DIS - Diseases of the Vasculature I: Systemic Cardiovascular Disease and Ocular Blood Flow - Week 9 Flashcards
List three things that can cause an unwanted platelet response. What ends up forming and what happens if it breaks?
Primary atheroma
Lodged embolus
Vascular wall anomalies
A thrombus forms, slowing down blood flow
Parts can break off and cause downstream blockage - embolus
What is atheromatosis mainly a disease of? What is it a consequence of? give two common causes. What can turbulent blood flow lead to? Can it cause an embolism?
Mainly a disease of large and elastic muscular arteries
Consequence of chronic endothelial injury
-smoking
-hypertension
Turbulent blood flow may lead to secondary thrombus formation
Pieces of plaque may become an embolus
What is a hollenhurst plaque?
ICA (or other major vessel) atheroma
What is endocarditis?
Endocardium infection
List 7 important sources of embolisms to the eye.
Hollenhurst plaque
Endocarditis
ICA stenosis
Mitral valve/aortic stenosis
ICA thrombus
IV drug use
Bone trauma - neutral fat
Why can drug use cause eye embolisms (2)?
They may contain talc/cornstarch
List 7 things that can cause blood flow abnormality.
Dissection/aneurysm
Blood dyscrasia (like sickle cell)
Hypertension
Vessel disease
Tumour
Arterial vasospasm
Mechanical pressure from neighbouring vessels
List three vessel diseases that can cause blood flow abnormalities.
Arteriosclerosis
Arteriolosclerosis
Giant cell arteritis
Describe how a tumour can case abnormal blood flow (2).
New vasculature competes with normal supply or pressure/occlusion
In which age population is arterial vasospasm more common?
Younger
Define ischaemia. How is it different to hypoxia?
State when tissue has arterial perfusion lowered relative to its metabolic requirement
Ischaemia relates to blood flow
Hypoxia relates to oxygen availability
What is an infarction and what causes it?
Extensive but localised area of necrotic tissue brought about by ischaemia
Does ischaemia affect local tissue only? Explain.
Both the local tissue and the vessel walls
What are haemorrhages due to, slowed blood flow or back pressure buildup?
Slowed blood flow, not due to back pressure buildup
What does blood stasis lead to? Particularly in which type of blood vessel?
Leads to vessel wall ischaemia
-particularly venous, but can be arterial
What happens with vascular endothelial damage? What happens as a result?
Breakdown of tight junctions
-blood products leak onto tissue
What two things exacerbate local tissue ischaemia?
Stagnant blood and reduced capillary perfusion
What is a consequence of arterial obstruction?
Deprives tissue of oxygenated blood
What is a consequence of venous obstruction (2)?
Slows arterial flow
Deprives tissue of oxygenated blood
Does reduced blood flow cause ischaemia of the vascular endothelium? Explain (2). Does it promote thrombosis?
Causes ischaemia of the vascular endothelium
Also causes oedema and haemorrhage as a consequence
Promotes thrombosis
What does tissue ischaemia cause the release of? What do they exacerbate?
Inflammatory mediator release
-exacerbates oedema and haemorrhage
What does haemorrhage stimulate and what is a consequence of this?
Stimulates clotting, interrupting blood flow
-causes further ischaemia
-vicious circle
Is haemorrhage usually a result of ischaemia? Do haemorrhages indicate ischaemia?
Haemorrhages are usually a result (and indicative) of ischaemia
How does retinal artery occlusion affect vision? Is pain involved?
Sudden painless loss of vision