Coagulation Flashcards

1
Q

What are the 3 constituents of the hemostatic system?

A

Coagulation proteins, endothelium, platelets

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2
Q

What is the purpose of the coagulation system

A

Thrombin formation leading to a fibrin clot

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3
Q

What is the purpose of the fibrinolytic system?

A

To lyse the clot

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4
Q

What is the purpose of the anticoagulant system?

A

Regulate all the enzymes so neither the coagulation or fibrinolytic system occurs in excess

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5
Q

What is the first stage of coagulation?

A

Vasoconstriction

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6
Q

In the first stage of coagulation, what causes vasoconstriction?

A

Reflexes and endothelin release from the site of injury

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7
Q

What is the second stage of coagulation?

A

Primary hemostasis where platelets aggregate

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8
Q

In the second stage of coagulation, how do platelets attach to collagen?

A

Via von willebrand factor

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9
Q

What substances are released from platelet granules and what does this cause?

A

ADP and TXA2 leading to further recruitment of platelets and the formation of a hemostatic plug

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10
Q

What is the 3rd stage of coagulation?

A

Secondary hemostasis or fibrin formation

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11
Q

What is released in the third stage of coagulation and what affect does it have?

A

Tissue factor, leads to thrombin activation. A plug is formed and WBC and RBCs are trapped

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12
Q

The 4th stage of coagulation is?

A

Crosslinking of fibrin and fibrinolysis

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13
Q

What two substances are released in the tertiary stage and what do they do?

A

t-PA for fibrinolysis

Thrombomodulin which blocks the coagulation cascade

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14
Q

Which factors are vitamin K dependent?

A

2,7,9,10, S, C

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15
Q

What testing good specimens what is used as an anticoagulant?

A

Sodium citrate

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16
Q

Prothrombin time measures what pathway?

A

Extrinsic to common

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17
Q

What 3 things can cause PT increase?

A
  1. VII deficiency or deficiency in other factors or inhibitors to them
  2. Vitamin K deficiency from liver disease, warfarin, or antibiotics
  3. Liver disease
  4. Deficiencies in common factor 1,2,5,10
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18
Q

aPTT measures what pathway?

A

Intrinsic to common

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19
Q

What is the heparin effect?

A

Increased aPTT time due to use of this injectable anticoagulant

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20
Q

What can cause factor deficiency or inhibitor?

A

Hemophilias A, B, and C and amyloid disorder

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21
Q

The thrombin time test is for?

A

Fibrin generation test, fibrinogen or factor 1

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22
Q

D-dimer is an indication of?

A

Fibrin has been formed and degraded

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23
Q

D-dimer and FDP are elevated in what conditions, what type of cancer?

A
  1. DIC
  2. Thrombosis
  3. End stage liver disease
  4. Mucin-secreting adenocarcinomas
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24
Q

In a mixing study, if clotting times are prolonged this means?

A

An inhibitor is present

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25
Q

In a mixing study, if clotting times decrease this means?

A

There is a factor deficiency

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26
Q

When do factors in neonates reach adult levels? Which factor is typically present at a similar level?

A

6 months

Factor VIII

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27
Q

How is hemorrhagic telangiectasia inherited? What does it cause?

A

Autosomal dominant, leads to abnormal blood vessel formation in the skin and organs. Leads to nosebleed and bleeding of the GI tract and other organs

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28
Q

How do you treat hemorrhagic telangiectasia?

A

Avoid bleeding as much as possible and supplement iron

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29
Q

What is Elhers-Danlos syndrome?

A

A group of inherited CT disorders caused by defects in collagen I and III synthesis

30
Q

Patients with Elhers-Danlos have what symptoms?

A

Thin skin that is pale and you can see their veins, bruise very easily

31
Q

What are the four acquired coagulation protein defects?

A
  1. Factor X deficiency
  2. Vitamin K deficiency
  3. DIC
  4. Liver disease
32
Q

What factor is deficient in the 3 hemophilias?

A

A is factor 8
B is 9
C is 11

33
Q

What is the severity of most hemophiliacs?

A

Severe

34
Q

What can cause bleeding in those with mild hemophilia?

A

Surgery or major trauma

35
Q

Female carriers of hemophilia often have factor VIII activity in what range?

A

Greater than 50% so normal

36
Q

Lab tests on carriers will show?

A

Normal PTT but increased vWF to factor VIII ratio, 2:1 as opposed to 1:1

37
Q

What can cause the presence of factor VIII inhibitors in non-hemophiliacs?

A

Idiopathic conditions, SLE or rheumatoid arthritis, lymphomas and solid tumors, drug reactions, pregnancy and postpartum state

38
Q

How is hemophilia C inherited?

A

Autosomal recessive

39
Q

Hemophilia C causes bleeding of what severity?

A

Mild

40
Q

Disseminated intravascular coagulation is caused by?

A

Numerous microvascular clots due to a substance that behaves similar to tissue factor.

41
Q

Disseminated intravascular coagulation leads to?

A

Bleeding diathesis

42
Q

What are causes of disseminated intravascular coagulation?

A

Snake venom, infections, obstetric complications, mucin-secreting adenocarcinomas

43
Q

What 4 things are decreased in DIC?

A

Platelet count, factor assay, fibrinogen, and antithrombin

44
Q

Thrombophilia is characterized by?

A

Hypercoagulability and an increased propensity for thrombosis

45
Q

What is the most common cause of acquired thrombophilia?

A

Antiphospholipid syndrome

46
Q

What are the two common clinical features of inherited thrombophilia?

A

Deep vein thrombosis of lower limbs, pulmonary embolism

47
Q

What two rare clinical features are characteristic of inherited thrombophilia?

A

Mesenteric vein thrombosis and cerebral vein thrombosis

48
Q

Protein C deficiency is inherited by?

A

Autosomal dominant

49
Q

The initial thromboembolic episode occurs normally or spontaneously?

A

Usually spontaneously

50
Q

Protein C deficiency usually affects what veins?

A

Deep veins of the leg, ileofemoral veins, and mesenteric veins

51
Q

Describe the 2 types of protein C deficiency?

A

Type 1 there is decreased protein C

Type 2 there is decreased functionality of protein C

52
Q

How does homozygous protein C deficiency present itself in newborns?

A

Purpura fulminans

53
Q

What is protein S?

A

An essential cofactor of protein C

54
Q

How does protein S circulate?

A

Freely or complex to c4b binding protein

55
Q

What is the most common hereditary thrombophilia?

A

APC resistance or activated protein C

56
Q

How is APC resistance inherited?

A

Autosomal dominant

57
Q

APC resistance is associated with a mutation in what gene>

A

Factor V gene, substitute arginine for glutamine

58
Q

What is the reference range for INR?

A

0.9-1.3

59
Q

What level INR indicates a high chance of bleeding? High chance of clot? What is the target range for anticoagulant use?

A

5, 0.5, 2-3

60
Q

Increased thrombin time if associated with what congenital disorders?

A

Afibrinogemia and hypofibrinogemia

61
Q

Results of factor activity tests for normal adults fall between?

A

60-150%

62
Q

In those with factor VIII inhibitor a mixing study will show?

A

Immediate correction of pTT that prolongs after 1 hour

63
Q

Hemophilia C is a deficiency in? What is the result?

A

Factor XI, results in mild bleeding

64
Q

What causes inherited afibrinogenemia and hypo?

A

Autosomal recessive mutations that truncate the protein

65
Q

What is associated with afribogenemia?

A

Prolonged pt and ptt and bleeding disorder similar to moderate to severe hemophilia A

66
Q

What is the first manifestation of inherited hypo or afibrinogenemia?

A

Umbilical cord hemorrhage then life long bleeding diasthesis

67
Q

Factor 13 deficiency will result in? Blood test will show?

A

Mild delayed bleeding, normal Pt, ptt, and tt

68
Q

Amyloidosis will result in decreased?

A

Factor X

69
Q

Vitamin K deficiency results in decreased?

A

Factors 2,7,9,10

70
Q

Pregnancy results in decreased and increased?

A

Decreased protein S, increased vWF