Mechanisms Of Atheroma And Infarction Flashcards
What is atheroma?
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
What is an infarction?
Obstruction of the blood supply to an organ or region of tissue, typically by a thrombus or embolus, causing local death of the tissue
What are infarctions mediated by?
Low density lipoproteins and angiotensin II
What can make infarctions worse?
Systemic inflammatory diseases like rheumatoid arthritis
What are common sites of infarction/atheroma?
- carotid arteries and a circle of Willis
- coronary arteries
- iliac arteries
- aorta
When does an atheroma become visible on a scan?
When a calcium deposit forms on it
Is calcium a good or bad thing?
Possibly stabilises the plaque?
Calcium is a bad thing but lots of deposits rather than a few could be a slight advantage
When do atheromas begin?
When we are young?
What happens from birth-> 10 years in the formation of atheromas?
Development of macrophage foam cells
What happens in the teen years and older in the formation of atheromas?
Development of smooth muscle foam cells
What happens between 30 and 40 years in atheroma formation?
Maturation of fibrous cap
What happens if there’s a plaque rupture?
The subendothelium is exposed
So clotting is done with a procoagulant surface in an artery
What are the consequences of occlusive thrombosis?
Myocardial infarction
What is a myocardial infarction?
Occurs when blood flow decreases or stops to a part of the heart, causing damage to the heart muscle
What are the consequences of thromboembolism?
Ischaemic stroke
What is an ischaemic stroke?
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
What are the consequences of an aneurism due to wall weakness?
Aortic aneurism
What is an aortic aneurism?
Causes weakness in the wall of the aorta and increases the risk of aortic rupture
What causes atheroma?
Possibly genetic and environmental influences but also lifestyle choices
What happens if there’s an arterial occlusion?
Anything downstream of the occlusion becomes starved of oxygen
What does venous occlusion cause?
Pain and swelling as hydraulic pressure causes oedema
What happens if a venal thrombus detaches?
Enter the pulmonary circulation causing a pulmonary embolism
What causes stable cardiac angina?
Atherosclerotic plaque in the cardiac artery, that partly blocks it
When do you get pain in a stable cardiac angina?
On exertion
What causes unstable cardiac angina?
When you start to get thrombosis on the plaque
What happens to a person’s ECG when they have had an MI?
They get an ST elevation
What causes the ST elevation after a persons had an MI?
Damaged heart tissue doesnt depolarise properly so this section is elevated above the base line
What proportion of people survive their first MI?
Half
What proportion of people die within a month of having an MI?
Half of the people who survived in the first place
What are the two types of ischemic strokes caused by?
A clot causing an embolism
Plaque causing thrombotic stroke
What are the two types of haemorrhagic strokes caused by?
Burst aneurysm causing a subarachnoid haemorrhage
Torn artery causing an inter cerebral haemorrhage
What is a non-thromboembolic stroke due to?
Hypotension, loss of blood pressure, or aneurism rupture and bleeding in the brain
