Blood supply and Stroke Flashcards
(31 cards)
Which parts of the brain does the internal carotid artery supply
- Anterior 3/5 of cerebrum
- Diencephalon
What the branches of the internal carotid artery
- Middle cerebral artery
- Anterior cerebral artery
- Perforating branches (e.g. striate, lenticulochoroidal)
Which parts of the brain do the vertebrobasilar arteries supply
- Brainstem
- Cerebellum
- Posterior 2/5 of cerebrum
- Diencephalon
What are the main branches of the vertebrobasilar arteries
- Cerebellar (PICA, AICA, SCA)
- Pontine
- Posterior cerebral arteries
- Striate and thalamic branches
Describe auto regulation of the blood supply
- Brain is well-adapted to keep cerebral blood flow in an optimal range
- Blood vessels respond to changes in blood pressure to maintain a steady and safe flow rate
What clinical sign would be present in stenosis of the subclavian artery
B.P. on both limbs would be different
What are the clinical signs of a stroke
- Sudden onset
- Facial asymmetry
- Speech disturbance (dysphasia)
- Asymmetrical weakness in muscles
What is a stroke
- Interruption of the blood supply to a focal part of the brain causing loss of neurological function
- Symptoms last >24 hours or lead to death with no apparent cause other than that of vascular origin
What is a TIA
- Same cause as a stroke
- HOWEVER symptoms last <24 hours
What are the different classes of stroke
- Ischaemic
- Haemorrhagic
- Subarachnoid haemorrhage
What can cause a haemorrhagic stroke
- Hypertension
- Tumour
- Bleeding disorders
- Vascular malformation
- Amyloid angiopathy
What is the most common site of haemorrhagic stroke
Basal nuclei and internal capsule
Where is the brain damage in haemorrhagic stroke
- Primary= mechanical damage associated with the mass effect and is within minutes/hours from the onset of bleeding
- Secondary= surrounding oedema, oxidative stress and inflammation
What are the causes of ischaemic stroke
- Small vessel disease
- Hypoperfusion
- Cardio-embolism (most common)
- Large vessel atheroma/thrombosis
Describe a lacunar stroke
- Type of ischaemic stroke that generally occurs in deep areas of the brain
- Perforating branches are blocked
Compare the ischaemic penumbra and core
- In the penumbra, there are neurones that can be saved
- Core is where the permanent damage takes place
What are the watershed areas
- Cortical border zone (between ACA and MCA)
- Internal border zone (between LCA and MCA)
- Cortical border zone (between MCA and PCA)
Describe the watershed areas
- Most vulnerable to hypo perfusion, as are furthest away from the blood source
- Can be caused by lowing b.p. too aggressively
What is the most common presenting symptom/sign
Motor
How to locate/classify strokes
- Oxford community stroke project (clinical)
- TOAST (mechanism- e.g. large vessel, small vessel etc)
- Carotid or vertebrobasilar territory
What are some indications for urgent head imaging
- Depressed level of consciousness
- Unexplained progressive or fluctuating symptoms
- Severe headache
- History of trauma prior to onset
- History of anticoagulant treatment
Describe CT for imaging stroke
- Fast image acquisition
- Widely available
- Less sensitive
Describe the mass effect on CT
-Loss of sulci due to brain swelling
What are some MRI variants
- T1 weighted MRI (normal anatomy)
- T2 weighted MRI (pathology)
- Perfusion MRI
- Diffusion Weighted Imaging
- Apparent Diffusion Coef. Imaging
- Flair
