Mechanisms Of Atheroma And Infarction

Question 1

What is atheroma?

Answer 1

Degeneration of the walls of the arteries caused by accumulated fatty deposits and scar tissue, leading to the restriction of the circulation and a risk of thrombosis

Question 2

What is an infarction?

Answer 2

Obstruction of the blood supply to an organ or region of tissue, typically by a thrombus or embolus, causing local death of the tissue

Question 3

What are infarctions mediated by?

Answer 3

Low density lipoproteins and angiotensin II

Question 4

What can make infarctions worse?

Answer 4

Systemic inflammatory diseases like rheumatoid arthritis

Question 5

What are common sites of infarction/atheroma?

Answer 5

• carotid arteries and a circle of Willis
• coronary arteries
• iliac arteries
• aorta

Question 6

When does an atheroma become visible on a scan?

Answer 6

When a calcium deposit forms on it

Question 7

Is calcium a good or bad thing?

Answer 7

Possibly stabilises the plaque?

Calcium is a bad thing but lots of deposits rather than a few could be a slight advantage

Question 8

When do atheromas begin?

Answer 8

When we are young?

Question 9

What happens from birth-> 10 years in the formation of atheromas?

Answer 9

Development of macrophage foam cells

Question 10

What happens in the teen years and older in the formation of atheromas?

Answer 10

Development of smooth muscle foam cells

Question 11

What happens between 30 and 40 years in atheroma formation?

Answer 11

Maturation of fibrous cap

Question 12

What happens if there’s a plaque rupture?

Answer 12

The subendothelium is exposed

So clotting is done with a procoagulant surface in an artery

Question 13

What are the consequences of occlusive thrombosis?

Answer 13

Myocardial infarction

Question 14

What is a myocardial infarction?

Answer 14

Occurs when blood flow decreases or stops to a part of the heart, causing damage to the heart muscle

Question 15

What are the consequences of thromboembolism?

Answer 15

Ischaemic stroke

Question 16

What is an ischaemic stroke?

Answer 16

Obstruction due to an embolus from elsewhere in the body (usually carotid artery) blocking blood supply to part of the brain- other types of ischaemic strokes occur

Question 17

What are the consequences of an aneurism due to wall weakness?

Answer 17

Aortic aneurism

Question 18

What is an aortic aneurism?

Answer 18

Causes weakness in the wall of the aorta and increases the risk of aortic rupture

Question 19

What causes atheroma?

Answer 19

Possibly genetic and environmental influences but also lifestyle choices

Question 20

What happens if there’s an arterial occlusion?

Answer 20

Anything downstream of the occlusion becomes starved of oxygen

Question 21

What does venous occlusion cause?

Answer 21

Pain and swelling as hydraulic pressure causes oedema

Question 22

What happens if a venal thrombus detaches?

Answer 22

Enter the pulmonary circulation causing a pulmonary embolism

Question 23

What causes stable cardiac angina?

Answer 23

Atherosclerotic plaque in the cardiac artery, that partly blocks it

Question 24

When do you get pain in a stable cardiac angina?

Answer 24

On exertion

Question 25

What causes unstable cardiac angina?

Answer 25

When you start to get thrombosis on the plaque

Question 26

What happens to a person’s ECG when they have had an MI?

Answer 26

They get an ST elevation

Question 27

What causes the ST elevation after a persons had an MI?

Answer 27

Damaged heart tissue doesnt depolarise properly so this section is elevated above the base line

Question 28

What proportion of people survive their first MI?

Answer 28

Half

Question 29

What proportion of people die within a month of having an MI?

Answer 29

Half of the people who survived in the first place

Question 30

What are the two types of ischemic strokes caused by?

Answer 30

A clot causing an embolism

Plaque causing thrombotic stroke

Question 31

What are the two types of haemorrhagic strokes caused by?

Answer 31

Burst aneurysm causing a subarachnoid haemorrhage

Torn artery causing an inter cerebral haemorrhage

Question 32

What is a non-thromboembolic stroke due to?

Answer 32

Hypotension, loss of blood pressure, or aneurism rupture and bleeding in the brain