6 - Clotting disorders

Question 1

What is the extrinsic pathway?

Answer 1

Exposer to tissue factor

F VII –> VIIa

=> activation of the common pathway

Question 2

What is the intrinsic pathway?

Answer 2

Platelets activate FXII

cascade activates XI, IX IXa and VIIIa

activates common pathway

Question 3

How does warfarin work?

Answer 3

Inhibits Vit. K reductase

inhibits protein C and S - inhibits clotting factors and enhances fibrinolysis decreases PT

Question 4

What is the common pathway?

Answer 4

FX become acite and with co FV helps activate FII (to thrombin), which in turn activates fibrin.

Question 5

How does Heparin?

Answer 5

inhibits FII and increase antithrombin activation.

Question 6

What effects PT?

Answer 6

Warfarin

Factor II

Factor V

Factor VI

Factor X

Measures the extrinsic and common pathway

Question 7

What effects APTT?

Answer 7

Heparin

Factor VIII

Factor IX

Factor XI

Factor XII (but no bleeding diathesis)

von Willebrand’s Disease

Measures the intrinxic and common pathway

Question 8

If APTT and PT are prolonged consider:

Answer 8

Vit K deficiency

disseminated intravascular coagulation

rarely vWF deficiency

Question 9

What are the VIt. K dependent factors?

Answer 9

Factor II

Factor VII

Factor IX

Factor X

Protein C

Protein S

Question 10

What is the 50/50 mixture test?

Answer 10

APTT and PT done compared to with 50% normal bloodcontent

same times = factor deficiency

still prolonged times = factor inhibition

Question 11

What is heamophillia A?

Answer 11

X linked disorder

deficiency of F VIII

Question 12

What is haemophilia B?

Answer 12

X linked disorder

deficiency of FIX

Question 13

What is Von Willibrand’s disease?

Answer 13

vWF deficiency which would have stabilised VIII and clotting

Question 14

Reasons for Vit. K deficiency?

Answer 14

1) inadequate stores - malnutrition and haemorrhage disease
2) Vit. K malabsorption - Jaundice (fat soluble)
3) Oral anticoagulants

Question 15

What is the treatment for haemophilia A?

Answer 15

IV FVIII concentrate

DDAVP

Tanexamic acid

Question 16

What is the treatment for haemophilia B?

Answer 16

IV FIX concentrate

Question 17

Which blood thinner can cause thrombocytopenia?

Answer 17

heparin

Question 18

Treatment for VTE?

Answer 18

Anti-embolism stockings

LMWH and UFH

DOACs

Do not use Wafrin

Question 19

What is Homan’s sign?

Answer 19

Tenderness with dorsiflexion of the ankle.

Indicates of DVT

Question 20

Calf has a circumference >3cm compared to other.

What does this indicate?

Answer 20

DVT

Question 21

What is Virchows triad?

Answer 21

1) Damaged endothelium
2) Blood stasis
3) Hypercoagulopathy

Question 22

What does Tranexamic acid do?

Answer 22

Anti-fibrinolytic

Question 23

What can Dessmopressin treat?

Answer 23

Haemophilia A and vW disease

Question 24

How is LWMH different?

Answer 24

Longer half life greater bio availability Greater activity against Xa than IIa

Question 25

What to ask in a history of bleeding?

Answer 25

bruising epistaxis greater than 30 mins GI tract bleeding menses heamaturia bleeding at dentist, surgery family history

Question 26

How to investigate a clotting disorder?

Answer 26

Thrombocytonpenia? 50/50 mixture test? consider vWF deficeincy?

Question 28

Management of PE

Answer 28

Start treatment unless investigations within 1 hour Initially start LMWH before investigations Later add warfarin or replace with DOAC Investigaiton include: CTPA or V/Q scan

Question 29

Diagnosis of PE

Answer 29

Wells score \> 4 Wells score \>4 and + D-dimer Can confirm with CTPA

Question 30

Symptoms of PE

Answer 30

Syncope Tachycardia Hypotension Heamoptysis Dyspnoea pleuritic chest pain

Question 31

What can mangement for recurrent PE/ DVT and not able to anti-coagulate sufficeintly?

Answer 31

IVC filter

Question 32

Risk factors for PE

Answer 32

Stasis recent surgery pregnancy oral contraceptive previous VTE FH malignancy or chemotherapy

Question 33

Diagnosis of DVT

Answer 33

Wells score \>/= 2 and positive USS Wells score = 1 and posotive D dimer

Question 34

Management of DVT

Answer 34

Start LMWH if unless \<4 hours until investigaiton Add warfarin or replace with DOAC

Question 35

What is an advantage of LMWH?

Answer 35

Quick onset Easily stopped with protamine

Question 36

How is anticoagulation via warfarin reversed?

Answer 36

PCC - prothrombine complex concentrate Contains F II, V, VII, IX and X takes 30 mins Used instead of FFP - fresh frosen plasma Vit. K takes 4-6 hours to work

Question 37

PT is prolonged and the patient is not on warfarin. What is the most likley cause?

Answer 37

FVII deficiency