Lecture 3 - Acquired Blood disorders Flashcards Preview

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Flashcards in Lecture 3 - Acquired Blood disorders Deck (27):
1

What is prothrombin time?

Measures external coagulation pathway.

When you get a break in vessel wall - tissue factor released .

Binds to factor 7

2

What does prothrombin time measure?

Factors 2, 5, 7, 10

Fibringoen

3

What causes prolonged prothrombin time?

o Deficiency/ inhibition of one of the factors
o Liver disease
o Warfarin
o Vit K deficiency (caused by haemorrhage in newborn/ obstructive jaundice)
o DIC
o Blood transfusion causes dilution of clotting factors
o Over-heparinisation (too much heparin in sysem)/ some lupus anticoagulants

4

What does activated partial thromboplastin time measure?

Factors 2, 5, 9, 10, 12, 13, HMWK

5

What causes prolonged APTT?

o Deficiency of one of the factors
o Liver disease
o Warfarin
o Vitamin K
o DIC
o Transfusion
o Heparin (unfractionated)
o Lupus anticoagulant
o Haemophilla

6

What causes prolonged PT and APTT?

o Deficiency of 2, 5, 10, fibrinogen
o DIC
o Vitamin K deficiency
o Liver failure
o Warfarin

If it's just Prothrombin time raised --> early signs of disease.

7

What does thrombin time measure?

Fibrinogen

8

What causes prolonged thrombin time?

Hypofibrinogenaemia

Hepatocellular disease

DIC

Heparin

9

What to look for in a clinical examination of a possible bleeding disorder?

Bruising pattern

Haemorrhagic signs
Signs of underlying disease (joints/ muscles/ skin)

Measure fibrinogen + D-Dimer

10

Give examples of anticoagulants?

Heparin

Warfarin

DOAC

Fondaparinux

11

How does heparin work?

Wraps around thrombin + factor 10a - switches off clotting cascade

LMWH - mostly inhibits factor 10 a

12

What's the difference between LMWH and UH

LMWH has a higher bioavailability + longer half life, so you don't need to routinely monitor.

More reliable

13

What are the side effects of heparin?

Thrombocytopenia

Bleeding

Allergic reactions

14

How to reverse heparin overdose?

Protamine

15

How does warfarin work?

Inhibit vitamin K uptake.

Affects factors 10, 9, 7, 2

16

What is INR?

Prothrombin ratio - Allows you to control anticoagulant dose.

17

How to treat warfarin overdose?

Give prothrombin complex concentrate

18

What are DOACs?

How do they work?

Inhibits factor 10a: Rivaroxaban, Apixaban, Edoxaban

Inhibits thrombin - Factor 1a, Dabigatran

19

How does fondaparinux work?

Indirectly inhibits 10a

20

What are the symptoms of bleeding in renal disease patients?

Easy bruising,

Gum bleeding

nosebleeds,

excessive bleeding from venepuncture

Pericardial tamponade

GI bleeds

Uncontrolled high BP + on dialysis incr risk of ICH

21

How to prevent bleeding in renal disease patients?

EPO/ transfusion

Avoid antiplatelets

Dialysis

Tranexamic acid

Cryoprecipitate

22

What is DIC?

Disseminated intravascular coagulation - small clots block small vessels.

Causes ischaemia --> organ damage --> bleeding

23

What causes acute DIC?

Sepsis

Obstetric complications

Tissue necrosis/ trauma

Liver disease

Organ destruction

Massive blood loss

24

What causes chronic DIC?

Cancer/ eng stage liver disease

25

How to diagnose DIC?

Order platelet count, PT, fibrinogen, D-Dimer.

Score each test. If >=5 DIC

26

What are the clinical features of IDC

Oozing mucosa

Bleeding for surgical wounds

Skin necrosis

Multiple organi failure

27

How to treat DIC?

Treat underlying cause + antibiotics