Cerebrovascular Disease 1 Flashcards
What occurs to the neuron in the setting of HYPOXIA or ischemia?
- acute neuronal injury
(RED neurone)
—-visible 12-24 hrs after irreversible insult
How does a red neuron appear?
- shrinking and ANGULATION of nuclei
- loss of nucleolus
- V.red cytoplasm
WHen do inclusions form in the brain cells?
- neurodegenrative conditions (Alzheimer’s; neurofibrillary tangles)
- ageing
- viral infections
Main roles of astrocytes?
- maintains BBB (along with endothelial cells)
2. involved in REPAIR and SCAR formation
What is gliosis?
- an astrocytic response
- v. important indicator of CNS injury
What cells wraps around axons in the CNS to form myelin sheath?
- Oligodendrocytes
Which cell in the CNS is involved in demyelinating d.o?
- Oligodendrocyte
What are oligodendrocyte sensitive to?
- oxidative damage
Which cells line the ventricular system?
- EPENDYMAL cells
Macrophage of the CNS
Microglia
- m1: Pro-inflammatory
- m2: aNTI-INFLAMMATORY
What causes neurones to die in the event of brain injury ?
excitotoxicity
Which type of stroke is seen in YOUNGER people (hemorrhagic or occlusive)?
- hemorrhagic
Causes of hemorrhagic stroke?
- amphetamine use (RAISE in BP)
- Cocaine use
What occurs with reduced ATP prodn in the neurone (d.t hypoxia) ?
- stops the Na+/K+ pump from working (causing NEURONE depolarization)
- activation of voltage-dependent Calcium channels (triggers the release of Glutamate into the ECM)
How much oxygen does the brain consume?
- 20%
What maintains blood flow at a constant rate in the cerebral vessels?
- Autoregulatory mechanisms by constant constriction and dilatation of cerebral vessels
When does global hypoxic ischemic damage usually occur?
The generalized reduction in blood flow
d.t CARDIAC arrest and severe hypotension (hypovolemic shock)
Area of the brain specifically sensitive to hypoxic ischemia?
-WATERSHED areas (zones between 2 arterial territories)
Areas in the brain with v. sensitive neurones?
- neocortex and hippocampus
Define stroke
sudden disturbance of cerebral function of vascular origin
- lasts over 24 hrs
53% of cerebral infarctions are ______ in orgin
THROMBOTIC
10% of cerebral hemorrhage is _____
intracerebral
MOST COMMON site of thrombotic stroke
MCA site
Cerebral infarction victims
- men >70y.o
Where may an emboli come from in the brain?
- atheroma in ICA or aortic arch
- heart
Risks of strokes
- atheroma
- H/T
- serum lipids, diet, obesity
- DM
- Heart disease
- neck artery disease
- drugs
- smoking
IF the vascular lesion is in the MCA - what is the presentation?
- weakness C/L FACE and ARM
ACA lesion==>
weakness and sensory loss in C/L leg
How would carotid artery disease present as?
- c/l WEAKNESS or SENSORY loss
- if dominant hemisphere= aphasia or apraxia
If its a vertibro-basilar artery disease?
vertigo- dizziness, loss of coordination ataxia dysarthria- slurred speech dysphagia loss of vision (in one/both eyes)
What are the consequences of H/T?
- LACUNAR infarcts
(atheroma/ embolism/ basal ganglia) - multi-infarct dementia
- ruptured aneurysm
- hypertensive encephalopathy
Name 4 less known causes of intracerebral hemorrhage?
- amyloid deposits
- Open heart surgry
- vasculitis
- neoplasms
Where do intracerebral hemorrhage usually occur?
Basal ganglia
thalamus, white matter, cerebllum
Describe the cut-surface of an intracerebral hemorrhage.
- asymmetrical distortion but well-demarcated
- herniations common
- softening of adjacent tissue
- surrounding edema
Which vascular malformation has a HIGH rebleed rate (4%/year)
Arteriovenous Malformations (AVM)…form abnormal tortuous vessels (usual rupture in MCA territory)
NAme other vascular malformations! And what do they additionally cause?
headaches and seizures
- cavernous angiomas
- venous angiomas
- capillary telangectases
Most COMMON cause of subarachnoid hemorrhage?
rupture of saccular aneurysm (berry aneurysm) —90% in ICA; 10% in vertebro-basillar circul….at arterial bifurcation
Berry aneurysm risk factors:
smoking/ H/T/ kidney disease
What are the signs of berry aneurysm?
- ACUTE onset severe headache
- vomiting
- LOC
(no hx of precipitating factor) —-50% die
Morphology fts of berry anuerysm?
- infarcts of brain parenchyma
- intracerebral hematoma
- hematoma and RAISED ICP
