Haemostasis And Thrombosis

Question 0

What does successful haemostasis rely on?

Answer 0

The vessel wall, platelets, the coagulation system and fibrinolytic system

Question 1

What is haemostasis?

Answer 1

The body’s response to stop bleeding and loss of blood

Question 2

What do platelets do?

Answer 2

Adhere to the damaged cell wall and to eachother to form a platelet plug

Question 3

What is the platelet release reaction?

Answer 3

ATP is converted to ADP. This releases chemicals. ADP and thromboxane cause platelet aggregation. Platelet factor 3 (PF3) is released which is important for coagulation.

Question 4

What does a cascade reaction allow?

Answer 4

Control, regulation and amplification

Question 5

What is made in coagulation?

Answer 5

Prothrombin to thrombin
which causes the change of
fibrinogen to fibrin

Question 6

How is the coagulation cascade regulated?

Answer 6

Thrombin positively feedback on factors V, VIII and XI.

There are thrombin inhibitors such as anti-thrombin III, α-1 antitrypsin and protein C/S

Question 7

What is thrombophilia?

Answer 7

An inherited deficiency in the thrombin inhibitors antithrombin III or protein C/S

Question 8

What is thrombosis?

Answer 8

The formation of a solid mass of blood within the circulatory system in life

Question 9

Give some reasons for thrombosis

Answer 9

Abnormalities in the vessel wall such as injury, atheroma or inflammation
Abnormalities in blood flow - stagnant/turbulent
Abnormalities of blood components - in smokers, post partum, post op

Question 10

What is the difference between clot and thrombosis

Answer 10

A clot is physiological - happens when you cut yourself and is outside of the circulatory system
Thrombosis is always pathological

Question 11

What is the appearance of an arterial thrombus?

Answer 11

Pale, granular tissue, lines of Zahn, fewer red blood cells

Question 12

What is the appearance of a venous thrombus?

Answer 12

Softer and gelatinous

Higher cell content

Question 13

What are the outcomes of thrombosis?

Answer 13

Lysis
Propagation
Organisation
Recanalisation
Embolism

Question 14

What is lysis?

Answer 14

Complete dissolution to the thrombus. Activation if fibrinolysis (with help of streptokinase). Blood flow is re-established.

Question 15

What is propagation of a thrombus?

Answer 15

Progressive spread of the thrombus. Distally in arteries and proximally in veins.

Question 16

What is organisation of a thrombus?

Answer 16

A reparative process with in-growth of fibroblasts and capillaries. The lumen remains obstructed

Question 17

What is recanalisation of a thrombus?

Answer 17

Blood flow is re established but usually incompletely. One or more channels are formed through organisation.

Question 18

What is an embolism?

Answer 18

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

Question 19

What are the effects if an arterial thrombus?

Answer 19

Ischaemia and infarction. Depends on site and collateral circulation.

Question 20

What are the effects of a venous thrombus

Answer 20

Congestion, oedema, ischaemia, infarction

Question 21

Types of embolism?

Answer 21

Thrombo-emboli
Air
Amniotic fluid
Tumour cells
Nitrogen
Fatty embolism after a fracture
Medical equipment

Question 22

Where can thrombo-embolisms from systemic veins travel to?

Answer 22

To the lungs and cause a pulmonary embolism.

Question 23

Where can embolism in the heart travel to?

Answer 23

The aorta to renal, mesentric and other arteries

Question 24

Where can atheromatous carotid arteries travel to?

Answer 24

The brain and cause a stroke

Question 25

Where can atheromatous abdominal aortic ones travel to?

Answer 25

Arteries of legs

Question 26

Causes of a deep vein thrombosis?

Answer 26

Immobility/bed rest
Post-o
Pregnancy and post partum
Oral contraceptives
Severe burns
Cardiac failure
Disseminated cancer

Question 27

Prevention of DVT?

Answer 27

High risk patients can by offered prophylaxis - heparin subcutaneously and leg compression during surgery

Question 28

Treatment of a DVT?

Answer 28

Intravenous heparin followed by oral warfarin

Question 29

Symptoms of a fat embolism?

Answer 29

Rash, shortness of breath, confusion

Question 30

What can a cerebral embolism be caused by?

Answer 30

Atrial fibrillation

Question 31

What is an iatrogenic embolism?

Answer 31

One caused by medical treatment such as air from an injection

Question 32

What is disseminated intra vascular coagulation?

Answer 32

Pathological activation of coagulation mechanisms that happen in response to a variety of diseases.

Question 33

What happens in disseminated intravascular coagulation?

Answer 33

Small clots form throughout the body, disrupting normal coagulation because they use up all the clotting factors.

Question 34

Triggers of disseminated intravascular coagulation?

Answer 34

Infection
Trauma
Liver disease
Obstetric complications

Question 35

What is haemophilia?

Answer 35

An X-linked recessive disease where there is a deficiency in clotting factors. Due to a nonsense point mutation.

Question 36

What do type A and type B haemophilia each have a deficiency in?

Answer 36

Type A - factor VIII

Type B - factor IX

Question 37

What symptoms can you get in haemophilia?

Answer 37

Haemorrhage into major joints
Synovial hypertrophy
Pain
Muscle bleeding causes pressure and necrosis of nerves
Can haemorrhage into retroperitoneum/urinary tract

Question 38

How is haemophilia treated?

Answer 38

Factor replacement therapy

Question 39

What is thrombocytopenia?

Answer 39

Low platelet count due to either failure of platelet production, increase in platelet destruction or sequestering of platelets.

Question 40

What is thrombocytopenia usually accompanied with?

Answer 40

A bone marrow dysfunction such as leukaemia or anaemia

Question 41

What is Virchow’s triad?

Answer 41

Hypercoagulability
Haemodynamic changes (turbulence/stasis)
Endothelial injury