Neuro Flashcards
(31 cards)
Appearance of cytotoxic edema?
Causes?
- Loss of greywhite differentiation
- Infarction
- Hypoxic injury
- HSV encephalitis
Appearence of vasogenic edema?
Cause?
- White matter only becomes hypodense
- Malignancy (primary or secondary)
- Abscess
What is the cellular etiology for cytotoxic edema?
- Failure of N/K pump
What is the cellular etiology for vasogenic edema?
BBB breakdown
How is area at risk defined on CT perfusion?
Time to maximal perfusion (Tmax) > 6.0s
How is the area of infarct core defined on CT perfusion?
Volume of brain tissue with cerebral blood volume <30% of the contralateral side.
How is penumbra defined on CT perfusion?
Brain volume with Tmax > 6.0s - Brain volume with cerebral blood flow <30% = penumbra volume
Whats the next step if vasogenic edema is spotted on a noncontrast head CT?
Give IV contrast to check for tumor or abcesss
Whats the classic appearance of abscess on contrast enchanced T1 and DWI?
Rim enhancement with central non-enhancing pus which is bright on DWI.
What is the classic territory of involvement of HSV encephalitis?
Temporal horn and insula sparing the basal ganglia
A perfectly round brain parenchymal hemorrhage should make you suspicious of what?
a metastasis that has bled into itself
How do you differentiate a primary vs secondary intraaxial bleed?
- Primary bleed will have very little vasogenic edema. A secondary bleed will have large amount of vasogenic edema secondary to the primary lesion.
- Irregular shape - primary
- Round - secondary
What are the most common locations for hypertensive headahce?
- Basal ganglia (putamen)
- Thalamus
- Pons
- Cerebellum (dentate nucleus)
What is a lobar intracranial hemorrhage ?
Superficial bleed involving within the lobes of the brain (i.e. not the basal ganglia) which is strongly associated with amyloid angiopathy in the elderly
What the etiology of lobar hemorrhage in a young person?
AVM
Can extraaxial hemorrhage cause cerebal edema?
No. Only intraaxial hemorrhage can cause cerebral edema.
What parts of the brain does diffuse axonal injury affect?
- Grey white matter junction
- Corpus callosum
- Brain stem (most severe cases)
Whats the most important prognostic factors for diffuse axonal injury?
- Age >35
- Involvement of mid-brain
What is a common sequela of venous infarcts?
50% of venous infarcts bleed. In contrast arterial bleeds don’t commonly bleed
16 year old boy with epistaxis, nasal mass and widening of sphenopalatine foramen?
Juvenile angiofibroma
Key anatomical landmark in orbital cellulitis
Orbital septum
- Preseptal (less severe)
- Postseptal (severe)
How to differentiate acute from choronic sinusitis
Acute: Air fluid level
Chronic: mucosal thickening
What is Potts Puffy Tumor?
Subperiostial abcess and osteomeylitis from direct extension of obstructed sinusitis
Normal variants of the dens
os odontinaum- childhood fxr that heals
os tirminale- small separate center of ossification
Both are fully cortiacted (unlike a fxr)
