2: Pathology of thrombosis & embolism

Question 1

What is the difference between a clot and a thrombus?

Answer 1

Clot - outside the vessel

Thrombus - inside the vessel

Clot often used colloquially.

Question 2

What is Virchow’s Triad?

Answer 2

Site of endothelial injury

Turbulent blood flow

Hypercoagulable blood

all favour thrombus formation.

Question 3

Thrombus is formed by intravascular coagulation. What are the two main steps of this?

Answer 3

1) Platelet activation

2) Fibrin production & coagulation cascade

Question 4

Activated platelets are more “___”.

Answer 4

sticky

Question 5

Platelets attract and aggregate with other __ and __.

Answer 5

platelets , fibrin

Question 6

Which chemical is the endpoint of the coagulation cascade?

Answer 6

Fibrin

Question 7

What activates platelets and how is it exposed?

Answer 7

Collagen of connective tissue

Exposed because of endothelial damage

Question 8

What chemical on platelets do collagen and vWF bind to?

Answer 8

Glycoprotein Ia/IIb

Question 9

What does glycoprotein IIb/IIIa bind to?

Answer 9

Fibrinogen

Question 10

Activated platelets release chemicals (granules) to attract other platelets - what are some examples?

Answer 10

vWF, PAF, Thromboxane A2, ADP

Question 11

The coagulation effect is also known as a ___.

Answer 11

cascade

Question 12

The coagulation cascade has a lot of opportunities for inhibition and stimulation, which can all be targeted by __.

Answer 12

drugs

Question 13

What chemical is important in the formation of specific factors?

Answer 13

Vitamin K

(II, XII, IX and X)

Question 14

Why does liver disease inhibit the coagulation cascade?

Answer 14

Vitamin K stored in the liver

So body can’t produce factors II, VII, IX and X

Question 15

Which drug stops the body’s production of II, VII, IX and X?

Answer 15

Warfarin

Question 16

If someone has been given too much warfarin, what can you do?

Answer 16

Give them Vitamin K injections

Question 17

Which condition can cause endothelial injury in the arteries?

Answer 17

Hypertension

Question 18

Why doesn’t high arterial flow damage the arteries?

Answer 18

Pro-coagulant materials (e.g platelets) are washed away before they stick

Question 19

When may high pressure arterial flow cause thrombosis?

Answer 19

If there is underlying atherosclerosis

Question 20

What is atherosclerosis?

Answer 20

Arterial hardening and thickening, formation of plaque at sites of endothelial damage

Question 21

Fibrous plaque caps which form during atherosclerosis are prone to ___.

Answer 21

rupture

Question 22

Arterial stenosis tends not to occur unless there is underyling ___.

Answer 22

atherosclerosis

Question 23

Stable angina tends to occur on __.

Answer 23

exertion

Question 24

Unstable angina is associated with __ and can occur at __.

Answer 24

rupture , rest

Question 25

What is the main factor affecting blood flow through a vessel?

Answer 25

**Radius**

Question 26

What are other causes of endothelial injury?

Answer 26

**Toxins** (e.g tobacco) **Infectious agents** **Autoimmune disease** (inflammation)

Question 27

What is a historic risk factor for DVT?

Answer 27

**Having had DVT already**

Question 28

What are two effects of **turbulent blood flow** on a vessel?

Answer 28

1. Swirling of blood (imagine getting stuck in a swirly pool at the bottom of a waterfall) 2. Stasis

Question 29

Blood flow is usually laminar. If it becomes turbulent, platelets move to the edge of the vessel - what is this called?

Answer 29

**Margination**

Question 30

In marginated blood flow, platelets are more likely to come into contact with?

Answer 30

**Endothelial wall** (or lack thereof)

Question 31

Where is blood flow most likely to slow down and produce stasis?

Answer 31

**Deep venous system** (low pressure, faulty valves etc.)

Question 32

Where do DVTs develop?

Answer 32

**Calf veins** **Femoral veins**

Question 33

Thrombi from __ veins tend to circulate further in the blood.

Answer 33

smaller A thrombus is only as wide as the vein it started in

Question 34

What is the name of the process which regulates, amongst other things, clotting and clot lysis in the body?

Answer 34

Homeostasis

Question 35

Hypercoagulability may be associated with __ disorders.

Answer 35

inherited

Question 36

If someone has developed a DVT on a long haul flight, they probably have...

Answer 36

an inherited mutation.

Question 37

Name some causes, other than **genetic disorders**, of clotting / DVT.

Answer 37

**Prolonged immobility** **Significant tissue injury** - burns, RTA **Autoimmune diseases** **MI** **Atrial fibrillation** - blood clots in atria

Question 38

What is an embolus?

Answer 38

A dislodged thrombus which travels around the vascular system until it gets stuck

Question 39

What would you see on an X-ray if a patient had suffered a pulmonary embolism?

Answer 39

**Wedge-shaped infarcs**

Question 40

What is ischaemia?

Answer 40

Insufficient blood supply

Question 41

What is infarction?

Answer 41

Tissue death as a result of ischaemia

Question 42

Turbulent blood flow occurs anywhere a vessel \_\_.

Answer 42

branches

Question 43

Branching vessels are a common site of __ \_\_.

Answer 43

endothelial damage

Question 44

The most common cause of thromboembolic stroke is embolism where?

Answer 44

Bifurcation of carotid arteries

Question 45

Name some anti-clotting proteins produced by the body.

Answer 45

Protein **C**, **S** and **antithrombin III**

Question 46

What is a natural **clot buster** produced by the body?

Answer 46

Plasmin

Question 47

Name an inherited genetic disorder causing **hypercoagulability** of the blood.

Answer 47

**Factor V Lieden**

Question 48

\_\_\_ increases the production of TNF, which causes hypercoagulability of the blood.

Answer 48

**Cancer**

Question 49

Which particular drug may increase the coagulability of the blood?

Answer 49

**Contraceptive pill**

Question 50

Give two examples of branching vessels which are vulnerable to embolism.

Answer 50

**Coronary vessels** **Bifurcation of aorta** **Bifurcation of the carotids** **Renal arteries** **Superior mesenteric artery**

Question 51

What may happen following embolism which blocks... 1) Bifurcation of carotids 2) Superior mesenteric artery?

Answer 51

1) Stroke 2) Small bowel infarction