S6) Atherosclerosis Flashcards
What is an atheroma?
Atheroma is the accumulation of intracellular and extracellular lipid in the intima and media of large and medium sized arteries
What is atherosclerosis?
Atherosclerosis is the thickening and hardening of arterial walls as a consequence of an atheroma
What is arteriosclerosis?
Arteriosclerosis is the thickening and hardening of arteries and arterioles due to conditions such as hypertension and diabetes mellitus
Identify three macroscopic features of atherosclerosis
- The fatty streak
- The simple plaque
- The complicated plaque
Describe the appearance of the fatty streak
- Lipid deposits in intima
- Yellow, slightly raised
Describe the appearance of the simple plaque
- Raised yellow/white
- Irregular outline
- Widely distributed
- Enlarged and coalesce
Describe the appearance of the complicated plaque
- Thrombosis
- Haemorrhage into plaque
- Calcification
- Aneurysm formation
Identify five common sites for atherosclerosis
- Aorta (especially abdominal)
- Coronary arteries
- Carotid arteries
- Cerebral arteries
- Leg arteries
Describe normal arterial structure
Describe the microscopic appearance of the early changes in atherosclerosis
- Proliferation of smooth muscle cells
- Accumulation of foam cells
- Extracellular lipid deposition
Describe the microscopic appearance of the later changes in atherosclerosis
- Fibrosis & necrosis
- Cholesterol clefts
- Disruption of internal elastic lamina
- Ingrowth of blood vessels
- Plaque fissuring (could lead to thrombosis)
Identify 5 clinical effects of atherosclerosis
- Ischaemic Heart Disease
- Cerebral ischaemia
- Mesenteric ischaemia
- Peripheral vascular disease
- Abdominal Aortic Aneurysm
Identify 5 complications of Ischaemic Heart Disease due to severe atherosclerosis in the heart
- Sudden death
- Myocardial infarction
- Angina pectoris
- Arrhythmias
- Cardiac failure
Identify 3 complications of cerebral ischaemia due to severe atherosclerosis in the brain
- Transient ischaemic attack
- Cerebral infarction (stroke)
- Multi-infarct dementia
Identify 3 complications of mesenteric ischemia due to severe atherosclerosis in the colon
- Ischaemic colitis
- Malabsorption
- Intestinal infarction
Identify 3 complications of peripheral vascular disease due to severe atherosclerosis in the peripheries
- Intermittent claudication
- Ischaemic rest pain
- Gangrene
What are the possible reasons for the genetic predisposition to atherosclerosis?
- Variations in apolipoprotein metabolism
- Variations in apolipoprotein receptors
Identify four theories / hypotheses explaining the pathogenesis of atherosclerosis
- Thrombogenic theory
- Insudation theory
- Monoclonal hypothesis
- Reaction to injury hypothesis
How does the thrombogenic / encrustation hypothesis explain the possible mechanisms of atherogenesis?
- Plaques formed by repeated thrombi
- Lipid derived from thrombi
- Overlying fibrous cap
How does the insudation hypothesis explain the possible mechanisms of atherogenesis?
- Endothelial injury
- Inflammation
- Increased permeability to lipid from plasma
How does the monoclonal hypothesis explain the possible mechanisms of atherogenesis?
- Crucial role for smooth muscle proliferation
- Each plaque is monoclonal
- Might represent abnormal growth control