Neurosurgery

Question 1

1. 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

Answer 1

1. (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.

Question 2

2. 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

Answer 2

2. (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

Question 3

3. 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

Answer 3

3. (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.

Question 4

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

Answer 4

4. (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.

Question 5

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

Answer 5

5. (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.

Question 6

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

Answer 6

6. (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.

Question 7

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)

Answer 7

7. (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.

Question 8

8. 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

Answer 8

8. (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).

Question 9

9. 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

Answer 9

9. (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.

Question 10

10. 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

Answer 10

10. (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.

Question 11

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.

11. 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

Answer 11

11. (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.

Question 12

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.

12. 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

Answer 12

12. (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.

Question 13

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

Answer 13

13. (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.

Question 14

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.

14. 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

Answer 14

14. (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.

Question 15

15. 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

Answer 15

15. (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.

Question 16

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

Answer 16

16. (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.

Question 17

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

Answer 17

17. (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.

Question 18

18. 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

Answer 18

18. (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).

Question 19

19. 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.

Answer 19

19. (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.

Question 20

20. 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

Answer 20

20. (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.

Question 21

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

Answer 21

21. (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.

Question 22

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.

22. 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

Answer 22

22. (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).

Question 23

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.

23. 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

Answer 23

23. (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.

Question 24

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.

24. 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

Answer 24

24. (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.

Question 25

25. 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

Answer 25

25. (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.

Question 26

``` 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 ```

Answer 26

26. (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.

Question 27

27. 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

Answer 27

27. (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.

Question 28

28. 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

Answer 28

28. (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.

Question 29

29. 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

Answer 29

29. (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.

Question 30

30. 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

Answer 30

30. (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.

Question 31

31. 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

Answer 31

31. (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).

Question 32

32. 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

Answer 32

32. (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.

Question 33

33. 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

Answer 33

33. (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.

Question 34

34. 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

Answer 34

34. (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.

Question 35

35. 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

Answer 35

35. (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.

Question 36

36. 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

Answer 36

36. (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.

Question 37

37. 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

Answer 37

37. (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.

Question 38

38. 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

Answer 38

38. (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.

Question 39

39. 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

Answer 39

39. (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.

Question 40

40. 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

Answer 40

40. (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.

Question 41

41. 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

Answer 41

41. (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.

Question 42

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. 42. 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

Answer 42

42. (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.

Question 43

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 ```

Answer 43

43. (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.

Question 44

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. 44. 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

Answer 44

44. (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.

Question 45

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 ```

Answer 45

45. (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.

Question 46

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 ```

Answer 46

46. (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.

Question 47

47. 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.

Answer 47

47. (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.

Question 48

48. 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

Answer 48

48. (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.

Question 49

49. 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

Answer 49

49. (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.

Question 50

50. 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

Answer 50

50. (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.

Question 51

``` 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 ```

Answer 51

51. (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.

Question 52

52. 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

Answer 52

52. (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.

Question 53

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. 53. Which one of the following medications is not indicated in treatment of this condition? (A) Carbamezapin (B) Cefatin (C) Phenytoin (D) Gabapentin (E) Baclofen

Answer 53

53. (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).

Question 54

54. 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

Answer 54

54. (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.

Question 55

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 ```

Answer 55

55. (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.

Question 56

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 ```

Answer 56

56. (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.

Question 57

57. 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

Answer 57

57. (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.

Question 58

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 ```

Answer 58

58. (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.

Question 59

Electromyography (EMG) and nerve conduction studies (NCS) are useful for assessing the function of A. Peripheral nerves B. Bilateralcarotidarteries C. Intracranialliquids D. Spinalnerves

Answer 59

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.)

Question 60

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 60

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.)

Question 61

3. According to the Glasgow Coma Scale (GCS), a patient withaheadinjuryscoreo 5isclassi edas A. Mild B. Moderate C. Severe D. Seizure

Answer 61

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.)

Question 62

4. 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 62

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.)

Question 63

5. 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 63

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.)

Question 64

6. Apatientwhowithdraws rompain,ismumblinginappro- priate words, and opens his eyes to pain has a GCSscore o A. 3 B. 6 C. 9 D. 12

Answer 64

Answer:C

Question 65

7. T emostcommonmalignanttumoro thebrainis A. Ependymoma B. Astrocytoma C. Ganglioglioma D. eratoma

Answer 65

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.)

Question 66

8. 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 66

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.)

Question 67

9. 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 67

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.)

Question 68

10. 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 68

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.)

Question 69

``` 11. T e most common intradural extramedullary tumors in children are A. Ependymomas B. Astrocytomas C. Dermoids D. eratomas ```

Answer 69

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.)

Question 70

``` 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 70

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.)