Cerebral vasculature and disorders

Question 1

What are the three main blood vessels which supply the brain with blood?

Answer 1

Common carotid (branches into internal carotid), vertebral artery

Question 2

Why is the brain vulnerable if blood supply is impaired?

Answer 2

2% body weight but 15% cardiac output, 20% O2 consumption, 2/3 liver glucose

Question 3

Talk through the structures in the Circle of Willis

Answer 3

Two vertebral arteries fuse to form basilar artery, bifurcates into posterior cerebral artery, posterior communicating artery joins this with middle cerebral artery and internal carotid. Anterior cerebral artery follows, both being connected by anterior communicating artery

Question 4

What is the advantage of having the Circle of Willis?

Answer 4

allows compensatory flow from the other side of the body. Ensures continuous blood flow in the case of occlusion on one side
One block does not restrict the entire brain’s blood supply

Question 5

How does venous drainage in the brain occur?

Answer 5

Cerebral veins drain into venous sinuses between two layers of dura mater which leads into internal jugular vein

Question 6

What are the 4 locations that an intracranial haemorrhage can occur?

Answer 6

Extradural (above dura and in skull),
Subdural (in the dural layer),
Subarachnoid (in the arachnoid space),
Intracerebral (aka intraparenchymal)

Question 7

What is the blood pressure like in extradural haemorrhage and what artery is usually responsible?

Answer 7

High pressure from arterial blood,
middle meningeal artery (surgical emergency) - can see fascia under bleed
immediate clinical effects, often due to trauma

Question 8

What is the blood pressure like in subdural haemorrhage and why?

Answer 8

Venous blood, low pressure
delayed clinical effects usually due to trauma

Question 9

What should A&E do to monitor a patient they suspect has a subdural haemorrhage?

Answer 9

CT Scan, monitor for 24 hours for observations

Question 10

What is the typical cause of a subarachnoid haemorrhage?

Answer 10

burst aneurysm (congenital) - blood usually goes everywhere bc of 3rd ventricle

Question 11

What is the unique thing about subarachnoid haemorrhages?

Answer 11

not immediately harmful, usually incidental findings

Question 12

What is the blood pressure like in an intracerebral haemorrhage?

Answer 12

Spontaneously hypertensive

Question 13

What is the definition of a stroke (cerebrovascular accident CVA)?

Answer 13

rapidly developing focal disturbance, presumed vascular origin, not resolved in 24 hours

Question 14

What are the two main causes of a stroke and what are the relative percentages?

Answer 14

Thromboembolism (85%) due to blockages
haemorrhage (15%), bleeds

Question 15

What is the definition of a TIA?

Answer 15

Transient Ischaemic Attack - rapidly developing focal disturbance, vascular origin, resolves in 24 hours

Question 16

What is the definition of an infarction?

Answer 16

Degenerative damage after the occlusion of an artery

Question 17

What is the difference between ischaemia and hypoxia?

Answer 17

Hypoxia is when there is a limit of blood oxygen, ischaemia is a limit of blood supply and therefore all blood nutrients

Question 18

What is thrombosis?

Answer 18

Blood clot

Question 19

Cerebral ischaemia

Answer 19

lack of blood supply to nervous tissue causing permanent damage if not restored quickly

Question 20

What is an embolism?

Answer 20

A fat or air blockage of a smaller blood vessel that had been brought from a larger vessel (fatty deposits from atherosclerosis)

Question 21

What is the public health acronym associated with strokes?

Answer 21

FAST -
Face, unilateral droop
Arms, can they raise their arms
Speech, slurred/expressive aphasia
Time, 999

Question 22

Why is essential that strokes are attended to as soon as possible?

Answer 22

50% left with permanent disability, 70% have some neurological deficit

Question 23

What are 5 risk factors for strokes?

Answer 23

Age, general wear and tear
Hypertension, spontaneous bleeds etc
Cardiac Disease, inv disturbed blood flow
Smoking, vascular risk factor
Diabetes Mellitus

Question 24

What areas of the cerebrum does the anterior cerebral artery supply?

Answer 24

Frontal lobe, strip of tissue in the middle part of the brain to the parietal-occipital notch

Question 25

What areas of the cerebrum does the middle cerebral artery supply?

Answer 25

Almost all lateral parts of cerebrum, and deep structures

Question 26

What areas of the cerebrum does the posterior cerebral artery supply?

Answer 26

occipital lobe and inferior part of the temporal lobe

Question 27

What are the 3 symptoms of an occlusion in the anterior cerebral artery?

Answer 27

Paralysis of contralateral structures (more upper limbs than lower - think cerebral homunculus) //
Loss of appropriate social behaviour //
Abulia - disturbance of intellect/judgement/DM

Question 28

What are 4 symptoms of an occlusion in the middle cerebral artery?

Answer 28

Contralateral hemiplegia (muscle weakness - more arm), Contralateral hemisensory deficits,
hemianopia,
aphasia - expressive Broca’s, receptive Wernicke’s

Question 29

What are 2 symptoms of an occlusion in the posterior cerebral artery?

Answer 29

Homonymous Hemianopia,
Visual Agnosia, inability to recognise family members