28. CNS Pathology Flashcards
Most common cerebrovascular diseases
- 1. Hypertensive intraparenchymal hemorrhage (MC)
- Global ischemia
- Embolism
- 4. Ruptured aneurism
When BF is reduced to the brain, survival depends on:
- 1. Collateral flow
- 2. Duration of ischemia (less than 24 hours = TIA; more than 24 hours = stroke)
- 3. Magnitude and rapidity of flow reduction
Watershed areas 1st to be damaged to ischemia and infarction in global ischemia, because they are the most distal branches of major arteries.
In global cerebral ischemia or hypoxic encephalopathy, what type of damage do we see when watershed areas are affected?
Sickle-shaped band of necrosis
- Watershed areas 1st to be damaged to ischemia and infarction in global ischemia, because they are the most distal branches of major arteries. The border zone between which arteries in the cerebral hemispheres are most at risk for an infarct following global ischemia?
- What can cause this?
ACA/MCA
- Occlusion of the internal carotid artery
- Hypotension in patients with carotid stenosis
Symptoms if ischemia and infarction of ACA/MCA?
- Proximal arm and leg weakness.
- Transcortical aphasia: language problems
Symptoms if ischemia and infarction of MCA/PCA?
- Higher-order visual processing
Which pattern of injury is seen in the cerebral neocortex following global ischemia?
Pseudolaminar necrosis
Carotid Stenosis
- What is it?
- What is it most commonly due to?
-
Carotid stenosis is MC due to atherosclerosis. Thrombi can form and embolize, leading to stenosis of the internal carotid artery. This can ⬇︎ blood and O2 to the following arteries:
- 1. MCA
- 2. ACA
- 3. Opthalamic artery
![](https://s3.amazonaws.com/brainscape-prod/system/cm/301/601/657/a_image_thumb.png?1581055365)
What are symptoms of carotid stenosis?
Bc can ⬇︎ blood and O2 to the MCA, ACA and opthalamic artery =>
- Contralateral face-arm or face-arm leg motor/sensory weakness
- Contralteral changes in visual field
- Aphasia or neglect
- Carotid bruit in diastole
Carotid bruit heard in diastole is indicative of what?
- stenosis of internal carotid artery
How to correct carotid stensois?
- Angioplasty/stenting
- Endarterectomy
Focal cerebral ischemia, focal neurological deficits is most often due to what?
- Embolism
- Thrombus
- Atherosclerosis in HTN
Symptoms of Focal Cerebral Ischemia
- Less than 24 hours: TIA
- More than 24 hours: stroke (regional ischemia that causes focal neurological deficits)
Thrombosis
- MC due to: ______
- MC sites of primary thrombosis: ________
- Atherosclerosis
- MC sites of primary thrombosis:
- Carotid bifurcation
- origin of Middle Cerebral Artery (MC)
- Either end of the basialr artery
How does a thrombus form?
- Rupture, ulceration or erosion of plaque exposes blood to thrombogenic substances => blood is exposed to subendothelial collagen/necrotic debris in plaque => thrombus => pale wedge-shaped infarction at periphery of CTX
what is this?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/301/602/689/q_image_thumb.jpg?1581057416)
subarachnoid hemorrhage: only thing that will cause bleeding at BOTTOM of brain
What is the risk factor most commonly associated with deep brain parenchymal hemorrhages?
HTN
What causes Charcot-Bouchard microaneurysms?
Chronic HTN
What is a Charcot-Bouchard microaneurysm vs. Saccular (berry) aneurysm?
Where is each most commonly seen?
- Charcot-Bouchard occur in vessels less than 300 um in diameter; most often within basal ganglia
- Saccular (berry) aneurysms occur in larger intracranial vessesl in the subarachnoid space
Intracerebral/ intraparenchymal hemorrhage vs subarachnoid hemorrage.
- MC due to what?
- MC seen in who?
- Sx?
Intracerebral/intraparenchymal hemorrhage
- MC due to: Rupture of Charcot Brousad microaneurysms (in pts who have HTN)
- MC in: HTN patients
- Sx: HA, N/V => coma
Subarachnoid hemorrhage
- MC due to: R_upture of Berry/Saccular aneurysms_ in the Anterior Circle of Willis at the branch points of Anterior Communicating Artery; rupture easily bc no media
- MC in: Marfans and APKD (bc they’re more likely to have berry aneuryms)
- Sx: Worse HA of life with nuchal rigidity
What is most commonly affected by a embolic infarction?
Where do emboli most often lodge?
- L side of heart => Middle cerebral artery (MCA)
- Where BV branch of pre-existing areas of stenosis