What does the internal carotid artery branch off to supply?
branches off to create the Anterior cerebral artery, as well as posterior communicating artery to join the circle of Willis
After this the ICA continues on as the Middle cerebral artery, which supplies the lateral portions of the cerebrum.
What does the middle cerebral artery supply?
MIDDLE CEREBRAL ARTERY—(huge artery) supplies majority of lateral surface of the hemisphere and deep structures of anterior part of cerebral hemisphere.
What does the anterior cerebral artery supply?
ANTERIOR CEREBRAL ARTERY (supplies and runs over Corpus Callosum and supplies Medial aspects of Hemispheres (anteromedial aspects of the cerebrum)
Outline the pathology behind an ischaemic stroke of atherosclerotic origin
Basically formation of atherosclerotic plaque:
Irritants damage the endothelium, damage becomes a site for atherosclerosis
A plaque forms, made of fats, cholesterol, proteins, calcium and immune cells encased in a fibrous cap.
If cap ruptures, (interestingly smaller plaques are more dangerous as they have weaker caps that are more prone to being ruptured),
then
Soft core is thrombogenic and platelets adhere to the exposed collagen, creating a clot,
= Known as an Atherothromboembolism
Outline the pathology behind an ischaemic stroke of emboli origin.
Blood clot from elsewhere in the body, typically from atherosclerosis or from the heart
Cardiac emboli from AF, MI or infective endocarditis 🡪 blood stasis, forming a blood clot.
Only emboli in the systemic circulation/aka left side of heart can cause an embolic stroke.
Emboli in right side of heart will go to the lung, *unless a patient has a Septal defect- they can travel through the septal defect and go up to brain
Outline the pathology behind an ischaemic stroke due to shock. What are watershed infarcts
A rapid drop in blood pressure/perfusion to brain means that areas in the brain furthest from arterial blood supply - Known as Watershed zones Can undergo infarction.
Watershed infarcts are unique ischemic lesions which are situated along the border zones between the territories of the major cerebral arteries.
Causes of ischaemic strokes - Where are the “Watershed zones” of the brain?
Define: stroke
rapidly developing clinical signs of focal disturbance of cerebral function lasting more than 24 hrs or leading to death with no apparent cause other than a vascular origin
Name some risk factors for a stroke
What risk factors in young people increase likelihood of stroke?
What is the Oxford stroke Bamford classification?
categorises stroke based on initial presenting symptoms + signs
What are the clinical manifestations of a stroke in the anterior cerebral artery?
Lower limb weakness and loss of sensation to the lower limb.
2. Gait apraxia (unable to initiate walking).
3. Incontinence.
4. Drowsiness.
Decrease in spontaneous speech.
Contralateral hemiparesis (weakness of one side of the entire body) and sensory loss with lower limbs > upper limbs
What are the clinical manifestations of a stroke in the middle cerebral artery?
(big artery so can cause weakness all along one side)
Contralateral hemiparesis with upper limbs > lower limbs
Facial drop
sensory loss with upper limbs > lower limbs
Homonymous hemianopia
Hemineglect syndrome: if affecting the ‘non-dominant’ hemisphere; patients fail to be aware of items to one side of space
Aphasia: if affecting the ‘dominant’ hemisphere (the left in 95% of right-handed people) as Brocas/Wernickes areas supplied by MCA)
Aphasia is the medical term for full loss of language, while dysphasia stands for partial loss of language.
Posterior circulation infarction
Wallenberg and weber syndrome
Wallenberg = occlusion of PICA
DANVAH
Dysphasia
Ataxia
Nystagus
Vertigo
anaesthesia
horners
Weber’s = occlusion of paramedic of posterior cerebral artery
‘Web in my eye’
What is a homonymous hemianopia?
a visual field defect involving either the two right or the two left halves of the visual fields of both eyes
Lacunar infarction
What are the clinical manifestations of a ischaemic stroke in the vertebral basilar arteries?
What is the first line investigation to do for a stroke, what would you see?
CT scan ASAP
- non-contrast
- Distinguishes ischaemic from haemorrhagic
Define hyperattenuation and hypo attenuation
hypoattenuation
- (darkness) of the brain parenchyma
loss of grey matter-white matter differentiation, and sulcal effacement
hyperattenuation
- (brightness) in an artery indicates clot within the vessel lumen
What are some other investigations you would do for a Stroke?
Management: ischaemic stroke
Thromboectomy
- mechanical recanalisation of culprit vessel
- do if can’t do thrombolysis
- up to 24hrs post stroke onset if imaging shows salvageable brain tissue
What are some complications of thrombylysis ?
Bleeding anywhere,
- especially in the brain haemorrhagic stroke,
NEVER FOR HAEMORRHAGIC STROKE
- and in the urinary tract - so try to avoid catherising patients who have just had thrombolysis
-
What are the contraindications to thrombolysis?
ABCDEFG
A - anticoagulation
B - BP >185/110
C - CNS procedure/ cranial trauma/ recent stroke 3/12
D - diathesis (ACTIVE BLEEDING)
E - endocarditis, every major surgery/surgery last 2/52
F - former history of ICH at any time
G - glucose <3 or >10, GI bleed,