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Flashcards in Haemostasis Deck (29)
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1

Define Haemostasis and state 2 functions

What are the 3 steps in Haemostasis

The stopping of bleeding

Prevents bleeding
Prevents unnecessary coagulation

Make clot
Control clotting
Breakdown of clot (Fibrinolysis)

2

What 5 things are essential for Haemostasis

Keep blood moving
Blood vessels
Platelets
Coagulation factors
Anticoagulant factors

3

Compare primary and secondary Haemostasis

Primary: Platelets aggregate to form a plug at the vessel hole

Secondary: Plug strengthened with fibrin filaments

4

Describe Platelet Adhesion

- Damage to vessel wall
- Exposure of underlying tissues
- Platelets adhere to collagen via vWF receptor

5

Describe platelet activation

- Platelets secrete ADP and other substances to become activated and activate other platelets
- Involved in activation of clotting cascade
- Secrete coagulation factors from internal stores

6

Describe Platelet Aggregation

Cross linking of platelets to form a platelet plug

7

Identify 7 mediating factors that stimulate clotting

Platelet receptors- Glycoprotein complexes
Von willebrands factor
Fibrinogen
Collagen surfaces
ADP
Thrombin
Thromboxane

8

Outline the clotting cascade mechanism to make fibrin

1. Intrinsic and extrinsic pathways activate Factor X
2. Factor Xa activates Prothrombin II-> Thrombin IIa
3. Thrombin IIa activates Fibrinogen 1-> Fibrin Ia

9

What are 2 ways that coagulation is controlled

- Natural anticoagulants inhibit activation of clotting cascade
- Clot destroying proteins, which are activated by the clotting cascade

10

Name 4 Natural Anticoagulants

Protein C
Protein S
Antithrombin
Tissue factor pathway inhibitor

11

What are Prothrombin Time (PT) and Activated Partial Thromboplastin Time (APTT)

PT: A diagnostic test used to evaluate the extrinsic and common pathway

APTT: A diagnostic test used to evaluate the intrinsic and common pathways

12

A problem with which factors cause Prolonged PT
Which pathways are each factor in

7- Extrinsic

5,10,Prothrombin, Fibrinogen- Common

13

A problem with which factors cause Prolonged APPT
Which pathways are each factor in

8,9,11,12- Intrinsic pathway

5,10, Prothrombin, Fibrinogen- Common Pathway

14

What are D dimers

Fibrin degradation products

15

What does Von Willebrand Factor do

Involved in;
- Platelet aggregation
- Platelet adhesion
- Carries factor 8

16

What are 3 functions of the vessel wall

- Vasoconstriction
- Production of Von Willebrand’s Factor
- Exposure of collagen and tissue factor, initiating activation of clotting factors

17

Outline fibrinolysis

Plasminogen activator activates PLASMIN from PLASMINOGEN

Plasmin breaks down FIBRIN to D-Dimers

18

What are 3 causes of bleeding disorders and what are the 2 types

Inherited and acquired

Abnormalities in;
- Vessel wall
- Platelets
- Coagulation factors

19

What are 2 types of Coagulative Disorders

Congenital and acquired

20

Identify 3 congenital coagulation factor disorders

Identify 3 acquired coagulation factor disorders

Haemophilia A ( Deficiency in factor 8)
Haemophilia B (Deficiency in factor 9)
Von Willebrand’s disease

Liver disease
Vit K deficiency (Causes more bleeding)
Anticoagulants

21

Identify 4 signs of Coagulation factor disorders

- Intercerebral haemorrhage
- Severe post op, post traumatic bleeding
- Joint pain and deformity
- Prolonged bleeding after dental extraction

22

What is the inheritance pattern for Haemophilia
How does it present
How is it treated

X-linked recessive

Bleeding into muscles and joints, and post-operatively

Treated with recombinant factor 8 or DDAVP (releases factor 8 from vessels)

23

What is the inheritance pattern for Von Willebrand’s Disease

Identify 2 signs

What is the main genetic defect

Autosomal dominant

- Abnormal platelet adhesion to vessel wall
- Reduced Factor 8 amount/ activity

Main: Reduced vWF production

24

What are 3 clinical signs of von Willebrand’s Disease

Skin and mucous membrane bleeding

Prolonged bleeding after trauma

Spontaneous joint/ muscle bleeds (Rare)

25

Name 2 vessel wall abnormalities
Where do these occur

Easy bruising
Spontaneous bleeding from small vessels

Mainly skin but can be from mucous membranes

26

How does Disseminated Intravascular Coagulopathy affect;

PT
APTT
Fibrinogen count
D dimer count

What must happen for DIC to occur

Raised PT
Raised APTT
Low fibrinogen
Raised D dimers

Must be a trigger

27

Identify 5 triggers for DIC

Malignancy
Massive tissue Injury
Infections
Massive haemorrhage and transfusion
ABO transfusion reaction

28

What are Thrombophilias

How common are these? Do patients with these develop clots

Acquired/ congenital defects of haemostasis

Rare conditions, not unless patients have additional risk factors

29

What are the Congenital and Acquired causes of Thrombophilias

Congenital causes include deficiency in Natural Anticoagulants and an Abnormal Factor 5

Acquired causes include Antiphospholipid syndrome