Cerebral Vasculature

Question 1

Describe the perfusion demands of the brain

Answer 1

Although the brain is only 2% of body weight, it uses:

• 10-20% of Cardiac output
• 20% of oxygen
• 66% of liveer glucose

Hence it’s very vulnerable if there’s impaired blood supply

Question 2

Label the main arteries that supply blood supply to the brain

Answer 2

Question 3

Label this Circle of Willis. Describe a possible advantage of this arrangement

Answer 3

If there’s plaque there’s a ppossibility for the communication arteries to compensate for the loss of blood supply. Although it’s n ot perfect as the communicatring arteries are thin.

Question 4

Describe the Venous drainage of the brain

Answer 4

From cerebral veins to dural sinuses which eventually drain into the internal jugular vein

Question 5

Label; these dural venous sinuses

Answer 5

Question 6

what are the types of brain haemorrhage ?

Answer 6

• Extradural
• Subdural
• Sub-arachnoid
• Intracerebral

N.B: normally there’s no extradural space

Question 7

Explain how an extradural haemorrgahe can occur and describe the presentations

Answer 7

Rupture of middle meneigeal artery. due to trauma.

it is very acute- IMMEDIATE.

there’s raised intracranial pressure- this can lead to hernaition which can affect the cardioresp centre.

Question 8

Describe the clinical features of subdural haemorrhage

Answer 8

• Trauma
• Occurs due to shearing of delicate bridging veins in the subdural space
• DELAYED clinical effects (venous, low pressure).

Question 9

What are the clinical features of intracerebral haemorrhage

Answer 9

Spontaneous hypertensive.

Headaches, etc- same as stroke

*RESEARCH MORE*

Question 10

What causes subarachnoid haemorrhage ?

Answer 10

Ruptured aneurysms.

Normally occurs at the base of the brain.

Question 11

What is stroke and what are the 2 types (causes) ?

Answer 11

CEREBROVASCULAR ACCIDENT: rapidly developing focal disturbance of brain function of presumed vasucal origin and MORE THAN 24 hrs duration.

2 types are:

1. thrombo-embolic (85%)
2. Haemorrhagic (15%)

Question 12

Define TIA

Answer 12

CVA but resolves withing 24 hrs. normally a few minutes to seconds.

Question 13

define infarction and cerebral ischaemia

Answer 13

infarction: degenrative chnages which occur due to occlusion of an artery.

Cerebral ischaemia: Lack of sufficient blood supply (not just O2) which can lead to permanent brain damage if blood supplyu isnt resotred quickly.

Question 14

Thromboembolic stroke.

define thrombosis and embolism

Answer 14

Thrombosis: formation of a blood clot

Embolism: plugging of small vessel by material carried from larger vessel e.g. thrombi from the heart or atherosclerotic debris from the internal carotid.

emboli can also be fat or air

Question 15

Why is stroke a major public health issue and what signs should you look for in a stroke?

Answer 15

3rd most common cause of death in uk

100k deaths per annum in UK

50% of survivors are permanently disabled.

70% of survivors show obvious neurological deifcits

Question 16

what are the risk factors for stroke?

Answer 16

• Age
• Lifestyle (diet and exercise)
• Smoking
• hypertension- aneurysm
• Diabetes Mellitus
• Cardiac disease- formation of cardaic thrombi due to ineffcient cardiac function.

Question 17

Draw out the arteiral cerebral perfusion fields

Answer 17

Question 18

what are the symptoms if a stroke occcur due to blockage of ANTERIOR CEREBRAL artery

Answer 18

• Paralysis of contralateral structures (legs particularly more than arms or face)
• Disturbance of intellect, executive function and judgement (abulia)
• Loss of appropriate social behaviour

N.B. abulia- loss of willpower

Question 19

What are the Middle cerebral artery symptoms for stroke

Answer 19

• “classic stroke”
• Contralateral hemiplagia (ARM more than legs)
• Contralateral hemisensory deficits
• Hemianopia (path for visual information to pass is affected)
• Aphasia (L sided lesion)

Question 20

What are the posterior cerebral artery symptoms for stroke?

Answer 20

• Homonymous hemianopia
• visual agnosia

Question 21

For the diagram below, what artery has been occluded. Explain

Answer 21

There’s no differentiaiton between grey and white matter on the right (compared to the left). Hence there’s infarction in that area.

RIGHT MIDDLE CEREBRAL ARTERY

Question 22

Describe where the lesion is in this image

what will this pt present with and how do you manage this patient

Answer 22

Hyperdense in cerebellum

hence fresh blood/bleed intracerebellar

its a subtype of intraparenchymal bleed

This pt will present with cerebellar symptoms like:

• Dysarthria
• ataxia
• loss of reflexes (nystagmus)

Treatment: manage with antihypertensive as it is difficult to access cerebellum surgically to remove blood

Question 23

how do you manage subdural haemorrhage

Answer 23

burr holes

refer to neurosurgeons

Question 24

What is the procedure for interpreting MRI or CT head

Answer 24

Orientate yourself

Look for asymmetry of ventricles, gyri and culci, etc

Look for midline shift

look for lesions