ABSITE: Neurosurgery
If not treated, what is the risk of rebleed within 2 weeks from an aneurysm that has ruptured?
20%
What % of AVM-associated hemorrhages is classified as severe?
25%
What is the site of CSF production?
arachnoid granulations
What is the risk of hemorrhage associated with an AVM?
4% per year
What GCS is considered the "cutoff" as an indication for ICP monitoring?
8
What is the most common CNS infection in patients with acquired immunodeficiency syndrome?
Toxoplasmi gondii
What is failure of proper capillary formation termed?
arteriovenous malformation (AVM)
Which class of tumors accounts for half of all primary brain tumors?
astrocytomas
What is the name of the process that maintains cerebral blood flow at a constant rate despite changes in systemic blood pressure?
autoregulation
What components are present in the cranium?
brain tissue CSF blood vessels and blood volume pathologic volume (eg, neoplasm, hematoma, abscess, etc)
What is the 2nd most common primary lesion for metastatic tumors of the brain?
breast (15-20%)
What dopamine agonist is useful in 75% of prolactinomas?
bromocriptine
What syndrome results in weakness of the upper extremities with relative sparing of the lower extremities?
central cord syndrome
Which medication is prescribed to reduce swelling related to brain tumors?
dexamethasone
What is the term for rotational acceleration and deceleration injuries that disrupt the white matter tracts of the brain?
diffuse axonal injury
What may cause an increase in brain tissue component (not including neoplasms)?
edema inflammatory perineoplastic vasogenic
What can be done to decrease volume due to mass lesion?
evacuation or removal of the cause of the mass lesion
What is the term for grade IV astrocytomas?
glioblastoma multiforme
What is the most common primary lesion for metastatic tumors of the brain?
lung (~50%)
What can be given to decrease swelling due to edema?
mannitol hypertonic saline
What is increased ventricular volume without increased intracranial pressure called?
normal pressure hydrocephalus
What brain tumor will tend to cause bitemporal hemanopsia?
pituitary adenomas
What is a raised ICP with no mass lesion termed?
pseudotumor cerebri or idiopathic intracranial hypertension
Chemotherapy is useful for brain metastatic tumors for which 2 primary lesions?
small cell lung cancer seminomas
What can be given to decrease the brain tissue component if swelling is caused by inflammation or perineoplastic syndrome?
steroids
What is the Monro-Kelly doctrine?
the total volume of the cranial vault is fixed, and thus an increase in one component must be offset by a decrease in another component
Why do older people tend to be more tolerant of mass lesions?
they tend to have larger ventricles, which are more tolerant of compression than brain tissue
What is the most common cause of subarachnoid hemorrhage?
trauma
Up to how many lesions can surgery be indicated for with metastatic disease in the brain?
up to 3 (provided they are accessible)
What is the most common schwannoma?
vestibular schwannoma
This process is caused by defects in the arterial media and is increased in patients with connective tissue disorders such as Ehlers-Danlos or Marfan syndromes
Berry aneurysms
Which syndrome results in ipsilateral paralysis and contralateral loss of sensation?
Brown-Sequard, or hemitransection of the spinal cord
What can be done to decrease the blood volume component?
- hyperventilation - diuretics - head elevation - remove venous obstruction
What are the symptoms of a carotid stenosis?
- ipsilateral amaurosis fugax (temporary blindness often described as a window shade caused by ophthalmic artery emboli) - ipsilateral TIA - stroke
What can be done to decrease the CSF component?
- drainage (either eternal or internal such as VP shunt) - acetazolamide (temporary) - steroids (temporary)
What is the risk of hemorrhage with an aneurysm measuring <1 cm?
0.05-0.5% per year
What is the risk of hemorrhage with an aneurysm measuring >1 cm?
1-2% per year
How can one differentiate between CSF and mucus secretions in cases of suspected ethmoid plate disruptions?
CSF will contain glucose
Which imaging test is paramount in assessing for brain injury following a trauma?
CT head
True or False: CSF production rate is affected by intracranial pressure (ICP).
False: CSF production rate is constant and is not affected by "back pressure"
Define cerebral perfusion pressure
MAP - ICP
Which cerebrovascular moniker derives from the Japanese term for "puff of smoke"?
Moyamoya - characterized by idiopathic narrowing of the major intracranial vessels with formation of a compensatory collateral circulation
Which syndrome is characterized by paralysis and sensory loss but preservation of deep sensation and proprioception?
anterior cord syndrome
