Ch4 - 1) Primary Hemostasis and Bleeding Related Disorders Flashcards Preview

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Flashcards in Ch4 - 1) Primary Hemostasis and Bleeding Related Disorders Deck (67)
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31

Platelet count

normal 150-400 K/pL; < 50 K/pL leads to symptoms,

32

Bleeding time

normal 2-7 minutes; prolonged with quantitative and qualitative platelet disorders

33

Blood smear

used to assess number and size of platelets

34

Bone marrow biopsy

used to assess megakaryocytes, which produce platelets

35

What is immune thrombocytopenic purpura?

(ITP) is an autoimmune production of IgG against platelet antigens (GPIIb/IIIa)

36

What is the most common cause of thrombocytopenia in children and adults?

immune thrombocytopenic purpura

37

In ITP what results in thrombocytopenia?

Antibody-bound platelets are consumed by splenic macrophages

38

ITP is divided into?

acute and chronic forms

39

Acute form of ITP?

arises in children weeks after a viral infection or immunization;selflimited, usually resolving within weeks of presentation

40

Chronic form of ITP?

arises in adults, usually women of chilbearing age. May be primary or secondary (e.g SLE).

41

What is the risk involved in chronic ITP?

May cause short-lived thrombocytopenia in offspring since antiplatelet IgG can cross the placenta.

42

laboratory findings for ITP include

decreased platelet count, often < 50 K/pL, Normal PT/FTT, Coagulation factors are not affected. increased megakaryocytes on bone marrow biopsy

43

What is the Initial treatment for ITP?

corticosteroids.

44

How will children and adults respond to the initial treatment for ITP?

Children respond well; adults may show early response, but often relapse.

45

In addition to corticosteroids what else is used in the treatment of ITP?

IVIG is used to raise the platelet count in symptomatic bleeding, but its effect is short-lived,

46

What is a permenant solution for patients with ITP?

Splenectomy eliminates the primary source of antibody and the site of platelet destruction (performed in refractory cases).

47

What is microangiopathic hemolytic anemia?

Pathologic formation of plateletmicrothrombin small vessels

48

How are plateletmicrothrombin formed and what is the result?

Platelets are consumed in the formation of microthrombi sheering the RBCs as they cross microthrombi, resulting in hemolytic anemiawith schistocytes

49

What is microangiopathic hemolytic anemia seen in?

thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS)

50

What is TTP due to?

decreased ADAMTS13 which is an enzyme that normally cleaves vWF multimers into smaller monomers for eventual degradation.

51

How does TTP lead to microangiopathic hemolytic anemia?

1. Large, uncleaved multimers lead to abnormal platelet adhesion, resulting in microthrombi.

52

Decreased ADAMTS13 is usually due what?

an acquired autoantibody;

53

TTP is most commonly seen in?

adult females

54

HUS is due to?

Hemolytic uremic syndrome is due to endothelial damage by drugs or infection.

55

HUS is classically seen in?

children with E coli G157;H7 dysentery, which results from exposure to undercooked beef

56

How is E Coli related to microangiopathic hemolytic anemia?

E coli verotoxin damages endothelial cells resulting in platelet microthrombi

57

The clinical findings for HUS and TTP include

Skin and mucosal bleeding, Microangiopathic hemolytic anemia, Fever, Renal insufficiency, CNS abnormalities

58

Renal insufficiency is more common in HUS or TTP?

HUS ? thrombi involve vessels of the kidney

59

CNS abnormalities are more common in HUS or TTP?

TTP ? Thrombi involve vessels of the CNS

60

Laboratory findings for microangiopathic hemolytic anemia include?

Thrombocytopenia with increased bleeding time Normal PT/PTT (coagulation cascade is not activated), anemia with schistocytes, increased megakaryocytes on bone marrow biopsy