MoD: Vascular Diseases

Question 1

What vessels are commonly affected by atheroma?

Answer 1

Bifurcations (sites of turbulent flow)
Abdominal aorta
Coronary arteries
Popliteal arteries
Carotid vessels
Circle of Willis

Question 2

What are the 6 stages in the ‘response to injury’ hypothesis of atherosclerosis?

Answer 2

1- Chronic endothelial injury
2- Accumulation of lipoproteins (oxidised LDL damaged arterial wall)
3- Platelet adhesion
4- Factor release
5- SMC (smooth muscle cell) proliferation and ECM (extra-cellular matrix) production
6- Lipid accumulation (gives rise to ‘fatty streaks’)

Question 3

What is a fatty streak?

Answer 3

The earliest lesion in atherosclerosis.

Composed of lipid filled foamy macrophages.

Question 4

Components of Virchow’s triad?

Answer 4

1- Endothelial damage (smoking/ hypertension/ surgery)
2- Hypercoagulability (hereditary/ acquired- cancer, obesity, pregnancy)
3- Stasis (immobility, polycythemia)

Question 5

Differences between Arterial thrombosis and Venous thrombosis… a)mechanism b)location c)composition d)treatment

Answer 5

a)Arterial= rupture of atheromatous plaque
Venous= combination of factors from Virchow’s triad
b)Arterial= Left heart chambers/ arteries
Venous= venous sinusoids of muscle and valves of veins
c) Arterial= mainly platelets
Venous= mainly fibrin
d) Arterial= anti-platelet agents (clopidogrel)
Venous= anticoagulants (heparin/ warfarin)

Question 6

Differences between a clot and a thrombus?

Answer 6

Clot= platelets not involved, red, gelatinous, not attached to vessel wall.
Thrombus= platelets involved, red (venous) pale (arterial), firm, attached to vessel wall.

Question 7

What is an embolus?

Answer 7

A detached intravascular solid, liquid or gaseous mass that is carried by the blood to a site distant from its point of origin.

Question 8

How harmful is ischaemic injury?

a) short duration?
b) long duration?

Answer 8

a) cell injury reversible (eg PPI for an MI)

b) irreversible cell damage

Question 9

What is ischaemia-reperfusion injury?

Answer 9

Tissue reperfusion is not always good, this is when repurfusion generates reactive oxygen species which cause further cell injury.

Question 10

What are the 2 types of infarction?

Answer 10

1) Red (haemorrhagic)- dual blood supply/ venous infarction.

2) White (anaemic)- single blood supply, hence totally cut off

Question 11

Why are infarctions usually wedge-shaped?

Answer 11

Because the vascular supply is ‘upstream’ or ‘proximal’ in the tissue, so therefore the entire downstream area will be infarcted.

Question 12

What type of necrosis is an infarction?

Answer 12

Coagulative necrosis (in the brain it is colliquative necrosis)

Question 13

What is Shock?

Answer 13

A pathophysiological state of reduced tissue perfusion resulting in decreased oxygen delivery to the tissues.
Leads to cellular hypoxia and derangement of cellular biochemistry (–> end organ dysfunction)

Question 14

What are the two main things that result in Shock?

Answer 14

• Decreased cardiac output

- Decreased systemic (peripheral) vascular resistance

Question 15

What are the 3 types of Shock?

Answer 15

1- Hypovolaemic Shock
2- Cardiogenic Shock
3- Distributive Shock

Question 16

What is hypovolaemic shock?

Answer 16

Intra-vascular fluid loss (blood, plasma etc)

• Decreased venous return to heart (‘pre-load’
• Decreased stroke volume–> decreased cardiac output

Question 17

What are 2 causes of hypovolaemic shock?

Answer 17

1- Haemorrhage (trauma, GI bleed, ruptured aneurism)

2- Non-haemorrhagic fluid loss (diarrhoea, vomiting, burns. Third spacing)

Question 18

What is third spacing?

Answer 18

Acute loss of fluid into internal body cavities. Common post-operatively and in intestinal obstruction, pancreatitis or cirrhosis.

Question 19

What is cardiogenic shock?

Answer 19

Cardiac Pump failure (compensate by increasing the Systemic Vascular Resistance)

Question 20

What are the 4 causes of cardiogenic shock?

Answer 20

1- Myopathic (heart muscle failure) from an MI or cardiomyopathies
2- Arrythmia-related (abnormal electrical activity)
3- Mechanical (valvular defects, ventricular septal defects)
4- Extra-cardiac (obstruction to blood outflow, anything outside heart impairing cardiac filling or ejection of blood)

Question 21

What is distributive shock?

Answer 21

Decreased SVR due to severe vasodilation (compensate by increasing cardiac output= flushed/ bounding heart, warm especially with septic shock)

Question 22

What are the 4 sub-types of distributive shock?

Answer 22

1- Septic shock (systemic infections, increases cytokines/mediators resulting in vasodilation)
2- Anaphylactic shock (severe type 1 hypersensitivity reaction)
3- Neurogenic shock (spinal injury/ anaesthetic accident–> loss of sympathetic vascular tone–> vasodilation)
4- Toxic shock syndrome (S. aureus/ S. pyogenes produce exotoxins. Widespread release of massive amounts of cytokines, reducing systemic vascular resistance)