Assessing haemostasis

Question 1

What are the five steps of haemostasis?

Answer 1

Vessel spasm
platelet plug formation
coagulation
Clot retraction
Clot dissolution

Question 2

Steps of platelet plug formation:

Answer 2

Adhesion
Activation
Aggregation

Question 3

Adhesion is where:

Answer 3

platelets stick to site of damage, occurs between GPIb complex and vW factor bridging site of injury
unstable reaction platelet roll along surface
rolling enables more interactions causing ACTIVATION

Question 4

Activation is where:

Answer 4

interaction between GPVI receptor on platelets and collagen triggering activation 3 things occur:

1. increase intracellular calcium stores
2. cause shape change of platelets
3. Secretion platelets release granules fro inside (alpha granules and dense granules)

Conversion of alpha two b beta 3 receptor, open intergrin = high affinity = bind fibrinogen and stick platelets togethwe

Question 5

Aggregation is the formation of the

Answer 5

platelet plug

Question 6

In coagulation _______ are wrapped with _______ this traps red cells

Answer 6

Platelets

fibrin

Question 7

fibrin is made up of monomers of

Answer 7

fibrinogen

Question 8

what converts fibrinogen to fibrin?

Answer 8

thrombin = protease

Question 9

thrombin circulates as what?

Answer 9

prothrombin

Question 10

Intrinsic pathway is triggered by?

Answer 10

Collagen

Question 11

Extrinsic pathways is triggered by?

Answer 11

tissue damage - calcium factor 4

Question 12

plasminogen breaks down?

Answer 12

fibrin

Question 13

what is protein C?

Answer 13

Serine protease

Question 14

What is protein S?

Answer 14

Cofactor

Question 15

what does fibrinolysis do?

Answer 15

the enzymatic breakdown of fibrin in clots

Question 16

Fibrin split products are cleared by what organ?

Answer 16

the liver

Question 17

What doe the breakdown of fibrin do?

Answer 17

produces D-dimers, made up of fragments X, Y, D, E

Question 18

What enzyme carries out fibrinolysis?

Answer 18

plasmin

Question 19

Where does plasmin come from?

Answer 19

plasminogen, activated by enzymes such s tissue plasminogen activator (tPA), these come from healthy endothelial cells

Question 20

High levels of D dimers in the blood indicate?

Answer 20

high level of fibrinolysis and a high burden of thrombus in the body

Question 21

assessing haemostasis involves asking?

Answer 21

is it a bleeding/thrombotic disorder?

is it under/over action of the system?

Question 22

Bleeding disorders can be broken down into:

Answer 22

Primary haemostats disorders - bleeding due to PP

Coagulation disorders - problem with coagulation

Question 23

Thrombotic disorders can be either:

Answer 23

platelet plug occurring at wrong time or over active causing ARTERIAL THROMBOSIS = MI/Stroke
Inappropriate activation of coagulation = VENOUS THROMBOSIS = DVT

Question 24

What can inappropriate activation of coagulation cause?

Answer 24

Venous thrombosis = DVT

Question 25

What can over active platelet plug formation or platelet plug formation occurring at the wrong time cause?

Answer 25

Arterial thrombosis = MI or strok

Question 26

what are the signs and symptoms of a bleeding disorder?

Answer 26

Bruising mucosal bleeding Haemarthrosis Complication with surgery, trauma or venipuncture

Question 27

What is a bruise?

Answer 27

micro/macroscopic tearing of a blood vessels

Question 28

Haematomas..

Answer 28

refers to purple/red colour caused by bleeding under the skin, the colour is non blanching upon pressure

Question 29

How big are petechiae?

Question 30

How big are purpura?

Answer 30

3mm-1cm

Question 31

How big are ecchymoses?

Answer 31

>1cm

Question 32

What are the 4 causes of bleeding defects?

Answer 32

Decreased platelet number decreased platelet function decreased coagulation Vascular defects

Question 33

What are the signs and symptoms of a thrombotic disorder?

Answer 33

These vary depending on location of thrombus: - Coronary arteries = chest pain - Carotid arteries = FAST aschemic stroke - Deep veins of the leg = unilateral leg pain

Question 34

What are the haemostatic investigations that are carried out?

Answer 34

``` FBC Blood film/smear Bleeding time PFA-100 Platelet aggregation studies Flow cytometry Serum thromboxane Aspirin works Coagulation assays Factor assay PCR D-dimer assay ```

Question 35

what is the normal bleeding time?

Answer 35

3-8min

Question 36

What does a prothrombin time assay assess?

Answer 36

Intrinsic pathway of coagulation

Question 37

What coagulation assay tests the intrinsic pathway?

Answer 37

activated partial thromboplastin time (aPTT)

Question 38

what does thrombin time assay asses?

Answer 38

common pathway of coagulation

Question 39

Which coagulation assay assess patients on warfarin?

Answer 39

PT

Question 40

What are the normal values of a PT time?

Answer 40

11-16 seconds

Question 41

what re the normal values of the aPPT test?

Answer 41

30-40 seconds

Question 42

What are the normal values of TT?

Answer 42

15-19 seconds

Question 43

What does a factor assay determine?

Answer 43

Helps to determine what clotting factors are missing or reduced by diluting pt plasma with normal plasma