Aetiology & Pathophysiology of Stroke Flashcards
What are the different types of ischemic stroke?
- Large artery disease
- Cardioembolic
- Lacunar
What are the types of hemorrhagic stroke?
- Hypertensive
- Cerebral amyloid angiopathy
What arteries are effected in Large artery disease?
Common carotids to middle cerebral arteries
What is the ischemic core in stroke?
Area of the brain that has developed necrosis
What level does cerebral blood flow need to reduce to to result in necrosis?
<20%
What is a penumbra in stroke?
Area of brain with reduced cerebral blood flow, but also getting O2 and glucose from collateral arteries
What are the steps in the ischemic cascade?
- Tissues switch from aerobic to anaerobic metabolism
- Accumulation of lactic acid
- Na/K channel dysregulation - Cytotoxic oedema
- Na/Ca channel dysregulation - Increases Ca within neuron:
1) Excitotoxicity
2) Degradative enzymes
3) formation of radicals - Mitochondrial apoptotic factors
What is vasogenic oedema?
Swelling of the basement membrane at the blood-brain barrier causing leakage of fluid and therefore oedema
When does vasogenic oedema take place?
4-6 hours after ischemia
What is post-stroke inflammation?
- Ischemia attracts macrophages to cause inflammation
- After inflammation the brain enters an anti-inflammatory mode
- This leads to liquefactive necrosis
What are the 5 TOAST classifications of stroke?
- Large artery atherosclerosis
- Cardioembolic
- Small artery disease
What is the most common TOAST classification of stroke?
Large artery atherosclerosis
What causes cardioembolic stroke?
Reduced flow from the heart
How does small artery disease stroke present?
Presents as a lacunar stroke
What causes small artery disease stroke?
Lipohyalinosis - Thickened vessel walls leading to luminal narrowing
