Neuro: 17.4: Cerebrovascular Disease Flashcards
Why are Berry aneurisms susceptible to rupture?
they lack a media layer
What is the most common site of an intracerebral hemorrhage?
the basal ganglia
Name 3 ways that an ischemic stroke can develop.
- thrombus
- embolus
- lacunar
Name 3 highly vulnerable areas of the brain because of their location in a watershed area.
- pyramidal neurons of cortex layers 3,5, and 6
- pyramidal neurons of the hippocampus
- purkinje layer of the cerebellum
Which race has an increased risk of Berry aneurisms?
blacks
What happens in severe global cerebral ischemia? What is the outcome?
- diffuse necrosis of the brain
- death or a chronic vegetative state
What is a Berry aneurism?
a thin-walled, saccular out pouching of a BV that lacks a media layer
Dx?
- a bleed on the bottom of the brain
a subarachnoid hemorrhage
Which BV feeds the surface of the cerebral cortex?
the middle cerebral artery
How does an intracerebral hemorrhage present?
- HA
- n/v
- coma
What will a lumbar puncture show in subarachnoid hemorrhage?
xanthochromia
From which artery do the lenticulostriate vessels branch off of?
the middle cerebral artery
What is Hemiballismus?
- a mvmt disorder characterized by a sudden, wild flailing of 1 arm +/- the ipsilateral leg
- *** “Half of body ballistic”
Where do atherosclerotic plaques usually develop?
at arterial branch points
What is another name for a Berry aneurism?
Saccular aneurism
What is a subarachnoid hemorrhage?
bleeding into the subarachnoid space
If the focal neurologic deficits last less than 24 hours, then it’s called a _________.
transient ischemic attack (TIA)
Why does an embolic stroke cause hemorrhagic infarcts, but a thrombotic stroke causes a pale infarct?
- embolus can be lysed by body –> blood returns
- thrombus can’t be lysed –> pallor
Where do lacunar strokes most often occur?
in the lenticulostriate vessels of the deep brain
What causes intracerebral hemorrhage?
rupture of Charcot-Bouchard microaneurisms
Where do Berry aneurisms most frequently occur?
in the anterior Circle of Willis (branch points of the anterior communicating artery)
What are horizontal lines of necrosis in the brain cortex layers called?
cortical laminar necrosis
What are the macrophages of the brain?
microglia
This is a thin-walled, saccular out pouching of a BV that lacks a media layer.
a Berry aneurism
What happens microscopically from time 0 up to 1 day post-ischemic event?
red neurons present
How long can neurons survive ischemia before undergoing necrosis?
3-5 mins
Which BV feeds the deep structures of the brain, including the basal ganglia?
the lenticulostriate vessels
If the focal neurologic deficits last more than 24 hours, then it’s called a _________.
ischemic stroke
What does gliosis refer to?
reactive astrocytes lining the cystic space with CT
Which conditions are Berry aneurisms associated with?
- Marfans
- ADPKD
- Ehlers-Danlos
- coarctation of the aorta
What is intracerebral hemorrhage?
bleeding into the brain parenchyma
What is a Charcot-Bouchard microaneurism? How do they occur?
- microaneurisms of the lenticulostriate vessels
- HTN –> hyaline arteriosclerosis –> weakening of BV wall
Name 4 general causes (and their underlying pathology) resulting in global cerebral ischemia.
- low perfusion (atherosclerosis)
- acute decrease in blood flow (shock)
- chronic hypoxia (anemia)
- repeated episodes of hypoglycemia (insulinoma)
Where does a thromboembolus causing an ischemic stroke most commonly occur in the brain?
the middle cerebral artery
How does a subarachnoid hemorrhage present?
- a sudden headache (“the worse HA of my life”)
- nuchal rigidity
What happens in moderate global cerebral ischemia? What is the outcome? Give an example.
- infarcts to watershed areas
- damage to highly vulnerable regions
- ex: pyramidal neurons of cortex layers 3,5, and 6
Dx?
- a bleed in the parenchyma of the brain
an intracerebral hemorrhage
What happens microscopically from time 1 day up to 1 week post-ischemic event?
inflammatory cells present (neutrophils, microglial cells)
What does a lacunar stroke involve?
the small BVs in the brain that undergo hyaline arteriolosclerosis
Intracerebral hemorrhage is a complication of _____.
HTN
What lesions characteristically causes Hemiballismus?
a lesion of the contralateral subthalamic nucleus (eg, lacunar stroke)
What happens to the BVs in hyaline arteriolosclerosis?
the lumen is narrowed by fibrosis
What is xanthochromia? What causes it?
- a yellow tinge to the CSF in a lumbar puncture
- bilirubin breakdown products
Where is the hippocampus located? What is its function?
- in the temporal lobe
- to transfer info to long-term memory
What is a mvmt disorder characterized by sudden, wild flailing of 1 arm +/- the ipsilateral leg?
Hemiballismus
The rupture of Charcot-Bouchard microaneurisms causes ______.
intracerebral hemorrhage
A lesion of the contralateral subthalamic nucleus (eg, lacunar stroke) causes what movement disorder?
Hemiballismus
What will the ischemic infarction look like due to embolus?
a hemorrhagic infarct in the periphery of the cortex
What is the most common source of a thromboembolus causing an ischemic infarct in the brain?
the L heart (A-fib)
What happens microscopically from time 1 week to 1 month post-ischemic event?
granulation-like tissue –> cystic space formation with gliosis and astrocytes
What will the ischemic infarction look like due to thrombosis?
a pale infarct in the periphery of the cortex
What is the end result of liquefactive necrosis in the brain?
a fluid-filled cystic space surrounded by gliosis
What are the 2 major causes of cerebrovascular disease? Which is more common?
- more common = ischemia
- hemorrhage
What happens in mild global cerebral ischemia? What is the outcome? Give an example.
- transient confusion
- complete recovery
- ex: an insulinoma
What is a watershed area of circulation?
an area fed by the very end of a circulation
What are the 3 layers of a BV wall?
- intima (inner)
- media (middle)
- adventitia (outer)
What are the 2 types of ischemic cerebrovascular disease that can occur?
- focal
- global
What are the 2 types of hemorrhagic cerebrovascular disease that can occur?
- intracerebral
- subarachnoid
What is cortical laminar necrosis?
horizontal lines of necrosis in the brain cortex layers
What causes hyaline arteriolosclerosis?
- HTN
- diabetes
What is one of the earliest findings on microscopy of an ischemic stroke? When does this present?
- red neurons
- 12 hours post-event
What is the most common cause of a subarachnoid hemorrhage?
rupture of a Berry aneurism
What kind of necrosis is seen in an ischemic stroke?
liquefactive
