Neurosurgery

Question 1

In an L1-L2 herniation, which nerve will be affected?

Answer 1

L2

Question 2

What is Brown Sequard syndrome?

Answer 2

1) diminished strength ipsilaterally to lesion
2) decreased vibration, light touch ipsilaterally
3) decreased temperature, pain contralaterally

Question 3

What is the conus medullaris and where does it end?

Answer 3

the most caudal tip of the spinal cord. In most people (~98%), it ends at L2 or above

Question 4

Continuous neck pain and prevertebral swelling on plain radiographs are strongly suggestive of what?

Answer 4

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)

Question 5

How is ligamentous injury ruled out?

Answer 5

obtaining lateral radiographs in flexion and extension to demonstrate any excessive movement between adjacent vertebrae

Question 6

What is the treatment for multiple brain metastases?

Answer 6

full course of fractionated radiation to the whole brain

Question 7

An MRI showing a ring pattern of enhancement with IV contrast and a nonenhancing necrotic center would suggest

Answer 7

GBM

Question 8

What is the most commonly encountered neoplasm in the cerebella-pontine angle?

Answer 8

acoustic neuroma arising from the Schwann cells that form the myelin sheath of the vestibular division of the 8th CN

Question 9

What should be on the differential diagnosis for medulloblastoma (or PNET, primitive neuroectodermal tumor)?

Answer 9

highly aggressive and rapidly growing tumor most often arising within the cerebellar vermis. Grows locally and can obliterate the 4th ventricle

DDX

1) Ependymoma (highly aggressive, but usually arise from the floor of the fourth ventricle)
2) Choroid plexus papilloma (can cause hydrocephalus, either by obstructing CSF pathway or by producing lots of CSF); benign

Question 10

While primary CNS neoplasms rarely metastasize outside of their site of origin, there are two exceptions to this statement, including: _________

Answer 10

medulloblastoma and ependymoma

Question 11

What is the treatment of drop metastases in the spine?

Answer 11

complete craniospinal irradiation with local boosts to the areas where tumor nodules are detected

CTX, particularly procarbazine, lomustine, and vincristine, given to disease that is locally recurrent after maximal irradiation

Question 12

Why are epidural hematomas more common in younger people?

Answer 12

The dura mater is less firmly adherent to the inner table of the skull

Question 13

Evidence of decerebrate rigidity, CT showing small punctate hemorrhages in the corpus callosum and midbrain tegmentum, but normal ventricles and no mass effect:

Answer 13

DAI. Caused by sharp accelerations or decelerations of the head and its contents seen in MVAs. During impact, shock waves are generated that travel through the brain, penetrate, and cause shear and stretch injury to multiple deep axonal tracts

Question 14

The presence of a Battle’s sign and hemotympanum is highly suggestive of _________

Answer 14

a left temporal bone fracture.
Dura mater at the site can be torn, and leakage of CSF into the mastoid air cells and middle ear can reach the nasopharynx via the eustachian tube = “paradoxical rhinorrhea”

Question 15

This disease is a result of abnormalities in the development of mesodermal elements (sclerotome) which form the dorsal elements of the lumbosacral spine.

Answer 15

Spina bifida occulta (tuft of hair, AND absence of spinous processes and laminae with displaced pedicles angled laterally)

Question 16

What is spondylolisthesis?

Answer 16

Occurs when there is disruption, most often by a fracture, of the pars intra-articularis of the L5 vertebra. Functional result of this disruption is that hte descending facets are “floating” and not able to function in stabilizing a joint. If this becomes progressive, anterior subluxation of the cephalad vertebral body with respect to the caudal can occur.

Question 17

All babies born with a defect in neural tube closure (including myelomeningocele, spina bifida) should also be checked for

Answer 17

Arnold-Chiari malformation

Question 18

T/F: The medulla and lower crania; nerves may be abnormally elongated in an Arnold-Chiari abnormality.

Answer 18

True

Question 19

What is NPH?

Answer 19

normal-pressure hydrocephalus. Seen in the elderly. Wacky, wobbly wet!!! (dementia, ataxia, urinary incontinence)

Question 20

These patients give a history of severe blows to the head and skull fractures and present with a chronic headache (no neurologic symptoms or deficits):

Answer 20

arachnoid cyst (CSF filled cyst that occur when leaves of arachnoidal tissue fuse, trapping CSF within them). Most common locations = middle cranial fossa, CPA, and suprasellar area

Question 21

Where would a Rathke’s cleft cyst be found?

Answer 21

within the sella turcica

Question 22

Ct shows large, nonenhancing cyst in the posterior cranial fossa with an enhancing tumor nodule in the left cerebellum:

Answer 22

cystic astrocytoma

Question 23

T/F: The presence of an intracranial hematoma following a gunshot wound to the head that is greater than 2x2x2 cm is a negative prognosticator.

Answer 23

False. It is positive, because it can be more readily evacuated via a craniotomy.

Question 24

T/F: Initial neurologic grade after a gunshot wound to the head does not reflect to heavily on prognosis.

Answer 24

True. The best prognostic indicator of survival and outcome in patients with missile wounds to the brain is mental status and level of responsiveness AFTER proper resuscitation.

Question 25

A bursting posterior communicating aneurysm could cause SAH with which neurologic features?

Answer 25

wide, fixed dilated pupil (due to disrupting the oculomotor nerve, which has PNS fibers on it)

Question 26

Pyridostigmine and neostigmine are both ________. How do their muscarinic effects and duration of effects compare to each other?

Answer 26

Both used in the reversal of nondepolarizing muscle relaxants. Pyridostigmine causes less muscarinic effect. Effect of pyridostigmine is more prolonged and produces fewer secretions/less severe bradycardia.

Question 27

How do narcotics, thiopental (rapid onset short acting barbiturate anesthetic), and N2O affect respiration?

Answer 27

All 3 depress respiration, so the response to hypercapnea is diminished.

Question 28

Calcified cystic lesion in the suprasellar hypothalamic region:

Answer 28

craniopharyngioma

Question 29

What is the cyst wall made of in craniopharyngiomas? What does the fluid contain?

Answer 29

cyst wall = squamous epithelium

fluid contains cholesterol crystals

Question 30

The clinical presentation of DI does not manifest until over __% of the ADH secretory capacity is damaged.

Answer 30

85%

Question 31

Trigeminal neuralgia is assumed to be caused by a loop of vessel, often _____ or ____, compressing the trigeminal nerve as it emerges from the brainstem.

Answer 31

superior cerebellar artery or posterior inferior cerebellar artery (PICA)

Question 32

How does sickle cell cause SAH?

Answer 32

sickle cell angiopathy from the subpial vessels

Question 33

T/F: In patients with SCD, the administration of high-osmolar contrast for examining SAH can precipitate sickle cell crisis.

Answer 33

True!

Question 34

Intracerebral hemorrhage with presence of edema (EARLY, not late resulting from the hemorrhage itself) and mass effect =

Answer 34

neoplastic bleed