What makes up the circle of willis?
Anterior cerebral artery ( left and right) Anterior Communicating artery Internal carotid artery Posterior cerebral artery Posterior communicating artery
What’s the correlation between CBF and BP?
Auto-regulation maintains the CBF at constant level of 50ml/100g of brain between mean arterial BP of 50-250mm HG
Which artery, Internal or external carotid artery supplies the brain?
Which artery supplies the anterior and posterior flow?
Internal
Anterior flow is supplied via iCAs (left and right branch), posterior flow is supplied through vertebral arteries which fuse to form the basilar artery
What is oligaemia?
Results from reduced perfusion or CBF over prolonged period; tissue which might be saved.
List the oxford classification of stroke and its presentations
- Total anterior circulation stroke:
3 of 3 of the following
- unilateral weakness (and/or sensory deficit) of face, arm, leg
- homonymous heminopia
- higher cerebral dysfuction (dysphagia, visuospatial) - Partial ant. circulation
2 of 3 of TACS
3. Lacunar syndrome 1of following: - pure sensory stroke - pure motor stroke - Sensori-motor stroke (one-sided) - ataxic hemiparesis: weakness and clumsiness, on the ipsilateral side of the body
- Posterior circulation syndrome:
1 of following:
- Cranial nerve palsy + contralateral motor/sensory deficit
- Bilateral motor/sensory deficit
- Conjugate eye movement disorder
- Cerebellar dysfunction
- isolated homonymous hemianopia or cortical blindness
Causes of stroke?
80% = ischaemic
- 50% atherosclerosis thromboembolism of arteries
- 20% emboli from circulation of heart: Af > MI, aneurysm, RHD, prosthetic valve
- Lacunar infarcts (large or small arteries
- Rare cause - vasculitidies, bacterial, arterial dissection
20% = haemorrhage
- extradural: The source of bleeding is typically from a torn meningeal artery, usually the middle meningeal artery (75%). But can also be caused by venous extradural hemorrhage.
- Subarachnoid: normally see bleeding at CoW area
- Subdural: The classic appearance of an acute subdural hematoma is a crescent-shaped homogeneously hyperdense extra-axial collection that spreads diffusely over the affected hemisphere.
Causes include hypertension, aneurysms, angiopathy
what are the risk factors for stroke?
Age male Asian, african FHx PMHx Vascular disease (HTN, DM, dyslipidemia) AF Smoking Diet
List the glasgow coma scale
Eye -
4: spontaneous
3: Verbal
2: Pain
1: none
Verbal -
5: oriented
4: confused
3: inappropriate
2: Incomprehensible
1: nothing
Movement -
6: obeys command
5: move to pain
4: away from pain
3: decorticate flexion
2: Decerebrate - extension
1: nothing
Haemorrhagic and ishchemic stroke visibility on CT scans
most of the time you can only see haemorrhagic stroke immediately o CT
When do we use MRI instead of CT?
Used in patients with more complex symptoms, where extent or location of stroke is unknown.
MRI diffusion weighted imaging is the best <1hour
PET/SPECT <1 hour
What are the 2 major forms of CVD leading to stroke (list the type of infarct they cause)?
- Large vessel, cardiac embolic events: Atherosclerosis, plaque rupture, thrombotic occlusion etc -> large cortical and subcortical infarcts
- Small vessel disease: Arteriolosclerosis, fibrinoid necrosis (tissue death involving formation of fibrin associated with vasculitis and transplant rejection), micro-aneurysm, cerebral amyloid angiopathy (amyloid forms on blood vessels in brain) -> small subcortical infarcts (deep micro-bleeds, lacuna infarcts) and diffuse white matter lesion
What are the pathophysiological features of small vessel disease?
- Loss of smooth mischle and media (arteriolosclerosis) Thickineing of intima Obliteration and occlusion BBB changes Increased resistance
List 3 small vessels that cen cause SVD infarcts
- lateral lenticulostriate arteries
- Medial lenticulostrate arteries
- Heubner arteries
List 3 main disease caused by global cerebral ischaemia
- White matter infarcts: silent infarcts that increase risk of stroke
- Laminar necrosis: Uncontrolled death of cells in cortex in a bond like pattern with presentation of cells immediately adjacent to meninges
- Watershed infarcts: Infarct in borderline zones of PCA, MCA, ACA that supply tissues as that is where blood supply decreased)
What are the cellular changes that takes place in cerebral infarction?
- Pyknotic neurones: Irreversible condensation of chromatin in nucleus of cells undergoing necrosis/ apoptosis
- Peri-infarct gliosis: Non-specific reactive changes of glial cells in response to CNS damage
It involves proliferation/ hypertrophy of different types of glial cells (astrocytes, microglial, oligodendrocytes) sometimes forming glial scar
What happens to the following in Global ischaemia and hypoxaemia?
- Electrical failure
- Decrease in ADP/ATP
- Increase in Lactate
- fatty acid and protein catabolism
- Tissue pathology
- Clinical context (cause)
Global ischaemia : Hypoxaemia
- : +
- +++ : +
- +++ : +
- Yes : No
- Selective necrosis/infarction : Synaptic changes
- Cardiac arrest, arrhythmia, hypotension (older) : Anaphylaxis, asthma, bronchitis, bronchiolitis
Describe the pathogenesis of brain to neuronal injury - damage of brain
Word document
How do we manage acute stroke?
Primary prevention: CT Thrombyolutics (alteplase) Antiplatelet (aspirin) lowering BP neuroprotection - NMDA, AMPA
Secondary prevention: Antiplatelet - aspirin, clopidegrol Anticoagulants: wafarin in AF, heparin lowering BP _ CCB Cholesterol lowering - Statin Carotid endarterectomy angioplasty
