Path- 3: Edema, ICP, herniations Flashcards
What causes vasogenic edema?
BBB disruption, resulting in focal or generalized increase in permability
What causes cytotoxic edema?
increase in intracellular volume
Where does interstitial edema (hydrocephalus) typically occur?
Around the lateral ventricles
With ischemia, what happens to the white matter?
It becomes more edematous
Why does the white matter become more edematous?
increase in salt because of pump inhibition
What produces CSF?
Choroid plexi
How much CSF is produced per day?
500mL
Where is CSF reabsorbed?
Arachnoid villi
What happens if there is an obstructuon ot flow of the CSF int he ventricles?
noncommunicating hydrocephalus
What causes noncommunicating hydrocephalus?
congnetial malformation, neoplasms, inflammation or hemorrhage
Wehre is the most common location of obstruction to cause noncommunicating hydrocephalus?
Aqueduct of Sylvius (IVF)
What causes ivf closure?
typically congentical malformations (viral ependymitis during engrogenesis)
What defines ICP?
increase mean CSF pressure greater than 200 mmH2O with pt recumbent
What would happen if ICP becomes devere?
Brain herniation
What is a subfalcine (cingulate) herniation?
asymmatric expanson of the cerebral hemispheres displaces the cingular gyrus under the faux cerebri
What is papilledema?
the edematous optic papillar protrude forward into the vitreous humor chamber
What are the physiological consequences of an increase of ICP > 30mmHg?
decrease in CBF (viscious cycle because cerebral ischemia causes an increased ICP)
What are the Sx of an icnreaase of ICP > 30mmHg?
headache, nausea/vomiting, papilledema, focal neurological deficits, ALOC, cushings response (increase in ICP with bradycardia)
What happens in transtentorial (uncinate) herniation?
medial aspects of the temporal lobe are compressed ahgainst the tenorium cerebelli –> herniate.
Sx of uncinate herniation?
Pupillary dilation and ocular movement impairment on side of lesion (remember it compresses III ipsilaterally), ipsilateral hemiparesis (b/c of CL cerebral preduncle compression)
What types of hemmorages are associated with uncinate herniations?
hemorrhages in pons and midbrain because of the tearing of the penetrating veins and arteries supplying under brainstem.
What happens in a tonsilar heerniation?
Displacement of the cerebellum through the foramen magnum. LIFE THREATENING b/c of compression of CV and resp center compression.
What is the Tx of a tonsilar herniation?
lumbar puncture
