Coagulation Flashcards

1
Q

What happens when MTHFR decreases?

A

Homocystine increases

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2
Q

Steps of hemostasis

A

Primary hemostasis
Secondary hemostasis
Fibrinolysis

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3
Q

Steps in primary hemostasis

A

Vasoconstriction
Platelet adhesion
Platelet aggregation - to form primary hemostatic plug at injury site

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4
Q

Steps of secondary hemostasis

A
  • Interaction of coag factors to produce fibrin (secondary hemostatic plug)
  • Fibrin stabilization by FXIII
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5
Q

Steps in fibrinolysis

A
  • Release tissue plasminogen activator
  • Plasminogen —> plasmin
  • Fibrin —> fibrin degradation products
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6
Q

What are the quantitative plt disorders?

A

Thrombocytopenia
Primary thrombocytosis
Secondary or reactive thrombocytosis

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7
Q

Thrombocytopenia

A

Decrease production, increase destruction

<30x10^9/L: petechiae, menorrhagia, spontaneous bruising

<10x10^9/L: severe spontaneous bleeding

Lab tests: Plt <150 x 10^9/L

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8
Q

Primary thrombocytosis

A

Unregulated production of megakaryocytes in BM (like ET)

Thrombosis (blood clots) or hemorrhage (damaged blood vessel)

Lab tests: >1000 x 10^9/L

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9
Q

Secondary or reactive thrombocytosis

A

Increased plt due to another condition (like hemorrhage, surgery, splenectomy)

No thrombosis or hemorrhage

Lab tests: 450-1000 x 10^9/L

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10
Q

Qualitative Platelet Disorders

A

Inherited: Bernard-Soulier syndrome, Glanzmann’s thrombasthenia, delta-storage pool disorder
Acquired

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11
Q

Bernard-Soulier syndrome

A

Lack of GP Ib/IX/V on plt surface —> no plt interaction w/ VWF —> abnormal adhesion to collagen

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12
Q

Glanzmann’s thrombasthenia

A

Deficiency or abnormality of plt membrane GP IIb/IIIa —> fibrinogen can’t attach to plt surface —> cannot do plt aggregation

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13
Q

delta-storage pool disorder

A

Dense granule deficiency —> no ADP released —> abnormal secondary aggregation with ADP & epinephrin

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14
Q

Acquired plt disorder

A

Functional plt disorder (occurs with renal failure, aspirin, etc) —> abnormal plt aggregation

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15
Q

Tests for platelet function

A

Platelet aggregation
Platelet function assay (PFA)
VWF:Ag

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16
Q

Platelet aggregation (plt function test)

A

Aggregating agent (ADP, collagen, ristocetin, epinephrine) added to plt suspension

Time it takes for plts to aggregate = increase in light transmittance

Curve = time vs % transmittance

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17
Q

Platelet function assay (PFA) - plt function test

A

Citrated WB in a capillary tube coated with ADP/collagen or epinephrine/collagen

Plts adhere and aggregate when exposed to collagen

Closure time = time it takes for plts to form a plt plug and close aperture of capillary tube

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18
Q

VWF:Ag

A

Immunologic test (ex: EIA) using monoclonal Abs to VWF

VWF needed for plts to connect to collagen (plts don’t function properly if decreased VWF — like in VWD)

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19
Q

Factor I

A

Fibrinogen

Fibrinogen —thrombin—> fibrin

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20
Q

Factor II

A

Prothrombin

Prothrombin —> thrombin

21
Q

Factor III

A

Tissue factor (in extrinsic pathway)

22
Q

Factor IV

A

Ca2+

With 8a and 5a

23
Q

Factor V

A

Labile factor (proaccelerin)

24
Q

Factor VII

A

Stable factor (proconvertin)

25
Q

Factor VIII

A

Antihemophilic factor

Deficiency = Hemophilia A

FVIII + VWF

26
Q

Factor IV

A

Christmas factor

Deficiency: Hemophilia B

27
Q

Factor X

A

Stuart factor

28
Q

Factor XI

A

Plasma thromboplastin antecedent

Deficiency: Hemophilia C (rare) - may or may not cause bleeding

29
Q

Factor XII

A

Hageman factor (contact factor)

Deficiency: no bleeding

30
Q

Factor XIII

A

Fibrin stabilizing factor (stabilizes fibrin clot)

31
Q

HMWK (high molecular weight kininogen) + PK (prekallikrein)

A

Fitzgerald factor & Fletcher factor, respectively

Used with (F12 and F11) to activate the intrinsic pathway

32
Q

What is a substrate? And what is the factor?

A

Substance changed by an enzyme

Factor: fibrinogen (F1)

33
Q

What is a cofactor? And factors associated?

A

Protein that accelerates enzymatic reactions

Factors: 5 (cofactor for 10a) and 8 (cofactor for 9a)

34
Q

What is an enzyme? And factors associated?

A

Protein that catalyzes a change in specific substrate

Serine proteases: 2a (thrombin), 7a, 9a, 10a, 11a, 12a, prekallikrein (PK) — (1972 + 11 + 12)

Transglutaminase: XIIIa

35
Q

Contact group

A

Factors involved in initiation of intrinsic pathway

HMWK, PK, F12, F11

36
Q

Prothrombin group

A

Vitamin K dependent factors

1972 (10, 9, 7, 2)

37
Q

Fibrinogen group

A

Factors acted on by thrombin

1, 13, 5,

Consumed in clotting (not in serum)

Increased in acute phase (pregnancy and inflammation)

38
Q

Extrinsic pathway factors

A

TF (F3) & F7

39
Q

Intrinsic pathway factors

A

F12, 11, 9, 8, HWMK, PK

40
Q

Common pathway factors

A

1, 2, 5, 10

41
Q

Extrinsic tenase complex

A

VIIa/TF

Acts on X

42
Q

Intrinsic tenase complex

A

9a/8a

Acts on X

43
Q

Prothrombinase complex

A

10a/5a

Acts on prothrombin

44
Q

Factor VIII complex

A

FVIII:C & VWF

VIII:C = procoagulant
VWF = carrier protein

45
Q

All factors are produced in what organ?

A

Liver

46
Q

What factors are affected by coumadin/warfarin?

A

Factors that need Vitamin K (1972)

47
Q

What factors are consumed during clotting?

A

1, 13, 5, 8, 2 (basically all of the fibrinogen group ones + 2)

48
Q

Labile factors

A

5, 8

49
Q

INR (international normalized ratio)

A

[patient PT/mean normal PT]^ISI