Neurosurgery Flashcards
- A 43-year-old man experiences lower back pain
after lifting a heavy object off the ground. The
following morning, he notices that the pain has
begun to radiate down the posterolateral aspect
of the right leg and across the top of the foot to
the big toe. The pain is severe, electric in quality, associated with paresthesia over the same
distribution, and made worse by coughing. On
examination, it is found that he has an area of
diminished sensation to pinprick over the
dorsum of the right foot and mild weakness in
his right extensor hallucis longus muscle. The
deep tendon reflexes are all intact. What is the
most likely diagnosis?
(A) Lumbar spinal fracture with compression
of the cauda equina
(B) Herniated lumbar disk on the right at
the level of L4–L5
(C) Herniated lumbar disk on the left at the
level of L4–L5
(D) Herniated lumbar disk on the right at
the level of S1–S2
(E) Intermittent claudication
- (B) The patient has a right-sided L5 radiculopathy, most likely resulting from a disk herniation
at the right L4–L5 interspace. The key to this
diagnosis is in understanding the dermatomal
anatomy of the lower extremity. The L5 dermatomal distribution involves the lateral calf
and the dorsomedial aspect of the foot. The dermatome also typically includes the big toe.
- A 48-year-old woman has a lower back pain
and hypoesthesia in the left S1 dermatomal distribution (left calf and lateral left foot). What is
the most likely cause?
(A) A lesion at the right L4–L5 interspace
(B) Pathology where the nerve exits the
spinal canal immediately above the
pedicle of S3 vertebra
(C) A herniated nucleus pulposus
(D) Compression by the L5 lamina
(E) A lesion outside the vertebral column
- (C) Thoracic, lumbar, and sacral nerves exit off
the spinal canal immediately below the pedicle
of the corresponding numbered vertebra. The
left S1 root, for example, passes immediately
dorsal to the L5–S1 disk, where it can be susceptible to compression by a herniated nucleus
pulposus. The root then swings laterally to exit
immediately caudal to the left L5 pedicle. For
a correlation between level of disk herniation
and the root affected, see the table below.
Level of Herniation Root Affected
L1–L2 L2
L2–L3 L3
L3–L4 L4
L4–L5 L5
L5–S1 S1
- A 35-year-old secretary complains of severe
pain in the neck that radiates down the right
arm. The pain is electric in quality and affects
specifically the radial aspect of the right forearm
and the thumb. She also describes numbness
and paresthesia over the same distribution. On
physical examination, she is found to have an
area of diminished sensation to pinprick over
the right wrist and thumb. The right biceps
tendon reflex is diminished, but there is no loss
of muscle strength. She has right C5–C6 disk
compression and radiculopathy affecting which
of the following?
(A) The right C4 root
(B) The right C4 mixed spinal nerve
(C) The right C4 anterior primary rami
(D) The right C6 root
(E) The right C6 spinal ganglion
- (D) This patient has radiculopathy of her right
C6 root. To make this diagnosis, it is essential
to understand the dermatomal anatomy of the
upper extremity. The C6 dermatome includes
the radial aspect of the distal forearm and
hand. The C4 dermatomes include the deltoid
region. The biceps tendon jerk is mediated by
the C5 and C6 roots.
A 47-year-old man presents to the emergency department after falling from his bicycle. He claims that
his neck was suddenly and violently hyperflexed.
Although he is currently complaining of neck pain,
his chief complaint is weakness of the arms. On
examination, he is found to have profound symmetric weakness of both hands and wrists. His
biceps and triceps are moderately weak. The lower
extremities are only minimally weak, and he is able
to ambulate, albeit with some difficulty. His sensation to all modalities is within normal limits. Plain
radiographs of his neck reveal no fracture or dislocation, but there is evidence of severe spondylosis
with osteophytes narrowing the neural canal at
C3–C4, C4–C5, and C5–C6.
4. What is the most likely mechanism of injury? (A) Brachial plexus injury (B) Epidural hematoma (C) Contusion of the spinal cord (D) External carotid artery occlusion (E) Internal jugular vein occlusion
- (C) The mechanism of injury was a contusion to
the cervical spinal cord. This probably occurred
when the violent hyperflexion of the neck
caused the cervical cord to bump against the
osteophytic ridges of the spine. The typical clinical picture of a spinal cord contusion is a central cord syndrome.
A 47-year-old man presents to the emergency department after falling from his bicycle. He claims that
his neck was suddenly and violently hyperflexed.
Although he is currently complaining of neck pain,
his chief complaint is weakness of the arms. On
examination, he is found to have profound symmetric weakness of both hands and wrists. His
biceps and triceps are moderately weak. The lower
extremities are only minimally weak, and he is able
to ambulate, albeit with some difficulty. His sensation to all modalities is within normal limits. Plain
radiographs of his neck reveal no fracture or dislocation, but there is evidence of severe spondylosis
with osteophytes narrowing the neural canal at
C3–C4, C4–C5, and C5–C6.
5. What is this pattern of motor findings that results from this injury termed? (A) Central cord syndrome (B) Cervical radiculopathy (C) Cauda equina syndrome (D) Lhermitte sign (E) Posterior cord syndrome
- (A) The central spinal cord syndrome describes
the following pattern of weakness: (a) weakness
in upper extremity is greater than weakness in
lower extremity; (b) weakness in distal muscles
is greater than weakness in proximal muscles
and limb girdle. This results from the distribution
of motor fibers within the corticospinal tracts of
the cervical cord. Fibers supplying the upper
extremity and more proximal muscles are more
centrally located and, thus, more susceptible to
dysfunction from a central injury. Within the
spinal cord, sensory fibers are more peripherally located and, thus, less frequently affected.
Sensory deficits, when present, are often variable and inconsistent. A Lhermitte’s sign or syndrome also results from stenosis of the cervical
canal, causing compression of the spinal cord.
The patient develops severe numbness and
paresthesia of the upper extremities as the result
of sustained hyperextension of the neck.
A 57-year-old woman is referred to you for evaluation of difficulty with ambulation. Her chief complaint is weakness of her left leg that has been slowly
progressive over the last 6 months. On neurologic
examination, her mental status and cranial nerve
findings are within normal limits. She has marked
(grade 4–5) weakness of both her left leg and arm.
On her left side, she has diminished sensation to
light touch and vibration below the C5 dermatome.
Sensation to pinprick and temperature are severely
diminished on the right side below approximately
the C8 dermatome. Her deep tendon reflexes and
muscle tone are increased on the left.
6. This pattern of neurologic deficits is which of the following? (A) Spondylolisthesis (B) Brown-Sequard syndrome (C) Central cord syndrome (D) Guillain-Barré syndrome (E) Poliomyelitis
- (B) Brown-Sequard syndrome (Fig. 11–3)
describe (a) weakness of muscle ipsilaterally
below the spinal cord lesion, (b) impaired sensation to light touch and vibration ipsilaterally
below the spinal cord lesion; and (c) impaired
sensation to pain and temperature contralaterally below the spinal cord lesion.
A 57-year-old woman is referred to you for evaluation of difficulty with ambulation. Her chief complaint is weakness of her left leg that has been slowly
progressive over the last 6 months. On neurologic
examination, her mental status and cranial nerve
findings are within normal limits. She has marked
(grade 4–5) weakness of both her left leg and arm.
On her left side, she has diminished sensation to
light touch and vibration below the C5 dermatome.
Sensation to pinprick and temperature are severely
diminished on the right side below approximately
the C8 dermatome. Her deep tendon reflexes and
muscle tone are increased on the left.
7. This pattern of neurologic deficits is explained by injury to the spinal cord with damage to which of the following? (A) Anterior horn cells (B) Peripheral neuropathy (C) Central cord (D) Right half (right hemicord) (E) Left half (left hemicord)
- (E) The motor deficit is on the left ipsilateral
side. Brown-Sequard syndrome is caused by
unilateral injury or dysfunction following
hemisections of the spinal cord. In the human
nervous system, motor and sensory functions
on one side of the body are under the direct
control of the opposite side of the brain. All
major motor and sensory tracts decussate. The
decussation of the various tracts occurs at different levels of the neuraxis.
- A 73-year-old man presents for evaluation of
weakness in his lower extremities and recurrent
falls. On further questioning, the patient admits
to having frequent spasms affecting both of his
lower extremities. He also claims that his legs
occasionally feel as if ants were crawling all over
them. On neurological examination, he is found
to have a slightly unstable gait and with minimal flexion of the knees. His strength is slightly
but symmetrically diminished in both lower
extremities and both triceps muscles. There is
decreased sensation to vibration and light touch
below approximately the level of the nipples
bilaterally. In both lower extremities, muscle
tone is markedly increased, and deep tendon
reflexes are hyperactive. Babinski’s reflex is present bilaterally. What is the most likely diagnosis?
(A) A thoracic spinal cord compression (B) A thoracic radiculopathy (C) A cervical myelopathy (D) Cerebellar tumor (E) Intracranial aneurysm
- (C) On subsequent MRI of the cervicothoracic
spine, this patient is found to have severe
spondylosis at multiple levels of the spine.
There is spinal cord compression by a large
osteophyte at the level of C6–C7. The patient
has all the signs and symptoms of cervical
spinal cord dysfunction. The weakness affecting the triceps muscles in addition to the lower
extremities indicates that the lesion is above
the level of the thoracic cord. Absence of similar symptoms on the face as well as the absence
of cranial nerve abnormalities indicate that
the lesion is not intracranial. The diffuseness of
the symptoms as well as the fact that they are
associated with increased reflexes and tone
indicate that the problem lies within the CNS
(upper motor neuron) rather than the peripheral nervous system (lower motor neuron).
- An 87-year-old woman is referred to you for
evaluation of lower back pain. It is exacerbated
by walking or prolonged standing and occasionally made better by bending over. Physical
examination reveals a thin, elderly woman
who walks with a cane with her lower back
moderately flexed. Motor power in her lower
extremities is normal, but she has impaired
sensation to light touch and vibration below
the L4 dermatome bilaterally. Deep tendon
reflexes are normal in her upper extremities
but absent in both lower extremities. You refer
her for magnetic resonance imaging (MRI) of
the lumbosacral spine. What will be the most
likely finding on this study?
(A) Lumbar spinal stenosis
(B) A fracture of the odontoid process
(C) A herniated L3–L4 disk causing unilateral
compression of the L4 root
(D) Spinal cord compression at the level of
L1 vertebra level
(E) Spinal cord compression at the T1
vertebra level
- (A) The clinical presentation indicates a lower
motor neuron lesion. The clinical diagnosis is
neurologic claudication secondary to lumbar
spinal stenosis, which is commonly seen in elderly persons in whom (as a consequence of
wear and tear over the years) bony structures
of the lumbar spine hypertrophy and develop
osteophytes. These bony changes, in turn, lead
to stenosis of the spinal canal and intervertebral
foramina. Thus, the result is compression and
dysfunction of multiple lumbosacral nerve
roots bilaterally. Bending over opens the
lumbar canal and relieves the stenosis.
- A 33-year-old man is brought to the emergency
department after being involved in a major
motor vehicle accident. He is unable to move his
legs and complains of severe pain in his mid
to lower back. On physical examination, he is
found to have exquisite tenderness over some of
the bony prominence of his lower back, but no
gross physical deformity can be appreciated. On
neurologic examination, flaccid paralysis of both
lower extremities and complete anesthesia to all
sensory modalities below approximately the L3
dermatome are noted. Catheterization of his
bladder yields approximately 700 mL of urine.
Plain radiographs of the spine reveal compression fracture in the body of L3 with greater than
50% of loss in its height. A computed tomography (CT) scan through this area reveals a burst
fracture of the body of L3. There are large fragments of bone driven dorsally with an 80% canal
compromise. What is the cause of weakness?
(A) Compression of the conus medullaris
(B) Compression of the spinal cord at the
level of L3
(C) Compression of the cauda equina
(D) Rupture of the anterior spinal ligament
(E) Associated epidural hemorrhage
- (C) This patient has suffered a traumatic fracture of L3 in which bony fragments were displaced dorsally to compress the cauda equina
at that level. It is important to remember that
the spinal cord does not extend along the entire
length of the spine. The conus medullaris, the
most caudal tip of the spinal cord, ends in 98%
of people at or above L2 vertebrae. Thus, it is
highly unlikely for an L3 fracture to cause compression of the spinal cord or conus medullaris.
A 17-year-old boy suffers a hyperextension injury of his
neck when he jumps headfirst into a shallow pool. He
does not lose consciousness. He arrives at the emergency department holding his neck stiffly and complaining of severe neck pain. He says the pain is
particularly severe whenever he tries to move his head.
He says he has no neurologic symptoms such as weakness, numbness, or paresthesia. On physical examination, he is found to have no areas of ecchymosis or deformity on the cervical spine. He has exquisite pain
on deep palpation of the bony prominence of the midcervical spine. There are no neurological signs. Routine
plain radiographs (anteroposterior [AP], lateral, openmouth view) of the cervical spine in the neutral position show no fracture or subluxation of the bony
elements. There is, however, thickening of the pretracheal space ventral to the body of C6, suggesting softtissue swelling.
- What would the next step in management
involve?
(A) Analgesics alone
(B) A hard cervical collar
(C) Internal fixation of the cervical vertebra
(D) Burr holes and traction
(E) Plaster cast to face, neck, and thorax
- (B) The most appropriate step is to place him in
a hard cervical collar to protect his neck and
obtain plain lateral radiographs in flexion and
extension. In this boy, the continuous neck pain
and the prevertebral swelling on the plain radiographs are strongly suggestive of an injury to
the ligamentous structures of the cervical spine.
A severe ligamentous tear can lead to instability of the spine from excessive movement
between adjacent vertebrae. Ligamentous
injury must be ruled out by obtaining lateral
radiographs in flexion and extension to demonstrate any excessive movement between adjacent vertebrae. This excessive movement, if
missed, can result in compression of the cervical spinal cord and a serious neurologic deficit.
These studies require supervision by appropriate specialist consultants.
A 17-year-old boy suffers a hyperextension injury of his
neck when he jumps headfirst into a shallow pool. He
does not lose consciousness. He arrives at the emergency department holding his neck stiffly and complaining of severe neck pain. He says the pain is
particularly severe whenever he tries to move his head.
He says he has no neurologic symptoms such as weakness, numbness, or paresthesia. On physical examination, he is found to have no areas of ecchymosis or deformity on the cervical spine. He has exquisite pain
on deep palpation of the bony prominence of the midcervical spine. There are no neurological signs. Routine
plain radiographs (anteroposterior [AP], lateral, openmouth view) of the cervical spine in the neutral position show no fracture or subluxation of the bony
elements. There is, however, thickening of the pretracheal space ventral to the body of C6, suggesting softtissue swelling.
- What would be the most appropriate radiologic examination?
(A) Plain lateral radiographs in flexion and
extension to rule out occult ligamentous
tear and instability of the cervical spine
(B) A CT scan of the cervical spine to rule
out the possibility of a bony fracture not
seen on plain radiographs
(C) Lateral tomogram of the cervical spine
to rule out the possibility of an occult
fracture
(D) Angiography
(E) Ultrasound of the neck
- (A) A CT scan of the cervical spine is more sensitive for fractures of the spine than are plain
Answers: 1–12 251
Figure 11–3.
Brown-Sequard syndrome. The lesion depicted here is at a lower
spinal cord level than that described in the text. (Reproduced, with
permission, from Lindner HH: Clinical Anatomy. Appleton &
Lange, 1989.)
radiographs. Because CT images are in the axial
plane, only one vertebral body can be seen at a
time. This makes CT scanning entirely inadequate to rule out all but large subluxation
resulting from the most major ligamentous disruptions. Sagittal MRI of the cervical spine in
this case may show swelling or hematoma
within the soft tissues of the spine. MRI, however, is poor in demonstrating bony anatomy
and detail. Furthermore, without flexion and
extension of the neck, an MRI of the cervical
spine is no better in showing bony instability
than plain radiographs in the neutral position.
A 63-year-old woman with a history of local inoperable breast cancer is referred to you for the evaluation of
new-onset diplopia. Upon questioning, she admits that
diplopia occurs mostly when she attempts to look at
objects in the distance and when she attempts to look
toward the left side. In addition, she reports having
severe headaches and an electric-type discomfort
affecting her right deltoid region for approximately
3 weeks. On neurologic examination, she is found to
have left abducens (sixth) nerve palsy; the rest of her
cranial nerves are intact. She also has mild weakness of
the right deltoid and a diminished biceps tendon jerk
on the same side. Findings on an MRI of the brain with
intravenous contrast are unremarkable.
13. In this patient, what would be the most likely site where metastasis occurs? (A) Brain (B) Orbital cavity (C) Meninges (D) Cerebellum (E) Optic chiasm
- (C) Meningeal carcinomatosis results when
malignant cells gain access to the CSF and are
able to disseminate within it. Cells most commonly adhere to and affect the neural structures traversing the CSF, such as cranial nerves
and peripheral nerve roots. Cells cause dysfunction at multiple sites of the CNS. This
patient has a left abducens nerve palsy and a
right C5 radiculopathy, making the diagnosis of
meningeal carcinomatosis highly likely.
A 63-year-old woman with a history of local inoperable breast cancer is referred to you for the evaluation of
new-onset diplopia. Upon questioning, she admits that
diplopia occurs mostly when she attempts to look at
objects in the distance and when she attempts to look
toward the left side. In addition, she reports having
severe headaches and an electric-type discomfort
affecting her right deltoid region for approximately
3 weeks. On neurologic examination, she is found to
have left abducens (sixth) nerve palsy; the rest of her
cranial nerves are intact. She also has mild weakness of
the right deltoid and a diminished biceps tendon jerk
on the same side. Findings on an MRI of the brain with
intravenous contrast are unremarkable.
- What would the next step in management
involve?
(A) An MRI of the cervical spine to rule out
metastatic deposits within the cervical
roots
(B) A CT scan of the brain with intravenous
contrast
(C) A lumbar puncture to measure opening
pressure and obtain cerebrospinal fluid
(CSF) for cytologic analysis
(D) Repeated breast biopsy
(E) No further tests until further symptoms
develop
- (C) In the presence of meningeal carcinomatosis (also called carcinomatous meningitis), the
lumbar puncture CSF examination may reveal
elevated protein and positive cytology. The sensitivity of MRI to detect small tumor deposits
within the intracranial compartment is much
greater than that of a CT scan. Thus, a CT scan
is unlikely to be helpful in this clinical scenario.
- A 57-year-old woman presents to the emergency
department with new-onset seizures. She was
witnessed by her husband to have a generalized seizure lasting approximately 1 minute. She
has smoked 1 pack of cigarettes a day for over
40 years. In the past 3 months, she has lost 25 lb
in weight. On examination, she appears thin
and nervous but findings on her neurologic
examination are otherwise essentially within
normal limits. Plain radiographs of the chest
obtained in the emergency department show a
4-cm nodule in the upper lobe of her right lung.
To exclude cerebral metastasis as a cause of her
seizure, what should the next test requested be?
(A) An electroencephalogram (EEG)
(B) A CT scan of the brain with intravenous
contrast
(C) A spinal tap to measure opening pressure
and obtain CSF for cytology
(D) An MRI of the brain with intravenous
contrast
(E) Doppler ultrasound
- (D) An adult with new onset seizures is considered to have a brain tumor until proved otherwise. The best test available to detect metastatic
deposits in the brain is the MRI with intravenous
contrast. MRI is exquisitely sensitive in diagnosing brain metastasis, sometimes detecting
them by the brain edema they induce even when
the lesion itself is too small to be seen. The EEG
may likely show the presence of seizure activity
and even localize it to a particular region of the
brain; it will not, however, answer the question
of what pathologic process is responsible. Also,
in this case, because a mass lesion is expected,
performing a spinal tap is relatively contraindicated for the fear of inducing uncal herniation in
a patient who may have increased ICP.
A 58-year-old woman is admitted from the emergency
department with a history of approximately 2 weeks
of headache. She has a history of breast cancer. Her
headache is severe, particularly in the mornings when
she wakes up. It is accompanied by occasional vomiting. She says she experiences no focal weakness,
numbness, or paresthesia. On physical examination,
she is found to have a mild weakness of her left arm.
An MRI of the brain with intravenous contrast reveals
the presence of a neoplasm in the right motor cortex
that is considered responsible for her weakness.
16. If the MRI shows multiple brain metastasis, what should be the treatment required in addition to corticosteroids? (A) Whole-brain radiotherapy (B) Craniotomy to resect the lesion responsible for her left arm weakness (C) Chemotherapy (D) Placement of an Ommaya reservoir for use in treatment by intrathecal chemotherapy (E) No further treatment
- (A) The optimal management of any intracranial
neoplasm includes use of corticosteroids. These
significantly diminish the amount of tumorinduced brain edema and are remarkably effective in ameliorating symptoms caused by CNS
neoplasms. The current recommendation for the
treatment of multiple brain metastasis is treatment with a full course of fractionated radiation to the whole brain. This is geared to treat all
visible lesions within the parenchyma as well as
those that may still be too small to be detected.
Intrathecal chemotherapy is effective in treating meningeal carcinomatosis, where the primary site of involvement is the meninges and
the surface of the brain. The two available agents
for this modality of treatment have very poor
penetration into deeper regions of the brain
when administered intrathecally.
A 58-year-old woman is admitted from the emergency
department with a history of approximately 2 weeks
of headache. She has a history of breast cancer. Her
headache is severe, particularly in the mornings when
she wakes up. It is accompanied by occasional vomiting. She says she experiences no focal weakness,
numbness, or paresthesia. On physical examination,
she is found to have a mild weakness of her left arm.
An MRI of the brain with intravenous contrast reveals
the presence of a neoplasm in the right motor cortex
that is considered responsible for her weakness.
17. If the MRI shows a single brain metastasis, what should be the next step in management? (A) Whole-brain radiotherapy (B) Craniotomy to resect the lesion responsible for her left arm weakness (C) Chemotherapy 240 11: Neurosurgery (D) Placement of an Ommaya reservoir for use in treatment by intrathecal chemotherapy (E) No further treatment
- (B) Surgical resection is recommended only for
cases involving a single brain metastasis that is
surgically accessible in patients with a reasonable life expectancy. It is also relatively indicated in patients with multiple brain lesions in
whom one particular lesion is imminently lifethreatening. Intravenous chemotherapy has,
unfortunately, yielded poor results in the
treatment of brain metastasis. This is particularly so in this patient, because her tumors are
already likely to be resistant to the chemotherapeutic agents with which she has already been
treated.
- A 63-year-old woman presents with a severalweek history of headaches and difficulties with
speech. A sister who lives with her claims that
her language “has recently not been making
much sense” and that she is a bit confused. Her
condition seems to be deteriorating. On neurologic examination, she has a moderately
severe aphasia, with difficulty understanding
language and following commands, and she
makes frequent paraphasic errors when she
speaks. There are no other motor or sensory
deficits. An MRI with intravenous contrast
reveals the presence of a ring-enhancing mass
lesion within the substance of the left temporal
lobe. The lesion is approximately 3 cm in greatest diameter, poorly demarcated from the surrounding brain, and surrounded by a moderate
amount of cerebral edema. Findings on routine admission tests, including a chest x-ray
and serum chemistry, are unremarkable. What
is the most likely diagnosis?
(A) Low-grade cerebral astrocytoma
(B) Glioblastoma multiforme
(C) Metastasis to the brain from an occult
primary cancer
(D) Meningioma
(E) Glomus tumor
- (B) Glioblastoma multiforme is a highly malignant neoplasm, arising from glial cells or their
precursors within the CNS. It is the most
common of all primary malignancies of the CNS
and its peak incidence is within the fifth to seventh decade of life. A low-grade astrocytoma is
a tumor derived from glial cells of astrocytes.
Fig. 11–4, shows a large cystic giant astrocytoma
on T2 weighted MRI where fluid is shown as a
white area with midline shift (not glioblastoma
multiforme presented in this question).
- A 64-year-old man presents with headache and
left-sided upper extremity weakness. The MRI
findings suggest that this is a glioblastoma
multiforme. This is because the tumor exhibits
which of the following?
(A) It is regular in shape.
(B) It is well demarcated from surrounding
brain tissue.
(C) It shows a ring pattern of enhancement
with intravenous contrast and has a
nonenhancing necrotic center.
(D) It shows an absence of surrounding
white-matter edema.
(E) It arises from the carotid body.
- (C) Glioblastoma multiforme grows rapidly, and
the tumor often contains a necrotic core that
occurs as its growth surpasses its blood supply.
Additional features on MRI include irregular
shape, poor demarcation from surrounding
252 11: Neurosurgery
brain tissue, and the presence of variable
amount of surrounding white-matter edema.
- A 63-year-old woman presents for workup to
determine the reason for a gradual hearing loss
over approximately 5 years and intermittent
tinnitus over the last several months. Findings
on physical and neurologic examination are
entirely within normal limits, except for the
presence of sensorineural hearing loss in the
left ear. She has no cranial nerve deficits. An
MRI of the brain with gadolinium reveals the
presence of an extra-axial tumor in the region
of the left cerebella-pontine angle. What is the
most likely diagnosis?
(A) Epidermoid tumor (cholesteatoma)
(B) Glioblastoma multiforme
(C) Meningioma
(D) Acoustic neuroma
(E) Glomus tumor
- (D) This cerebella-pontine angle tumor is most
likely an acoustic neuroma. This is the most
commonly encountered neoplasm in this
region. It arises from the Schwann cells that
form the myelin sheath of the vestibular division of the eighth cranial nerve (hence a more
accurate name is vestibular schwannoma). This
tumor typically arises within the internal
acoustic canal and growths in the direction of
least resistance—through the meatus into the
cerebellopontine angle cistern.
A 4-year-old boy is brought to the emergency department with the complaint of approximately 2 weeks of
headache and vomiting. He was seen in the emergency department 1 week earlier with the same complaints. At that time, his parents were told that the
probable cause was a gastrointestinal virus, and
the boy was sent home. His symptoms have not
improved. On general examination, the child appears
somewhat dehydrated and has a dry mouth and
sunken eyes. His examination findings are also
remarkable for the presence of bilateral papilledema
and marked nystagmus. An MRI with intravenous
contrast is obtained that reveals the presence of a
2-cm mass in the posterior fossa. The mass is entirely
within the fourth ventricle and appears to be arising
from the vermis of the cerebellum. It enhances uniformly with contrast. The lateral and third ventricles
are moderately dilated with hydrocephalus.
21. What is the most likely diagnosis? (A) Acoustic neuroma (B) Craniopharyngioma (C) Medulloblastoma (D) Brain metastasis (E) Polycystic cerebellar astrocytoma
- (C) An astute neurologist once said that in neurologic diagnosis, as in real estate, location is
everything. He alluded to the fact that in the
diagnosis of neurologic ailments, one can often
generate lists of possible diagnoses based solely
on the location of the lesion in question. With
unusual exceptions, each location within the
CNS is likely to be associated with a certain type
of neoplasm. The medulloblastoma (also called
a primitive neuroectodermal tumor or PNET) is
a highly aggressive and rapidly growing tumor
that most often arises within the cerebellar
vermis. It usually grows locally as a roughly
spherical mass to bulge into and obliterate
the adjacent fourth ventricle. Ependymoma or
choroid plexus papilloma should also be considered in the differential diagnosis.
A 4-year-old boy is brought to the emergency department with the complaint of approximately 2 weeks of
headache and vomiting. He was seen in the emergency department 1 week earlier with the same complaints. At that time, his parents were told that the
probable cause was a gastrointestinal virus, and
the boy was sent home. His symptoms have not
improved. On general examination, the child appears
somewhat dehydrated and has a dry mouth and
sunken eyes. His examination findings are also
remarkable for the presence of bilateral papilledema
and marked nystagmus. An MRI with intravenous
contrast is obtained that reveals the presence of a
2-cm mass in the posterior fossa. The mass is entirely
within the fourth ventricle and appears to be arising
from the vermis of the cerebellum. It enhances uniformly with contrast. The lateral and third ventricles
are moderately dilated with hydrocephalus.
- If at craniotomy the tumor found is not that
listed in question 21 and the pathologist reports
that it is a benign lesion, what is that lesion?
(A) Ependymoma
(B) Choroid plexus papilloma
(C) Polycystic (cystic) cerebellar astrocytoma
(D) Teratoma
(E) Dermoid cyst
- (B) Choroid plexus papillomas are benign
tumors of the CNS that arise from the cells that
form the choroid plexus. These tumors can be
found wherever choroid plexus is present,
including the lateral and fourth ventricles.
They cause symptoms of increased ICP, most
commonly by causing massive degrees of
hydrocephalus. This can be from two mechanisms—obstruction of normal CSF pathways or
production by the tumor of excessive volumes
of CSF. (Remember that CSF is produced
mainly by the choroid plexus.) Ependymomas
are also highly malignant tumors usually
found in the fourth ventricle of children. Its
precursor cell is the ependymal cell that lines
the ventricular system. As medulloblastomas,
these tumors are highly aggressive and fast
growing. Contrary to the former, however,
ependymomas tend to arise from the floor of
the fourth ventricle (the dorsal surface of the
brainstem).
A 5-year-old girl undergoes debulking of medulloblastoma. She undergoes a repeat MRI of the brain
with intravenous contrast, which shows a small
amount of enhancement consistent with limited residual tumor. She is given a full course of radiotherapy
to the posterior fossa and does very well for 6 weeks,
until she experiences difficulty in walking. Physical
examination at this time indicates moderate weakness of both lower extremities (particularly on the
right side) but strength in her upper extremities and
cranial nerves are normal. Her sensation to light touch
and vibration are intact, but she has diminished sensation to pinprick throughout her left leg.
- What should be the next step in management?
(A) Repeat the MRI of the brain to rule out
an early recurrence
(B) Obtain a single-photon-emission CT
(SPECT) scan of the brain to rule out the
possibility of radiation-induced toxicity
(C) Begin treatment with chemotherapy for
the residual tumor within the brain
(D) Obtain an MRI or myelogram of the
entire spinal axis to rule out the
possibility of “drop metastasis” from the
medulloblastoma
(E) Obtain an ultrasound of the lumbar spine
- (D) Obtain an MRI or myelogram of the entire
spinal axis to rule out the possibility of “drop
metastasis” from the medulloblastoma. The
constellation of emerging new symptoms
points toward spinal cord dysfunction; the
Answers: 13–23 253
Figure 11–4.
Large cystic giant astrocytoma on T2 weighted MRI where fluid is shown as a white area. Midline shift.
most likely cause is the presence of drop metastasis from the medulloblastoma. Primary CNS
neoplasms rarely metastasize outside of their
site of origin. Exceptions to this statement
include both medulloblastoma and ependymoma. These tumors shed viable cells into the
CSF, where they are transferred to such distant
areas as the intracranial or, more commonly,
the spinal subarachnoid space. There they can
lodge and replicate to form tumor nodules that
can compress adjacent neural structures. The
test of choice for diagnosing the presence of
these drop metastasis is a MRI of the spine with
intravenous contrast or a myelogram.
A 5-year-old girl undergoes debulking of medulloblastoma. She undergoes a repeat MRI of the brain
with intravenous contrast, which shows a small
amount of enhancement consistent with limited residual tumor. She is given a full course of radiotherapy
to the posterior fossa and does very well for 6 weeks,
until she experiences difficulty in walking. Physical
examination at this time indicates moderate weakness of both lower extremities (particularly on the
right side) but strength in her upper extremities and
cranial nerves are normal. Her sensation to light touch
and vibration are intact, but she has diminished sensation to pinprick throughout her left leg.
- What should treatment of this girl involve?
(A) Removal of recurrent medulloblastoma
and neck dissection
(B) Ventriculoperitoneal shunt
(C) Repeat irradiation to the posterior cranial
fossa
(D) Complete craniospinal irradiation with
local boosts to the areas where tumor
nodules are detected
(E) Cortisone alone
- (D) Treatment of drop metastasis consists primarily of complete craniospinal irradiation with
local boosts to the areas where tumor nodules
are detected. Chemotherapy, particularly a combination of procarbazine, lomustine (CCNU),
and vincristine (PCV), is usually given to treat
disease that is locally recurrent after maximal
irradiation. Radiation-induced toxicity or radionecrosis is highly unlikely to be the cause of
these newly developed symptoms. The first
reason for this is that the child’s new symptoms
and findings appear to be exclusively spinal in
origin. Second, radiation-induced necrosis, a
feared complication of CNS irradiation, is never
observed in such a short interval after completing treatment.
- A 35-year-old man is brought to the hospital
unconscious after being resuscitated in an ambulance from the site of a motor vehicle accident.
No other history or information is available.
On general inspection, he is found to have multiple bruises over his body and has a massively
swollen left thigh. His vital signs are stable with
a heart rate of 100 beats per minute (bpm) and
a blood pressure of 150/75 mm Hg. He is
obtunded and does not follow commands or
open his eyes. He withdraws his left arm and
leg from painful stimuli, but not his right. His
left pupil is 3 mm in diameter, and it is sluggishly reactive to light, while his right is 5 mm
in diameter and fixed. Corneal reflexes are present bilaterally. His pulse rate is 120 bpm and respiration rate is 40 breaths per minute. To avoid
injury to his spinal cord by an unstable cervical
spine, an order is issued to not perform testing
of his doll’s eye reflex. Intracranial hemorrhage
causing increased intracranial pressure (ICP) is
suspected, along with a right uncal herniation.
What is the next step in management?
(A) Intubation of his airway for
hyperventilation and administration of
intravenous mannitol
(B) Immediate CT scanning of the brain to
confirm the presence of the suspected
intracranial hemorrhage
(C) Intubation of his airway for
hyperventilation and intravenous
administration of corticosteroids
(D) Immediately evacuation of the suspected
intracranial hematoma
(E) Controlled hypoventilation
- (A) Intubation will accomplish two purposes.
First, it will protect the airway and prevent
the possibility of aspiration. Second, it will
allow controlled hyperventilation (PCO2 of
25–30 mm Hg), which causes cerebral vasoconstriction, which, in turn, transiently lowers
ICP and reduces intracranial intravascular
blood volume. Mannitol will reduce intracerebral pressure and volume. The role of corticosteroids in the management of cerebral
trauma is controversial at best. Their advocates propose that corticosteroids work by
reducing the amount of traumatically induced
brain edema. Even these investigators concur
that their effect is not immediate and that they
take at least 4–6 hours to work. The subdural
space is between the inner layer of dura and
the arachnoid.
26. In the management of a 64-year-old woman struck by a car, mannitol is given to do which of the following? (A) Increase CSF formation (B) Increase the respiratory rate 242 11: Neurosurgery (C) Increase the pulse rate (D) Replace extensive fluid loss (E) Lower raised ICP
- (E) Mannitol is a complex sugar that remains in
the intravascular space because of its high
molecular weight. When it is given in large
doses (1–2 g/kg of body weight), water is
extracted from the cerebral interstitium by its
osmotic effect, causing reduction in total brain
volume. Both these measures are temporizing
steps to allow enough time for definitive diagnosis and treatment to take place. The effect of
hyperventilation on ICP rapidly wears off after
a few hours. Over time, mannitol will diffuse
into the cerebral interstitium, losing its effectiveness and even exacerbating cerebral edema.
A note of caution, however, mannitol is an
osmotic diuretic and as such must be given
with extreme caution in the setting of hypotension due to excessive blood loss.
- A 17-year-old boy is brought to the emergency
department after he was assaulted. Witnesses
claim that he was hit on the head with a lead
pipe, after which he was unconscious for several minutes. No seizure activity was witnessed. On arrival, he complains of a headache,
particularly severe at the point where he was
hit in the right frontoparietal region. On examination, he is found to have swelling and ecchymosis over this region. He is awake, alert, and
fully oriented. A complete neurologic examination reveals no deficit. Plain radiographs of
the skull show a linear, nondepressed skull
fracture in the frontoparietal skull that crosses
the groove of the medial meningeal artery.
During the following hour, he becomes sleepier
and begins to vomit. A repeat neurologic examination at that time reveals him to be lethargic
but without weakness, numbness, paresthesia,
or other focal deficit. What is the most likely
cause of the neurologic deterioration?
(A) Diffuse axonal injury (DAI)
(B) Todd’s phenomenon
(C) Subdural hematoma
(D) Epidural hematoma
(E) Trigeminal ganglion hematoma
- (D) This is the classic presentation of an acute
epidural hematoma (Fig. 11–5) transient traumatic loss of consciousness, followed by a lucid
interval and then by neurologic deterioration.
Epidural hematomas are frequently associated
with linear skull fractures, which cause injury
to the middle meningeal artery located immediately deep to the overlying fracture. They are
more common in younger individuals, because
in younger people, the dura mater is less firmly
adherent to the inner table of the skull. Todd’s
phenomenon is a transient focal weakness or
paralysis that results after a seizure. The particular pattern of weakness is often a clue to the
site of the seizure focus within the brain.
- Following a sudden impact in an accident, the
34-year-old race car driver becomes unconscious and is admitted to the hospital. A CT
scan is performed, and a right space-occupying
lesion is noted (Fig. 11–1). What is the most
likely diagnosis?
(A) Corpus callosum injury
(B) Pituitary apoplexia
(C) Acute subdural hematoma
(D) Acute epidural hematoma
(E) Chronic subdural hematoma
- (C) Acute subdural hematomas (Fig. 11–1)
occur most commonly when violent accelerations or deceleration injuries of the head cause
tearing of the bridging veins within the subdural potential space. They generally imply a
much more severe injury to the brain itself than
in the case of their epidural counterpart. For
this reason, they are associated with cerebral
contusions in over 30% of cases.
- A 44-year-old woman was brought to the emergency department after she was involved in a
high-speed motor vehicle accident. She was
extracted from the wreckage by paramedics.
She was intubated at the site and rushed to the
emergency department. On arrival, her blood
pressure was 160/80 mm Hg and heart rate
was 100 bpm, and exam showed evidence of
decerebrate rigidity. A CT scan of the head
revealed small punctate hemorrhages in the
corpus callosum and the midbrain tegmentum,
but there was no mass effect on adjacent structures. The size of the ventricles was normal.
This grave clinical presentation and these CT
findings are most consistent with the diagnosis
of which of the following?
(A) DAI
(B) Cerebral contusion
(C) Cerebral concussion
(D) Traumatic subarachnoid hemorrhage
(SAH)
(E) Petrous temporal lobe fracture
- (A) This entity is caused by sharp accelerations
or decelerations of the head and its contents as
seen in high-speed motor vehicle accidents.
During impact, shock waves are generated that
are able to travel through the semisolid substance
of the brain. These shock waves penetrate and
254 11: Neurosurgery
cause shear and stretch injury to multiple deep
axonal tracts. DAI represents a severe diffuse
injury to the entire brain. For this reason, victims present with marked neurological dysfunction. CT scan typically shows no evidence or
reason to suspect increased ICP; it merely shows
punctate hemorrhages in many of the tracts that
are affected.
- A 43-year-old man presents to the emergency
department after falling down a flight of stairs
and landing on his head. He did not lose consciousness. He complains of severe headache,
marked decreased acuity in hearing in the left
ear, and a “runny nose” since the fall. On physical examination, he is found to have a leftsided Battle’s sign (an ecchymosis in the area of
the left mastoid process) and hemotympanum.
He has a constant dripping of a clear, watery
fluid through his nose. Findings on his neurologic examination, other than the hearing loss,
are completely normal. X-ray studies will
reveal which of the following?
(A) A fracture of the cribriform plate with a
CSF leak into the paranasal sinuses
(B) A skull-base fracture with a mucocele
(C) A temporal bone fracture with
paradoxical rhinorrhea
(D) Occipital bone fracture
(E) Fracture of the maxillary antrum and
greater wing of the sphenoid
- (C) The presence of a Battle’s sign and hemotympanum is highly suggestive of the possibility of a left temporal bone fracture. When
this occurs, it is common for the dura mater at
this site to be torn. This leads to leakage of CSF
into the mastoid air cells and middle ear. CSF
is subsequently able to reach the nasopharynx
via the eustachian tube, a phenomenon called
paradoxical rhinorrhea, which is a serious but
usually self-limiting condition. Most cases of
traumatic CSF leaks heal spontaneously within
approximately 1 week. Patients require close
in-hospital observation, however, because bacterial meningitis readily occurs in the presence
of CSF leakage to the outside.
- A 52-year-old painter injured his lower back 3
weeks ago when he fell off a ladder. He presents for evaluation of abnormal findings on
plain radiographs of his lumbar spine. His pain
has subsided, and he is now asymptomatic.
Physical examination reveals a dense tuft of
hair in his lumbosacral region that has been
present for as long as he can remember. There
is no tenderness or palpable abnormality in his
spine. Findings on his neurologic examination
are unremarkable. The radiographs mentioned
show absence of the spinous processes and
laminae at the levels of L5 and S1, with their
corresponding pedicle displaced and angled
laterally. What is the diagnosis?
(A) An L5–S1 spondylolisthesis
(B) A burst fracture of L5 and S1
(C) Spina bifida
(D) Spinal stenosis
(E) Fracture of the vertebral bodies and
nucleus pulposus
- (C) Spina bifida occulta does not cause symptoms and is frequently found incidentally in the
workup of other conditions. The presence of a
tuft of hair and the radiographic abnormalities
described above are consistent with the diagnosis of spina bifida occulta. This is a congenital
abnormality that results from abnormalities in
the development of mesodermal elements (sclerotome) which form the dorsal elements of the
lumbosacral spine. A burst fracture of the spine
is found after acute excessive axial loading of the
spine. The features of such a fracture are reduced
height of the affected vertebral body and displacement of bony fragments centrifugally in
the axial plane (hence the term burst).
- In the investigation of chronic back pain, a
72-year-old man is found on radiologic examination to have congenital spondylolisthesis.
The pathology is based upon disruption
between two adjacent vertebra at which site?
(A) Bodies and disks
(B) Spinous process
(C) Transverse process
(D) Articular process(pars interarticularis)
(E) Pedicle
- (D) Spondylolisthesis occurs when there is disruption, most often by a fracture, of the pars
intra-articularis of the L5 vertebra. The pars is
the bony element that is found between the
ascending facets of L5 (that articulate with the
L4 vertebra) and the descending facets of L5
(that articulate with S1). The functional result of
this disruption is that the descending facets are
“floating” and not able to function in stabilizing the L5–S1 joint. If this becomes progressive, then anterior subluxation of the L5
vertebral body with respect to that of S1 occurs.
- A baby is born with a 2.5- × 2.0-cm myelomeningocele in the mid to lower lumbar region.
Just hours after birth, he is rushed to the operating room (OR) for repair of this defect.
Approximately 48 hours later, the baby is doing
well, but it is noted that his head circumference
has increased by 2 cm. On examination, the
fontanelle is found to be slightly bulging and
tense. On neurologic examination, the baby is
awake but is found to have no spontaneous sensory or motor function below approximately the
L3 dermatome. An ultrasound of the brain is
obtained through the open fontanelle. This study
shows an enlarged ventricular system, consistent with the presence of hydrocephalus. What is
the related abnormality responsible for the
hydrocephalus?
(A) A fourth-ventricle ependymoma
(B) Stenosis of the aqueduct of Sylvius
(C) Amelia (failure of limbs to develop)
(D) Arnold-Chiari malformation
(E) Nasopharyngeal hamartoma
- (D) There is a high degree of correlation in the
occurrence of defects in neural tube closure and
Arnold-Chiari malformations, and all babies
born with one should be examined for the other.
Answers: 24–33 255
Figure 11–5.
Epidural hematoma. CT of the head windowed for brain (left) and bone (right)
shows and epidural hematoma resulting from an underlying occipital skull fracture.
This injury was caused by a blow to the back of the head. Notice the classic lensshaped hematoma. The brain window also shows a thin left tentorial subdural
hematoma appearing as a white line running from the midline posteriorly and curving toward the left of the pons. (Reproduced, with permission, from Doherty GM:
Current Surgical Diagnosis and Treatment, 12th ed. 876. McGraw-Hill, 2006.)
Development of communicating hydrocephalus
is a feature of a type-II Arnold-Chiari abnormality. Stenosis of the aqueduct of Sylvius and
the presence of an ependymoma in the fourth
ventricles are other reasons for the development of hydrocephalus in children. There is,
however, no incidental correlation between
these and defects of neural tube closure.
- A 4-month-old infant has undergone surgical
treatment for meningomyeloencephalocele. A
CT tomogram of head was made immediately
after birth (see Fig. 11–2). At birth, an operation
was carried out in the posterior cranial fossa to
partially replace brain cerebellar contents to
an intracranial position. In investigations for
progressive hydrocephalus, it is noted that
there is herniation of the cerebellar tonsils
through the foramen magnum, and a diagnosis of Arnold-Chiari syndrome is established.
This syndrome may also include which of the
following?
(A) Fusion of the frontal lobes
(B) Fusion of the temporal, parietal, and
occipital lobes
244 11: Neurosurgery
(C) Abnormal elongation of the medulla
and lower cranial nerves
(D) Partial or complete absence of the
pituitary gland
(E) Hypertrophy of cerebral lobes
- (C) Abnormal elongation of the medulla and
lower cranial nerves may be evident in ArnoldChiari syndrome. Additional features include
fusion of the corpora quadrigemina, leading to a
“beaked” tectum; partial or complete absence of
the corpus callosum; and microgyria. The corpora quadragemina are relay stations for hearing
(inferior corpora quadragemina) and the light
reflex (superior copora quadragemina), and they
form the posterior surface of the midbrain.
- During a regular visit to the pediatrician 1 week
after birth, an infant’s size and head circumference are recorded as being in the seventy-fifth
percentile. Repeat measurement 1 month later
still shows the size of the baby at the seventy-fifth
percentile, but the baby’s head circumference is
now at the ninty-fifth percentile. The pediatrician
notices that the baby’s anterior fontanelle is tense
and that the skull sutures are open. He obtains an
MRI of the brain with intravenous contrast. This
study shows the presence of greatly dilated lateral and third ventricles. The aqueduct of Sylvius
cannot be easily visualized. The fourth ventricle
is small. There are no lesions within the subarachnoid space or cerebral parenchyma. The
appearance of the MRI is consistent with which
of the following?
(A) Noncommunicating hydrocephalus
(B) Communicating hydrocephalus
(C) Normal-pressure hydrocephalus
(D) Arnold-Chiari malformation with
herniation of the cerebellum into the
foramen magnum
(E) Anencephalus
- (A) Noncommunicating hydrocephalus is defined as hydrocephalus caused by obstruction
of CSF flow and obstruction within the ventricular system. In this case, the ventricular system
is dilated upstream from the obstruction caused
by stenosis of the aqueduct of Sylvius and collapsed distally. Communicating hydrocephalus
occurs when the obstruction to CSF flow occurs
within the subarachnoid space or at the level of
its resorption into the bloodstream by the arachnoid granulations. In this case, all ventricles are
dilated proportionately.
- A 64-year-old woman complains of gait imbalance, headache and deterioration of mental
status over the past several months. Her vision
is normal. A CT scan reveals hydrocephalus,
but the lumbar puncture pressure is unexpectedly low. What does she have?
(A) Meningitis
(B) Normal-pressure hydrocephalus
(C) Sigmoid sinus thrombosis
(D) Echinococcus
(E) Glioblastoma multiforme
- (B) Normal-pressure hydrocephalus is a condition seen in the elderly in which there is symmetrical enlargement of the entire ventricular
system. When patients with this condition are
studied by lumbar puncture, it is found that
despite ventriculomegaly, the ICP is abnormally low. This syndrome presents with a characteristic triad of symptoms—dementia, ataxia,
and urinary incontinence.
- A 23-year-old woman complains of progressive
loss of vision and papilledema. Investigations
show normal findings on CT scan. A lumbar
puncture shows marked elevation of pressure.
What is the most likely diagnosis?
(A) Pseudotumor cerebri
(B) Corpus cavernous thrombosis
(C) Cavernous sinus thrombosis
(D) Retinoblastoma
(E) Chordoma
- (A) Pseudotumor cerebri is a condition that
most commonly occurs in young adults, particularly in females. In this condition, ICP as
measured by a lumbar puncture is elevated,
while the size of the cerebral ventricles on imaging studies is small or normal. It is a generally
progressive condition that causes headache and
damage to the optic nerve, sometimes leading
to loss of peripheral vision and blindness.
- During her eighth month of pregnancy, a
29-year-old woman is noted to have hydramnios. Further testing shows anencephalus. In
this case hydramnios is caused by which of the
following?
(A) Impairment of the fetus’s swallowing
mechanism
(B) Tumor of the fetus’s brain
(C) A secretory peptide from the placenta
(D) Excess antidiuretic hormone (ADH)
from the fetus
(E) Renal agenesis
- (A) This abnormality is relatively common and
occurs in 1 of 1000 pregnancies. It occurs four
times more commonly in whites than blacks and
four times more commonly in female fetuses
than in male fetuses. The abnormality can be
identified on an x-ray, because the vault of the
skull is absent. Anencephalus is caused by failure
of the cephalic part of the neural tube to close off.
- A 28-year-old man presents with a history of
chronic headache. The headache is intermittent, severe, poorly localized, and most often
present when he arises in the morning. He suffered a severe blow to the head and sustained
a skull fracture at the age of 15. Findings on his
physical and neurologic examinations are
within normal limits. An MRI of the brain with
gadolinium reveals the presence of a large,
nonenhancing extra-axial cyst in the region of
the right temporal tip. This most likely represents which of the following?
(A) An arachnoid cyst
(B) A cystic astrocytoma
(C) Rathke’s cleft cyst
(D) A Dandy-Walker cyst (failure of proper
formation of the foramina of Lushka
and Magendie)
(E) Polycystic disease
- (A) This cystic structure is an arachnoid cyst.
These are CSF-filled cysts that occur when
leaves of arachnoidal tissue fuse, trapping CSF
within them. These cysts slowly grow over
time, sometimes attaining very large size. They
cause symptoms by virtue of their large size, as
they are able to compress adjacent structures.
Patients with these cysts most commonly
present with a history of chronic headache.
Neurologic symptoms or deficits are unusual.
Patients with arachnoid cysts frequently give a
history of severe blows to the head and skull
fractures, perhaps implying head trauma as a
causative agent. The most common locations of
arachnoid cysts are the middle cranial fossa,
the cerebellopontine angle, and the suprasellar
area. Dandy-Walker cysts are the result of an
intrauterine developmental abnormality in
which there is failure of proper formation of the
foramina of Lushka and Magendie. As a consequence, the main egress of CSF out of the
ventricular system is obstructed, leading to
hydrocephalus and a massively enlarged, cystlike fourth ventricle.
- A 15-year-old boy complains of right-sided
weakness and gait impairment. ACT scan shows
a large, nonenhancing cyst in the posterior
cranial fossa, with an enhancing tumor nodule in
the left cerebellum. What is the most likely
diagnosis?
(A) An arachnoid cyst
(B) A cystic astrocytoma
(C) Rathke’s cleft cyst
(D) Glioblastoma multiforme
(E) A large sebaceous cyst
- (B) Cystic astrocytomas are neoplasms of the
CNS. They usually consist of a large, nonenhancing cyst on the wall of which is an enhancing tumor nodule. They are most commonly
found within the substance of the cerebellar
hemispheres of children and young adults. A
Rathke’s cleft cyst is a remnant of the embryologic Rathke’s pouch. These are found within
the sella turcica.
- A 56-year-old woman presents with a history of
several months of pain involving both hands.
She describes the pain as electric and severe. It
is localized to the palmar aspect of the first three
digits of each hand and associated with numbness. The pain is particularly severe in the
morning when she wakes up. She reports no
weakness of the hands, but she says that sometimes objects fall off her hand because she
cannot feel them. Physical examination reveals
atrophy and weakness in the muscles of the
thenar eminence bilaterally. She also has numbness in the distribution of the median nerve
within the hands. Phalen test is positive. Which
is the best test to confirm the clinical diagnosis?
(A) An MRI of the hand to visualize an
enlarged carpal ligament
(B) An EMG and nerve-conduction study
(C) MRI of the cervical spine to rule out
radiculopathy
(D) An x-ray of the hand
(E) Physical examination
- (B) CTS is a condition in which the median
nerve is compressed at the level of the wrist by
a thickened carpal flexor retinaculum. This
256 11: Neurosurgery
leads to numbness and painful paresthesia
along the median nerve distribution within the
hand. It also causes weakness and atrophy of
the thenar muscles within the hand, innervated
by the superficial recurrent branch of the
median nerve. Once there is clinical suspicion,
the best diagnostic test to confirm the presence
of CTS is a nerve-conduction study. This study
often shows a block or delay in conduction of
the median nerve at the level of the carpal
tunnel. Conduction within all branches of the
ulnar nerve should be normal. This test is often
also useful in distinguishing between CTS and
the possibility of a C6 radiculopathy.
A 28-year-old police officer is brought to the emergency room (ER) by ambulance following a gunshot to
the head. Emergency medical services (EMS) reports
that he was found unresponsive at the site of the shooting and was immersed in a pool of blood. There were
no witnesses. On arrival to the emergency department, he is noted to have a bullet entry wound on the
right frontal region without any exit wound. His blood
pressure is 80/35 mm Hg, pulse rate 150 bpm, and on
examination, he does not open his eyes or follow commands. He is unresponsive to deep painful stimuli
such as testing by sternal rub. His pupils are dilated
approximately 4 mm bilaterally, but sluggishly reactive. He is aggressively resuscitated with colloid and blood products. The blood pressure is now 140/75
mm Hg. There is improvement in his neurologic examination—1 hour after admission, he withdraws his
limbs from painful stimuli. A CT scan shows a smallskull defect in the right frontal region, representing the
bullet entry site. The bullet is lodged within the cerebral parenchyma, approximately 2 cm from the surface
of the brain, and there is a trail of bone fragments
along the bullet path. The bullet has not crossed the
midline. There is a 2 × 2 × 2.5-cm hematoma within the
substance of the right frontal lobe with surrounding
edema and subfalcian herniation.
- Which item is least likely to be useful as a prognostic marker for subsequent recovery?
(A) Neurologic examination upon
presentation and early response
(B) The fact that the bullet did not cross the
midline
(C) The presence of an intracerebral
hematoma
(D) The presence of edema with subfalcian
herniation
(E) Bullet crosses the midcoronal plane
- (A) The best prognostic indicator of survival
and outcome in patients with missile wounds to
the brain is the mental status and level of
responsiveness after proper resuscitation. His
initial poor neurologic grade can be attributed
to cerebral injury itself or to cerebral hypoperfusion in a patient with clear hemodynamic
shock. Initial presentation is, thus, of little value
in judging the prognosis for these types of
injuries. Other prognostic factors that have been
identified as important in predicting the outcome of gunshot wounds to the head include:
(a) Path of the bullet. A missile that crosses
the midline or the midcoronal plane is
associated with a much worse outcome
than one that stays unilaterally.
(b) The presence of an intracranial
hematoma of greater than 2 × 2 × 2 cm is
ironically a positive prognosticator,
because it represents a mass lesion that
can be causing intracranial hypertension
and can be more readily evacuated via a
craniotomy.
A 28-year-old police officer is brought to the emergency room (ER) by ambulance following a gunshot to
the head. Emergency medical services (EMS) reports
that he was found unresponsive at the site of the shooting and was immersed in a pool of blood. There were
no witnesses. On arrival to the emergency department, he is noted to have a bullet entry wound on the
right frontal region without any exit wound. His blood
pressure is 80/35 mm Hg, pulse rate 150 bpm, and on
examination, he does not open his eyes or follow commands. He is unresponsive to deep painful stimuli
such as testing by sternal rub. His pupils are dilated
approximately 4 mm bilaterally, but sluggishly reactive. He is aggressively resuscitated with colloid and blood products. The blood pressure is now 140/75
mm Hg. There is improvement in his neurologic examination—1 hour after admission, he withdraws his
limbs from painful stimuli. A CT scan shows a smallskull defect in the right frontal region, representing the
bullet entry site. The bullet is lodged within the cerebral parenchyma, approximately 2 cm from the surface
of the brain, and there is a trail of bone fragments
along the bullet path. The bullet has not crossed the
midline. There is a 2 × 2 × 2.5-cm hematoma within the
substance of the right frontal lobe with surrounding
edema and subfalcian herniation.
43. What is the next step in management? (A) Administration of mannitol (1 g/kg) through a rapid IV infusion followed by the placement of an intracranial pressure monitor (B) Administration of mannitol (1 g/kg) through a rapid IV infusion followed by urgent craniotomy (C) Administration of mannitol (1 g/kg) through a rapid IV infusion followed by the placement of burr holes for emergent decompression of raised intracranial pressure (D) No treatment should be administered, because the patient’s prognosis is poor, and he is unlikely to survive (E) Steroids and antibiotics alone
- (B) A markedly diminished level of consciousness coupled by a CT scan that shows a
hematoma, edema, and subfalcian herniation
indicate that the patient is suffering from
intracranial hypertension. Hyperventilation and
mannitol are quick and effective ways to reduce
intracranial pressure temporarily. However,
these measures are only temporary, and the
patient needs urgent decompression by craniotomy. Placement of burr holes in the ER is of no
value in the management of these injuries.
Placement of an ICP monitor may be helpful for
the postoperative period, but is likely to be of
limited help without prior craniotomy.
A 28-year-old police officer is brought to the emergency room (ER) by ambulance following a gunshot to
the head. Emergency medical services (EMS) reports
that he was found unresponsive at the site of the shooting and was immersed in a pool of blood. There were
no witnesses. On arrival to the emergency department, he is noted to have a bullet entry wound on the
right frontal region without any exit wound. His blood
pressure is 80/35 mm Hg, pulse rate 150 bpm, and on
examination, he does not open his eyes or follow commands. He is unresponsive to deep painful stimuli
such as testing by sternal rub. His pupils are dilated
approximately 4 mm bilaterally, but sluggishly reactive. He is aggressively resuscitated with colloid and blood products. The blood pressure is now 140/75
mm Hg. There is improvement in his neurologic examination—1 hour after admission, he withdraws his
limbs from painful stimuli. A CT scan shows a smallskull defect in the right frontal region, representing the
bullet entry site. The bullet is lodged within the cerebral parenchyma, approximately 2 cm from the surface
of the brain, and there is a trail of bone fragments
along the bullet path. The bullet has not crossed the
midline. There is a 2 × 2 × 2.5-cm hematoma within the
substance of the right frontal lobe with surrounding
edema and subfalcian herniation.
- Intraoperative management of this patient
should be avoidance of which of the following?
(A) Placement of an intracranial pressure
monitor
(B) Performance of a wide craniotomy for
evacuation of the intraparenchymal
hematoma
(C) Extensive debridement of all bullet and
bone fragments
(D) Reconstruction of the cranial defect
caused by the bullet
(E) Removal of necrotic brain material
- (C) The ideal intraoperative management of
this patient would begin by performance of a
wide craniotomy through which the intracerebral hematoma can be evacuated. Necrotic
brain tissue if left alone is likely to worsen the
occurrence of cerebral edema postoperatively,
and for that reason, every measure should be
taken to debride it as thoroughly as possible.
Easily accessible bone and bullet fragments can
also be removed. Bone and bullet fragments
that are deeply located and difficult to locate
should be left intact. Persistence in their
removal often leads to a greater risk of brain
injury by intraoperative manipulation and dissection. If problems with raised intracranial
pressure are expected, placement of a suitable
ICP monitoring device is highly recommended
as part of the surgical procedure.
A 54-year-old-man comes to the emergency department complaining of a severe headache for several
hours. He describes this headache as the worst of his
life. It started suddenly “like a firecracker had gone
off” inside his head. He has had no loss of consciousness but has had several episodes of vomiting.
General physical examination reveals a patient who
is in severe distress due to the headache. His blood
pressure is 180/70 mm Hg, and his pulse racing at
120 bpm. He is afebrile. He has photophobia and
gross neck rigidity. Neurologically, he is fully alert
and oriented. He has a normal motor and sensory
examination. His left pupil is 2 mm and briskly reactive to light; his right is 4.5 mm and fixed to both
light and accommodation.
45. What is the most likely diagnosis? (A) Acute bacterial meningitis (B) Incipient uncal herniation due to an expanding lesion in the right temporal lobe (C) Acute SAH from an anterior communicating artery aneurysm (D) Acute SAH from a right posterior communicating aneurysm (E) Cavernous sinus thrombosis Questions: 37–45 247
- (D) This is the classic history for acute SAH—the
acute onset of a massive headache. The acuity
should suggest nothing other than a vascular
phenomenon. Furthermore, the presence of a
right occulomotor nerve palsy strongly suggests
bleeding from an aneurysm of the right posterior communicating artery. Anatomically, most
posterior communicating aneurysms point their
domes laterally and inferiorly, in the direction
toward the occulomotor nerve. In general, when
the dome of the aneurysm ruptures, the jet of
blood injures the adjacent nerve. In this situation, the lesion results in complete occulomotor
nerve palsy with a fixed dilated pupil. It is a
neurosurgic dogma that complete occulomotor
palsy should be regarded as a ruptured posterior
communicating artery aneurysm until proved
otherwise. Acute bacterial meningitis also presents with headache and meningism. The onset
of the symptoms is, however, much more gradual, and high fever is usually present.
A 54-year-old-man comes to the emergency department complaining of a severe headache for several
hours. He describes this headache as the worst of his
life. It started suddenly “like a firecracker had gone
off” inside his head. He has had no loss of consciousness but has had several episodes of vomiting.
General physical examination reveals a patient who
is in severe distress due to the headache. His blood
pressure is 180/70 mm Hg, and his pulse racing at
120 bpm. He is afebrile. He has photophobia and
gross neck rigidity. Neurologically, he is fully alert
and oriented. He has a normal motor and sensory
examination. His left pupil is 2 mm and briskly reactive to light; his right is 4.5 mm and fixed to both
light and accommodation.
46. What is the most appropriate test to establish the diagnosis? (A) MRI of the brain with and without gadolinium (B) CT scan of the brain without contrast (C) A lumbar puncture (D) An electroencephalogram (E) Optometry
- (B) The best test in the diagnosis of an acute
SAH is a nonenhanced CT of the brain. In this
study, subarachnoid blood can easily be seen as
a hyperdense substance filling the otherwise
Answers: 34–46 257
hypodense cisterns of the subarachnoid space.
Its sensitivity is greater 95%, but sensitivity
falls to 50% by 1 week after the hemorrhage.
Lumbar puncture can also be used to diagnose
SAH, but it is an invasive procedure that
should be reserved for cases in which the suspicion of such hemorrhage remains following
a negative CT scan. MRI (with or without
gadolinium), despite its exquisite sensitivity
for the diagnosis of intracerebral lesions, is
notoriously poor in its ability to detect acute
blood within the subarachnoid space. EEG is of
no value for the diagnosis of an acute SAH.
- A 43-year-old man is treated with pyridostigmine for facial, ocular, and pharyngeal weakness due to myasthenia gravis. Which statement
is true of pyridostigmine?
(A) It is unrelated to neostigmine.
(B) It has far more side effects than
neostigmine.
(C) Pyridostigmine and neostigmine reverse
depolarizing neuromuscular blockade.
(D) It causes greater muscarinic effect than
neostigmine.
(E) It is an anticholinesterase agent.
- (E) Neostigmine and pyridostigmine are both
anticholinesterase agents and can be used in
the reversal of nondepolarizing muscle relaxants. Pyridostigmine causes less muscarinic
effect than does neostigmine. The effect of pyridostigmine is more prolonged and produces
fewer secretions and less severe bradycardia.
- During anesthesia using a narcotic, thiopental,
and N2
O, the respiratory response to a rising
end-respiratory CO2 tension is which of the following?
(A) Depressed only by the narcotic
(B) Depressed only by thiopental
(C) Depressed progressively by the addition
of each agent
(D) Depressed by the narcotic and thiopental,
then elevated by N2
O
(E) Unchanged from control response
- (C) Both narcotics and thiopental depress respiration, and the addition of N2
O further augments this depressant action. Thus, the response
to hypercapnea is diminished.
- A plastic surgeon is performing a minor procedure on the face of an 18-year-old woman.
She has a seizure that is attributed to the local
anesthetic agent. Convulsion following an
overdose of local anesthesia is best treated by
which of the following?
(A) Droperidol
(B) Hydroxyzine (Vistaril)
(C) Diazepam (Valium)
(D) Fentanyl ketamine
- (C) Diazepam is a benzodiazepine derivative
that seems to have a calming effect on part of the
limbic system, thalamus, and hypothalamus. It
should be injected slowly (<1 mg/min) into a
larger vein to avoid phlebitis and local irritation.
- A 17-year-old male presents with 3-month
history of headache, weight gain, decreased
concentration, polyuria, and polydypsia. His
headaches are mostly in morning and involves
the frontal region. On examination he was found
to have bitemporal visual field defect and no
facial hair. MRI scan revealed a suprasellar partially calcified cystic lesion with displacement of
optic chiasm. The most likely pathology is:
(A) Giant aneurysm of carotid artery
(B) Pituitary macroadenoma
(C) Glioblastoma multiforme
(D) Craniopharyngioma
(E) Testicular metastasis
- (D) Weight gain, DI, decreased memory, and
visual field defect are consistent with a suprasellar hypothalamic lesion. Calcified cystic lesions
in this location, particularly in adolescents, are
characteristic of craniopharyngiomas. The rate
of calcification in childhood is about 85% and in
adult is about 40%. Craniopharyngiomas are
pathologically benign but due to their location
and their firm attachment to critical structures
surrounding them can result in severe neurofunctional impairment. The cyst wall is lined
with squamous epithelium and the fluid contains cholesterol crystals.
51. He underwent a craniotomy for resection of his lesion. Twelve hours postoperatively, he developed diuresis of over 500 mL/h. The diagnosis of (DI) was entertained. What laboratory findings are most consistent with the clinical impression? (A) Urine specific gravity of over 1010 (B) Serum sodium of less than 135 (C) Decreased both serum and urine osmololity (D) Increased serum osmololity and decreased urine osmololity (E) Increased both serum and urine osmololity
- (D) DI is commonly precipitated by low level of
ADH secretion. The clinical presentation does
not manifest until over 85% of ADH secretory
capacity is damaged. Rarely it is nephrogenic
and is caused by lack of renal response to ADH
hormone. Nephrogenic form is often produced
by toxic effect of certain drugs or familial Xlinked recessive genetic disorder. DI is defined
by increased diluted urinary output, constant
thirst for usually cold water, and high serum
osmololity. If it is not properly treated it can
lead to extreme dehydration and electrolyte
imbalance. The best test is water deprivation
for 4 hours while monitoring the urine output
and urine and serum osmololity. If urine
osmololity remains flat or changes less than 30
mOsm and the serum osmololity approaches
300 mOsm/L, the diagnosis of DI is confirmed.
At this point the patient should be given 5 U of
an exogenous pitressin subcutaneously. By
comparing the urine osmololity after Pitressin
to the initial values, the extent of the DI can be
determined. The increase in urine osmololity
by more than 67% is indicative of severe ADH
deficiency. The increased levels of 6–67% is suggestive of partial deficiency.
- A 55-year-old female presents with 3-years history of severe lancinating pain extending from
left ear to her maxillary area. Pain is triggered
by chewing and brushing teeth. She was
treated by otolaryngologist for sinus infection
a year ago and undergone multiple dental
work and teeth extraction with transient or no
improvement. The most likely diagnosis is:
(A) Maxillary sinusitis
(B) Trigeminal neurolgia
(C) Maxillary osteomyelitis
(D) Gradenigo’s syndrome
(E) Otitis media
- (B) Trigeminal neuralgia or Tic Douloureux is
clinically characterized by paroxysmal lancinating pain in the distribution of one or two
division of trigeminal nerve. There is commonly
no sensory or motor impairment on examination. The pain is triggered by certain mild stimuli such as touching, chewing, brushing teeth,
and cold breeze. If any objective neurological
findings are detected, other pathologies causing
compression of the nerve at its exit zone from
the brainstem must be suspected. Such pathologies as AVM, tumors, and aneurysm must be
ruled out by MRI. This disease is assumed to be
caused by a loop of a vessel, often superior
cerebellar artery or posterior inferior cerebellar
artery (PICA), compressing the trigeminal
nerve as it emerges from brainstem.
A 55-year-old female presents with 3-years history of severe lancinating pain extending from
left ear to her maxillary area. Pain is triggered
by chewing and brushing teeth. She was
treated by otolaryngologist for sinus infection
a year ago and undergone multiple dental
work and teeth extraction with transient or no
improvement.
- Which one of the following medications is not
indicated in treatment of this condition?
(A) Carbamezapin
(B) Cefatin
(C) Phenytoin
(D) Gabapentin
(E) Baclofen
- (B) Most antiepileptic medications are effective to
control the pain in this condition. The drug of
choice is Carbamazepin which is effective in twothirds of the patients. Phenytoin is an intravenous
option in those who cannot take oral medication
due to severe pain. Baclofen is an effective medication in conjunction with Carbamazepin.
Gabapentin is another antiepileptic medication
258 11: Neurosurgery
which is useful in mild forms of the TN or in
association with other medications. Other medications that are being used for this condition
include Amitriptyline (Elavil) and Clonazepam
(Klonopin).
- A 45-year-old woman was brought to emergency
department for sudden onset of severe headache
associated with photophobia, nausea, and transient loss of consciousness. On examination, she
is awake and alert with normal cranial nerve
function. She also exhibits normal muscle
strength and sensation.Her past medical history
is significant for sickle cell disease (SCD) and
hypertension. CT scan confirms the diagnosis of
SAH without any intraparenchymal abnormality.
What is the least likely cause of SAH?
(A) Aneurysmal bleed
(B) Sickle cell angiopathy
(C) Arteriovenous malformation (AVM)
(D) Hemorrhagic meningioma
(E) Blood dyscrasia
- (D) The most common cause of the spontaneous
SAH is berry aneurysm and AVM. Aneurysms
are often located on the circle of Willis in the
subarachnoid space hence bleeding occurs in
this space. Massive hemorrhages can break in
the parenchyma and produce intraparenchymal
clot. AVMs usually bleed in the parenchyma but
frequently is superficial and present with associated SAH. Sickle cell angiopathy can also present as SAH from subpial vessels. In a patient
with history of SCD, angiopathy as the cause of
SAH should be considered. On other hand,
bleeding is extremely rare in meningiomas and
when it occurs it is often intratumoral or intraparenchymal and do not appear as a SAH.
A 45-year-old woman was brought to emergency
department for sudden onset of severe headache
associated with photophobia, nausea, and transient loss of consciousness. On examination, she
is awake and alert with normal cranial nerve
function. She also exhibits normal muscle
strength and sensation.Her past medical history
is significant for sickle cell disease (SCD) and
hypertension. CT scan confirms the diagnosis of
SAH without any intraparenchymal abnormality.
55. What is the most definitive diagnostic test in this condition? (A) CT angiography (B) Magnetic resonance angiography (MRA) (C) Cerebral angiogram (D) MR spectroscopy (E) Positron emission tomography (PET) scan
- (C) Four vessel angiography remains a gold standard vascular study for detecting aneurysms
and AVMs. It provides the detail and definition
that are required for surgical intervention. MRA
and CTA are often very helpful to detect and
provide some detail. The newer high speed CT
scans with angiography software can produce
the definition close to standard angiography. PET
scan and spectroscopy are primarily used to
determine the metabolic activities of the brain
and are incapable of detecting vascular lesions.
A 45-year-old woman was brought to emergency
department for sudden onset of severe headache
associated with photophobia, nausea, and transient loss of consciousness. On examination, she
is awake and alert with normal cranial nerve
function. She also exhibits normal muscle
strength and sensation.Her past medical history
is significant for sickle cell disease (SCD) and
hypertension. CT scan confirms the diagnosis of
SAH without any intraparenchymal abnormality.
56. What is the most likely complication of angiography in this patient? (A) Cerebral stroke (B) Aneurysmal rupture (C) Increased intracranial pressure (D) Vascular wall damage (E) Sickle cell crisis
- (E) The rate of complications in cerebral
angiography is relatively low and in experienced hands is less than 1%. Among the potential complications, cerebral ischemic or
hemorrhagic stroke, vascular dissection, and
aneurysmal rupture are frequently reported.
In patients with SCD administration of the
high-osmolar contrast often precipitate sickle
cell crisis. Therefore, these patients should be
pretreated with exchange transfusion and
maintained in a well hydrated state. Steroids
are also used prior to angiography to reduce
the postangiography complications.
- A 69-year-old well-controlled, hypertensive man
was seen in ER with 3-month history of mild
headache and sudden onset of hemiparesis. On
examination, he exhibit mild dysphasia and
lethargy. His cognitive function testing indicates
moderate diminution of his recent memory and
executive function. His hemiparesis is more
dense in arm and leg and is mild in his face.CT
scan without contrast demonstrates a 3-cm irregular hemorrhage surrounded by marked edema
and mass effect in frontal-temporal region. The
most likely cause of bleed is?
(A) Amyloid angiopathy
(B) Hypertensive hemorrhage
(C) Hemorrhagic neoplasm
(D) Arterial-venous malformation
(E) Coagulopathy
- (C) History of recent onset of headache in adult
should always raise the suspicion of neoplasm.
Amyloid angiopathy and hypertension are frequent cause of the intracerebral hemorrhage in
elderly, but the critical difference with neoplastic bleed is the presence of edema and mass
effect which is disproportionate to the size of
the hemorrhage. The presence of edema suggests a preexisting lesion with recent bleed.
Although intraparenchymal hemorrhage can
produce edema but it takes many hours to
develop. Therefore, the presence of edema in
early hours after the ictus is indicative of
underlying pathology. AVMs and coagulopathies also can cause intraparenchymal
bleed without surrounding edema which is the
hallmark of an underlying lesion.
A 69-year-old well-controlled, hypertensive man
was seen in ER with 3-month history of mild
headache and sudden onset of hemiparesis. On
examination, he exhibit mild dysphasia and
lethargy. His cognitive function testing indicates
moderate diminution of his recent memory and
executive function. His hemiparesis is more
dense in arm and leg and is mild in his face.CT
scan without contrast demonstrates a 3-cm irregular hemorrhage surrounded by marked edema
and mass effect in frontal-temporal region.
58. What is the next diagnostic test that should be ordered? (A) EEG (B) Cerebral angiography (C) MRI with contrast (D) Spinal tap to determine the ICP (E) Transcranial Doppler
- (C) MRI with contrast is the study of choice to
determine the presence of underlying pathology. The pattern of enhancement can identify
such lesions as primary brain tumor or hemorrhage in a metastatic lesion. Although lung and
breast are the most common neoplasm that
metastasis to brain, the incidence of bleeding is
more common in melanomas and lymphomas.
AVMs also have special MRI features that make
the diagnosis possible. The vascular details
nonetheless require angiographic studies. The
vascular study is ineffective in determining the
presence of neoplastic lesions unless an AVM or
aneurysms are suspected. Transcranial Doppler
is used to determine the circulation velocity in
the intracranial vessels particularly in middle
cerebral artery. This test is used to monitor the
vasospasm occurring after aneurysmal SAH and
has no role in identifying any other pathology.
Electromyography (EMG) and nerve conduction studies (NCS) are useful for assessing the function of
A. Peripheral nerves
B. Bilateralcarotidarteries
C. Intracranialliquids
D. Spinalnerves
Answer:A
Electromyography and nerve conduction studies (EMG/ NCS) are use ul or assessing the unction o peripheral nerves. EMG records muscle activity in response to a proxi- mal stimulation o the motor nerve. NCS record the velocity and amplitude o the nerve action potential. EMG/NCS typi- cally is per ormed approximately 3 to 4 weeks a ter an acute injury, as nerves distal to the injury continue to transmit elec- tricalimpulsesnormallyuntildegenerationo thedistalnerve progresses. (See Schwartz 10th ed., p. 1712.)
T e lesion that can cause mass ef ect and rapidly kill the patient is
A. In erior ossa lesions
B. Posterior ossalesions C. Progressiveobtundation D. Bradycardiallesions
Answer:B
heposterior ossa(brainstemandcerebellum)requiresspe- cial consideration because the volume o the posterior ossa within the cranial vault is small. Posterior ossa lesions such as tumors, hemorrhage, or stroke can cause mass e ect that can rapidly kill the patient in two ways. Occlusion o the ourth ventricle can lead to acute obstructive hydrocephalus, raised intracranial pressure (ICP), herniation, and eventually death.
his mass e ect can also lead directly to brain stem com- pression (Fig. 42-1). Symptoms o brain stem compression include hypertension, agitation, and progressive obtundation,
ollowed rapidly by brain death. A patient exhibiting any o these symptoms needs an emergent neurosurgical evalua- tion orpossibleventriculostomyorsuboccipitalcraniectomy (removal o the bone covering the cerebellum). his situation is especially critical, as expeditious decompression can lead to signi icant unctional recovery. (See Schwartz 10th ed., Figure 42-5, pp. 1714–1715.)
- According to the Glasgow Coma Scale (GCS), a patient withaheadinjuryscoreo 5isclassi edas
A. Mild
B. Moderate C. Severe
D. Seizure
Answer:D
raumatic brain injury ( BI) can be classi ied as mild, moder- ate, or severe. For patients with a history o head trauma, clas- si ication is as ollows: severe head injury i the GCS score is 3 to 8, moderate head injury i the Glasgow Coma Scale (GCS)scoreis9to12,andmildheadinjuryi theGCSscoreis 13 to 15. Many patients present to emergency rooms and trauma bays with a history o BI. A triage system must be used to maximize resource utilization while minimizing the chance o missing occult or progressing injuries. (See Schwartz 10th ed., p. 1718.)
- In regard to the halo test, a positive indicator
spinal uid (CFS) when tinged with blood will show the
ollowing when dropped on an absorbent tissue
A. A single ring with a darker center spot containing
bloodcomponentssurroundedbyalighthaloo CFS. B. A double ring with a darker center spot containing
bloodcomponentssurroundedbyalighthaloo CFS.
C. A single ring with a lighter center spot containing CFS
surroundedbyadarkerhaloo bloodcomponents.
D. A double ring with a lighter center spot containing CFS
surroundedbyadarkerhaloo bloodcomponents
Answer:B
Copious clear drainage rom the nose or ear makes the diag- nosis o cerebrospinal luid (CSF) leakage obvious. O ten, however, the drainage may be discolored with blood or small in volume i some drains into the throat. he halo test can help di erentiate. Allow a drop o the luid to all on an absorbent sur ace such as a acial tissue. I blood is mixed with CSF, the drop will orm a double ring, with a darker center spot con- taining blood components surrounded by a light halo o CSF. I this test is indeterminate, the luid can be sent or beta-2 trans errin testing, a carbohydrate- ree iso orm o trans-
errin exclusively ound in the CSF. (See Schwartz 10th ed., pp. 1716–1717.)
- Neurapraxiaisde nedas
A.T e disruption o axons and myelin.
B.T e disruption o axons and endoneurial tubes.
C.T e temporary ailure o nerve unction without physi-
cal axonal disruption.
D. T e temporary ailure o nerve unction with physical
axonal disruption.
Answer:C
Neurapraxia is de ined as the temporary ailure o nerve unc- tion without physical axonal disruption. Axon degeneration does not occur. Return o normal axonal unction occurs over hours to months, o ten in the 2- to 4-week range. (See Schwartz 10th ed., p. 1026.)
- Apatientwhowithdraws rompain,ismumblinginappro- priate words, and opens his eyes to pain has a GCSscore o
A. 3 B. 6 C. 9 D. 12
Answer:C
- T emostcommonmalignanttumoro thebrainis A. Ependymoma
B. Astrocytoma
C. Ganglioglioma
D. eratoma
Answer:B
Astrocytoma is the most common primary central nervous sys- tem (CNS) neoplasm. he term glioma o ten is used to re er to astrocytomas speci ically, excluding other glial tumors. Astro- cytomas are graded rom I to IV. Grades I and II are re erred to as low-grade astrocytoma, grade III as anaplastic astrocytoma, and grade IV as glioblastoma multiforme (GBM). Prognosis var- ies signi icantly between grades I/II, III, and IV, but not between I and II. Median survival is 8 years a ter diagnosis with a low- grade tumor, 2 to 3 years with an anaplastic astrocytoma, and roughly 1 year with a GBM. GBMs account or almost two- thirdso allastrocytomas,anaplasticastrocytomasaccount or two-thirdso therest,andlow-gradeastrocytomastheremain- der.Figure42-2demonstratesthetypicalappearanceo aGBM. (See Schwartz 10th ed., Figure 42-20, pp. 1733–1734.)
- A 25-year-old man is seen in the emergency department af er he struck his head against the windshield in an auto- mobile accident. He opens his eyes and withdraws his arm during pain ul stimulation o his hand. He responds verbally to questions with inappropriate words. His GCSscore is
A. 6 B. 9 C. 12 D. 15
Answer:B
heinitialassessmento thetraumapatientincludesthepri- mary survey, resuscitation, secondary survey, and de initive care. Neurosurgical evaluation begins during the primary sur- vey with the determination o the GCS score (usually re erred to simply as the GCS) or the patient. he GCS is determined by adding the scores o the best responses o the patient in each o three categories. he motor score ranges rom 1 to 6, verbal rom 1 to 5, and eyes rom 1 to 4. he GCSthere ore ranges rom 3 to 15, as detailed in able 42-1. racheal intu- bation or severe acial or eye swelling can impede verbal and eye responses. In these circumstances, the patient is given the score o 1 with a modi ier, such as verbal “1 ” where = tube. (See Schwartz 10th ed., p. 1715.)
- T e most common level o cervical radiculopathy rom cervical disc herniation is
A. C4–C5 B. C5–C6 C. C6–C7 D. C7– 1
Answer:C
he cervical nerve roots exit the central canal above the ped- icle o the same-numbered vertebra and at the level o the higher adjacent intervertebral disc. For example, the C6 nerve root passes above the C6 pedicle at the level o the C5–C6 discs. he cervical nerve roots may be compressed acutely by disc herniation, or chronically by hypertrophic degenerative changes o the discs, acets, and ligaments. able 42-2 sum- marizesthee ectso variousdischerniations.Mostpatients with acute disc herniations. Most patients with acute disc herniations will improve without surgery, nonsteroidal anti- in lammatory drugs (NSAIDs), or cervical traction may help alleviate symptoms. Patients whose symptoms do not resolve
or who have signi icant weakness should undergo decompres- sive surgery. he two main options or nerve root decompres- sionareanteriorcervicaldiscectomyand usion(ACDF)and posterior cervical oraminotomy (keyhole oraminotomy). ACDFallowsmoredirectaccesstoandremovalo thepathol- ogy (anterior to the nerve root). However, the procedure requires usion because discectomy causes a collapse o the interbody space and instability will likely occur. Fig. 42-3 demonstrates a C6–C7 ACDF with the typical interposed gra t and plating system. Keyhole oraminotomy allows or decompressionwithoutrequiring usion,butitislesse ective
or removing centrally located canal pathology. (See Schwartz 10th ed., able 42-6 and Figure 42-27, pp. 1740–1741.)
- A 35-year-old mother o two children, 5 and 6 years, has had amenorrhea and galactorrhea or the past 12 months. Her serum prolactin level is elevated, and radiographs o herskullshowan“emptysella.”T emostlikelydiagnosisis A. Menopause
B. Pregnancy
C. Pituitarytumor
D. Sheehansyndrome
Answer:C
Pituitary adenomas arise rom the anterior pituitary gland (adenohypophysis). umors <1 cm diameter are considered microadenomas; larger tumors are macroadenomas. Pitu- itarytumorsmaybe unctional(ie,secreteendocrinologically active compounds at pathologic levels) or non unctional (ie, secrete nothing or inactive compounds). Functional tumors are o ten diagnosed when quite small, due to endocrine dys unction. he most common endocrine syndromes are Cushing disease, due to adrenocorticotropic hormone secretion, Forbes-Albright syndrome, due to prolactin secretion, and acromegaly, due to growth hormone secre- tion.Non unctionaltumorsaretypicallydiagnosedaslarger lesions causing mass e ects such as visual ield de icits due to compression o the optic chiasm or panhypopituitarism duetocompressiono thegland.Figure42-4demonstrates a large pituitary adenoma. Hemorrhage into a pituitary tumor causes abrupt symptoms o headache, visual distur- bance, decreased mental status, and endocrine dys unction.
his is known as pituitary apoplexy. (See Schwartz 10th ed., Figure 42-23, pp. 1735–1736.)
11. T e most common intradural extramedullary tumors in children are A. Ependymomas B. Astrocytomas C. Dermoids D. eratomas
Answer:B
Astrocytomasarethemostcommonintramedullarytumorsin children, although they also occur in adults. hey may occur at all levels, although more o ten in the cervical cord. he tumor may inter ere with the CSF-containing central canal o the spinal cord, leading to a dilated central canal, re erred to as syringomyelia (syrinx). Spinal astrocytomas are usually low grade, but complete excision is rarely possible due to the nonencapsulated, in iltrative nature o the tumor. As a result, patients with astrocytomas are worse overall than patients with ependymomas. (See Schwartz 10th ed., pp. 1738–1739.)
12. Diabetics, intravenous (IV) drug abusers, and dialysis patients have an increased risk o contracting the CNS in ection A. Pyogenic vertebral osteomyelitis B. Subdural empyema C. Discitis D. Epidural abscess
Answer:A
Pyogenic vertebral osteomyelitis is a destructive bacterial in ection o the vertebrae, usually o the vertebral body. Ver- tebral osteomyelitis requently results rom hematogenous spread o distant disease, but may occur as an extension o adjacent disease, such as psoas abscess or perinephric abscess. Staphylococcus aureus and Enterobacter spp. are the most
requent etiologic organisms. Patients usually present with
ever and back pain. Diabetics, IV drug abusers, and dialysis patients have increased incidence o vertebral osteomyelitis. Epiduralextensionmayleadtocompressiono thespinalcord or nerve roots with resultant neurologic de icit. Osteomyelitis presents a lytic picture on imaging and must be distinguished
rom neoplastic disease. Adjacent intervertebral disc involve- mentoccurs requentlywithpyogenicosteomyelitis,butrarely with neoplasia. Plain ilms and computed tomography (C ) helpassesstheextento bonydestructionordeormitysuchas kyphosis. Magnetic resonance imaging (MRI) shows adjacent so t tissue or epidural disease. Most cases can be treated suc- cess ully with antibiotics alone, although the organism must be isolated to steer antibiotic choice. Blood cultures may be positive. Surgical intervention may be required or debride- ment when antibiotics alone ail, or or stabilization and
usioninthesettingo instabilityanddeormity.(SeeSchwartz 10th ed., p. 1745.)
