Blood supply to the brain

Question 1

What is the impact of 20 seconds and >5 minutes without oxygen respectively?

Answer 1

20 seconds = unconsciousness

>5 minutes = permanent unconsciousness

Question 2

If cerebral perfusion pressure of the brain is 60-100mmHg then what should the cerebral blood flow be?

Answer 2

~50 ml per 100g of brain tissue

Question 3

What areas/structures do the lenticulostriate arteries supply?

Answer 3

internal capsule and white matter tracts

if there is a blockage in one of these arteries then this will impact sensations such as pain and vibration

Question 4

What parts of the cerebral cortex doe the ant., middle and post. cerebral arteries supply?

Answer 4

ACA = medial + superior cerebral cortex
MCA = lateral + inferior cerebral cortex
PCA = posterior +  inferior cerebral cortex

Question 5

What part of the CNS do the vertebral arteries supply?

Answer 5

Posterior and anterior spinal arteries supply the spinal cord
PICA = dorsal medulla of the brainstem

Question 6

What part of the CNS does the basilar artery supply?

Answer 6

Pons and cerebellum

Question 7

What part/s of the CNS does the posterior cerebral artery supply?

Answer 7

inferior and medial aspects of the temporal and occipital cortex
thalamus and posterior internal capsule
midbrain

Question 8

What will be the result of an MCA stroke in the dominant hemisphere?

Answer 8

Global aphasia

Sensorimotor loss on contralateral face, upper limb and trunk

Question 9

What will be the result of an MCA stroke in the non-dominant hemisphere?

Answer 9

Neglect syndrome

Question 10

What will be the result of an ACA stroke?

Answer 10

Contralateral sensorimotor loss below the waist
Urinary incontinence
Personality defects
Split-brain syndrome

Question 11

What will be the result of an PCA stroke?

Answer 11

Contralateral homonymous hemianopia
Reading and writing deficits
Impaired memory

Question 12

What are the symptoms of a TIA in the anterior circulation?

Answer 12

Motor weakness
Hemisensory loss
Dysarthria
Transient monocular blindness

Question 13

What are the symptoms of a TIA in the posterior circulation?

Answer 13

Vertigo
Diplopia
Ataxia
Amnesia

Question 14

Where does an epidural haematoma occur? What is the mortality rate? What are the symptoms?

Answer 14

Between the dura mater and skull
Arterial bleed therefore rapid bleeding
Mortality is 10%
Symptoms:
- compress CNIII
- weakness of extremities on opposite side of lesion
- loss of visual field opposite to lesion (compress PCA)

Question 15

What does an epidural haematoma look like on CT/MRI?

Answer 15

Convex lens

expansion stops at sutures and then pressure pushes inwards

Question 16

Where does a subdural haematoma occur? What is the mortality rate? what are the symptoms?

Answer 16

Between dura and arachnoid mater 
Rupture to bridging veins and therefore a slower bleed 
Mortality is 40-60%
Symptoms:
- irritability 
- seizures
- headache 
- numbness
- disorientation

Question 17

What does a subdural haematoma look like on CT/MRI?

Answer 17

crescent shape with concave surface

will cross suture lines

Question 18

Where does a subarachnoid haematoma occur? What are the symptoms?

Answer 18

Spontaneous
Between arachnoid + pia mater 
arterial bleed 
Symptoms:
- vomiting 
- THUNDERCLAP HEADACHE
- confusion 
- reduced levels of consciousness

Question 19

What does a subarachnoid haematoma look like on CT/MRI?

Answer 19

CT = white signal diffuse over sulci on both sides

Question 20

List the 3 types of cerebral aneurysm

Answer 20

Saccular
Fusiform
Berry

Question 21

What is the importance of arachnoid granulations?

Answer 21

• Allow CSF to flow into venous blood of sinuses

- prevent backflow of blood into subarachnoid space