13 - Blood supply + Stroke 1 Flashcards
In which 2 sites do 75% of berry aneurysms occur?
- Junction of ACA and ant. communicating artery
- Junction of ACA and MCA
Which artery supplies 2/3rds of the brain convexity?
MCA
Which artery supplies the majority of the medial side of the hemispheres?
ACA
Which artery supplies the majority of the lateral side of the hemispheres?
MCA
Which artery supply’s the occipital lobe?
PCA
Where does the thalamus get most of its blood supply from?
PCA
Which artery supplies the lentiform nucleus and the basal ganglia?
MCA via lenticulostriate arteries
Which artery supplies the internal capsule?
MCA via lenticulostriate arteries
Name the arteries which supply the cerebellum:
- Superior cerebellar artery
- Anterior inferior cerebellar artery
- Posterior inferior cerebellar artery
Define stroke:
Clinical syndrome of focal loss of brain function due to haemorrhage or inadequate blood supply lasting >24hrs
Define TIA:
A stoke which recovers < 24hrs from onset of symptoms
What is the most common type of stroke?
Ischaemic (85%)
List some causes of ischaemic stroke:
- Atheroma
- Cardiac embolism
- Small vessel disease
- Non-atheromatous arterial disease ie Arteritis
- Blood disorders
List some causes of haemorrhage stroke:
- Hypertension
- Aneurysm
- Amyloid angiopathy
- Thrombocytopenia
- Tumour
- Venous thrombosis
- Drugs: cocaïne, amphetamines
What areas of the brain does the anterior cerebral artery supply?
- Medial side of the frontal lobe
- Medial side of the parietal lobe
- Anterior part of the corpus callosum
- Pre-frontal cortex
Apart from ischaemic and haemorhagic, what are 2 other causes of stroke?
- Dissection
- Venous sinus thrombosis
A left anterior cerebral artery occlusion will most likely affect what part of the body? Why?
- Right lower limb and genitals, as they are represented medially on the pre and post central gyrus, and the ACA supplies the medial aspect
Which artery supplies blood to the paracentral lobules? Occlusion of this artery and ischaemia of this area will then present how?
- Loss of motor and sensory innervation to the contralateral side of the body (lower limbs and genitals)
- Loss of control of micturition and defecation
Which arteries supply the corpus callous? Ischaemia of either of these arteries would then present how?
- Anterior and Posterior cerebral arteries
- ACA occlusion = split brain syndrome, alien hand syndrome
- PCA occlusion = Alexia without agraphia (supplies selenium which carries fibres connecting R + L visual ass. centers)
What is the role of the prefrontal cortex? Where does it get its blood supply from?
Volition, motivation, planning, organising, complex behaviours
Anterior cerebral artery
What are the potential visual disorders caused by a left middle cerebral artery occlusion?
Proximal occlusion = R homonymous hemianopia
Distal = R superior/inferior homonymous hemianopia
What are the potential speech disorders caused by a left middle cerebral artery occlusion?
MCA superior divisions = Broca’s area in the frontal lobe = Expressive aphasia
MCA inferior divisions = Wernicke’s area in the temporal lobe = Receptive aphasia
IF main trunk occlusion = global aphasia
Which artery supplies the macular cortex?
Middle cerebral artery
A left middle cerebral artery occlusion will most likely affect what part of the body? Why?
Right sided (contralateral) head, neck, upper limb and trunk, as the middle cerebral artery supplies the lateral aspect of the pre-/post-central gyrus, where the head, neck, upper limb and trunk is represented.
What areas of the brain does the posterior cerebral artery supply?
- Occipital lobe
- Inferior temporal lobe
- Thalamus
- Splenium of the corpus callosum
- Part of post limb of internal capsule
What is the most likely visual defect to result from a posterior cerebral artery occlusion?
Contralateral homonymous hemianopia with macular sparing
Following an occlusion of the cerebellar arteries, how will the patient present?
Cerebellar signs:
- Dysdiadochokinesia
- Ataxia
- Nystagmus
- Intention tremor
- Slurred speech
- Hypotonia
If proximal occlusion = brainstem signs:
- Ipsilateral CN signs
- Contralateral signs of damaged asc/desc tracts
Occlusion of what artery results in ‘locked-in’ syndrome? What is this?
Basilar artery (proximally) (+ therefore pontine arteries)
Intact consciousness and sensation, lost all control of voluntary movements except vertical eye movements and blinking.
Which artery supplies the posterior limb of the internal capsule?
Lateral lenticulostriate arteries (from MCA)
How would the patient present after an occlusion of the left lenticulostriate arteries?
PURE MOTOR STROKE
- Right-sided hemiplegia
