[6] Carotid Artery Disease Flashcards
What is carotid artery disease?
The build-up of atherosclerotic plaque in one or more common and internal carotid arteries, resulting in stenosis or occlusion
Is carotid artery disease always symptomatic?
No, the majority of cases are asymptomatic
What % of ischaemic strokes are due to carotid artery disease?
15%
How can carotid artery disease cause ischaemic strokes?
Plaque rupture and/or atheroembolism
What is the pathophysiology of carotid artery disease?
Same as for atheroma elsewhere, starting with fatty streak, accumulating a lipid core, and formation of a fibrous cap
What predisposes the atheromatous process specifically at the carotid artery?
The turbulent flow at the bifurcation of the carotid artery
What is carotid artery disease usually classified based on?
Classified radiologically by the degree of stenosis
What is considered to be mild carotid artery disease?
<50% reduction in diameter
What is considered to be moderate carotid artery disease?
50-69% reduction in diameter
What is considered to be severe carotid artery disease?
70-99% reduction in diameter
What is considered to be total occlusion in carotid artery disease?
100% reduction in diameter
What are the major risk factors for carotid artery disease?
>65 years Smoking Hypertension Hypercholesterolaemia Obesity Diabetes mellitus History of cardiovascular disease Family history of cardiovascular disease
How does carotid artery disease present?
It will often be asymptomatic, however may present as a focal neurological deficit
How can carotid artery disease lead to focal neurological disease?
Can lead to transient ischaemic attack or stroke
How long does a TIA last before resolution?
24 hours
What is amaurosis fugax?
Transient visual loss that may be associated with TIA
How long does a stroke last?
24 hours or more without full resolution
How are strokes classified?
Oxford Stroke (Bamford) Classification
What is the Oxford Stroke Classification based on?
The stroke symptoms in relation to the arterial regions involved
What may be found on examination in carotid artery disease?
A carotid bruit may be auscultated in the neck
What proportion of carotid bruits auscultated in the neck are associated with carotid stenosis?
About half
Why is carotid stenosis likely to be asymptomatic if unilateral (apart from clinical features of stroke)?
Due to collateral supply from the contralateral internal carotid artery and vertebral arteries, via the Circle of Willis
What are the different classifications of stroke according to the Oxford Stroke Classification?
Total Anterior Circulation Stoke (TCAS)
Partial Anterior Circulation Stroke (PACS)
Lacunar Stroke (LACS)
Posterior Circulation Stroke (POCS)
What % of strokes are total anterior circulation strokes?
20%
What are total anterior circulation strokes?
Large cortical stroke in middle or anterior cerebral artery areas
What are the signs and symptoms of a total anterior circulation stroke?
Must have all of;
Motor weakness or sensory deficit of >2/3 of face, arm, and leg
Homonymous hemianopia
High cortical dysfunction
How can high cortical dysfunction manifest?
Dysphagia
Dyspraxia
Neglect
What % of strokes are partial anterior circulation strokes?
35%
What are partial anterior circulation strokes?
Cortical strokes in middle or anterior cerebral artery areas
What are the signs and symptoms of partial anterior circulation strokes?
Will present with either;
2/3 of TACS criteria
Limited motor or sensory deficit (1 of leg, arm, or face)
High cortical dysfunction alone
What % of strokes are lacunar strokes?
20%
What are lacunar strokes?
Occlusion of deep penetrating arteries
How will lacunar strokes present?
With any of;
Pure motor in 2 or 3 of face, arm, and leg
Pure sensory in 2 or 3 of face, arm, and leg
Pure sensorimotor in 2 or 3 of face, arm, and leg
Ataxic hemiparesis
What % of strokes are posterior circulation strokes?
20%
What are posterior circulation strokes?
Occlusion of vertebrobasilar or PCA circulation, affecting brainstem, cerebellum or occipital lobe
How do posterior circulation strokes present?
Variety of presentations can occur, but typically;
Ipsilateral CN palsy with contralateral motor or sensory defects
Bilateral motor or sensory defects
Isolated homonymous hemianopia
Cerebellar dysfunction
What is the most common form of carotid artery disease?
Atherosclerosis