Vascular Disease (week 6)

Question 1

What is the defintion of atheroma?

Answer 1

Intimal lesion that protrudes into vessel wall. Consists of soft lipid core (mainly cholesterol) and covered by fibrous cap.

Question 2

Which vessels are commonly affected by atheroma?

Answer 2

AA
Coronary arteries
Popliteal arteries
Carotid arteries
Circle of willis
Any bifurcations (turbulent flow)

Question 3

Which gender is more likely to have atheroma?

Answer 3

Male

Question 4

What factros may cause initial damage to inner layer of artery?

Answer 4

hypertension
high cholesterol
irritants e.g. nicotine
diabetes

Question 5

What type of cells form the initial fatty streak in the intima?

Answer 5

lipid filled foamy macrophages

Question 6

Name the differences between a clot and a thrombus in:

1) platelets
2) location
3) colour
4) structure

Answer 6

1) platelets only involved in thrombus
2) clots can be in or outside vessel, thrombus is only inside vessl. Clots are not attached to vessel wall, thrombi are.
3) clots are red, venous thrombus is red, arterial thrombus is pale
4) clot = gelatinous, thrombus = firm

Question 7

Where are likely locations of arterial and venous thrombi, and what diseases are each involved in?

Answer 7

Aterial = left heart chambers, arteries. ACS, ischaemic stroke, claudication. 
Venous = venous sinusoids of muscle, venous valves. DVT, PE.

Question 8

How does the composition and therefore treatment of arterial thrombi differ to venous?

Answer 8

Arterial = platelets, treat with anti-platelet agents e.g. aspirin, clopidogrel
Venous = fibrin, treat with anticoagulants e.g. warfarin

Question 9

Define the terms ischaemia and infarction.

Answer 9

Ischaemia: pathological reduction in blood flow to tissues, usually as a result of arterial occlusion. Leads to hypoxia.
Infarction: obstruction of blood supply to tissue resulting in tissue death.

Question 10

What may cause an infarction?

Answer 10

Occlusion by thrombus / embolus
Atheroma expansion 
Vasospasm
Extrinsic compression e.g. from tumour.
Twisting of vessel roots e.g. volvulus
Rupture of vascular supply

Question 11

What is the differnece between an infarction that is red in colour and one that is white?

Answer 11

red infarction = haemorrhagic. Venous infarction, blood not drained.
white infarction = anaemic. single blood supply that is totally cut of.

Question 12

Which type of necrosis is characteristic of infarction?

Answer 12

Coagulative

colliquitive in brain

Question 13

What is meant by shock?

Answer 13

State of reduced tissue perfusion resulting in decreased oxygen delivery to tissues - decreased mean arterial pressure. Leads to cellular hypoxia.

Question 14

What causes hypovolaemic shock and what are the consequences?

Answer 14

Intra-vascular fluid loss: haemorrhage, diorrhoea, vomiting, burns

Decreased venous return to the heart (preload) –> decreased stroke volume –> decreased cardiac output. Compensate by vasoconstriction to increase systemic vascular resistance.

Question 15

What is cardiogenic shock?

Answer 15

Cardiac failure leading to decreased cardiac output.

Question 16

What might cause cardiogenic shock?

Answer 16

Cardiac myopathy (muscle)
Arrhythmia: abnoraml electrical activity
Mechanical e.g. valvular defects
Extra-cardiac: obstruction to blood flow - anything outside heart that imparis contraction / filling e.g. PE, tension pneumothorax, constrictive pericarditis

Question 17

What is distributive shock?

Answer 17

Decreased SVR due to severe vasodilation

Question 18

What is septic shock?

Answer 18

Severe infections with bacteria / fungi cause very high cytokine levels, which stimulate vasodilation.

Question 19

What is anaphylactic shock?

Answer 19

Severe type I sensitivity reaction where allergen leads to IgE cross-linking causing mast cell degranulation. This leads to vasodilation, contraction of bronchioles, laryngeal oedema and circulatory collapse.

Question 20

What is neurongenic shock?

Answer 20

Injury to nervous system leading to loss of sympathetic vascular tone. This causes severe vasodilation.

Question 21

What happens in TSS?

Answer 21

S. aureus/pyogenes produce exotoxins that stimulate T cells. Massive cytokine release leading to vasodilation.

Question 22

Component of bacterial cell wall released after cell lysis which causes harmful effects

Answer 22

Endotoxin

Question 23

Classification of bacteria with an extra membrane beyond the cell wall

Answer 23

Gram negative

Question 24

Acronysm denoting main agent responsible for cell injury during reperfusion

Answer 24

ROS
Reactive oxygen species. Ischaemic damage leads to generation of free radicals. In reperfusion, oxygen binds to these to form ROS which can damage cell membranes.

Question 25

Causative agent and symptoms of Botulism

Answer 25

Clostridium botulinum. Double vision and dysphagia

Question 26

Growth factor released by platelets

Answer 26

PDGF

Question 27

Area of body likely to detect S. Aureus in a healthy individual

Answer 27

Nose

Question 28

Area of body likely to detect coagulase negative staph in a healthy individual

Answer 28

Skin