Atheroma

Question 0

Define atherosclerosis

Answer 0

Thickening and hardening of arterial walls as a consequence of atheroma.

Question 1

Define atheroma

Answer 1

Accumulation of intracellular and extracellular lipids in the intima and media of large and medium sized vessels

Question 2

How do fatty streaks appear?

Answer 2

They are lipid deposits in the intima. They are yellowish and appear slightly raised.

Question 3

What are simple plaques like?

Answer 3

Raised yellow/white, irregular outline, widely distributed, enlarge and coalesce

Question 4

What are complicated plaques like?

Answer 4

They are formed in thrombosis. Haemorrhage into plaques. Can undergo calcification.

Question 5

Where are common sites for atheroma formation?

Answer 5

Aorta (especially abdominal aorta)
Coronary arteries
Carotid arteries
Cerebral arteries
Leg arteries

Question 6

How is a normal artery structured?

Answer 6

Endothelium, sub-endothelial connective tissue, internal elastic lamina, muscular media, external elastic lamina, adventitia

Question 7

What are the early changes in atheroma formation?

Answer 7

Proliferation of smooth muscle cells, accumulation of foam cells, extracellular lipid

Question 8

What are later changes of atheroma formation?

Answer 8

Fibrotic cap, necrosis, cholesterol clefts, disruption of internal elastic lamina, damage extending into media, ingrowth of blood vessels, plaque fissuring

Question 9

What are the consequences of ischaemic heart disease?

Answer 9

Sudden death, myocardial infarction, angina pectoris - chest pain on exertion, arrhythmias, cardiac failure

Question 10

What are consequences of cerebral ischaemia?

Answer 10

Transient ischaemic attack (“mini stroke”), cerebral infarction (stroke), multi-infarct dementia - small infarcts built up

Question 11

What are the consequences of mesenteric ischaemia?

Answer 11

Ischaemic colitis, malabsorption, intestinal infection

Question 12

What are the consequences of peripheral vascular disease?

Answer 12

Intermittent claudication, Leriche syndrome (iliac artery affected), ischaemic rest pain, gangrene

Question 13

List a few risk factors for atherosclerosis

Answer 13

Hyperlipidaemia, cigarette smoking, age, gender (women protected before menopause), hypertension, diabetes mellitus, alcohol, infection

Question 14

What is the thrombogenic theory?

Answer 14

Plaques are formed by repeated small thrombi

Question 15

What is the insudation theory?

Answer 15

Endothelial injury, inflammation and increased permeability to lipids from plasma causes plaque formation

Question 16

What does the reaction to injury hypothesis state?

Answer 16

Plaques form in result of endothelial injury. Injury increases permeability and allows platelet adhesion, monocytes penetrate endothelium, smooth muscle cells proliferate and migrate. (oxidised LDLs could be dangerous)

Question 17

What does the monoclonal hypothesis state?

Answer 17

Smooth muscle cells play a crucial role in proliferation because each plaque is monoclonal.

Question 18

What are the processes involved in atheroma formation?

Answer 18

Thrombosis, lipid accumulation, production of intercellular matrix and interactions between cell types

Question 19

What are the cells involved in atheroma formation?

Answer 19

Endothelial cells, platelets, smooth muscle cells, macrophages, lymphocytes and neutrophils

Question 20

What role do endothelial cells have?

Answer 20

They have an altered permeability to lipoproteins, secrete collagen, stimulation and proliferation of smooth muscle cells.

Question 21

What role do smooth muscle cells have?

Answer 21

Take up LDL and other lipids to become foam cells. They synthesis collagen and proteoglycans.

Question 22

What role do macrophages have?

Answer 22

They oxidise LDLs, take up lipids to become foam cells, secrete proteases which modify the matrix and stimulate proliferation of smooth muscle cells.

Question 23

What role do lymphocytes have?

Answer 23

T lymphocytes can produce TNF which may affect lipoprotein metabolism. Also stimulate proliferation and migration of smooth muscle cells.

Question 24

What roles do neutrophils play?

Answer 24

They secrete proteases leading to continued local damage and inflammation

Question 25

What role do platelets play?

Answer 25

Key role in haemostasis. They stimulate proliferation and migration of smooth muscle cells (PDGF)

Question 26

What causes endothelial injury?

Answer 26

Raised LDL, toxins, haemodynamic stress and hypertension

Question 27

What does endothelial injury cause?

Answer 27

Platelet adhesion, PDGF release, smooth muscle cell proliferation and migration, insudation of lipids, LDL oxidation, uptake of lipids by smooth muscle cells and macrophages, migration of monocytes into the intima

Question 28

What happens in the final stage of the unified theory of atheroma formation?

Answer 28

Stimulated smooth muscle cells produce matrix material, foam cells secrete cytokines causing further smooth muscle stimulation, recruitment of inflammatory cells

Question 29

How can atheroma formation be prevented?

Answer 29

No smoking, reduce fat intake, treatment of hypertension, not too much alcohol, regular exercise (weight control)

Question 30

What steps can be take in an intervention for someone with atheroma formation?

Answer 30

Stop smoking, modify diet, treat hypertension, treat diabetes, lipid lowering drugs.

Question 31

What is angiotensin converting enzyme?

Answer 31

An enzyme which indirectly increases blood pressure by causing blood vessels to constrict. It does this by converting angiotensin I to angiotensin II, which constricts the vessels.

Question 32

How might an abdominal aortic aneurysm cause death?

Answer 32

Haemorrhage into his abdomen, therefore loss of blood to vital organs causing shock and eventually death. Retroperitoneal (might tamponade) or intraperitoneal leakage of blood. Tamponade (compression).
Grey turner’s sign - bruising of flesh

Question 33

What dietary factors influencing atherosclerosis?

Answer 33

High intake of fatty foods, cholesterol rich foods and alcohol. Smoking can also affect the likelihood of developing atheromas.

Question 34

What is prostacyclin and what does it do?

Answer 34

Prostacyclin is a prostaglandin which prevents adhesion and aggregation of platelets to endothelium.

Question 35

What does thrombomodulin do?

Answer 35

Thrombomodulin binds to any locally formed thrombin and this complex initiates the anti-coagulant effects of protein C and protein S
These molecules inhibit elements of the normal coagulation cascade