Pathophysiology of atheroma, thrombosis and embolism, ischaemia and infarction

Question 1

what is atheroma made up of?

Answer 1

fibrous cap

lipid core

Question 2

what is the difference between atherosclerosis and arteriosclerosis?

Answer 2

atherosclerosis - atheroma formation in endothelium

arteriosclerosis - fibrosis of tissue with age

Question 3

what is contained within the fibrous cap of atheroma?

Answer 3

collagen

inflammatory cells

Question 4

what is the collagen in the fibrous cap of atheroma produced by and how?

Answer 4

smooth muscle cells, platelets, macrophages

through secretion of PDGF - platelet derived growth factor

Question 5

which arteries are more likely to be affected?

Answer 5

muscular arteries

Question 6

what are the chronological stages of an atheroma plaque, and when do they occur?

Answer 6

fatty streak (childhood)
early atheromatous plaque (young adult)
fully developed atheromatous plaque (30+ years)

Question 7

what is the main culprit for developing atherosclerosis?

Answer 7

hypercholesterolaemia

Question 8

what are possible signs of hypercholesterolaemia?

Answer 8

high LDL/total cholesterol in blood
genetically low LDL receptors
tendon xanthomata
xanthalasma
corneal arcus

Question 9

what are the main risk factors for developing atherosclerosis?

Answer 9

hypertension
smoking
diabetes
age
male
(obesity)
(sedentary lifestyle)

Question 10

what does a complicated atheroma mean and what are its consequences?

Answer 10

the rupture/fissure of a plaque, exposing its contents to the lumen –> trigger inflammatory reaction, thrombosis/embolism

Question 11

what are the main features of a vulnerable atheroma plaque?

Answer 11

thin fibrous cap
large lipid core
active visible inflammation

Question 12

what are the main non-drug prevention mechanisms for atherosclerosis?

Answer 12

stop smoking
weight loss
exercise
diet changes

Question 13

what are the main drug prevention mechanisms for atherosclerosis and how do they affect atherosclerosis?

Answer 13

ACEI - reduce blood pressure (reduce risk of plaque rupturing)
statins - stabilise fibrous plaque and reduce cholesterol production
aspirin - antiplatelet (reduce risk of thrombosis on plaques)

Question 14

what are the four main types of hypoxia?

Answer 14

hypoxic
anaemic
stagnant
cytotoxic

Question 15

what are the six main factors affecting oxygen supply?

Answer 15

inspired O2
lung function
blood components (Hb)
blood flow
vasculature
tissue mechanisms

Question 16

what are the two main factors affecting oxygen demand?

Answer 16

tissue specific demands

level of tissue activity above normal threshold

Question 17

what are the different types of necrosis which can happen post-infarction, and where do they occur?

Answer 17

coagulative - heart, lung, kidneys

colliquative/liquefactive - brain

Question 18

why are some tissues more sensitive to ischaemia than others?

Answer 18

because of different cell/tissue metabolism (some fast metabolism, some slow)

Question 19

what is a biochemical and cellular result of infarction?

Answer 19

anaerobic metabolism –> cell death –> necrosis

Question 20

what are the effects of infarction?

Answer 20

acute/chronic reduction in O2 supply
loss of function/dysfunction/pain
anaerobic metabolism –> cell death –> necrosis
effects depend on metabolism of affected cells

Question 21

what are the two different appearances of infarctions, how and when do they occur?

Answer 21

pale (anemic) infarct (arterial occlusion) - solid tissue (heart, kidney)
red (hemorragic) infarct (venous congestion) - loose tissue (liver, lungs, GI)

Question 22

what is the endstage of infarction in tissue appearance?

Answer 22

scar formation

Question 23

what are possible types of embolus?

Answer 23

thrombus (arterial or venous)
gas embolus (nitrogen)
mural embolus (ventricle dilation, AF)
air embolus
fat embolus (fat embolism syndrome)
placental/amniotic fluid embolus
tumour embolus
septic embolus
foreign object embolus
bone marrow embolus

Question 24

how does rheumatic fever cause emboli?

Answer 24

inflammation in endocardium/valves can cause thrombi forming on top of inflamed area and dislodge

Question 25

what is a typical hystological feature of rheumatic heart disease?

Answer 25

presence of aschoff bodies (containing anitschkow cells)

Question 26

what are lines of Zahn and how are they formed?

Answer 26

it’s alternation of RBC and fibrin deposition in thrombus formation, due to the inflammatory/clotting process involved

Question 27

how can rheumatic fever lead to rheumatic heart disease?

Answer 27

fever causes inflammation of joints and heart (pancarditis)

acute pancarditis can progress into rheumatic heart disease

Question 28

what is the most common effect of rheumatic heart disease?

Answer 28

mitral valve dysfunction

Question 29

other than lung cancer, what are some lung conditions for which surgery is sometimes required?

Answer 29

lung transplants (CF, emphysema, IPF)
lung abscess
empyema
thymus tumours
benign lung tumours
tracheal surgery
pneumothorax
bullous disease
bronchogenic cysts

Question 30

what are the stages of surgical removal of empyema called?

Answer 30

parietal pleural layer - pleurectomy

visceral pleural layer - decortication