IX.1. A 40-year-old woman had right-sided neck pain after riding on a
roller coaster. Within an hour, right hand and leg weakness
developed with numbness of the left arm and leg that did not
progress further. On examination, she had an upper motor neu-
ron pattern of weakness in the right arm and leg and reduced
proprioception in the right great toe. She also had reduced sen-
sation to pinprick on the left arm and leg up to C4. What is the
most likely cause of her symptoms?
a. Traumatic contusion of the cervical spine
b. Infarction of the anterior spinal artery
c. Cervical myelopathy due to multiple sclerosis
d. Infarction of the sulcal artery
e. Transverse myelitis
IX.1. Answer d.
The patient has sulcal artery syndrome of the cervical cord
that probably resulted from a vertebral artery dissection.
Although it is less common than infarction of the anterior
spinal artery, sulcal artery syndrome is characterized by a
partial Brown-Séquard syndrome. Anterior spinal artery
syndrome typically involves bilateral corticospinal tracts
and bilateral anterolateral tracts with sparing of the posterior
columns. The acute nature of the symptoms suggests that the
cause was vascular rather than inflammatory or infectious.
IX.2. A 60-year-old man has progressive weakness of the lower
extremities with ascending sensory changes and mild pain. On
examination, he has mild upper motor neuron weakness in both
legs and a sensation to pinprick at T10. Magnetic resonance
imaging of the spine shows congestion of the lower spinal cord
and multiple flow voids in the perimedullary region. What can
be stated about his prognosis?
a. He may have some recovery, and the progression of his condition
can be halted with surgical intervention
b. His condition will likely progress to paraplegia, and the lesion will
require radiotherapy
c. His condition should improve with a 3-day course of corticosteroids
d. With intravenous immunoglobulin therapy, his condition should
improve during the next 30 days
e. With plasma exchange therapy, the progression of his condition
should halt
IX.2. Answer a.
The findings describe a spinal dural arteriovenous (AV) fis-
tula. Surgical intervention often halts progression, and
patients have some recovery after the spinal cord congestion
improves. Spinal dural AV fistulas typically present in a
subacute fashion and are more common in older patients.
IX.3. An 18-year-old man who abuses nitrous oxide has a subacute
decline in balance and strength in his legs. On examination, he
has reduced proprioception in the feet, reduced vibration sensa-
tion at the ankles and knees, and hyperreflexia in the lower
extremities. Which test would be most important for assessment?
a. Thyrotropin
b. Vitamin B12 and methylmalonic acid
c. Syphilis
d. HIV
e. Very-long-chain fatty acids
IX.3. Answer b.
Nitrous oxide can convert the active, monovalent form of
vitamin B12 to the inactive, bivalent form and result in defi-
ciency. Vitamin B12 deficiency is associated with subacute
combined degeneration as described for this patient. Any
patient with myelopathy should also undergo magnetic reso-
nance imaging to rule out structural causes.
IX.4. A 30-year-old woman has subacute, progressive myelopathic
symptoms and a history of optic neuritis. Magnetic resonance
imaging (MRI) findings are shown in the image below.
Which test would be most useful diagnostically?
a. Angiotensin-converting enzyme
b. Fungal smear of cerebrospinal fluid
c. Serum aquaporin-4 (AQP4) antibody
d. Anti-Hu antibody
e. Long-chain fatty acids
IX.4. Answer c.
The MRI shows a longitudinally extensive T2-signal change
in the cervical cord. In a patient with optic neuritis and a
longitudinally extensive T2-signal change in the cervical
cord, neuromyelitis optica should be considered. Testing for
serum AQP4 antibody (as a biomarker for neuromyelitis
optica) should be performed. This test has a sensitivity of
about 73% and a specificity of about 91%.
IX.5. A 56-year-old woman presents with gradually progressive, pain-
less right foot drop. She says that she has difficulty opening jars.
Fasiculations and atrophy are apparent bilaterally in the plantar
interossei muscles and the right tibialis anterior muscle. What
pathologic finding might accompany this disease?
a. Lafora body
b. Bunina bodies
c. Vasculitis
d. Onion bulbs and demyelination
e. Antoni B areas
IX.5. Answer b.
This patient most likely has amyotrophic lateral sclerosis
(ALS). Bunina bodies are intraneural eosinophilic cytoplas-
mic inclusions of ubiquitinated protein aggregates seen in
patients with ALS. Lafora bodies are seen in Lafora disease,
which is characterized by seizures, myoclonus, and demen-
tia. Onion bulbs, which are common in demyelinating neu-
ropathies, are formations of concentric Schwann cells and
collagen surrounding an axon. Antoni A and B areas are
seen in patients with peripheral schwannoma.
IX.6. Which of the following would not be a typical finding in a patient
with amyotrophic lateral sclerosis (ALS)?
a. Asymmetric weakness
b. Painless weakness
c. Extraocular muscle involvement
d. Tongue involvement
e. Babinski sign
IX.6. Answer c.
ALS does not typically involve extraocular muscles or vol-
untary sphincters. Patients may present with progressive,
painless, often initially asymmetric weakness. Patients may
initially have limb weakness or bulbar weakness (or both).
IX.7. A 43-year-old man presents with progressive proximal weakness,
bulbar weakness, and fasciculations. Reflexes are mildly dimin-
ished and the Babinski sign is absent. He also has mild gyneco-
mastia and testicular atrophy. His grandfather had similar
symptoms. What is the inheritance pattern of this disease?
a. Autosomal recessive
b. Autosomal dominant
c. X-linked dominant
d. Mitochondrial inheritance
e. X-linked recessive
IX.7. Answer e.
This patient has Kennedy disease, also known as spinobul-
bar muscular atrophy (SBMA), which is an X-linked reces-
sive disorder caused by a trinucleotide repeat within the
androgen receptor gene.
IX.8. A 20-year-old man presents with a 5-year history of gradual,
painless progressive weakness of his right hand. There is evi-
dence of weakness of the interossei muscles with fasciculation
and no sensory loss. Reflexes are normal in both upper and lower
extremities. What could be said about this man’s prognosis?
a. Average lifespan is 2.3 years
b. Progression to involve other limbs is expected
c. Ulnar sensation will be lost within 2 years
d. Pain in the weak limb is expected
e. Symptoms will likely stabilize and stop progressing
IX.8. Answer e.
This patient likely has Hirayama disease (a monomelic
motor neuron disease that is also called Sobue disease). It
occurs almost exclusively in young persons and predomi-
nantly in males. The presentation is typically unilateral
hand weakness and atrophy. After the weakness progresses
for about 5 years, the deficits plateau and stabilize.
IX.9. A 35-year-old woman has ascending weakness 1 week after she
had an illness involving the gastrointestinal tract. On examina-
tion she has bilateral foot drop, bilateral weakness of the ham-
strings and quadriceps muscles, and reduced reflexes in the
upper and lower extremities. If electromyography were per-
formed approximately 2 weeks after the onset of symptoms,
which of the following would be the most likely finding?
a. Normal F waves
b. Uniformly slow conduction velocities
c. Conduction block and temporal dispersion
d. Myokymia
e. Low-amplitude compound muscle action potential (CMAP) with
normal conduction velocities
IX.9. Answer c.
On electromyography, acute inflammatory demyelinating
polyneuropathy may show prolonged or absent F waves,
conduction block and temporal dispersion, and prolonged
distal latencies and slow conduction velocities. In contrast,
inherited demyelinating neuropathies are characterized by uniformly slow conduction velocities without conduction
block and temporal dispersion.
IX.10. A 56-year-old woman with a history of breast cancer treated
with lumpectomy and radiotherapy presents with weakness of
her right arm. On examination she has weakness of the right
supraspinatus, deltoid, biceps, and brachioradialis muscles.
What is the most likely localization?
a. Axillary nerve mononeuropathy
b. Suprascapular neuropathy
c. Upper trunk plexopathy
d. Lower trunk plexopathy
e. Radial nerve mononeuropathy
IX.10. Answer c.
The patient does not have a mononeuropathy because the
affected muscles are innervated by more than 1 nerve. The
deltoid muscle is innervated by the axillary nerve; the
biceps muscle, by the musculocutaneous nerve; and the
brachioradialis muscle, by the radial nerve. The supraspi-
natus muscle is innervated by the suprascapular nerve,
which is from the upper trunk (C5-C6). Upper trunk
plexopathy can occur in patients who have had radiother-
apy involving the chest.
IX.11. Which of the following describes Charcot-Marie-Tooth disease
(CMT) type 1A (CMT1A), which is also known as hereditary motor
and sensory neuropathy 1A?
a. CMT1A is an axonal neuropathy
b. CMT1A is inherited in an autosomal recessive fashion
c. CMT1A is commonly accompanied by autonomic symptoms
d. CMT1A is caused by duplication or mutation of the peripheral
myelin protein 22 gene (PMP22)
e. CMT1A is a rare form of CMT1
IX.11. Answer d.
CMT has a prevalence of around 1 per 2,500 people.
Duplication or mutation of PMP22, which encodes a myelin
protein, causes CMT1A, which is the most common cause
of inherited demyelinating neuropathy and is inherited in
an autosomal dominant fashion.
IX.12. A 38-year-old woman is referred for evaluation of progressively
worsening, fatigable weakness. The neurologic examination is
notable for mild flaccid dysarthria and moderately severe prox-
imal upper limb weakness without ocular signs or symptoms.
After she is given a provisional diagnosis of myasthenia gravis
(MG), initial therapy is begun with pyridostigmine while labora-
tory and electrodiagnostic testing is in progress. Five days after
the initiation of pyridostigmine, the patient reports worsening
symptoms, fasciculations, and excessive salivation, which seem
to be associated with the timing of pyridostigmine. Which of
the following antibodies would most likely be detected with
this patient’s laboratory evaluation?
a. Acetylcholine receptor (AChR)-binding antibodies
b. Muscle-specific kinase (MuSK) antibodies
c. Striated muscle antibodies
d. Low-density lipoprotein-related protein 4 (LRP4) antibodies
e. P/Q-type calcium channel antibodies
XI.12. Answer b.
MuSK antibodies are detected in 40% to 50% of patients
with MG who do not have AChR antibodies. Patients with
MuSK antibodies typically have generalized MG but may
have clinical features that distinguish them from patients
with AChR antibodies. MuSK MG often more prominently
affects neck, shoulder girdle, bulbar, and respiratory mus-
cles and spares ocular muscles. Many patients with MuSK
MG either will not respond to pyridostigmine or will have
adverse effects to pyridostigmine as this patient did. The
adverse response to pyridostigmine and the absence of ocu-
lar symptoms and signs are more typical of MuSK MG than
MG associated with LRP4 or AChR antibodies. Striated
muscle (or striational) antibodies may be present in younger
patients with thymoma but would not necessarily be abnor-
mal in this patient. P/Q-type calcium channel antibodies
are associated with Lambert-Eaton myasthenic syndrome.
IX.13. A 58-year-old man with a 2-month history of worsening symp-
toms attributed to myasthenia gravis (MG), including diplopia,
ptosis, and proximal limb weakness, presents to the emergency
department for new-onset swallowing and breathing issues. He
had begun taking pyridostigmine 1 month previously and had
initial benefit. On neurologic examination, he has fatigable
ptosis, proximal limb weakness (more pronounced than distal
limb weakness), and flaccid dysarthria. Which of the following
is the most appropriate next step in the management of this
patient’s condition?
a. Increase the dosage of pyridostigmine
b. Initiate a high dose of prednisone
c. Admit him to the hospital for respiratory monitoring, inspira-
tory and expiratory pressures, and initiation of immunotherapy
with either intravenous immunoglobulin or plasma exchange
d. Thymectomy
e. Initiate 3,4-diaminopyridine
IX.13. Answer c.
This patient presented in myasthenic crisis with symptoms
of bulbar impairment and dyspnea. He should be admitted
to an intensive care unit and undergo serial monitoring of
vital capacity along with inspiratory and expiratory pres-
sures. Prompt initiation of immunotherapy with either
intravenous immunoglobulin or plasma exchange is the
treatment of choice for patients with myasthenic crisis.
Typically, pyridostigmine would be discontinued so as to
not increase secretions; this potential adverse effect can be
problematic in patients with marked bulbar impairment or
myasthenic crisis. Furthermore, patients taking high doses
of pyridostigmine may be at risk for cholinergic crisis,
which can be difficult to differentiate from myasthenic cri-
sis. Initiation of a high dose of prednisone is not appropri-
ate as an initial therapeutic option in myasthenic crisis
because in a large percentage of patients the myasthenic
symptoms may worsen transiently 5 to 10 days after the
initiation of prednisone. Thymectomy, although not an
appropriate intervention in a patient with myasthenic cri-
sis, should be considered in early-onset MG for patients
who are clinically stable or who have thymoma. The drug
3,4-diaminopyridine is used to treat Lambert-Eaton myas-
thenic syndrome and would not be appropriate for this
patient.
IX.14. A 62-year-old man reports a 6-month history of proximal limb
weakness, difficulty climbing stairs, and dry mouth. On neuro-
logic examination, he has moderately severe, proximal lower
limb weakness with global deep tendon areflexia and normal
sensory findings. After he contracts his quadriceps muscles
against resistance, he has a normal patellar reflex. Which of the
following laboratory studies is most likely to have an abnormal
result?
a. P/Q-type calcium channel antibody
b. Creatine kinase
c. Acetylcholine receptor‒binding antibodies
d. Aldolase
e. Angiotensin-converting enzyme
IX.14. Answer a.
This patient’s history is typical of Lambert-Eaton myas-
thenic syndrome (LEMS), which is associated with autoan-
tibodies against P/Q-type calcium channels. Creatine
kinase and aldolase levels are normal in patients with LEMS. This patient’s examination findings are not typical
of myasthenia gravis; therefore, acetylcholine receptor‒
binding antibodies would not be expected to be abnormal.
Abnormal levels of angiotensin-converting enzyme can be
present with sarcoidosis, which would be a highly unlikely
cause of this patient’s presentation.
IX.15. A 55-year-old man had a 4-month history of progressive proxi-
mal limb weakness and elevated creatine kinase (5,300 U/L;
reference range <308 U/L). He reported no rash. He had been
taking a statin for a year before the onset of weakness. The
statin was discontinued with no improvement a couple weeks
after symptom onset. What is the most likely diagnosis?
a. Statin-associated toxic myopathy
b. Dermatomyositis
c. Necrotizing autoimmune myopathy (NAM)
d. Inclusion body myositis (IBM)
e. Limb-girdle muscular dystrophy (LGMD)
IX.15. Answer c.
The subacute progressive course of weakness points away
from a hereditary myopathy (eg, LGMD) and favors an
acquired myopathy. Although IBM is an acquired, inflam-
matory myopathy, it typically presents with an insidious
onset and a chronic course. Patients with dermatomyositis
and NAM generally have subacute progressive weakness.
Without a rash, dermatomyositis is unlikely. Statins can
cause toxic myopathy and immune-mediated myopathy
(NAM). Discontinuation of statins leads to improvement of
weakness in patients with statin-associated toxic myopathy
but not in patients with statin-associated NAM.
IX.16. If a patient is suspected of having necrotizing autoimmune
myopathy (NAM), for which of the following autoantibodies
should the patient be tested?
a. 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR)
b. Cytosolic 5′-nucleotidase 1A (NT5C1A)
c. Melanoma differentiation-associated gene 5 (MDA5)
d. Nuclear matrix protein 2 (NXP2)
e. Transcriptional intermediary factor 1γ (TIF-1γ)
IX.16. Answer a.
Statin-associated NAM is commonly associated with anti-
HMGCR antibody. Anti-NT5C1A antibody is seen in
approximately 70% of patients with inclusion body myosi-
tis. Anti-MDA5, NXP2, and TIF-1γ antibodies are specific to
dermatomyositis.
IX.17. A 77-year-old woman had a 6-year history of hand and proximal
lower limb weakness and a 1-year history of difficulty swallow-
ing. Neurologic examination showed prominent but asymmet-
ric weakness and atrophy of finger flexors and quadriceps.
Creatine kinase was 455 U/L (reference range <192 U/L).
Electromyography (EMG) showed early recruiting and mixed
small and large motor unit potentials associated with fibrillation potentials. The patient underwent biopsy of the
quadriceps, which confirmed a diagnosis. What are the most
likely muscle biopsy findings?
a. Atrophic muscle fibers in the perifascicular regions
b. Nemaline rods
c. Necrotic and regenerating fibers without inflammation
d. Autoaggressive inflammation, rimmed vacuoles, and intracellu-
lar congophilic inclusions
e. Selective loss of myosin thick filaments
IX.17. Answer d.
The history and clinical and EMG findings are typical of
inclusion body myositis (IBM). The canonical biopsy find-
ings of IBM include an autoaggressive inflammatory exu-
date, rimmed vacuoles, and intracellular congophilic
deposits. Perifascicular muscle fiber atrophy is the patho-
logic hallmark of dermatomyositis. In necrotizing autoim-
mune myopathy, muscle biopsy typically shows necrotic
and regenerating fibers without inflammation. Nemaline
rods can occur in congenital nemaline myopathy and an
acquired sporadic late-onset nemaline myopathy. Selective
loss of myosin thick filaments is the typical finding in criti-
cal illness myopathy.
IX.18. A 22-year-old woman had a 5-year history of progressive proxi-
mal weakness and an elevated creatine kinase (CK) level (4,350
U/L; reference range <176 U/L). Clinical and electrical myotonia
were not observed. Contractures were absent. Cardiac evalua-
tion findings were unremarkable. Her brother had a markedly
elevated CK level and similar symptoms. What is the most likely
diagnosis?
a. Congenital muscular dystrophy
b. Duchenne muscular dystrophy
c. Emery-Dreifuss muscular dystrophy
d. Myotonic dystrophy type 1
e. Limb-girdle muscular dystrophy
IX.18. Answer e.
Limb-girdle muscular dystrophies are autosomally inher-
ited muscular dystophies with predominantly proximal
weakness and may manifest from childhood to adulthood.
Bulbar and extraocular muscles are usually spared.
Duchenne muscular dystrophy is an X-linked disorder, and
weakness typically starts in early childhood. Emery-
Dreifuss muscular dystrophy often presents in early to
middle childhood with a predominant scapulohumeroper-
oneal weakness associated with early joint contractures
and cardiac involvement. It can be X-linked or autosomally
inherited. Myotonic dystrophy type 1 is an autosomal dom-
inant disorder, which typically presents with distal muscle
weakness and clinical myotonia.
IX.19. A 15-year-old boy presented with chronic progressive ophthal-
moparesis and retinitis pigmentosa. Which of the following
would a muscle biopsy most likely show?
a. Central cores
c. Ragged red fibers
d. Rimmed vacuoles
e. Subsarcolemmal glycogen accumulations
IX.19. Answer c.
The description of this patient is suggestive of mitochondrial
disorders. Retinitis pigmentosa is commonly seen in mito-
chondrial disorders, although ophthalmoparesis can be seen
in other myopathies, including oculopharyngeal muscular
dystrophy, some congenital myopathies (eg, RYR1-related
myopathies), and immune checkpoint inhibitor–associated myopathy. The pathologic hallmarks of mitochondrial dys-
function include ragged red fibers, ragged blue fibers, and
cytochrome-c oxidase-negative fibers. Central cores and
nemaline rods are characteristic features of congenital
myopathies. Rimmed vacuoles can be seen in various
acquired and hereditary myopathies, including oculopha-
ryngeal muscular dystrophy. Glycogen accumulation is a
diagnostic feature of glycogen storage diseases.
IX.20. A 32-year-old man had progressive dyspnea on exertion and
required bilevel positive airway pressure. On examination, he
had mild proximal weakness. Clinical myotonia was not observed.
Needle electromyography showed myopathic motor unit poten-
tials and myotonic discharges. Muscle biopsy showed vacuoles overreactive for acid phosphatase activity. What is the most likely
a. Acid α-glucosidase deficiency (Pompe disease)
b. Congenital muscular dystrophy due to merosin deficiency
c. Myotonic dystrophy type 1
d. Myotonia congenita
e. Paramyotonia congenita
IX.20. Answer a.
In acid α-glucosidase deficiency (Pompe disease), muscle
biopsy shows vacuoles containing glycogen and overreac-
tivity for acid phosphatase because of their lysosomal ori-
gin. Respiratory muscle weakness is frequently present in
the juvenile and adult forms and can be the presenting sign.
IX.21. What type of glial cytoplasmic inclusions characterize multiple
system atrophy (MSA)?
a. Tau
b. α-Synuclein
c. Lewy body
d. Cowdry type A inclusion body
e. Bunina body
IX.21. Answer b.
MSA is characterized neuropathologically by glial cyto-
plasmic inclusions with positive α-synuclein staining and
neuronal loss in the brainstem, cerebellum, basal ganglia,
cortex, and spinal cord. Tau is present in neurodegenera-
tive diseases such as Alzheimer disease. Lewy bodies are
characteristic of Parkinson disease and diffuse Lewy body
disease. Cowdry type A inclusion bodies are eosinophilic
or basophilic nuclear inclusions that are composed of
nucleic acid and protein and are seen in cells infected with
viruses such as herpes simplex virus. Bunina bodies are
seen in amyotrophic lateral sclerosis and are intraneuronal
inclusions in lower motor neurons.
IX.22. A 19-year-old woman presents with mental fog, postural light-
headedness, and fatigue. While sitting, she has a blood pressure
of 110/60 mm Hg and a heart rate of 60 beats per minute. While
standing, she has a blood pressure of 105/60 mm Hg and a
heart rate of 96 beats per minute. Which of the following state-
ments is true?
a. She does not meet the criteria for postural orthostatic tachycar-
dia syndrome (POTS)
b. She meets the criteria for POTS
c. The likely underlying condition for her symptoms is amyloid
neuropathy
d. The use of an abdominal binder while she is upright probably
would not help her
e. Midodrine would be first-line therapy for her condition
IX.22. Answer b.
A diagnosis of POTS is confirmed with a tilt table or stand-
ing test that shows a sustained orthostatic increase in heart
rate of more than 30 beats per minute and reproduces
symptoms of orthostatic intolerance. Conservative mea-
sures to treat orthostatic symptoms would be considered
before pharmacologic therapy.
IX.23. Multiple system atrophy can be distinguished from diffuse Lewy
body disease by which of the following?
a. Positive family history
b. Presence of autonomic symptoms
c. Presence of severe cognitive impairment
d. Presence of bradykinesia
e. Presence of a tremor
IX.23. Answer c.
Both diffuse Lewy body disease and multiple system atro-
phy are typically sporadic conditions, and patients may
have autonomic symptoms, bradykinesia, and tremor.
However, the degree of cognitive impairment is generally
more severe in patients with diffuse Lewy body disease.
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