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ESA2 - Mechanisms Of Disease > Atheroma > Flashcards

Flashcards in Atheroma Deck (11):
1

Define atheroma

The accumulation of intracellular and extracellular lipid in the tunica intima and media of large and medium sized arteries

2

Define atherosclerosis

Thickening and hardening of arterial walls as a consequence of atheroma

3

What is the difference between atherosclerosis and arteriosclerosis?

Arteriosclerosis is thickening and hardening of arterial walls as a result of hypertension and/or diabetes, not atheroma

4

What are the macroscopic appearances of atheromas?

- Fatty streak (yellow, raised with a regular outline)
- Simple plaque (yellow/white, raised with an irregular outline, can enlarge and coalesce)
- Complicated plaque (calcification of plaque with possible haemorrhage and necrosis, increases risk of thrombosis and aneurysm formation)

5

What are the microscopic appearances of atheromas?

- (early) Accumulation of foam cells and proliferation of smooth muscle cells
- (later) Distribution of internal elastic lamellae, cholesterol clefts, inflammatory response, fibrosis, necrosis, plaque fissuring

6

What are the clinical effects of atheroma?

- Ischaemic heart disease (narrowing of coronary arteries)
- Cerebral ischaemia (narrowing of carotid arteries, infarct may result in transient ischaemic attack/stroke)
- Mesenteric ischaemia (malabsorption, infarct may result in black bowel)
- Peripheral vascular disease (intermittent claudication, buttock claudication, ischaemic rest pain)

7

Describe the unifying hypothesis of the formation of atheroma

- Chronic endothelial injury due to oxidised LDL, smoking or hypertension
- Endothelial injury stimulates platelet adhesion and release of PDGF which attracts macrophages and smooth muscle cells (from TM)
- SMC proliferation and insudation of lipid lead to accumulation of foam cells
- Migration of foam cells into intima (release cytokines which recruit further cells)

8

What are the main factors that relate to the PATHOGENESIS of atheroma? (7)

- Smoking
- Age and gender (males more prone, females protected pre-menopause but catch up post menopause)
- Diabetes
- Hypertension
- Infection (cytomegalovirus, h.pylori, chlamydia pneumoniae)
- Hyperlipidaemia
- Other factors e.g stress, genetic predisposition, obesity, ethnicity

9

How can you prevent atherosclerosis?

- Stop smoking
- Decrease fat intake
- Treat hypertension and/or diabetes
- Aspirin
- Reduce alcohol consumption
- Regular exercise and control of weight

10

What are the clinical presentations of hyperlipidaemia?

- Xanthelasma
- Tendon xanthoma
- Corneal arcus

11

What is type II hyperlipidaemia caused by?

Defect in LDL receptor