Pathology of Cerebrovascular Disease

Question 1

How much of CO does cerebral blood flow account for?

Answer 1

20%

Question 2

How is regional variation in cerebral blood flow regulated?

Answer 2

Cerebral arteriolar tone (cerebrovascular resistance)

Question 3

What happens to cerebral blood flow in profound hypotension?

Answer 3

CBF inadequate for metabolic demands → impaired cellular metabolism → decreased neuronal activity

Question 4

What happens to cerebral blood flow in severe hypertension?

Answer 4

Hyperaemia - increased blood flow to tissues

Cerebral oedema

Hypertensive encephalopathy

Question 5

What are the ischaemic thresholds in terms of CBF%

Answer 5

<50% → Tissue at risk of iscahemic injury

acidosis tissue oedema, K⁺ Ca²⁺ transients, loss of protein synthesis

<25% → electrical failure

Uncontrolled ion fluxes irreversible cell death

Question 6

Do glia metabolise glucose aerobically or anaerobically? How to they contribute to neuron metabolism?

Answer 6

They metabolise glucose both aerobically and anaerobically.

They supply lactate to adjacent neurons.

Question 7

Name two causes of General Cerebral Ischaemia

Answer 7

Cardiact arrest

Severe hypotension (shock)

Question 8

Define ischaemic encephalopathy.

Answer 8

Widespread neuronal injury.

Question 9

Name 3 pathological factors for Global Cerebral Ischaemia

Answer 9

Selective neuronal necrosis

Laminar necrosis of cortical neurons

Watershed infarction - infarct in regions between blood supply regions

Question 10

What are the most susceptible neurons in the brain?

Answer 10

Pyramidal cells of hippocampus/neocortex

Purkinje cells of cerebellum

Question 11

What is respirator brain?

Answer 11

It is where the brain is ventilated after global cerebral ischaemia and a process of autolysis occurs

Question 12

What happens to a non-perfused brain?

Answer 12

With low perfusion, the ICP increases, and a process of autolysis occurs

Question 13

What is the possible cause of reperfusion injury?

Answer 13

Oxygen free radicals

Question 14

Define a focal ischaemic stroke/CVA

Answer 14

Rapid onset of focal cerebral dysfunction of presumed vascular origin, more than 24h

Question 15

What is a lacunar stroke?

Answer 15

Occlusion of the penetrating arteries into deep structures.

Basal ganglia, thalamus, internal capsule, pons

e.g. Lenticulostriate arteries

Question 16

What is multi-infarct dementia?

Answer 16

multiple cerebral infarcts

combination of atherosclerosis, embolism, chronic hypertension

→ dementia, abrnormal gait, focal neurological deficits

Question 17

What is Binswanger’s disease?

Answer 17

Subcortical leukoencephalopathy

Question 18

Of haemorrhagic stokes, what proportion are Primary intracerebral haemorrhage and** Primary sub-arachnoid haemorrhage**?

Answer 18

2/3 Primary intracranial haemorrhage

1/3 Primary sub-arachnoid haemorrhage

Question 19

What is a Charcot-Bouchard aneurysm?

Answer 19

Vascular coil

Question 20

What does hypertensive haemorrhage involve bleeding from?

Answer 20

Bleeding from small diameter arterioles

Question 21

What is the most common cause of sub-arachnoid haemorrhage?

Answer 21

Saccular aneurysm.

Question 22

Name three associated causes of primary SAH.

Answer 22

Coarctation of aorta (narrowing)

Polycystic kidney disease

Renal artery stenosis

Question 23

How would you get vertebral infarction with aneurysmal rupture?

Answer 23

Vasospasm → vertebral infarction