MoD Session 6- Atheroma Flashcards
Define atherosclerosis
A hardening and thickening of arterial walls as a result of atheroma.
Define atheroma
An accumulation of intracellular and extracellular lipid in the intima and media of large and medium sized arteries.
Define arteriosclerosis
A hardening and thickening of artery and arteriole walls as a result of hypertension and DM.
What are the 3 macroscopic features of atheroma?
- Fatty streak
- Simple plaque
- Complex plaque
What is a fatty streak?
A yellow, raised lipid deposit in the intima.
What is a simple plaque?
A yellow/white raised, widely distributed deposit.
How does a complex plaque form?
By the enlargement and coalescing of simple plaques.
What are the complex plaque complications? (4)
Calcification, thrombosis, haemorrhage and aneurysm formation.
What are the 5 common sites of atheroma formation?
- aorta (abdominal)
- carotid arteries
- cerebral arteries
- leg arteries
- coronary arteries
What are the 3 early microscopic features of atheroma?
- smooth muscle cell proliferation
- foam cell accumulation (phagocytosis of lipids)
- extracellular lipid deposition
What are the 5 later microscopic features of atheroma?
- fibrosis and necrosis
- cholesterol clefts
- disrupted internal lamina which extends into media
- in growth of blood vessels
- plaque fissuring
What is the difference between angina and an MI?
If you stop what is causing the pain, in angina the pain will go away, whereas it will not in an MI.
Define infarction
Obstruction of the blood supply to an organ or tissue causing local death of the tissue.
Typically by a thrombus/embolus
Define Ischaemia
An inadequate blood supply to an organ.
Define aneurysm
A excessive, localised swelling of the wall of an artery.
Name 5 clinical effects of atheroma
- cerebral Ischaemia
- ischaemic heart disease
- mesenteric Ischaemia
- peripheral vascular disease
- abdominal aortic aneurysm
5 things ischaemic heart disease can cause
- angina pectoris
- MI
- arythmias
- cardiac failure
- sudden death
How does a cerebral infarction/stroke come about in cerebral Ischaemia?
Atherosclerosis in carotid arteries
Thrombus and then embolus formation
Embolus occludes cerebral arteries
Stroke
What 3 things can mesenteric Ischaemia cause?
- ischaemic colitis
- malabsorption
- intestinal infarction
What is intermittent claudication in peripheral vascular disease?
It is interval pain in calves due to exercise
What is leriche syndrome?
It is claudication of the buttocks, and impotence
What is ischaemic rest pain?
When there is claudication (due to artery obstruction) even when no exercise is being performed.
Name 11 risk factors of atheroma
- age
- gender
- hyperlipidaemia
- smoking
- hypertension
- DM
- alcohol
- infection
- geography
- familial hypercholesterolaemia
- apolipoprotein E genotype
Which gender is more susceptible to atheroma formation?
Males
What are associated physical signs of familial hypercholesterolaemia? (3)
- xanthelasma
- tendon xanthomas
- arcus
What are xanthelasmas?
Foam cell accumulations in the dermis
What is corneal arcus?
A thin pale arc around the cornea of the eye that is cholesterol deposits
What is the predicted link between hypertension and IHD?
That the higher pressure damages endothelial cells
By what proportion does DM increase IHD risk by?
Doubles the risk
What infections are associated with atheroma?
- chlamydia pneumoniae
- helicobacter pylori
- cytamegalovirus
What are the processes involved in atheroma formation? (4)
- thrombosis
- lipid accumulation
- production of intercellular matrix
- cell type interactions
What are the 6 cell types involved?
- endothelial cells
- lymphocytes
- neutrophils
- platelets
- macrophages
- smooth muscle cells
What is the function of endothelial cells?
- haemostasis
- collagen secretion
- proliferation and migration stimulus for smooth muscle cells
What is the function of platelets?
- haemostasis
- proliferation and migration stimulus for smooth muscle cells
What is the function of smooth muscle cells?
- take up LDLs to become foam cells
- synthesise collagen and proteoglycans
What is the function of macrophages?
- phagocytosis of LDLs to become foam cells
- oxidise LDLs
- stimulate proliferation and migration of smooth muscle cells
What is the function of neutrophils?
-secrete proteases that lead to continued local damage and inflammation
What is endothelial injury due to? (3)
- raised LDLs
- hypertension
- toxins
What does endothelial injury cause? (3)
- platelet adhesion and SMC proliferation
- lipid accumulation and taken up by SMCs and macrophages
- monocytes migration into the intima
