Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pathology > Haemostasis/Clotting cascade > Flashcards

Haemostasis/Clotting cascade Flashcards

1
Q

Conditions where wound healing impaired that may be mistaken for a clotting disorder?

A

Ehlers Danlos
Scurvy
Cushings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is haemostasis?

A

The stopping of blood and forming of a clot following an injury so it can be repaired

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the rough order of events from injury to the clotting cascade (4)

A

Injury
Vasoconstriction
Platelet plug (vWF, platelets, tissue factor, clotting cascade activated)
Coagulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What cells produce platelets?

A

Megakaryocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is normal platelet count?

A

150-400 x 10^9/L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the normal lifespan of platelets? Why would you stop a patients aspirin for this time before surgery?

A

7-10 days

As it inhibits platelets and therefore may inhibit healing post surgery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the three A’s of platelets in forming a plug? What happens at each of them?

A

Adhesion - adhere to collagen in endothelial wall via vWF receptor
Activation - secrete ADP, thromboxane etc to bring other platelets
Aggregation - adhesion of platelets together to form a platelet plug

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is a natural anticoagulant? What happens if you are deficient in one? Give 3 examples of these in the body

A 
Stop further coagulation
Can get VTEs e.g. DVT if deficient in these
e.g. 
Protein C
Protein S
Anti-thrombin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where are clotting factors made? Where are anticoagulation factors made?

A

Both liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What do proteinC proteinS and antithrombin do?

A

They inhibit parts of the coagulation cascade pathway to prevent further coagulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What happens at the beginning of extrinsic vs intrinsic cascade?

A

Intrinsic - collagen exposed by injury - initiates cascade vWF binds to collagen

Extrinsic - tissue factor exposed —> initiates cascade

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the role of vWF (3)?

A

Stabilises factor VIII is vital
Platelet adhesion
Platelet aggregation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is Vit K needed for?

A

Needed for synthesis of lots of coagulation factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is Ca needed for?

A

Clotting factor - needed for many things e.g. conversion of factor VII to X factor IX to X and X to prothrombin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which clotting blood test measures intrinsic which measures extrinsic? Which one could indicate a vit K deficiency if prolonged?

A

PT - extrinsic - this one

APTT - intrinsic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What would you expect the result to be for PT/APTT in liver disease? Why?

A

Prolonged as clotting factors made in liver and if liver damaged sufficient clotting factors may not be made

17
Q

How does the thrombin burst occur?

A

Tissue factor exposed leads to a small amount of thrombin being formed, that then feeds back and produces a thrombin burst

18
Q

What is the role of thrombin in fibrin?

A

Thrombin cleaves fibrinogen to fibrin

19
Q

What is fibrinolysis?

A

Break down of clot

20
Q

What breaks down the clot?

A

Plasmin

21
Q

How is plasmin activated and what’s its precursor?

A

By plasminogen activator, precursor plasminogen

22
Q

What is the end product?

A

D-Dimers - fibrin degradation products

23
Q

What three things can cause a bleeding disorder?

A

Abnormality in vessel wall
Platelets
Coagulation factors

24
Q

What are some complications of clotting factor disorders?

A 
Haemorrhage
Bruising - e.g. muscle
Joint pain and deformity 
Prolonged bleeding post dental extraction
Post op bleeds
25
Q

What happens with a disorder of vessel wall abnormality? Give an example of congenital vs acquired

A

Easy bruising
Spontaneous bleeding from small vessels - eg. red small spots over tongue/lips/arms

Congenital: HHT (Hereditary haemorrhage telangiectasia)
Ehlers Danlos

Acquired: Senile purpura, steroids, infections, vit C deficiency

26
Q

What are some reasons for low platelets (4)?

A

Immune destruction: Immune thrombocytopenia purpura
Non Immune destruction: Microangiopathic haemolytic state e.g. DIC, cardiopulmonary bypass machine
Reduced production - folate vit b12 deficiency, cancer prolif in marrow, drugs - chemo, viruses - hepatitis, HIV< EBV, CMV
Pooling: Splenic pooling in splenomegaly

27
Q

Generally below what level of platelets will patients be symptomatic?

A

30

28
Q

What is DIC? What does it lead to?

A

Disseminated intravascular coagulation

Many causes - always a cause

Leads to microangiopathic haemolytic anaemia

Pathological activation of coagulation cascade - uses up all clotting factors platelets etc

29
Q

What lab results would you see for DIC?

A

Raised PT, APTT, D dimer, INR

Lowered fibrinogen, platelets

30
Q

An increased APTT with normal PT could indicate a deficiency in which factors?

A

All intrinsic and common
e.g. 12, 11, 9, 10, 8
vWF

31
Q

An increased PT with normal APTT could indicate a deficiency in which factors?

A

All extrinsic and common

e.g. 7, 3, 5, 10

32
Q

If you see low Hb and low MCV what is the most common cause?

A

Normally indicates a microcytic anaemia, most common is iron deficient anaemia

33
Q

Where are the common sites of bleeding in haemophilia compared to low platelets?

A

Haemophilia - intramuscular and joints

Platelets - mucosal (nose/mouth), skin (purpura)

34
Q

Can vit B12/folate deficiency cause a platelet deficiency?

A

Yes

35
Q

If someone has low platelets with normal bone marrow and absence of other causes what are they diagnosed with?

A

Immune thrombocytopenic pupura

36
Q

What are some causes of prolonged PT that aren’t directly due to coagulation factor deficiencies?

A

Vit K deficiency - malnourished
Use of antibiotics - can affecting clotting time
Liver disease
Paracetamol overdose can affect vit K

37
Q

How do you treat DIC?

A

Not specific
Treat cause
Can give platelets

38
Q

Would a deficiency in protein C cause bleeding or clotting?

A

Predisposes to clotting - DVT

As it normally is a natural anticoagulant

Pathology (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions