Pathophysiology of atheroma Flashcards
What is atherogenesis?
Atherogenesis is the process of atherosclerotic plaque formation in arteries, leading to narrowing and hardening of blood vessels.
What are the key stages of atherogenesis?
Endothelial dysfunction → Damage to the arterial wall (due to smoking, hypertension, high LDL).
Lipid accumulation → LDL cholesterol deposits in the damaged endothelium.
Inflammation & foam cell formation → Macrophages ingest LDL and become foam cells, creating fatty streaks.
Plaque development → Smooth muscle cells migrate, forming a fibrous cap over the fatty core.
Plaque rupture & thrombosis → Unstable plaques can rupture, leading to clot formation (thrombosis), which may cause a heart attack or stroke.
What are the key components of an atheromatous plaque?
Lipid core: Contains cholesterol, foam cells, and cellular debris.
Foam cells: Macrophages that have engulfed oxidized LDL.
Smooth muscle cells: Migrate from the tunica media to form a fibrous cap.
Fibrous cap: Made of collagen and smooth muscle cells, covering the lipid core.
How do lipids contribute to atheroma formation?
High LDL (low-density lipoprotein) → Deposits cholesterol in artery walls.
Oxidized LDL → Triggers inflammation, attracting macrophages to form foam cells.
Low HDL (high-density lipoprotein) → Reduces cholesterol clearance, increasing plaque formation.
What lifestyle factors contribute to high LDL?
Diet (high in saturated fats & trans fats).
Obesity, sedentary lifestyle, smoking.
Genetic factors (e.g., familial hypercholesterolaemia).
What are the key clinical signs of hyperlipidaemia?
Xanthomas → Cholesterol deposits in the skin (e.g., around eyes or tendons).
Xanthelasma → Yellowish plaques near the eyelids.
Corneal arcus → White/gray ring around the cornea.
Pancreatitis → Can occur in severe hypertriglyceridaemia.
How does atheroma contribute to cardiovascular diseases?
Coronary artery disease (CAD) → Atheroma in coronary arteries leads to angina and myocardial infarction (heart attack).
Cerebrovascular disease → Atheroma in carotid arteries can cause strokes.
Peripheral arterial disease (PAD) → Atheroma in leg arteries causes claudication (pain on walking) and risk of gangrene.
