[3] Hemostasis and Bleeding Disorders

Question 1

What is the goal of Primary Hemostasis?

Answer 1

Formation of a platelet plug

Question 2

What is the goal of Secondary Hemostasis?

Answer 2

Stabilization of the platelet plug

Question 3

What is the first reaction of a vessel to injury?

Answer 3

Vasoconstriction

Question 4

What mediates the initial vasoconstriction of the damaged vessel?

Answer 4

Release of endothelin from damaged vessels

Question 5

Platelets bind to VWF using?

Answer 5

GP1b Receptor

Question 6

Where does Von Willebrand Factor come from?

Answer 6

Platelets

Weibel-Palade Bodies of Endothelial Cells (Vast majority)

Question 7

Function of ADP

Answer 7

Promotes exposure of GpIIb/IIIa receptor on platelets

Question 8

Function of GPIIb/IIIa

Answer 8

Allows platelet aggregation

Question 9

Platelet degranulation releases these two mediators that are important for platelet aggregation

Answer 9

ADP

TXA2

Question 10

Function of TXA2

Answer 10

Platelet aggregation

Question 11

What is the linking molecule of GpIIb/IIIa for platelet aggregation?

Answer 11

Fibrinogen

Question 12

Disorders of primary hemostasis are usually due to?

Answer 12

Platelet Abnormalities

Question 13

Define: Purpura

Answer 13

~3mm size of skin bleeding

Question 14

Define: Ecchymoses

Answer 14

> 1cm size of skin bleeding

Question 15

Having a platelet count less than this amount is associated with appearance of symptoms

Answer 15

<50,000/uL

Question 16

This disease is an autoimmune production of IgG against platelet antigens

Answer 16

Idiopathic Thrombocytic Purpura

Question 17

This disease is the most common cause of Thrombocytopenia in Children and Adults

Answer 17

Idiopathic Thrombocytic Purpura

Question 18

[Pathophysiology]

Acute Idiopathic Thrombocytic Purpura

Answer 18

Autoantibodies (IgG) made in the spleen bind platelets, which are then consumed by macrophages in the spleen

Question 19

[Treatment]

Acute Idiopathic Thrombocytic Purpura

Answer 19

Supportive

The disease is self-limiting and should resolve within weeks

Question 20

What could you give a patient to raise platelet count with symptomatic bleeding in ITP?

Answer 20

IVIG

Short-lived effect as the spleen targets the exogenous Igs, leaving the platelet bound Igs free

Question 21

What is the final treatment resort in cases of refractory ITP?

Answer 21

Splenectomy

Question 22

[Pathophysiology]

Microangiopathic Hemolytic Anemia

Answer 22

Pathologic formation of platelet microthrombi in small vessels

Question 23

Under microscopy, what is the characteristic RBC morphology when a patient has microangiopathic hemolytic anemia?

Answer 23

Schistocytes

Question 24

Thrombotic Thrombocytopenic Purpura is caused by a decrease of what enzyme?

Answer 24

ADAMTS13

Cleaves vWF multimers into smaller monomers for degradation

Question 25

Most common cause of TTP

Answer 25

Acquired autoantibody to ADAMTS13 | Classically seen in adult females

Question 26

Cause of Hemolytic Uremic Syndrome

Answer 26

Endothelial damage from drugs or infections

Question 27

HUS is classically seen in which patients?

Answer 27

Children with E. coli O157:H7 Dysentery

Question 28

What does E. coli release to damage endothelial cells in HUS?

Answer 28

E. coli verotoxin

Question 29

Is the PT/PTT value elevated, unchanged, or decreased in patients with TTP/HUS?

Answer 29

Normal

Question 30

These cells undergo hyperplasia in bone marrow in patients with TTP/HUS

Answer 30

Megakaryocytes | To produce more platelets

Question 31

[Treatment] TTP/HUS

Answer 31

Plasmapheresis and Corticosteroids

Question 32

This disease is characterized by a Genetic GP1b deficiency What is impaired?

Answer 32

Bernard-Soulier Syndrome Platelet adhesion is impaired

Question 33

This disease is characterized by a Genetic GIIb/IIIa deficiency What is impaired?

Answer 33

Glanzmann Thrombasthenia Platelet aggregation is impaired

Question 34

This drug irreversibly inactivates cyclooxygenase

Answer 34

Acetylsalicylic Acid

Question 35

End product of the coagulation cascade

Answer 35

Thrombin

Question 36

Activation of Factors of the Coagulation Cascade require?

Answer 36

1. Exposure to activation factors 2. Phospholipid surface of proteins 3. Calcium

Question 37

What does PT measure?

Answer 37

Extrinsic and Common Pathways

Question 38

What does PTT measure?

Answer 38

Intrinsic and Common Pathways

Question 39

What activates Factor XII?

Answer 39

Subendothelial Collagen

Question 40

What activates Factor VII?

Answer 40

Tissue Thromboplastin

Question 41

This disease is characterized by a Genetic Factor VIII deficiency

Answer 41

Hemophilia A

Question 42

This disease is characterized by a Genetic Factor IX deficiency

Answer 42

Hemophilia B

Question 43

What is the PT/PTT findings in a patient with Hemophilia A What is the platelet count and bleeding time?

Answer 43

Elevated PTT Normal PT Normal Platelet Normal Bleeding Time

Question 44

[Treatment] Hemophilia A

Answer 44

Recombinant Factor VIII

Question 45

Hemophilia B is also called?

Answer 45

Christmas Disease

Question 46

The most common coagulation factor inhibitor

Answer 46

Anti-FVIII

Question 47

How can you differentiate an Anti-FVIII from Hemophilia A?

Answer 47

Perform a mixing study PTT does not correct with patient's with Anti-FVIII Patient's with Hemophilia A will have PTT Correction

Question 48

This disease is the most common inherited coagulation disorder

Answer 48

Von Willebrand's Disease

Question 49

Why do patients with Von Willebrands Disease present with increased PTT?

Answer 49

vWF stabilizes Factor VIII

Question 50

[Treatment] Von Willebrands Disease

Answer 50

Desmopressin Increases vWF release from Weibel-Palade bodies of endothelial cells

Question 51

Vitamin K is activated by?

Answer 51

Epoxide Reductase

Question 52

How do you test the effect of liver failure on coagulation?

Answer 52

PT

Question 53

[Mechanism of Action] Heparin

Answer 53

Forms a Heparin-PF4 complex with platelets, allowing antibodies to be made against it leading to subsequent destruction

Question 54

What is a feared complication of Heparin-induced Thrombocytopenia?

Answer 54

Thrombosis Results from activation of fragments of destroyed platelets

Question 55

[Pathophysiology] Disseminated Intravascular Coagulopathy

Answer 55

Pathologic activation of the coagulation cascade causing consumption of platelets and factors as well as widespread microthrombi formation resulting in ischemia and infarction

Question 56

Common Causes of DIC

Answer 56

1. Obstetric Complications 2. Sepsis 3. Adenocarcinoma 4. Acute Promyelocytic Leukemia 5. Rattlesnake Bite

Question 57

[Laboratory Findings] Effect of DIC on: 1. Platelet Count 2. PT 3. PTT 4. Fibrinogen 5. Name the elevated fibrin split product

Answer 57

1. Decreased Platelet 2. Elevated PT 3. Elevated PTT 4. Decreased Fibrinogen 5. D-Dimer

Question 58

Best screening test for DIC

Answer 58

D-Dimer Test

Question 59

[Treatment] Disseminated Intravascular Coagulopathy

Answer 59

Transfuse blood products and cryoprecipitate as needed

Question 60

What is responsible for cleavage of Fibrin

Answer 60

Plasmin

Question 61

What enzyme is responsible for conversion of plasminogen to plasmin

Answer 61

tPA

Question 62

[Function] Plasmin

Answer 62

1. Cleaves serum fibrinogen 2. Inhibits coagulation factors 3. Inhibits platelet aggregation

Question 63

Define: Thrombosis

Answer 63

Pathologic formation of an intravascular blood clot

Question 64

Most common location of thrombosis

Answer 64

Deep Vein of the leg below the knee

Question 65

Histologic presentation that can differentiate post from pre-mortem clots

Answer 65

Lines of Zahn

Question 66

Three Major Risk Factors for Thrombosis

Answer 66

1. Disruption in blood flow 2. Endothelial cell damage 3. Hypercoagulable state