Bleeding and Clotting

Question 1

haemostasis

Answer 1

the arrest of bleeding and the maintenance of vascular patency

Question 2

what is primary haemostasis?

Answer 2

primary haemostasis

Question 3

what is secondary haemostasis?

Answer 3

formation of fibrin clot

Question 4

platelets are formed by

Answer 4

budding on megakaryocytes

Question 5

lifespan of platelets

Answer 5

7-10 days

Question 6

endothelial wall damage leads to

Answer 6

exposure of collagen
release of von Willebrand factorrelease of proteins to which platelets attach
secretion of chemicals which leads to platelet aggregation

Question 7

causes of failure of platelet plug

Answer 7

vascular
platelets (reduced number or function)
von Willebrand factor

Question 8

screening tests for primary haemostasis

Answer 8

platelet

Question 9

what is extrinsic pathway of secondary haemostasis?

Answer 9

TF / VIIa acting on

factor V/Xa

Question 10

what is intrinsic pathway?

Answer 10

VIII/IXa acting on factor V/Xa

Question 11

what is the common pathway for secondary haemostasis?

Answer 11

V/Xa activates propagation of prothrombin to thrombin

fibrinogen to fibrin

Question 12

Causes of failure of secondary haemostasis

Answer 12

Single clotting factor deficiency
usually hereditary
eg Haemophilia
Multiple clotting factor deficiencies
usually acquired
eg Disseminated Intravascular Coagulation
Increased fibrinolysis
usually part of complex coagulopathy

Question 13

what is fibrinolysis ?

Answer 13

plasminogen to plasmin activated by tPA

leads to conversion of fibrin to FDPs

Question 14

prothrombin time

Answer 14

extrinsic pathway

Question 15

APTT

Answer 15

intrinsic pathway

Question 16

Naturally occurring anticoagulants

Answer 16

Serine protease inhibitors (anti thrombin 1)

Protein C and S

Question 17

what is thrombophilia?

Answer 17

Deficiency of naturally occuring anticoagulants may be hereditary
Increased tendency to develop venous thrombosis (deep vein thrombosis/pulmonary embolism)

Question 18

what happens as a direct result of hypoperfusion?

Answer 18

acidosis
microcapillary thrombus
eventual cellular necrosis

Question 19

urine output in sepsis

Answer 19

<0.5

Question 20

lactate levels

Answer 20

> 0.2

Question 21

massive haemorrhage clinical definition

Answer 21

bleeding which leads to a heart rate of >110 beats per minute and/or systolic blood pressure less than 90mmHg
bleeding which has already prompted use of emergency O Rh(D) negative red cells.

Question 22

multiple factor deficiency

Answer 22

factor concentrates

Question 23

what replaces fibrinogen?

Answer 23

cryoprecipitate

Question 24

vascular causes of failure of the platelet plug

Answer 24

HSP - vasculitis

Question 25

acquired causes of thrombocytopenia

Answer 25

``` reduced production (marrow problem) Increased destruction (DIC/ITP/ hypersplenism) ```

Question 26

platelet functional defects - acquired

Answer 26

drugs (nsaids) | renal failure

Question 27

vwf deficiency is autdom or aut rec

Answer 27

aut dom

Question 28

commonest cause of primary haemostatic failure

Answer 28

thrombocytopenia

Question 29

multiple factor deficiencys causes

Answer 29

Liver failure Vitamin K Deficiency/Warfarin therapy Complex coagulopathy Disseminated intravascular coagulation

Question 30

PT and APTT prolongued

Answer 30

multiple factor deficiencies

Question 31

what are reduced n liver failure

Answer 31

coag factors

Question 32

Factors ..... are carboxylated by vitamin K which is essential for function

Answer 32

II, VII, IX & X

Question 33

vitamin k absorbed in

Answer 33

upper intestine

Question 34

vitamin k requires ….. for absorption

Answer 34

bile salts

Question 35

causes of vitk deficiency

Answer 35

``` Poor dietary intake Malabsorption Obstructive jaundice Vitamin K antagonists (warfarin) Haemorrhagic disease of the newborn ```

Question 36

what is dic?

Answer 36

Excessive and inappropriate activation of the haemostatic system Primary, secondary and fibrinolysis Microvascular thrombus formation end organ failure Clotting factor consumption Bruising, purpura and generalised bleeding

Question 37

causes of dic

Answer 37

sepsis obstetric emergencies malignancy hypovolaemic shock

Question 38

treat dic

Answer 38

``` Treat the underlying cause Replacement therapy Platelet transfusions Plasma transfusions Fibrinogen replacemen ```

Question 39

what is haemophilia

Answer 39

An X-linked, hereditary disorder in which abnormally prolonged bleeding recurs episodically at one or a few sites on each occasion

Question 40

what are the two types of haemophilia and what are they deficient in?

Answer 40

``` Haemophilia A (factor VIII deficiency) five times as common as ``` Haemophilia B (factor IX deficiency)

Question 41

haemophilia is a defect of …. haemostasis

Answer 41

secondary

Question 42

common cause of arterial thrombosis

Answer 42

atherosclerosis

Question 43

type of clot - arterial

Answer 43

platelet rich

Question 44

treat arterial clot

Answer 44

aspirin or other antiplatelets

Question 45

type of clot in venous thrombosis

Answer 45

fibrin clot

Question 46

virchows traid

Answer 46

stasis vessel wall hypercoag

Question 47

treat vt

Answer 47

heparin/ warfarin/ new oral anti coags

Question 48

what are the 5 main hereditary thrombophilias?

Answer 48

``` Factor V Leiden Prothrombin 20210 mutation Antithrombin deficiency Protein C deficiency Protein S deficienc ```

Question 49

when do you give long term anticoag in thrombophilia patients

Answer 49

recurrent thrombotic events

Question 50

genetics of APS

Answer 50

Antibodies lead to a conformational change in β2 glycoprotein 1 (a protein with unknown function in health) which leads to activation of both primary and secondary haemostasis and vessel wall abnormalities.

Question 51

antibodies in aps

Answer 51

lupus anticoagulants

Question 52

treat aps

Answer 52

it causes activation of both primary and secondary haemostasis so you need both aspirin and warfarin

Question 53

how do you reverse warfarin?

Answer 53

omit warfarin administer oral vitk (takes 6 hours to work) give clotting factors