Haemostasis and Thrombosis Flashcards

1
Q

Main 3 components of coagulation?

A

Coagulation - making the clot
Anticoagulants - limiting the size of the clot
Fibrinolysis - remodel the clot and resolve the clot

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2
Q

What can contribute to clotting?

A

Endothelial surface (when activated)
Platelets
Von Willebrand factors
Coagulation Factors

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3
Q

What can aid bleeding?

A

Natural anticoagulants (help control the clot)

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4
Q

What is the function of fibrinolysis?

A

Remodel or remove clot

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5
Q

If there is a problem with clotting how will this manifest?

A

Patient has bleeding tendency

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6
Q

If there is a problem with natural anticoagulants/bleeding how will this manifest?

A

Patient has clotting tendency

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7
Q

First response to injury?

A

Vasoconstriction

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8
Q

During vasoconstriction how do platelets react?

A

Release serotonin and thromboxane A2 which activates them - forms platelet plug

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9
Q

Why do we feel pain during vasoconstriction?

A

Sympathetic interpretation to help vasoconstriction

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10
Q

What is the next step of clotting after vasoconstriction

A

Formation of platelet plug

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11
Q

How is a platelet plug formed?

A

When collagen is exposed platelets release serotonin and thromboxane A2 which activates them - they change shape and become adhesive

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12
Q

When does the first response to injury occur in terms of clotting?

A

When collagen is exposed (damaged endothelium)

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13
Q

How can platelets bind directly to the endothelium?

A

Von Willebrand factor

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14
Q

What does the platelet plug bind to?

A

Exposed collagen

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15
Q

What are the 3 parts of the coagulation cascade?

A

Intrinsic Extrinsic and common

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16
Q

What is the first clotting factor of the common pathway?

A

10

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17
Q

What activates the extrinsic pathway?

A

Tissue factor

18
Q

What is the end result of the common pathway?

A

Clotting factors activate thrombin which activates fibrin

19
Q

What 4 things do we need to healthy coagulation?

A

Platelets - number and function
Von willebrand factor
coagulation factor
Clot stability

20
Q

What type of condition is Haemophilia? How does it cause problems?

A

X-linked condition - genetic = deficiency of clotting factor 8 and 9

21
Q

How is haemophilia classified?

A

Severity based on normal concentration of coagulation factor %

22
Q

How does a patient with very severe haemophilia (concentration of coagulation factor less than 1%) react?

A

Spontaneous bleeding

23
Q

How does a patient with moderately severe haemophilia react?

A

Severe bleeding after surgery

24
Q

Risk of haemophilia in young?

A

Not yet diagnosed so spontaneous bleeding in joints leads to arthritis

25
Q

How is haemophilia now treated?

A

Recombinant gene therapy treatment - gene cloned

26
Q

How is haemophilia C transmitted?

A

Blood transfusion

27
Q

Hemlibra is a new gene therapy for haemophilia treatment. How does it work?

A

It is an antibody that binds factor 9 and 10 and leads to activation and formation of fibrin

28
Q

Why is hemlibra (new gene therapy treatment) better than previous treatments?

A

Doesn’t get injected into the vein only under the skin once every 2 weeks = less often so better quality of life

29
Q

How does von Willebrand disease present?

A

Mucosal bleeding - bruising, nosebleeds, heavy periods, GI bleeding

30
Q

Function of Von Willebrands factor?

A

Helps bind Platelets to endothelium and each other

31
Q

How can Von Willebrand disease be classified?

A

Type I = mild deficiency in VWD
Type II - normal number but mutation effecting the function of VWD
Type III - severe deficiency

32
Q

How can problems with platelets be classfied?

A

Low number or functional defects

33
Q

What drugs is given to treat functional defects of platelets?

A

Aspirin

34
Q

In general how should a patient with bleeding disorders be managed during surgery (5)

A

Close liaison with haemophilia centre
Platelets transfusion or DDAVP (increase VWF)
Atraumatic technique to secure local haemostasis
Oral tranexamic acid = antifibrinolytic = stabilise clot

35
Q

Warfarin mechanism of action?

A

inhibit thrombin (vit K reductase inhibitor)

36
Q

How is warfarin dealt with in surgery?

A

Don’t alter - check INR

37
Q

Why is it advisable to not stop warfarin treatment (especially when INR is normal)?

A

Can increase risk of thrombosis

38
Q

Name 2 type of DOAC?

A

Direct thrombin inhibitors

Xa inhibitors

39
Q

Dabigatran is a direct thrombin inhibitor, describe its mechanism of action?

A

Reversible thrombin inhibitor

40
Q

Mechanism of action fo Xa inhibitors?

A

Bind to activated factor 10