Session 6

Question 1

What is an atheroma?

Answer 1

The accumulation of intracellular and exit acellular lipid in the intima and media of large and medium sized arteries.

Question 2

What is atherosclerosis?

Answer 2

The thickening and hardening of arterial walls as a consequence of atheroma.

Question 3

What is arteriosclerosis?

Answer 3

The thickening of the walls of arteries and arterioles as a result of hypertension or diabetes mellitus.

Question 4

What are the macroscopic characteristics of an atheroma?

Answer 4

A yellow and slightly raised fatty streak.
Simple plaque - irregular outline.
Complicated plaque - thrombosis, haemorrhage, calcification.

Question 5

What are the common sites of an atheroma?

Answer 5

Aorta, especially abdominal.
Coronary
Carotid
Cerebral
Leg arteries

Question 6

What are the early microscopic characteristics of an atheroma?

Answer 6

Proliferation of smooth muscle cells.
Accumulation of foam cells.
Extra cellular lipid.

Question 7

What are the later microscopic characteristics of an atheroma?

Answer 7

Fibrosis.
Necrosis.
Cholesterol clefts - occur as organic solvent destroys the cholesterol.
Disruption of internal elastic lamina.
Damage extends into media.
In growth of blood vessels.
Plaque fissuring.

Question 8

What are some of the effects of an atheroma?

Answer 8

Ischaemic heart disease.
Sudden death.
Myocardial infarction.
Angina pectoris.
Arrhythmias.
Cardiac failure.

Question 9

What other types of ischaemia are there?

Answer 9

Cerebral (and transient ischaemic attack)
Mesenteric ischaemia (malabsorption, infarction)

Question 10

What are some of the consequences of peripheral vascular disease?

Answer 10

Intermittent claudication - pain on walking.
Leriche syndrome - aortiliac occlusive disease.
Ischaemic rest pain - pain on rest after walking.
Gangrene - necrosis due to loss of blood supply.

Question 11

How does age effect the risk of atheroma?

Answer 11

As the patient gets older, the chances of atheroma slowly increase?

Question 12

How does gender effect the risk of atheroma?

Answer 12

Women are protected more before menopause.

Question 13

How does hyperlipidaemia effect the risk of atheroma?

Answer 13

There is high plasma cholesterol which increases the risk.

Question 14

How does smoking effect the risk of atheroma?

Answer 14

Smoking increases the risk, then this risk radially falls after quitting smoking.

Question 15

How does hypertension effect the risk of atheroma?

Answer 15

The mechanism is uncertain, but it does increase the risk. Possibly due to the high pressures damaging endothelium.

Question 16

How does diabetes mellitus effect the risk of atheroma?

Answer 16

Increases the risk by about double. This makes pre menopausal women loose their protective effect.

Question 17

How does alcohol effect the risk of atheroma?

Answer 17

More than 5 units a day increases the risk. Small amounts may be protective.

Question 18

How does infection effect the risk of atheroma?

Answer 18

It is thought that it can increase the risk. Examples would be chlaymidia pneumoniae, helicobacter pylori.

Question 19

How does genetics effect the risk of atheroma?

Answer 19

It may increase the risk if there is a mutation I’m the apolipoprotein metabolism or receptors.

Question 20

What other lifestyle choices increase the risk of atheroma?

Answer 20

Obesity
No exercise
Soft water
Oral contraceptives
Stress
Personality

Question 21

What are the 4 theories for the causes of atheroma?

Answer 21

Thrombogenic theory
Insudation theory
Monoclonal hypothesis
Reaction to injury hypothesis

Question 22

What does the insudation theory state?

Answer 22

That endothelial injury causes inflammation and an increased permeability to lipids from the plasma.

Question 23

What does the monoclonal hypothesis state?

Answer 23

The the crucial role in atheroma formation is the proliferation of smooth muscle. Each plaque is monoclonal and starts from one cells. Abnormal growth occurs. (In a similar way to tumour formation)

Question 24

What does the reaction to injury hypothesis state?

Answer 24

There is endothelial injury, this causes a plaque to form. Platelet adhesion occurs and PDGF is released (causing more smooth muscle proliferation) Monocytes penetrate the endothelium and smooth muscle cells proliferate more.
LDL is especially bad, when oxidised, for endothelium.

Question 25

What are the cells involved in atheroma?

Answer 25

Endothelial cells
Platelets
Smooth muscle cells
Macrophages
Lymphocytes
Neutrophils

Question 26

What is the accepted theory for atheroma formation?

Answer 26

There is an altered permeability to lipoproteins.
Secretion of collagen and stimulation of proliferation of smooth muscle cells. PDGF.
Take up LDL and other lipids to become foam cells.
Oxidise LDL, take up lipids to be foam cells, secretes proteases.
TNF may effect lipoprotein metabolism. Stimulates proliferation of SMC.
Secretes proteases which continue to lead damage and inflammation.

Question 27

How do you prevent atheroma?

Answer 27

No smoking
Reduced fat intake
Treatment for the hypertension
Small amount of alcohol
Regular exercise and weight control

Question 28

How would you intervene with someones lifestyle to reduce the risk of an atheroma?

Answer 28

Stop smoking
Modify the diet so it is lower in fat and cholesterol
Treat the hypertension
Treat the diabetes
Take lipid lowering drugs eg statins