Pathologies of cerebrovascular disease Flashcards
Three most common causes of a localised interrupted blood flow?
- Atheroma + thrombosis leading to ischaemia
- Thromboembolism causing Ischaemia
- Ruptered vessel wall leading to hemorrage
What happens when atheroma and thrombosis present ?
- Tend to present in the MCA
- Interrupt blood flow to the lateral aspect of the brain
- This interrupts oxygen flow which can lead to localised brain tissue damage
- If last a short period of time it causes transient neurological symptoms lasting less than 24h- TIA
- If the ischaemia lasts a long period of time it can lead to neurological symptoms lasting more than 24 hours- STROKE
What leads to irreversible neurological damage?
Stroke
Characters of a localised region of brain death?
Known as a regional cerebral infarct
- Usually wedged shaped
- Initially soft tissue which becomes cystic
- Yellow discolouration
- Area surrounding swells up
- Vessels around it become congested
- There is tissue disintegration which eventually will lead to loss of brain tissue
Histological properties of an infarct?
- Loss of neurones
- Presence of foamy macrophages
What is the name for fibrosis in brain tissue?
Gliosis
What are the two common sites for ruptured vessels in the brain?
Basal ganglia: microvascular
Circle of willis: berry aneurysm
Why are hemorrages from ruptured vessels so common in the brain
- Beyond the basilar an vertebral arteries the wall of the blood vessels is very thin
- This means that if there is damage to the blood vessel+ hypertension there is a high possibility of an aneurysm forming
- If the aneurysm burst= hemorrage
Main causes for generalised reduced blood flow in the brain
- Poor perfusion of blood
- Small amounts of oxygen in the blood
- Rare: inability of the brain to use oxygen
Reasons for poor amount of oxygen in the blood?
- Co2 poisoning
- Drowning
- Respiratory failure
Reasons for poor perfusion to the brain?
- Hypotension
- Brain swelling
- Cardiac arrest
Type of infarct in hypotension
Watershed infarct:
-On border between well perfused areas of the brain and poorly perfused areas of the Brain
Type of infarct in cardiac arrest
Laminar necrosis
Due to thinning/ necrosis of the grey matter of the cortex
Example of a complicated case of infarct
- Cardiac disease
- Pneumonia
- Cardiac arrest
- Cardiac disease: regional cerebral infarct
- Pneumonia: watershed infarct
- Cardiac arrest: laminar necrosis
What could cause a stroke?
Vessel Wall:
- Aneurysm
- Atheroma
- Vasculitis
- Strangulation
Blood Constituents
- Thrombosis
- Bleeding due to anticoags or reduced platelet/clotting factors
Blood flow:
- Hypotension
- Hypertension -> Bursting
