Lecture 9- Haemostasis, Thrombosis And Embolism

Question 1

What is thrombosis?

Answer 1

Formation of solid mass of blood within circulatory system. Only a thrombus if inside blood vessel during life. After death is just a clot

Question 2

What abnormalities of vessel wall cause thrombosis?

Answer 2

Atheroma
Direct injury
Inflammation

Question 3

What is atheroma?

Answer 3

Deposition of fat and scar tissue in arterial wall which restricts flow

Question 4

What causes thrombosis other than vessel wall abnormalities?

Answer 4

Flow alterations such as turbulence or stagnation

Abnormalities of blood composition eg smokers, post op and post partum

Question 5

What is virchows triad?

Answer 5

Three conditions that increase likelihood of thrombosis. Hypercoagulability, haemodynamic change such as turbulence, endothelial injury

Question 6

How to tell an arterial from a venous thrombus?

Answer 6

Arterial has lines of zany and is pale and granular with lower cell content

Venous is softer and gelatinous, deep red with higher cell content

Question 7

What are the outcomes of thrombosis?

Answer 7

Lysis- fibrolyticnsystem can dissolve small thrombi

Propagation- thrombus grows, obstructs flow downstream from it leading to further larger thrombi

Organisation- repair through fibroblasts etc obstructs lumen

Recanicularisation- re establish blood flow in lumen but not completely

Embolism

Question 8

What can propagation lead to?

Answer 8

A thrombus a few mm becoming a thrombus a few cm in a larger vessel

Question 9

Arterial effects of thrombosis?

Answer 9

Ischaemia and infarctionalthough collaterals and location will determine extent

Question 10

Effects of thrombosis in veins?

Answer 10

Oedema and congestion most likely but can also cause infarction and ischaemia

Question 11

What is a hyperaemic border?

Answer 11

The red tissue that forms around an infarct. It consists of blood vessels etc

Question 12

What is an embolism?

Answer 12

Blockage of a blood vessel by a solid, liquid or gas at a site distant to its site of origin

Question 13

What other types of embolism are there?

Answer 13

Air,amniotic fluid, nitrogen , medical equipment and tumours

Question 14

Where could an embolus in the brain have come from?

Answer 14

Carotid artery

Question 15

What is a pulmonary embolus?

Answer 15

One which has passed from the systemic veins to the lungs

Question 16

DVT predisposing factors?

Answer 16

Immobility
Post operation 
Pregnancy 
Oral contraceptives with high oestrogen 
Severe burns
Cardiac failure 
Disseminated cancer

Question 17

What is disseminated cancer?

Answer 17

Cancer that has spread into the blood

Question 18

Can DVT be prevented?

Answer 18

No but risk can be reduced through administration of IV heparin, oral warfarin and leg compression during surgery

Question 19

What can an inferior vena cava filter do?

Answer 19

Trap emboli

Question 20

Effects of pulmonary embolism?

Answer 20

Major will reduce blood flow by more than 60% leading to fast death

Minor may appear assymptomatic or have shortness of breath

Recurrent minor PEs can lead to pulmonary hypertension

Question 21

Latrogenic meaning?

Answer 21

Caused by a physician or therapy

Question 22

What is fat embolism?

Answer 22

When bone fractured and marrow leaks out into capillaries. Feared but rare complication