Pathology of Cerebrovascular Disease Flashcards Preview

Systems: Neurology AB > Pathology of Cerebrovascular Disease > Flashcards

Flashcards in Pathology of Cerebrovascular Disease Deck (36)
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1
Q

How does the vasculature of the brain differ from other parts of the body?

A

Vein do not accompany arteries

2
Q

How are the veins arranged in the brain?

A

There are large venous sinuses within the dura

3
Q

Give examples of the venous sinuses found within the brain.

A
  • Superior sagittal sinus
  • Inferior sagittal sinus
  • Transverse sinus
  • Sigmoid sinus
  • Straight sinus
4
Q

What is the WHO definition of stroke?

A

Focal neurological deficit (loss of function affecting a specific region of the central nervous system) due to disruption of blood supply

5
Q

What causes a stroke??

A

Interruption of supply of oxygen and nutrients, causing damage to brain tissue

6
Q

Interruption of supply of oxygen caused by changes in…

A
  • Vessel wall
  • Blood flow (including blood pressure)
  • Blood constituents
7
Q

What can cause changes in the vessel wall?

A

Abnormality of wall

  • Atheroma
  • Vasculitis

Outside pressure

  • Strangulation
  • Spinal cord compression
  • Compression of veins
8
Q

What can cause changes in blood flow?

A
  • Decreased blood flow

- Increased blood pressure bursting vessels

9
Q

What can cause changes in blood constituents?

A
  • Thrombosis of arteries and rarely veins

- Bleeding due to anticoagulation, reduced platelets anc clotting factors

10
Q

What are the 3 main causes of localised interrupted blood supply?

A
  • Atheroma and thrombosis of artery causing ischaemia
  • Thromboembolism (for examples from the left atrium) causing ischaemia
  • Ruptured aneurysm of cerebral vessel causing haemorrhage
11
Q

Where is a common place for atheroma and thrombosis?

A

Carotid artery bifurcation

12
Q

What is a thrombosis formed from?

A

Platelets and fibrin

13
Q

What does atheroma and thrombosis of a vessel lead to?

A

Severe narrowing of the vessel

14
Q

Where does ischaemia typically occur with internal carotid artery thrombosis?

A

Middle cerebral artery territory

15
Q

Ischaemia

A

Relative of absolute lack of blood supply In a tissue or organ

16
Q

What is the outcome of ischaemia causing transient symptoms?

A
  • Last <24 hours
  • Due to reversible ischaemia (TIA)
  • Tissue still available
17
Q

What is the outcome of ischaemia causing longstanding symptoms?

A
  • Last >24 hours
  • Due to irreversible ischaemic causing localised brain death
  • Infarction
18
Q

What is the brain very sensitive to?

A

Oxygen ischaemia

19
Q

What will a few minutes of hypoxia or anoxia cause?

A

Brain ischaemia which can lead to infarction

20
Q

Why is the damage permanent of infarction occurs?

A

The damage to the neurones is permanent. Neurons do not regenerate

21
Q

How does localised area of brain death appear?

A

-There will be regional cerebral infarct-Classically wedge shaped reflecting arterial perfusion territory-Soft and then becomes cystic

22
Q

What does the histology of infarct look like?

A
  • Loss of neurones which cause clinical functional deficit
  • Foamy macrophages: repair process leading to gliosis
  • Gliosis is CNS equivalent of fibrosis
23
Q

Why is the location of ischaemia very important?

A
  • Small affected area of one part of brain may not cause too much impairment
  • Similar size of affected area in another part of brain may be devastating
24
Q

Who is thromboembolism of atrial appendage common in?

A

People with arrhythmias such as AF

25
Q

How does thromboembolism occur from the left atrium?

A
  • Heart with left atrial appendage thrombosis
  • Left atrium is connected directly to outflow of left side of the heart
  • If thrombosis in left atrial appendage breaks off it will embolise to aorta and possibly the carotid (or any other) arteries
26
Q

How can vessel walls rupture to cause a stroke?

A
  • Beyond carotids and vertebral arteries the cerebral arteries have thin wall.
  • Weakening of wall and hypertension causes aneurysm to form
  • Wall can then rupture, especially if severe hypertension
  • Decreased blood flow distally to brain due to spasm of artery
27
Q

What are 2 common sites of ruptured vessels causing haemorrhagic stroke?

A
  • Basal ganglia: microaneursyms form in hypertensive patients
  • Circle of Willis: Berry aneurysm forms in hypertensive patient
28
Q

What are the causes of generalised interrupted blood supply or hypoxia?

A
  • Low O2 in blood (hypoxia with intact circulation of blood)
  • Inadequate supply of blood (flow of blood not occurring) (blood may be oxygenated or not)
  • Rarely: Inability to use O2 such as cyanide poisoning
29
Q

What can cause low O2 levels in the blood?

A
  • CO poisoning
  • Near drowning
  • Respiratory arrest
30
Q

What can cause inadequate supply of blood?

A
  • Cardiac arrest with immediate resuscitation
  • Hypotension
  • Brain swelling (trauma)
31
Q

Describe the what would happen if someone experience a prolonged period of hypotension but was kept well oxygenated?

A
  • There is prolonged period of poor perfusion but blood is oxygenated
  • Central part of arteries territories are perfused OK
  • Watershed zones are poorly perfused
  • Zonal pattern of ischaemia and infarction at interface of territories
32
Q

What are watershed zones?

A

Zones at interface of artery perfusion territories

33
Q

What does pure hypotension with oxygenated blood lead to?

A

Watershed infarcts

34
Q

What may found on autopsy of someone with a period of no oxygenation and no circulation to the brain?

A
  • Large areas of grey matter thinning and necrosis

- Laminar appearance

35
Q

What does complete loss of perfusion and oxygen lead to?

A

Cortical necrosis

36
Q

What will a complex case lead to?

A

Complex pattern