cerebral vasculature

Question 1

What percentage of cardiac output, body O2 consumption, and liver glucose does the brain use despite only accounting for 2% of body weight?

Answer 1

10-20% cardiac output, 20% O2 consumption, 66% liver glucose

Question 2

Where does blood supply to the vertebral artery (posterior) originate?

Answer 2

subclavian artery

Question 3

where does blood supply to the internal carotid originate?

Answer 3

brachiocephalic then to common carotid

Question 4

what term best describes the structure of the arteries of the brain?

Answer 4

anastomotic circuit

Question 5

what is the circle of Willis?

Answer 5

anastomotic circuit of arteries at the base of the brain

Question 6

what structure do the vertebral arteries fuse to form and where does this sit?

Answer 6

basilar artery, sits on the pons

Question 7

what is the name of the main branch of the internal carotid?

Answer 7

middle cerebral artery

Question 8

what is the advantage of the circle of Willis being an anastomotic circuit?

Answer 8

if there is an atherosclerosis in one area there is a chance of compensatory flow from the other side (communicating arteries)

Question 9

Outline the order of venous drainage of the brain

Answer 9

cerebral veins drain into venous sinuses which drain into internal jugular veins

Question 10

How does the venous system drain from the superior sagittal sinus to the jugular foramen?

Answer 10

superior sagittal sinus, confluence of sinuses, transverse sinuses, sigmoid sinus.

Question 11

what is a thrombosis?

Answer 11

formation of a blood clot

Question 12

What are the four types of haemorrhage in the brain?

Answer 12

extradural, subdural, subarachnoid, intracerebral

Question 13

what is an extradural haemorrhage?

Answer 13

an arterial, high pressure hemorrhage usually due to trauma to the pterion, resulting in the dura being stripped away from the skull creating an extradural space.

Question 14

what is a subdural haemorrhage?

Answer 14

a venous, low pressure haemorrhage in which the clinical effects may be delayed

Question 15

what is a subarachnoid haemorrhage?

Answer 15

ruptured aneurysms often only found incidentally, are congenital, are relevant at the circle of Willis

Question 16

If a subarachnoid hemorrhage is found incidentally, what determines whether it needs intervention?

Answer 16

if the patient is hypertensive then likely to intervene

Question 17

What is an intracerebral haemorrhage?

Answer 17

spontaneous hypertensive haemorrhage in the brain parenchyma

Question 18

what is a stroke?

Answer 18

a cerebrovascular accident defined as rapidly developing focal disturbance of brain function of presumed vascular origin and of >24 hours duration

Question 19

what are the two categories of stroke?

Answer 19

thrombo-embolic or hemorrhagic

Question 20

What percentage of strokes are thrombo-embolic?

Answer 20

85%, 15% hemorrhagic

Question 21

what is a transient ischaemic attack (TIA)?

Answer 21

a rapidly developing focal disturbance of brain function of presumed vascular origin that resolves completely within 24 hours

Question 22

what is an infarct?

Answer 22

dead tissue

Question 23

define cerebral ischaemia

Answer 23

lack of sufficient blood supply to nervous tissue resulting in permanent damage if blood flow is not restored quickly

Question 24

what is the difference between ischaemia and hypoxia?

Answer 24

ischaemia is a lack of blood flow, hypoxia is a component of ischaemia but specifically a lack of oxygen.

Question 25

What are the main risk factors associated with a stroke?

Answer 25

age, hypertension, cardiac disease, smoking, diabetes

Question 26

What is an embolism?

Answer 26

plugging of a small vessel by material carried from larger vessels e.g. atherosclerotic debris

Question 27

which cerebral artery has the largest perfusion field

Answer 27

the middle cerebral artery, perfuses lateral and deep structures of the brain

Question 28

what is the perfusion field of the anterior cerebral artery?

Answer 28

parasagittal midline up to parieto-occipital fissure

Question 29

what is the perfusion field of the posterior cerebral artery?

Answer 29

occipital and inferior part of temporal lobe

Question 30

What are the symptoms for a stroke of the anterior cerebral arteries?

Answer 30

paralysis of contralateral structures. disturbance of intellect, executive function and judgement. loss of appropriate social behaviour

Question 31

what does a left sided lesion of the middle cerebral artery lead to?

Answer 31

aphasia as brocas and wernickes areas will be effected

Question 32

What is Brocas aphasia?

Answer 32

expressive aphasia, patient understands but cannot answer correctly, will be visibly frustrated

Question 33

what is hemiplegia?

Answer 33

weakness, stiffness (spasticity) and lack of control in one side of the body.

Question 34

what are the symptoms for a stroke in the posterior cerebral arteries?

Answer 34

visual defecits, homonymous hemianopia, visual agnosia

Question 35

what is hemianopia

Answer 35

loss of one half of visual field

Question 36

what is agnosia?

Answer 36

inability to recognize and identify objects or persons

Question 37

what percentage of stroke survivors are left permanently disabled?

Answer 37

50%

Question 38

stroke is the ___ most common cause of death in the UK

Answer 38

3rd

Question 39

How does blood appear on CT scans?

Answer 39

Acute bleeding = white (blood is hyper dense), old blood = darker

Question 40

What is seen in the CT scan of someone with a subdural haematoma?

Answer 40

Dark blood, asymmetry in lateral ventricles, asymmetry in cortical surface

Question 41

How would you treat a subdural haematoma?

Answer 41

Surgical - craniotomy or burr holes to relieve intercranial pressure

Question 42

What symptoms are indicative of cerebellar bleeding?

Answer 42

Dysarthria, wobbly eye movements, ataxia, broad based gait

Question 43

What is seen on the CT scan of someone with an intraparenchymal bleed?

Answer 43

Acute bleed so white blood in the cerebellum

Question 44

How is an intraparenchymal bleed treated?

Answer 44

Manage risk factors, if hypertensive neurosurgeon may try to remove bleed