Dementia and Cognitive Disorders Flashcards
Items 221–223
An 82-year-old man has 6 months of worsening memory loss. His fam-
ily is concerned, and he is taken to a physician. Following an extensive
evaluation and neuropsychological testing, he is diagnosed with dementia.
221. The most common cause of dementia in the general population is
a. Epilepsy
b. Vascular disease
c. Alzheimer’s disease
d. Parkinson’s disease
e. Head trauma
c. Alzheimer’s disease
( Bradley, p 1703.) Alzheimer’s disease accounts for
as much as 50% of the dementia in the general population confirmed at
autopsy; Parkinson’s disease accounts for only about 1%. Only 80 years
ago, neurosyphilis was the most common cause of dementia, but the introduction
of penicillin reduced—though it did not eliminate—this spirochetal
disease
as
a
cause
of
dementia.
As
the
population
ages,
the
incidence
and
prevalence
of Alzheimer’s
disease are
increasing.
The dementia caused
by
Alzheimer’s disease is progressive over the course of years. Language
disturbances may appear even before memory problems.
- His physician believes that the patient has Alzheimer’s disease.
Which of the following is most characteristic of the brain in patients with
Alzheimer’s disease?
a. Neuronal loss in the cerebral cortex
b. Demyelination in the cerebral cortex
c. Posterior column degeneration
d. Neuronal loss in the cerebellar cortex
e. Pigmentary degeneration in the hippocampus
a. Neuronal loss in the cerebral cortex
( Bradley, pp 1707–1708.) The most prominent
characteristics of Alzheimer’s disease are neuronal loss, fibrillary tangles,
loss of synapses, and amyloid (or neuritic) plaque formation. These
histopathologic features are evident throughout the cerebral cortex, but the
neurofibrillary tangles and neuronal loss are most prominent in the hippocampus
and
adjacent
structures
of
the
temporal
lobe.
The
tangles
and
loss
of
synapses
are
most
closely
linked
to
the
development
of
dementia.
The
cell
loss
may
be
so
substantial
that
the
patient
develops
marked
compensatory
enlargement
of
the
ventricles,
a
condition
called
hydrocephalus
ex
vacuo.
- In the dementia associated with Alzheimer’s disease, the EEG will
usually show
a. Spike-and-wave discharges
b. Periodic frontal lobe discharges
c. Focal slowing
d. Generalized background slowing
e. An isoelectric record
d. Generalized background slowing
( Rowland, pp 70–71.) The background rhythm on
the normal adult EEG is α activity at 8 to 12 Hz. With Alzheimer’s disease,
the frequency of this rhythm may slow, and the amount of time in which this
rhythm is evident when the patient is lying relaxed with eyes closed may
drop substantially. Periodic discharges in the form of sharp waves or spikes
may develop during Creutzfeldt-Jakob disease. EEG is otherwise not especially
helpful in distinguishing between the common causes of dementia.
- A 55-year-old man has steep decline in his cognitive abilities over a
3-month period. Initial testing is nondiagnostic. He continues to progress
and develops myoclonus and a left hemiparesis. Eventually he dies of an
aspiration about 8 months after the onset of symptoms. In the diseases that
cause dementia, myoclonus is usually most evident in
a. Alzheimer’s disease
b. Creutzfeldt-Jakob disease
c. Parkinson’s disease
d. Huntington’s disease
e. Pick’s disease
b. Creutzfeldt-Jakob disease
( Rowland, p 171.) Creutzfeldt-Jakob disease is a
spongiform encephalopathy that produces dementia over the course of months. It is caused by the accumulation within the brain of an abnormal
form of a normal protein that resists degradation by proteinases (a proteinaseresistant
protein, prion protein, or PrP). Myoclonic jerks—abrupt involuntary
muscle contractions that may produce brief limb or facial
movements—usually appear at some time in the course of this disease. These
are often stimulus-sensitive, such that loud noises may provoke them. Similar
movements may develop with Huntington’s disease, but these patients
usually develop more constant and fluid limb movements called chorea.
- The brain of the adult with trisomy 21 (Down syndrome) exhibits
many of the histopathologic features of which of the following?
a. Tay-Sachs disease
b. Friedreich’s disease
c. Pick’s disease
d. Parkinson’s disease
e. Alzheimer’s disease
e. Alzheimer’s disease
( Bradley, pp 1712–1713.) Up to 90% or more of
patients with trisomy 21 who die after age 30 have Alzheimer’s-type
changes in the brain. The histopathologic features of Alzheimer’s disease
may be evident in the person with Down syndrome at any age. That a
hereditary form of Alzheimer’s disease was found linked to chromosome 21
raised hopes that a single mutation was the cause of the problem, but this
was subsequently negated by the finding of hereditary forms of Alzheimer’s
linked to chromosome 19 and sporadic Alzheimer’s associated with defects
on neither of these chromosomes. Aside from persons with Down syndrome,
Alzheimer’s
disease
only
rarely
develops
in
relatively
young
people.
Items 226–228
An 80-year-old man has a history of 2 years of progressive gait distur-
bance and incontinence, which had been attributed to old age and prostatism.
Within the past 3 months, he has been forgetful, confused, and
withdrawn. His gait is short-stepped, and he turns very slowly, almost toppling
over.
He has a history of head trauma from 30 years ago.
His CT scan is shown below.
- The most likely diagnosis is
a. Alzheimer’s disease
b. Creutzfeldt-Jakob disease
c. Progressive multifocal leukoencephalopathy (PML)
d. Normal-pressure hydrocephalus
e. Chiari malformation
d. Normal-pressure hydrocephalus
( Bradley, pp 1556–1557.) Normal-pressure hydrocephalus
(NPH)
is
a
chronic,
communicating
form
of
hydrocephalus
affecting
elderly adults. The cause is unknown, but it may relate to prior
episodes of trauma, infection, or subarachnoid hemorrhage. The clinical
picture typically includes a triad of gait disturbance, dementia, and incontinence.
The gait disorder may be difficult to distinguish from that of
Parkinson’s disease, and has been labeled an apraxic gait as patients often
have difficulty even lifting their feet off the floor, though they have no
weakness and may perform motor tasks well with the legs when seated. CT
or MRI in these patients usually shows enlargement of the temporal and
frontal horns of the lateral ventricles out of proportion to the degree of cor-
tical atrophy. There may also be a squaring off or blunted appearance of the
frontal horns, and increased signal on T2-weighted images may be seen in
the periventricular regions, consistent with the presence of fluid related to
transependymal flow of CSF.
- The patient undergoes lumbar puncture. Forty milliliters of fluid are
removed. Three hours later, he is able to walk unassisted and turns well.
Spinal fluid would be expected to show
a. No abnormalities
b. Elevated protein
c. Low protein
d. Atypical lymphocytes
e. Low glucose
a. No abnormalities
( Bradley, pp 1556–1557.) The CSF in patients with
NPH is typically normal. Abnormalities in protein or cellularity should suggest an alternate diagnosis. The pressure of the CSF is also usually normal,
although studies using long-term pressure monitoring in these
patients has shown that they have periods of pressure elevation, often at
night.
- The patient undergoes ventriculoperitoneal shunt placement. He is
discharged 2 days later, his gait and cognition much improved. The following
morning, his wife finds him lying in bed, very confused and complaining of a headache. He is unable to walk. The surgeon who performed the procedure is concerned
that these new symptoms are due to
a. Chemical meningitis
b. Subdural hematoma
c. Epidural hematoma
d. Seizures
e. Bacterial ventriculitis
b. Subdural hematoma
( Bradley, pp 1556–1557.) Up to 28% of patients
who undergo ventriculoperitoneal shunting for NPH may suffer major
complications, including subdural hematoma. Subdural hematoma occurs
because the reduction in intracranial pressure brought on by the reduction
in CSF volume may cause the brain to pull away from the covering
meninges, stretching and potentially rupturing the bridging veins.
Items 229–231
A 67-year-old man has a history of progressive memory loss for 2
years. His examination is otherwise normal. A diagnosis of Alzheimer’s disease
is made.
229. Which of the following medications may retard the progress of this patient’s deterioration?
a. Donepezil
b. L-dopa
c. Risperidone
d. Prednisone
e. Vitamin B
12
a. Donepezil
( Bradley, p 1712.) Several modest advances in the
treatment of Alzheimer’s disease have occurred in the past decade. Recognition
of
the
fact
that
there
is
a
cholinergic
deficit
in
the
brains
of
patients
with
Alzheimer’s
disease
has
led
to
the
development
of
acetylcholinesterase
inhibitors
designed to augment the cholinergic neurotransmitter system.
Two different agents that have been used in the United States are tacrine,
which can cause hepatic dysfunction, and donepezil, which is better tolerated.
The
effects
are
modest
and
act
to
slow
cognitive
decline
as
assessed
by
scales
of cognitive function. There
is still no cure
for Alzheimer’s
disease.
- Which of the following medications may reduce the chances of his
being placed into a nursing home?
a. Vitamin B
12
b. Vitamin E
c. Estrogen therapy
d. Amantadine
e. Haloperidol
b. Vitamin E
( Bradley, p 1712.) Vitamin E has also been shown
to delay the progression of dementia in Alzheimer’s disease. Its mechanism
of action is presumed to be related to its ability to limit free radical formation,
oxidative
stress,
and
lipid
peroxidation.
In
one
clinical
trial,
2000
IU
of
vitamin
E
daily
led
to
a
delay
in
time
to
institutional
placement,
dependence,
severe
dementia, or death. Interestingly,
it did not appear to reduce
the
decline on cognitive test scores. The effect is similar to that of the
monoamine oxidase inhibitor selegiline, but there was no benefit to using
both drugs together.
- Language testing is most likely to uncover which of the following
deficits?
a. No abnormalities
b. Mutism
c. Conduction aphasia
d. Transcortical sensory aphasia
e. Transcortical global aphasia
d. Transcortical sensory aphasia
( Victor, p 1110.) The major clinical features of
Alzheimer’s disease are memory impairment, aphasia, apraxia, and neuropsychiatric
impairment, including mood disturbances, delusions and
hallucinations, personality changes, and behavior disturbances. The language
disturbance
may
take
the
form
of
decreased
fluency,
dysnomia,
and
transcortical
sensory
aphasia,
which
refers
to
a
reduction
in
the
ability
to understand complex linguistic structures. Repetition of verbal material is
intact.
DIRECTIONS: Each group of questions below consists of lettered
options followed by a set of numbered items. For each numbered item,
select the one lettered option with which it is most closely associated. Each
lettered option may be used once, more than once, or not at all.
Items 232–237
For each clinical scenario, choose the most likely diagnosis.
a. Transient global amnesia
b. Normal-pressure hydrocephalus
c. Alzheimer’s disease
d. Parkinson’s disease
e. Creutzfeldt-Jakob disease
f. Vitamin B
deficiency
g. Hypothyroidism
h. Huntington’s disease
i. Rett syndrome
j. Multi-infarct dementia
k. General paresis
l. Temporal lobe epilepsy
12
232. A 73-year-old man steps out of the shower on a Saturday evening
and is unable to remember that he and his wife have tickets to a play. He
asks her repeatedly, “Where are we going?” He appears bewildered, but is
alert, knows his own name, speaks fluently, and has no motor deficits. He
has no history of memory disturbance, and after 8 h returns to normal.
a. Transient global amnesia
( Bradley, pp 1129–1130.) Transient global amnesia
(TGA) refers to an episode of complete and reversible anterograde and retrograde
memory
loss
lasting
up
to
24
h.
Patients
have
a
persistent
loss
of
memory
for the time of the attack. During the episode, patients often
appear bewildered and ask repeated questions. They retain personal identity
(unlike
characters
suffering
from
transient
amnesia
in
television
shows)
and
can perform complex cognitive and motor tasks. Transient global
amnesia usually affects middle-aged or older men and often occurs in the
setting of an emotional or other stressor, such as physical or sexual exertion.
Although it shares features of TIA, it is not associated with an
increased risk of stroke. Nonetheless, a vascular evaluation is often appropriate,
particularly in atypical or repeated
cases and in the presence
of risk
factors
for stroke. Most patients experience only a single episode. Some
have stressed TGA’s similarity to migraine and hypothesized that it is
related to migrainous ischemia of the medial temporal lobe structures.
- A 50-year-old woman began complaining of double vision and
blurry vision 3 months ago and has since had diminishing interaction with
her family, a paucity of thought and expression, and unsteadiness of gait.
Her whole body appears to jump in the presence of a loud noise. An MRI
scan and routine CSF examination are unremarkable. (SELECT 1 DIAGNOSIS)
a. Transient global amnesia
b. Normal-pressure hydrocephalus
c. Alzheimer’s disease
d. Parkinson’s disease
e. Creutzfeldt-Jakob disease
f. Vitamin B
deficiency
g. Hypothyroidism
h. Huntington’s disease
i. Rett syndrome
j. Multi-infarct dementia
k. General paresis
l. Temporal lobe epilepsy
e. Creutzfeldt-Jakob disease
( Bradley, pp 1424–1425.) The neurological complaints
occurring
early
in
the
course
of
Creutzfeldt-Jakob
disease
are
often
cerebellar
or visual. Patients may complain of ataxia, clumsiness, or
dysarthria, as well as diplopia, distorted vision, blurred vision, field
defects, changes in color perception, and visual agnosia. Ultimately cortical
blindness may occur. The diagnosis may be supported by the finding of
periodic sharp waves at a 1- to 2-Hz frequency on EEG and the finding of
elevated protein 14-3-3 in CSF. The typical EEG pattern is found in up to
80% of patients at some point during the course of the illness. An MRI may
show a pattern of increased T2 signal in the basal ganglia in many, but not
all, cases.
- A 2-year-old girl developed normally until the past year. She has
since become unable to speak or otherwise communicate with her parents,
sits in a chair, and makes nearly continuous wringing movements with her
hands. She also has episodes of breath holding alternating with hyperventilation.
(SELECT
1 DIAGNOSIS)
a. Transient global amnesia
b. Normal-pressure hydrocephalus
c. Alzheimer’s disease
d. Parkinson’s disease
e. Creutzfeldt-Jakob disease
f. Vitamin B
deficiency
g. Hypothyroidism
h. Huntington’s disease
i. Rett syndrome
j. Multi-infarct dementia
k. General paresis
l. Temporal lobe epilepsy
i. Rett syndrome
(Swaiman, pp 612, 836–839.) Rett syndrome is a
presumed X-linked genetic disorder that affects only girls; the homozygous
version is thought to be fatal in male offspring. Usually the prenatal, perinatal,
and
early
childhood
development
appear
normal
or
nearly
so,
and
then
the
girl
undergoes
rapid
regression
in
cognitive
status
in
early
childhood,
generally
during
the
second
year
of
life.
There
is
loss
of
previously
acquired
language skills and effective eye contact, as well as purposeful hand movement. Stereotypic hand movements develop, usually taking the
form of hand wringing, but also including tapping, patting, and at times
hand-mouth movements. Seizures may also occur. Etiology is unknown,
and there is no treatment.
- A 17-year-old girl develops mild dementia, tremor, and rigidity. Her
father died in his fourth decade of life of a progressive dementing illness
associated with jerking (choreiform) limb movements. On exposure to
Ldopa,
she becomes acutely agitated and has jerking limb movements.
(SELECT 1 DIAGNOSIS)
a. Transient global amnesia
b. Normal-pressure hydrocephalus
c. Alzheimer’s disease
d. Parkinson’s disease
e. Creutzfeldt-Jakob disease
f. Vitamin B
deficiency
g. Hypothyroidism
h. Huntington’s disease
i. Rett syndrome
j. Multi-infarct dementia
k. General paresis
l. Temporal lobe epilepsy
h. Huntington’s disease
( Bradley, pp 1719–1720.) Dementia is a prominent
feature of Huntington’s disease. Apathy and depression occur commonly,
and a schizophreniform illness may be the presenting manifestation at
times. The dementia itself is subcortical, characterized by impairment in
executive function and concentration, without the classic cortical features
of Alzheimer’s disease, such as aphasia, apraxia, and amnesia.
