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Flashcards in Coagulation Deck (38):
1

Which interaction leads to adhesion? Which leads to aggregation?

Adhesion between GPIba:vWF
Aggregation between GPIIb/IIIa:Fibrinogen

2

What are some molecules that bind receptors on passing platelets for recruitment/activation?

5-HT and ADP

3

What are the vitamin K dependent cofactors?

II, VII, IX and X
Protein C & Protein S

4

What screening tests should be done for mucosal bleeding (nosebleeds, menorrhagia)?

Platelet defect and vWF

5

What screening tests should be done for deep bleeding (joints, muscles, intracranial)?

Factor deficiency tests

6

Thrombocytopenia due to decreased production

Vit B12 deficiency, marrow failure or disease

7

Thrombocytopenia non-immune mediated

blood film often abnormal (DIC)

8

Thrombocytopenia immune mediated--Fab mediated

Blood film usually normal (ITP)

9

Thrombocytopenia immune mediated--Non-fab mediated

Heparin induced thrombocytopenia (Fc mediated)
Immune complex disease (HIV)
TTP (autoantibody to ADAMTS13-->deficiency)

10

Transient autoimmune disease about 10 days after heparin therapy

Heparin-induced Thrombocytopenia
Auto-antibodies to PF4:Heparin

11

Congenital absence of GPIb

Bernard Soulier Syndrome
Failure of adhesion

12

Congenital absence of GPIIb/IIIa

Glanzman's Thrombasthenia
Failure of platelets to aggregate

13

Autoimmune production of IgG against platelet antigens (eg GPIIb/IIIa) --> consumed by splenic macrophages

Immune Thrombocytopenic Purpura

14

What are some differences between the acute and chronic form of ITP?

Acute: usually in children, weeks after viral infection/immunization; self-limiting
Chronic: usually adults (women of child-bearing age), less likely to recover --> txt: corticosteroids, IVIG, Rituximab, last resort splenectomy

15

Platelets consumed in formation of microthrombi --> RBCs are sheared as they cross microthrombi (hemolytic anemia with schistocytes)

Microangiopathic hemolytic anemia

TTP
HUS

16

What is the PFA-100 lab test?

Screens for platelet and vWF function
Membrane is coated with collagen, blood is drawn through membrane, vWF sticks to collagen, platelets stick to vWF and eventually clog the hole --> measure the time to occlusion

17

What causes TTP?

An acquired auto-antibody or congenital mutation to ADAMTS13 that results in large uncleaved multimers that lead to abnormal platelet adhesion --> develop microthrombi

18

What form of E. coli will put you at risk for HUS?

O157:H7

19

What is added to a prothrombin time?

Tissue factor, phospholipid and calcium to citrated plasma

20

What is added in a PTT?

Surface activator, phospholipid and calcium to citrated plasma

21

What does it mean if the clotting time corrects with a 1:1 mix test?

A factor deficiency is likely
If it does not correct than it is likely an inhibitor

22

How is hemophilia inherited?

X linked recessive

23

What are some things that may cause vitamin K deficiency?

Drugs (warfarin, antibiotics that decrease bowel flora)
Malabsorption or dietary deficiency
Liver disease
Newborns

24

What will the labs look like in someone who has vWF deficiency?

Increased bleeding time
Increased PTT
Normal PT

25

What is the pathophysiology behind vWF deficiency?

vWF normally stabilizes factor VIII -- deficiency ruins this and decreased the half life of factor VIII

26

What is a treatment for vWF deficiency?

Desmopressin (Increases vWF release from Weibel Palade bodies)

27

Treatment for heparin induced thrombocytopenia

Stop heparin
Start direct thrombin inhibitor

28

Which factors does antithrombin inactivate?

IIa and Xa

29

Which factors does Protein C inactivate?

Va and VIIIa

30

Widespread microthrombi result in ischemia and infarction --> consumption of platelets and factors results in bleeding (IV and mucosal sites)

DIC

31

Mutated form of factor V that lacks the cleavage site for deactivation by protein C

Factor V Leiden -- VENOUS thrombotic risk factor
Arg 506 replaced with Gln

32

what increases the risk of warfarin skin necrosis?

Protein C deficiency

33

Antibodies against phospholipids that damage cells leading to the formation of clots in arteries and veins

Antiphospholipid Antibody Syndrome

34

What are some antiphospholipid antibodies to test for?

Anti-cardiolipin
Lupus anticoagulant

35

Some syndromes associated with DIC?

Malignancy
Amniotic fluid
Fat embolism
Acute hemolytic process
Heparin assoc thrombocytopenia
Sepsis

36

what might Purpura Fulminans be a presenting symptom for?

Meningococcal sepsis
Severe protein C deficiency in a newborn

37

What is hemophilia C?

Deficiency in factor XI affecting men and women equally

38

What is the clinical pentad of TTP?

Thrombocytopenia
Microangiopathic hemolytic anemia (schistocytes/RBC fragments)
Renal insufficiency
Neurological symptoms
Fever