Cerebral Vasculature Flashcards
Describe the perfusion demands of the brain
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
Label the main arteries that supply blood supply to the brain
Label this Circle of Willis. Describe a possible advantage of this arrangement
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.
Describe the Venous drainage of the brain
From cerebral veins to dural sinuses which eventually drain into the internal jugular vein
Label; these dural venous sinuses
what are the types of brain haemorrhage ?
- Extradural
- Subdural
- Sub-arachnoid
- Intracerebral
N.B: normally there’s no extradural space
Explain how an extradural haemorrgahe can occur and describe the presentations
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.
Describe the clinical features of subdural haemorrhage
- Trauma
- Occurs due to shearing of delicate bridging veins in the subdural space
- DELAYED clinical effects (venous, low pressure).
What are the clinical features of intracerebral haemorrhage
Spontaneous hypertensive.
Headaches, etc- same as stroke
*RESEARCH MORE*
What causes subarachnoid haemorrhage ?
Ruptured aneurysms.
Normally occurs at the base of the brain.
What is stroke and what are the 2 types (causes) ?
CEREBROVASCULAR ACCIDENT: rapidly developing focal disturbance of brain function of presumed vasucal origin and MORE THAN 24 hrs duration.
2 types are:
- thrombo-embolic (85%)
- Haemorrhagic (15%)
Define TIA
CVA but resolves withing 24 hrs. normally a few minutes to seconds.
define infarction and cerebral ischaemia
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.
Thromboembolic stroke.
define thrombosis and embolism
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
Why is stroke a major public health issue and what signs should you look for in a stroke?
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
Draw out the arteiral cerebral perfusion fields
what are the symptoms if a stroke occcur due to blockage of ANTERIOR CEREBRAL artery
- 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
What are the Middle cerebral artery symptoms for stroke
- “classic stroke”
- Contralateral hemiplagia (ARM more than legs)
- Contralateral hemisensory deficits
- Hemianopia (path for visual information to pass is affected)
- Aphasia (L sided lesion)
What are the posterior cerebral artery symptoms for stroke?
- Homonymous hemianopia
- visual agnosia
For the diagram below, what artery has been occluded. Explain
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
Describe where the lesion is in this image
what will this pt present with and how do you manage this patient
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
