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Flashcards in Hemostasis: Pathoma Deck (59):
1

What is hemostasis

Repair to damaged blood vessels through formation of a clot/thrombus

2

Hemostasis occurs in what stages?

Primary
Secondary

3

Primary hemostasis forms what?
What mediates this?

Weak platelet plug

Interaction between platelets and vessel wall

4

Secondary hemostasis has what effect?
What mediates?

Platelet plug

Coagulation cascade

5

4 steps of primary hemostasis

1. Transient vasoconstriction of BV
2. Platelet adhesion
3. Platelet degranulation
4. Platelet aggregation

6

What mediates transient vasoconstriction of BV?

Reflex neural stimulation
Endotheli release from endothelial cells

7

How do platelets adhere to surface of damaged BV? 2

1. vWF binds to exposed collagen
2. Platelets bind to vWF using GPIb receptor

8

vWF is derived from what two locations?

1. Weibel-Palade bodies of endothelial cells
2. Alpha granules of platelets

9

In platelet degranulation, what is released? 2

1. ADP from platelet dense granules
2. TXA2 from platelet COX enzyme

10

ADP has what effect?

Promotes exposure of GPIIb/IIIa receptor on platelets

11

TXA2 has what funciton?

Promotes platelet aggregation

12

Platelet aggregation occurs how?

Platelets aggregate at site of injury via GPIIb/IIIa using fibrinogen as a linking molecule

13

Disorders of primary hemostasis are due to what?

Qualitative or quantitative changes to platelets

14

2 sets of clinical features of primary hemostasis

Mucosal bleeding
Skin bleeding

15

Most common skin bleeding symptom in primary hemostasis disorder?

Epistaxis

16

Most feared complication of mucosal bleeding?

Intracranial bleeding

17

4 useful platelet counts in determining disorders?

1. Platelet count
2. Bleeding time
3. Blood smear
4. Bone marrow biopsy

18

Immune thrombocytopenic purpura definition

Autoimmune production of IgG against platelet antigens

19

Who makes the antibodies in ITP?
What eats the antibody-bound platelets?

Spleen
Spleen

20

Acute form of TPP is in what age?

Kids

21

Chronic ITP is in what age?

Adults

22

What happens if pregnant woman gets ITP?

Fetus will get some anti-platelet Ab's that will cross placenta and have effects for awhile.

23

Lab findings in ITP? 3

1. Decrease platelet count
2. normal PT/PTT
3. Increase in megakaryocytes in BM biopsy

24

First Treatment of ITP?

Corticosteroids

25

Secondary treatment of ITP?

1. IVIG to raise platelet count
2. Splenectomy to remove source of Ab's and platelet destruction

26

Microangiopathic hemolytic anemia results in formation of what?

Platelet microthrombi in small vessels

27

MHA has what effect on platelets and RBC's

Consumes platelets

RBC's are sheared resulting in hemolytic anemia with schistocytes

28

Two causes of MHA?

Thrombotic thrombocytopenic purpura

Hemolytic Uremic syndrome

29

TTP is due to what?

Auto Antibodies against the enzyme ADAMS13 which results in large polymers of vWF causing abnormal platelet adhesion and microthrombi

30

TTP common population?

Adult females

31

HUS is due to what?

Main example

Endothelial damage by drugs or infection causing platelet microthrombi to form

E. coli O157:H7 verotoxin

32

Clinical findings of both MHA's?

1. Skiin and mucosal bleeding
2. Hemolytic anemia
3. Fever
4. Renal insufficiency (HUS)
5. CNS problems (tTP)

33

Lab findings in both MHA's? 5

1. Thrombocytopenia
2. Increased bleeding time
3. Normal PT/PTT
4. Anemia with schistocytes
5. Increase in megakaryocytes

34

Treatments of hemostasis? 2

Plasmapheresis and corticosteroids

35

Bernard Soulier syndrome is a genetic deficiency in what?
Result?

GPIb deficiency

Platelet adhesion impaired

36

Glanzmann thrombasthenia is due to what?

What is result

Genetic GPIIb/IIIa deficiency

Platelet aggregation impaired

37

Aspirin's effect on platelets?

Inhibits COX --> lack of TXA2 --> Impaired aggregation

38

Uremia effect on platelets?

Impairs platelet function --> Both adhesion and aggregation impaired

39

Purpose of secondary hemostasis?

Stabilize weak plug via the cogulation cascade

40

End product of coagulation cascade?

Thrombin

41

What does thrombin do?

Converts fibrinogen in the platelet plug to fibrin.

42

Function of fibrin?

Cross-link and yield a stable platelet fibrin thrombus

43

Coagulation factors are produced where?

Liver

44

Activation of coagulation factors requires what? (3)

1. Exposure to an activating substance
2. Phospholipid surface of platelets
3. Calcium

45

Disorders of secondary hemostasis is usually due to what?

Factor abnormalities

46

Clinical features of secondary hemostasis?

Deep tissue bleeding into muscles and joints
Rebleeding after surgical procedures

47

What is goal of both coag pathways?

Make 10

48

Intrinsic factor pathway?

12, 11, 9, 8, 10

49

Extrinsic factor pathway?

Just 7

50

What activates Factor 12 in intrinsic?

Subendothelial collagen

51

What activates Factor 7 in extrinsic?

Tissue thromboplastin

52

PT measures what?

Extrinsic pathway (factor VII)

53

PTT measures what?

Intrinsic pathway (factors XII, XI, IX, VIII)

54

PTT measures what drug?

Heparin

55

PT measures what drug?

Coumadin

56

Hemophilia A is defect in what?
Heredity?
Can you acquire the mutation?

Factor 8 deficiency
X-linked recessive`
Yes

57

Lab findings in hemophilia A?
PTT/PT
Blood serum
Platelet count and bleeding time

High PTT, normal PT
Decrease factor 8 in blood
Normal platelet count and bleeding time

58

Treatment of hemophilia A?

recombinant factor 8

59

Hemophilia B is also known as?
Deficiency of what?
Difference from hemophilia A?

Christmas disease

Factor 9

Factor 9 levels are decreased