Movement Disorders Flashcards
241. A patient gives a history of chorea gravidarum. This condition only occurs in a. Newborns b. Depressed men c. Pregnant women d. Pubescent girls e. Pubescent boys
c. Pregnant women
( Victor, p 78.) Chorea gravidarum designates an
involuntary movement disorder that occurs during pregnancy and involves
relatively rapid and fluid, but not rhythmic, limb and trunk movements.
This type of movement disorder may also appear with estrogen use, but the
fundamental problem is a dramatic change in the hormonal environment
of the brain. At the end of pregnancy or with the withdrawal of the offending
estrogen, the movements abate. The movements that develop with
chorea gravidarum may be quite asymmetric and forceful.
242. The influenza epidemic of 1918 to 1926 was associated with von Economo’s encephalitis and left many persons with a syndrome indistinguishable from which of the following? a. Sydenham’s chorea b. Alzheimer’s disease c. Multiple sclerosis d. Amyotrophic lateral sclerosis e. Parkinson’s disease
e. Parkinson’s disease
( Victor, p 813.) A variety of agents can induce signs
and symptoms of parkinsonism on a temporary basis, but few will evoke a
persistent Parkinsonian syndrome. After the epidemic of encephalitis
lethargica of 1918 to 1926, there were many cases of postencephalitic
parkinsonism. The causative agent was believed to be an influenza virus,
but it could not be isolated with the techniques available at the time of the
epidemic. Postinfluenzal parkinsonism still develops, but the incidence is
too rare to establish that this virus is the only virus capable of producing
parkinsonism. Early in the infection, patients may exhibit a transient
chorea. As the chorea abates, the parkinsonism appears and persists.
Items 243–245
243. A 43-year-old man has a father who died from Huntington’s disease.
The son was tested and found out that he does have the gene for Huntington’s
disease.Whichofthe following is true regarding the offspring of those with Huntington’s disease?
a. Half the offspring are at risk only if the affected parent is male
b. Half the offspring are at risk only if the affected parent is female
c. Half the offspring are at risk if either parent is symptomatic for the disease
before the age of 30
d. Half the offspring are at risk for the disease
e. One out of four children is at risk for the disease
d. Half the offspring are at risk for the disease
( Kandel, p 865.) Huntington’s disease is transmitted
in an autosomal dominant fashion. The age at which the patient
becomes symptomatic is variable and has no effect on the probability of
transmitting the disease. The defect underlying this degenerative disease is
an abnormal expansion of a region of chromosome 4 containing a triplicate
repeat (CAG) sequence. Normal individuals have between 6 and 34 copies
of this CAG section; patients with Huntington’s disease may have from 37
to over 100 repeats. Once expanded beyond 40 copies, the repeats are
unstable and may further increase as they are passed on from one generation
tothenext.An increased number of repeats leads to a phenomenon known as anticipation, by which successive generations have earlier disease onset.
244. Atrophy in the head of the caudate nucleus in patients with Huntington’s disease affects the shape of the a. Cerebellum b. Lateral ventricle c. Third ventricle d. Lenticular nuclei e. Temporal lobe
b. Lateral ventricle
(Greenberg, 2/e, pp 14–16.) As the caudate atrophies,
the frontal tip of the lateral ventricle becomes increasingly rhomboidal
in
shape. The head of the caudate is usually atrophic early in the
course of Huntington’s disease, and this will usually be evident by the time
the patient is symptomatic, if not sooner. On MRI or CT scanning, the head
of the caudate gives the frontal and parietal components of the lateral ventricle
its typical comma, or boomerang, appearance.
- If this patient were to be exposed to L-dopa, which of the following
would most likely be evoked?
a. Generalized seizures
b. Partial seizures
c. Intention tremor
d. Scanning speech
e. Writhing and jerking movements of the limbs
e. Writhing and jerking movements of the limbs
( Victor, p 1125.) Writhing and jerking movements
of the limbs are part of the chorea that typically develops with Huntington’s
disease. Dopaminergic drugs, such as
L-dopa, bromocriptine, and
lisuride, may unmask chorea. This is inadvisable as a diagnostic technique
because it may contribute to the premature symptom of chorea.
Dopamine antagonists, such as haloperidol, may be used to suppress
chorea, but also carry the risk of provoking tardive dyskinesia. Huntington’s
disease is characterized pathologically by loss of several neuronal
types in the striatum (caudate and putamen). It has been hypothesized
that the occurrence of dopaminergic-induced chorea in Huntington’s disease
is related to increased sensitivity of the dopamine receptors in the
remaining striatal neurons, although there are abnormalities in several
other neurotransmitters as well. Choreiform movements develop in a
variety of other conditions; the one most similar to Huntington’s disease
is hereditary acanthocytosis.
- A 26-year-old heroin addict has been using a street version of
artificial heroin. The drug actually contains 1-methyl-4-phenyl-1,2,3,6tetrahydropyridine
(MPTP).
The neurological syndrome for which he is at risk is clinically indistinguishable from
which of the following?
a. Huntington’s disease
b. Friedreich’s disease
c. Sydenham’s chorea
d. Parkinson’s disease
e. Amyotrophic lateral sclerosis
d. Parkinson’s disease
( Victor, p 73.) Young adults who have selfadministered MPTP
in an effort to achieve an opiate high
have developed progressive damage to the substantia nigra. The neurologic syndrome
that results from this damage is indistinguishable from Parkinson’s disease,
except that it evolves over weeks or months rather than years. Affected persons exhibit
rigidity, tremor, and bradykinesia. That a toxin can produce a syndrome indistinguishable from Parkinson’s disease
has increased speculation that some—perhaps many—persons with Parkinson’s disease have had environmental exposure to a toxin that produced degeneration of the
substantia nigra.
Items 247–250
A 61-year-old right-handed man presents with involuntary twitches of
his left hand. He first noticed between 6 months and 1 year ago that when
he is at rest, his left hand shakes. He can stop the shaking by looking at his
hand and concentrating. The shaking does not impair his activities in any
way. He has no trouble holding a glass of water. There is no tremor in his
right hand, and his lower extremities are not affected. He has had no trouble walking, and there have been no falls.
There have been no behavioral or language changes. On examination, a left hand tremor is evident when the man is
distracted. His handwriting is mildly tremulous. He has bilateral cogwheel rigidity with contralateral activation, which is worse on the left. His rapid alternating movements are bradykinetic on the left.
247. The most likely diagnosis in this case is which of the following?
a. Epilepsy
b. Guillain-Barré syndrome
c. Multiple sclerosis
d. Parkinson’s disease
e. Stroke
d. Parkinson’s disease
( Rowland, pp 679–682.) The tremor is of a Parkinsonian type.
The patient also has the classic findings of
Parkinson’s disease: asymmetric tremor, rigidity, and bradykinesia.
Epilepsy is characterized by repeated unprovoked seizures. Hand shaking can be the result of a focal motor seizure, but the presentation overall makes epilepsy an unlikely diagnosis. Guillain-Barré syndrome is a peripheral demyelinating disease
that usually presents as an ascending motor deficit. Multiple sclerosis is a
central nervous system (CNS) demyelinating disease. It presents with individual episodes of CNS deficits, which usually recover to some extent.
Stroke is characterized by the acute onset of a neurological deficit due to
nerve infarction. Tremor would be an exceedingly rare presentation for
stroke, and it would not evolve over 6 to 12 months.
- Which brain structures are currently targets for deep brain stimulation
in patients with this disease?
a. Globus pallidus, medulla, and parietal lobe
b. Globus pallidus, subthalamic nucleus, and thalamus
c. Hippocampus, medulla, and thalamus
d. Medulla, occipital lobe, and subthalamic nucleus
e. Parietal lobe, temporal lobe, and thalamus
b. Globus pallidus, subthalamic nucleus, and thalamus ( Rowland, pp 686–687.) Current theory of Parkinson’s disease pathology is based on the premise that the substantia nigra pars compacta
has decreased dopamine production, which eventually leads to overinhibition of thalamocortical pathways. The thalamus may be directly intervened on to decrease this overinhibition. Alternatively, the globus pallidus interna may be lesioned or stimulated, because it directly inhibits the thalamus. A third approach is to lesion or stimulate the subthalamic nucleus, which has an excitatory connection on the globus pallidus interna and substantia nigra pars reticulata. The medulla, hippocampus, temporal lobe, and occipital lobe are not involved in this pathway.
- Which of the following would you use to treat this person?
a. Alteplase
b. Carbidopa-levodopa
c. Glatiramer
d. Interferon β-1A
e. Sertraline
b. Carbidopa-levodopa ( Rowland, pp 686–687.) Parkinson’s disease symptoms are due in large part to dopamine depletion. Carbidopa-levodopa can replete
dopamine and alleviate symptoms. Alteplase is used to dissolve
blood clots during acute strokes or heart attacks. Glatiramer and interferon
β-1A are used to treat multiple sclerosis, and have been shown to decrease
attacks. Both are thought to work through immunomodulation. Sertraline
is a selective serotonin reuptake inhibitor. By increasing serotonin concentrations,
it is effective
for the treatment
of depression.
- Neurons remaining in the substantia nigra of the patient with this
disease may exhibit
a. Intranuclear inclusion bodies
b. Intranuclear and intracytoplasmic inclusion bodies
c. Intracytoplasmic inclusion bodies
d. Neurofibrillary tangles
e. Amyloid plaques
c. Intracytoplasmic inclusion bodies
( Rowland, p 681.) The intracytoplasmic inclusion
bodies commonly seen in patients with idiopathic Parkinson’s disease are
called Lewy bodies. They are eosinophilic inclusions with poorly staining
halos surrounding them. They may be round or oblong in shape and are
most common in the substantia nigra, locus coeruleus, and substantia
innominata. They appear to consist of aggregated neurofilaments. Degenerative
changes
may
be
remarkably
asymmetric
in
patients
with
Parkinson’s
disease.
251. A 48-year-old female psychiatric patient has parkinsonism secondary to long-term neuroleptic use. Which of the following medications might minimize her parkinsonism? a. Trihexyphenidyl (Artane) b. Haloperidol (Haldol) c. Methamphetamine d. Thioridazine (Mellaril) e.L-dopa
a. Trihexyphenidyl (Artane) ( Rowland, p 683.) Trihexyphenidyl (Artane) is an anticholinergic drug. It is presumed to decrease signs of parkinsonism caused by drugs that interfere with dopamine neurotransmission by creating a relative deficiency of acetylcholine neurotransmission. In a very simplistic
view of the CNS, the cholinergic and dopaminergic systems have
antagonistic actions.
Items 252–253 252. A 70-year-old woman has 1 year of worsening gait, right hand tremor, and rigidity. She is diagnosed with Parkinson’s disease and improves dramatically with treatment. If her disease progresses, the decrement in speech which would be expected would result in which of the following? a. Progressively inaudible speech b. Receptive aphasia c. Expressive aphasia d. Word salad e. Neologisms
a. Progressively inaudible speech
( Victor, p 1130.) Language is not disturbed in
Parkinson’s disease, as it is with aphasias. It is the clarity and volume of
speech that suffers. Handwriting is similarly disturbed. The patient has
increasingly smaller and less legible penmanship as he or she continues to
write. This is referred to as micrographia.
- Even though the physiologic deficiency in Parkinson’s disease is of
dopamine,
L-dopa rather than dopamine is given to patients because
a. L-dopa induces less nausea and vomiting than dopamine
b. Dopamine is readily metabolized in the gastrointestinal tract to ineffective com-
pounds
c.
L-dopa is more readily absorbed in the gastrointestinal tract than is dopamine
d. Dopamine cannot cross the blood-brain barrier and therefore has no therapeu-
tic effect in the CNS
e.
L-dopa is more effective at dopamine receptors than is dopamine itself
d. Dopamine cannot cross the blood-brain barrier and therefore has no therapeu- tic effect in the CNS ( Victor, pp 1133–1134.) L-dopa crosses the bloodbrain barrier easily and is subsequently converted to dopamine in the CNS. Conversion of
L-dopa to dopamine occurs outside the CNS in a wide variety of tissues, but once converted to dopamine in the periphery, the drug becomes
inaccessible to the brain. Peripheral conversion of
L-dopa to
dopamine is routinely inhibited by adding a dopa decarboxylase inhibitor
to the therapeutic regimen. Carbidopa, the inhibitor most widely used,
does not penetrate the blood-brain barrier substantially. Because it is
largely excluded from the CNS, carbidopa cannot inhibit the conversion of
L-dopa to dopamine in the brain
- A 25-year-old man has had motor tics since age 13. They seem to be getting
worse, and now he also has involuntary obscene vocalizations. He may
have largely normal behavior while being treated with which of the following?
a. L-dopa
b. Trihexyphenidyl (Artane)
c. Phenytoin (Dilantin)
d. Carbamazepine (Tegretol)
e. Haloperidol (Haldol)
e. Haloperidol (Haldol)
( Rowland, pp 668–669.) The scenario described is
that associated with Tourette syndrome. The affected person is usually over
21 years of age and cannot control the obscene and scatological remarks.
With Tourette syndrome there appears to be an autosomal dominant pattern
of inheritance with variable penetrance. Most affected persons are
men. A variety of drugs may help suppress the tics that are characteristic of
this syndrome. These include haloperidol, pimozide, trifluoperazine, and
fluphenazine. Antiepileptics, such as carbamazepine and phenytoin, are
not useful. Trihexyphenidyl and benztropine are useful in suppressing the
parkinsonism that may develop with haloperidol administration, but are
not useful in the management of Tourette syndrome.
255. A 72-year-old man was diagnosed with Parkinson’s disease after pre- senting 2 years ago with asymmetric rigidity, bradykinesia, and tremor. He is being treated with carbidopa and L-dopa. Carbidopa is used in combination with L-dopa because it a. Has anticholinergic activity b. Has dopaminergic activity c. Is an antihistaminic d. Is an antiemetic e. Is a dopa decarboxylase inhibitor
e. Is a dopa decarboxylase inhibitor
( Rowland, pp 686–687.) Dopa decarboxylase converts
L-dopa to dopamine. Carbidopa crosses the blood-brain barrier poorly, and so its inhibition of this enzyme is restricted to activity outside the CNS. Conversion of L-dopa to dopamine continues to occur in the CNS when the patient takes Sinemet, a combination of L-dopa and carbidopa.
