Stroke Flashcards
Most Common Clinical Manifestation of CVD
Stroke
3rd most common cause of death in high income countries
CVD
Most common cause of severe physical disability
CVD
Arterial supply of the brain
Internal Carotid - anterior brain
Vertebrobasilar system - brain stem, mid-brain and cerebellum
Frontal and Parietal lobes - anterior and middle cerebral arteries
Occipital lobe - posterior cerebral artery
Mainstay of Stroke Imaging
Computed Tomography (CT) scan
Indication for MRI
- diagnostic uncertainty
- delayed presentation
- more information on brain structure and function required
Vascular imaging techniques
Doppler Scanning
MR Angiography
Intra-arterial Angiography
Blood tests
Blood glucose
Lipid profile
FBC
Dysphasia
Damage to the dominant frontal or parietal lobe
3rd most common cause of death in high income countries
CVD
Most common cause of severe physical disability
CVD
Arterial supply of the brain
Internal Carotid - anterior brain
Vertebrobasilar system - brain stem, mid-brain and cerebellum
Frontal and Parietal lobes - anterior and middle cerebral arteries
Occipital lobe - posterior cerebral artery
Mainstay of Stroke Imaging
Computed Tomography (CT) scan
Indication for MRI
- diagnostic uncertainty
- delayed presentation
- more information on brain structure and function required
Vascular imaging techniques
Doppler Scanning
MR Angiography
Intra-arterial Angiography
Blood tests
Blood glucose
Lipid profile
FBC
Dysphasia
Damage to the dominant frontal or parietal lobe
Presenting Problems
Weakness: unilateral weakness, reduced reflexes initially then increased later on with spastic increased tone, UMN weakness of the face is often present
Speech disturbance: dysphasia, dysarthria
Visual deficit
Visuo-spatial dysfunction - damage time the non-domination cortex results in contra lateral vision-spatial dysfunction such as sensory or visual neglect and apraxia
Ataxia
Headache
Seizure - unusual in stroke but may be generalized or focal in cerebral venous disease
Coma - occurs with a brain stem event, of present in the first 24 hrs, it indicates a subarachnoid or intracerebral hemorrhage
Is stroke a medical emergency?
Yes
Non-modifiable Risk factors of stroke
Age >65yrs
Gender: male>female except at extremes of age
Race: Afro-Caribbean> Asian> European
Previous vascular event: MI, Stroke, PVD
Heredity
High fibrinogen
Modifiable risk factors
Blood pressure
Cigarette smoking
Hyperlipidemia:
Heart disease: AFib, MI, CCF, infective endocarditis
DM - makes blood vessels hard and stiff and damaged blood vessels
Excessive alcohol intake
Oestrogen containing drugs: OCP, HRT
Polycythemia
How does hypertension lead to stroke
Hyaline arteriolosclerosis: hardening and stiffening if blood vessels with eventual narrowing and blockage- ischemic stroke
Aneurysms - hemorrhagic stroke
How does hyperlipidemia lead to stroke
LDL cholesterol accumulated in damaged parts of the blood vessel and induce formation of blood clots or break off and embolise a smaller vessel
Compensatory mechanisms of Infarction
- Infarction can be delayed by opening of anastomotic channels from other arterial territories that restore perfusion to its territory
- Reduction in perfusion pressure leads to compensatory homeostatic changes to maintain tissue oxygenation, sometimes preventing the occlusion of a carotid artery from having any clinically apparent effect
Causes of cerebral infarction
-thromboembolic disease secondary to atherosclerosis in the major extracranial arteries (carotid artery and aortic arch).
20% due to embolism from the heart
Another 20% due to thrombosis in situ caused by intrinsic disease of small perforating vessels (lenticulostriate arteries), producing lacunar infarctions.
5% due to vasculitis, endocarditis and cerebral venous disease
Ischemia occurs when
The homeostatic mechanisms fail and leads to infarction unless vascular supply is restored
Most common cause of stroke
Cerebral Infarction
