Hemostasis: Pathoma Flashcards

1
Q

What is hemostasis

A

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

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2
Q

Hemostasis occurs in what stages?

A

Primary

Secondary

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3
Q

Primary hemostasis forms what?

What mediates this?

A

Weak platelet plug

Interaction between platelets and vessel wall

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4
Q

Secondary hemostasis has what effect?

What mediates?

A

Platelet plug

Coagulation cascade

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5
Q

4 steps of primary hemostasis

A
  1. Transient vasoconstriction of BV
  2. Platelet adhesion
  3. Platelet degranulation
  4. Platelet aggregation
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6
Q

What mediates transient vasoconstriction of BV?

A

Reflex neural stimulation

Endotheli release from endothelial cells

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7
Q

How do platelets adhere to surface of damaged BV? 2

A
  1. vWF binds to exposed collagen

2. Platelets bind to vWF using GPIb receptor

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8
Q

vWF is derived from what two locations?

A
  1. Weibel-Palade bodies of endothelial cells

2. Alpha granules of platelets

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9
Q

In platelet degranulation, what is released? 2

A
  1. ADP from platelet dense granules

2. TXA2 from platelet COX enzyme

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10
Q

ADP has what effect?

A

Promotes exposure of GPIIb/IIIa receptor on platelets

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11
Q

TXA2 has what funciton?

A

Promotes platelet aggregation

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12
Q

Platelet aggregation occurs how?

A

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

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13
Q

Disorders of primary hemostasis are due to what?

A

Qualitative or quantitative changes to platelets

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14
Q

2 sets of clinical features of primary hemostasis

A

Mucosal bleeding

Skin bleeding

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15
Q

Most common skin bleeding symptom in primary hemostasis disorder?

A

Epistaxis

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16
Q

Most feared complication of mucosal bleeding?

A

Intracranial bleeding

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17
Q

4 useful platelet counts in determining disorders?

A
  1. Platelet count
  2. Bleeding time
  3. Blood smear
  4. Bone marrow biopsy
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18
Q

Immune thrombocytopenic purpura definition

A

Autoimmune production of IgG against platelet antigens

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19
Q

Who makes the antibodies in ITP?

What eats the antibody-bound platelets?

A

Spleen

Spleen

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20
Q

Acute form of TPP is in what age?

A

Kids

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21
Q

Chronic ITP is in what age?

A

Adults

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22
Q

What happens if pregnant woman gets ITP?

A

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

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23
Q

Lab findings in ITP? 3

A
  1. Decrease platelet count
  2. normal PT/PTT
  3. Increase in megakaryocytes in BM biopsy
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24
Q

First Treatment of ITP?

A

Corticosteroids

25
Q

Secondary treatment of ITP?

A
  1. IVIG to raise platelet count

2. Splenectomy to remove source of Ab’s and platelet destruction

26
Q

Microangiopathic hemolytic anemia results in formation of what?

A

Platelet microthrombi in small vessels

27
Q

MHA has what effect on platelets and RBC’s

A

Consumes platelets

RBC’s are sheared resulting in hemolytic anemia with schistocytes

28
Q

Two causes of MHA?

A

Thrombotic thrombocytopenic purpura

Hemolytic Uremic syndrome

29
Q

TTP is due to what?

A

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

30
Q

TTP common population?

A

Adult females

31
Q

HUS is due to what?

Main example

A

Endothelial damage by drugs or infection causing platelet microthrombi to form

E. coli O157:H7 verotoxin

32
Q

Clinical findings of both MHA’s?

A
  1. Skiin and mucosal bleeding
  2. Hemolytic anemia
  3. Fever
  4. Renal insufficiency (HUS)
  5. CNS problems (tTP)
33
Q

Lab findings in both MHA’s? 5

A
  1. Thrombocytopenia
  2. Increased bleeding time
  3. Normal PT/PTT
  4. Anemia with schistocytes
  5. Increase in megakaryocytes
34
Q

Treatments of hemostasis? 2

A

Plasmapheresis and corticosteroids

35
Q

Bernard Soulier syndrome is a genetic deficiency in what?

Result?

A

GPIb deficiency

Platelet adhesion impaired

36
Q

Glanzmann thrombasthenia is due to what?

What is result

A

Genetic GPIIb/IIIa deficiency

Platelet aggregation impaired

37
Q

Aspirin’s effect on platelets?

A

Inhibits COX –> lack of TXA2 –> Impaired aggregation

38
Q

Uremia effect on platelets?

A

Impairs platelet function –> Both adhesion and aggregation impaired

39
Q

Purpose of secondary hemostasis?

A

Stabilize weak plug via the cogulation cascade

40
Q

End product of coagulation cascade?

A

Thrombin

41
Q

What does thrombin do?

A

Converts fibrinogen in the platelet plug to fibrin.

42
Q

Function of fibrin?

A

Cross-link and yield a stable platelet fibrin thrombus

43
Q

Coagulation factors are produced where?

A

Liver

44
Q

Activation of coagulation factors requires what? (3)

A
  1. Exposure to an activating substance
  2. Phospholipid surface of platelets
  3. Calcium
45
Q

Disorders of secondary hemostasis is usually due to what?

A

Factor abnormalities

46
Q

Clinical features of secondary hemostasis?

A

Deep tissue bleeding into muscles and joints

Rebleeding after surgical procedures

47
Q

What is goal of both coag pathways?

A

Make 10

48
Q

Intrinsic factor pathway?

A

12, 11, 9, 8, 10

49
Q

Extrinsic factor pathway?

A

Just 7

50
Q

What activates Factor 12 in intrinsic?

A

Subendothelial collagen

51
Q

What activates Factor 7 in extrinsic?

A

Tissue thromboplastin

52
Q

PT measures what?

A

Extrinsic pathway (factor VII)

53
Q

PTT measures what?

A

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

54
Q

PTT measures what drug?

A

Heparin

55
Q

PT measures what drug?

A

Coumadin

56
Q

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

A

Factor 8 deficiency
X-linked recessive`
Yes

57
Q

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

A

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

58
Q

Treatment of hemophilia A?

A

recombinant factor 8

59
Q

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

A

Christmas disease

Factor 9

Factor 9 levels are decreased