Neurosurgery

CHAPTER 29
Neurosurgery


Joshua Gish


Test Taking Tips


Make sure that you are familiar with the Glasgow Coma Score prior to the test.


Review the neurosurgery section in the trauma chapter.


What components are present in the cranium?


Brain tissue, cerebrospinal fluid (CSF), blood vessels and blood volume, pathological volume (eg, neoplasm, hematoma, abscess, etc)


What may cause an increase in the brain tissue component (not including neoplasms)?


Edema, inflammatory, perineoplastic, vasogenic


What can be given to decrease swelling due to edema?


Mannitol, hypertonic saline


What can be given to decrease the brain tissue component if swelling is caused by inflammation or perineoplastic syndrome?


Steroids


What can be done to decrease the blood volume component?


Hyperventilation, diuretics, head elevation, remove venous obstruction


What can be done to decrease the CSF component?


Drainage (either external or internal such as a VP shunt), acetazolamide (temporary), steroids (temporary)


What can be done to decrease volume due to a mass lesion?


Evacuation or removal of the cause of the mass lesion


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.


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.”


What is the site of CSF production?


The arachnoid granulations


What is the name of the process that maintains cerebral blood flow at a constant rate despite changes in systemic blood pressure?


Autoregulation


Define cerebral perfusion pressure:


Mean arterial pressure (MAP) – ICP


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 a raised ICP with no mass lesion termed?


Pseudotumor cerebri or idiopathic intracranial hypertension


What is increased ventricular volume without increased intracranial pressure called?


Normal pressure hydrocephalus


What is a failure of proper capillary formation termed?


Arteriovenous malformation (AVM)


What is the risk of hemorrhage associated with an AVM?


4% per year


What percentage of AVM-associated hemorrhages is classified as severe?


25%


image


FIGURE 29-1. Cerebral angiogram demonstrating a frontal arteriovenous malformation filling from the left anterior cerebral artery. (Reproduced from Doherty GM. Current Diagnosis and Treatment: Surgery. 13th ed. www.accessmedicine.com. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.)


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


What is the risk of hemorrhage with an aneurysm measuring less than 1 cm?


0.05% to 0.5% per year


What is the risk of hemorrhage with an aneurysm measuring more than 1 cm?


1% to 2% per year


If not treated, what is the risk of rebleed within 2 weeks from an aneurysm that has ruptured?


20%


Which cerebrovascular moniker derives from the Japanese term for “puff of smoke?”


Moyamoya—it is characterized by idiopathic narrowing of the major intracrainial vessels with formation of a compensatory collateral circulation.


Which medication is prescribed to reduce swelling related to brain tumors?


Dexamethasone

Aug 13, 2019 | Posted by in ABDOMINAL MEDICINE | Comments Off on Neurosurgery
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