Review of Week 2

Question 1

screening test for primary haemostasis?

Answer 1

platelet count

no simple screening test really for other components

Question 2

screening tests for secondary haemostasis?

Answer 2

prothrombin time (PT)
activated partial thromboplastin time (APTT)

Question 3

what does PT test?

Answer 3

CF 7
tissue factor
(intrinsic pathway??)

Question 4

what does APTT test?

Answer 4

CF 8 and 9

extrinsic pathway??

Question 5

acquired causes of thrombocytopaenia?

Answer 5

reduced production (marrow problem)
increased destruction (coagulopathy such as DIC, autoimmune such as ITP, hypersplenism)

Question 6

what is ITP?

Answer 6

immune thrombocytopenic purpura

Question 7

acquired causes of platelet dysfunction?

Answer 7

drugs (aspirin, NSAIDs)

renal failure

Question 8

what can cause failure of formation of fibrin clot?

Answer 8

multiple clotting factor deficiency (eg DIC0

single clotting factor deficiency (e.g haemophilia)

Question 9

which is inherited and which is acquired out of multiple and single clotting factor deficiency?

Answer 9

multiple = acquired
single = inherited

Question 10

what can cause multiple clotting factor deficiency?

Answer 10

liver failure
vit K dependency/warfarin therapy
complex coagulopathy such as DIC

Question 11

how are PT and APTT affected in multiple clotting factor deficiency?

Answer 11

both prolonged

Question 12

describe DIC

Answer 12

excessive and inappropriate activation of all parts of the haemostatic system (often after trauma, sepsis etc)
causes formation of multiple microvascular thrombus resulting in end organ failure
body tried to break down clots but more are continually made
results in clotting factors being used up

Question 13

features of DIC?

Answer 13

bruising
purpura
generalised bleeding

Question 14

causes of DIC?

Answer 14

sepsis
obstetric emergencies
malignancy
hypovolaemic shock

Question 15

signs of shock?

Answer 15

pale, clammy hands (warm and flushed in distributive)
tachycardia
hypotension
hypoxia

Question 16

causes of shock in general?

Answer 16

sepsis
blood loss
obstruction
pump failure
etc

Question 17

treatment pathway in shock?

Answer 17

get help
IV access
fluid replacement
oxygen
treat cause

Question 18

signs of PE?

Answer 18

SOB
pleuritic chest pain
pleuritic rub
hypoxia

Question 19

virchows triad?

Answer 19

relates to venous thrombosis

stasis, vessel wall injury, hypercoagulability

Question 20

risk factors for venous thromboembolism?

Answer 20

age
obesity
pregnancy/puerperium
oestrogen
previous VTE
thrombophilia 
trauma/surgery
malignancy
heart failure
recent MI
immobility
infection
abdo/pelvic mass

Question 21

how is VTE diagnosed?

Answer 21

imaging

• doppler US
• can do venography/VQ/angiography if needed
• history and clinical examination
• D-dimers

Question 22

what are D-dimers?

Answer 22

breakdown products of fibrin clot
produced whenever fibrin is generated therefore produced when coagulation has been activated
presence indicates coagulation

Question 23

efficiency of D-dimer test?

Answer 23

sensitive but not specific
(lots of things can cause elevated D dimers but D dimers are basically always generated in DVT)
i.e elevated D dimers doesn’t confirm DVT but normal D dimers basically rules it out

Question 24

when should D dimer test be done?

Answer 24

use D dimers to exclude need for imaging

if patient is deemed low risk of DVT by scoring system then a D dimer can rule out DVT without need for imaging

Question 25

what gives 1 point in clinical scoring system for DVT (wells score)?

Answer 25

active cancer
paralysis, plaster
bed bound > 3 days or surgery within 4 weeks
tenderness along vein
entire leg swollen
calf swollen >3cm
pitting oedema
collateral veins
low risk = 0
mod = 1-2
high = 3+

Question 26

DVT prophylaxis?

Answer 26

TED stockings
physio
early mobilisation

Question 27

DVT treatment?

Answer 27

heparin

warfarin

Question 28

how does heparin work?

Answer 28

binds to anti-thrombin and potentiates its effect on thrombin
also inactivates CF 10

Question 29

vit K dependant clotting factors?

Answer 29

2, 7, 9 and 10
also proteins C and S
vit K needed for carboxylation in final step needed to function

Question 30

how does Vit K carboxylate clotting factors?

Answer 30

adds second COOH group which stabilises bond between coagulation factor and platelet

Question 31

what is the INR?

Answer 31

international normalised ratio

correction of PT which allows comparison of results between labs and standardises reporting of PT

Question 32

step wise reversal of warfarin action in event of raised IRN or bleeding?

Answer 32

INR raised but no big bleeding = omit dose/reduce future doses
persistently high INR but no massive bleeding = oral vit K (takes 6 hrs to work)
massive bleeding = clotting factors (works immediately)