifestations (i.e., antidepressants,
stimulants, antipsychotics, sedatives); experimental drugs include cholinergic,
dopamine, and serotonin precursors; neuropeptides; and transcerebral dilators
General
Structured,
supportive, familiar environment; orientation and cueing program for daily
tasks; safety program; family support and counseling; respite care;
institutionalization when home care is no longer possible
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Excerpted from
Mosby's Medical Encyclopedia
Copyright (c)
1994-5, 1996, 1997 The Learning Company Inc. All Rights Reserved