Haemostasis and Thrombosis Flashcards Preview

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Flashcards in Haemostasis and Thrombosis Deck (50):
1

is blood clotted in plasma

no (it is clotted in serum)

2

what is haemostasis

process by which blood loss is prevented

3

what is required for primary haemostasis

vWF, platelets

4

what is required for secondary haemostasis

fibrin

5

what should you administer if low VWF

cryoprecipitate- high in VWF

6

what blood product to give if platelets low

platelets

7

what blood product to give if missing clotting factors

FFP

8

what type of sample for haemostasis test

plasma sample

9

what does the APTT measure

intrinsic pathway (activated partial thromboplastin time)

10

what does the PT measure

extrinsic pathway (prothrombin time)

11

what if the APTT is abnormal and PT normal

problem in the intrinsic pathway

12

what if the PT is abnormal and the APTT is normal

problem in the extrinsic pathway

13

what if APTT and PT are abnormal

problem in the common pathway

14

what factors are involved in intrinsic pathway

XII, XI, IX, X

15

what factors involved in extrinsic pathway

VII, X

16

what is the fibrinogen assay for (clauss assay)

fibrinogen- fibrin (IIa- thrombin). see how long it takes fibrin to form

17

why do you need to test LFTs

as this is where coag factors are produced

18

what is the normal INR

2-3

19

what is INR based on

PT: PT patient/PT normal

20

what factors are affected by warfarin

2,7,9,10

21

how does warfarin work

blocks vitamin K cycle, which is needed for carboxylation of factors 2,7,9,10

22

what is the intrinsic pathway responsible for

fibrin production

23

which pathway is the initiation phase

extrinsic pathway- makes just enough thrombin to trigger- initiation, but not enough to make the fibrin

24

normal lifespan platelet

7-10 days

25

when is there reduced lifespan platelets

incr consumption- infection, thrombosis, splenic enlargement

26

normal conc platelets

140-400 x 10^9/l

27

what stimulates platelet production

TPO- thrombopoietin

28

what are coagulation inhibitory factors for

inhibit coag cascade and ensure action of thrombin is limited to site of injury

29

what are the coagulation inhibitory factors

antithrombin, proteins C and S , tissue factor pathway inhibitor

30

inherited disorders of vessel wall

hereditary haemorrhagic telangiectasia, Ehlers Danl;os, Marfan

31

acquired disorders vessel wall

vit C def (scurvy), steroids, normal ageing, amyloid, immune complex deposition

32

what is Henoch schlonein purpura

allergic vasculitis, after an infection- arthropathy, haematuria, GI

33

what is thrombocytopenia

decr platelets- below 140

34

congenital causes thrombocytopenia

fanconi (aplastic anaemia), rare selective congenital defects of platelet production

35

acquired causes thrombocytopenia

increased destruction- autoimmune, DIC, TTP, drugs, hypersplenism. failure production- bone marrow failure (leukaemia, myeloma, AA, HIV), infiltration (lymphoma, carcinoma)

36

treatment autoimmune thrombocytopenia

prednisolone, IV Ig, immunosuppressive therapy, splenectomy

37

what happens in TTP

thrombosis in small vessels, red cell fragmentation, haemolytic anaemia, thrombocytopenia

38

what happens to PT and APTT in TTP

normal

39

what is there a deficiency of in TTP

ADAMTS13- normally cleaves VWF

40

what is haemolytic uraemic syndrome

occurs in childhood. thrombosis in small vessels. follows infection- E coli..

41

treatment TTP

plasma exchange- FFP. antiplatelets, corticosteroids

42

target INR pulmonary embolism and DVT

2-3, 3.5 if recurrent

43

target INR AF

2-3

44

target INR prosthetic metallic heart valves for stroke prevention

3-4

45

anticoag in DVT/PE

at least 6 weeks for below knee DVT, at least 3 months for above the knee DVT or PE. at least 6 months if no cause found

46

what to do if INR is 4.5-6

reduce warfarin dose or omit.restart when INR

47

what to do if INR is 6-8

stop warfarin. restart when INR

48

what to do if INR is >8

if no bleeding stop warfarin. 0.5-2.5mg vitamin K if risk factors for bleeding

49

what to do with warfarin if any major bleed

stop warfarin. give prothrombin complex concentrate. FFP. vitamin K

50

problem with vitamin K

may take some hours to work and can cause prolonged resistance when restarting warfarirn so avoid if possible if need long term coag