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HemOnc Week 2 > LM 6.4: Disorders of Hemostasis > Flashcards

LM 6.4: Disorders of Hemostasis Flashcards

1
Q

what are the types of defects of the coagulation pathway?

A
  1. reduced synthesis of coagulation factors
  2. synthesis of abnormal coagulation factors
  3. excessive consumption of coagulation factors by acceleration of the coagulation cascade
  4. destruction of coagulation factors by antibodies (inhibitors)
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2
Q

what are the types of disorders that effect the coagulation pathway?

A
  1. inherited/congenital
    usually only a single coagulation factor deficiency
  2. acquired
    usually associated with medications or secondary to other medical conditions - often has multiple factor deficiencies
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3
Q

do disorders effecting the coagulation cascade usually have single or multi site bleeding?

A

multi site bleeding that is deeper bleeding into joints and muscles

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4
Q

what is the age of onset for inherited vs. acquired disorders of the coagulation pathway

A

inherited usually present at a younger age than acquired

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5
Q

what are some things you would notice in a physical exam of a patient with a coagulation pathway disorder?

A

hematomas

hemarthrosis

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6
Q

what is hemarthrosis?

A

bleeding into the joints

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7
Q

which lab tests are used to evaluate the coagulation cascade?

A

aPTT

PT

INR

TCT

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8
Q

what is aPTT?

A

used to evaluate the intrinsic and final common pathway of coagulation

normal: 25-35 seconds

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9
Q

what is PT?

A

prothrombin time

used to evaluate the extrinsic and the final common pathway of coagulation

normal: 12.3-14.8 seconds

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10
Q

what is INR?

A

used to monitor warfarin

based on the PT test

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11
Q

what is TCT?

A

thrombin clotting time

measures the time for the conversion of fibrinogen to fibrin so it’s an indirect measure of the fibrinogen level

normal: 15-20 seconds

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12
Q

what are finrinogen/fibrin split products test?

A

measures the effect of plasmin on both fibrinogen and fibrin

so its a measure of fibrinolysis

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13
Q

what is the D-dimer test?

A

measures the effect of plasmin on cross-linked fibrin

so it’s a measure of clot formation and fibrinolysis

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14
Q

what is hemophilia A?

A

x-linked inheritance

the reduction of factor VIII clotting activity but NOT the absence of the factor VIII protein

severity of the disease is based on the factor VIII clotting activity level:

severe: <1% activity
moderate: 1-5% activity
mild: 5-20% activity

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15
Q

what are the lab results you would get in a hemophilia A patient?

A
  • prolonged aPTT
  • normal PT
  • normal platelet function
  • factor VIII clotting activity reduced
  • factor VIII antigen is normal
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16
Q

how do you treat hemophilia A?

A
  • factor VIII concentrates
  • desmopressin (DDAVP)
  • EACA mouth wash = epsilon amino caproic acid
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17
Q

what does desmopressin do?

A

used to treat hemophilia A

releases von willebrand factor from storage sites causing vWF levels to rise and thus factor VIII levels to rise because vWF circulates bound to factor VIII and protects it from destruction

18
Q

what is EACA?

A

a mouthwash used to treat hemophilia A

slows destruction of clots in the mouth after tooth extraction b blocking the fibrinolytic pathway

19
Q

what is the inheritance of von willebrand disease?

A

autosomal dominant

20
Q

what is von willebrand disease?

A

bleeding is mucocutaneous due to reduced VW factor activity failing to assist in platelet function

21
Q

what lab test results would you see in a patient with von willebrand disease?

A

aPTT is prolonged

PT and platelet count is normal

22
Q

whats the treatment for vonwillebrand disease?

A
  1. DDAVP
  2. von willebrand/factor VIII concentrates
  3. vonvendi-recombinant von willebrand factor
  4. cryoprecipitate (not commonly used)
  5. estrogen therapy in females
23
Q

what does estrogen do?

A

increases von willebrand factor

more likely to clot

this is why pregnant people and people on birth control are at an increased risk for clots

24
Q

which disorders are rare inherited coagulation disorders?

A
  1. congenital hypofibrinogenemia
  2. factor VII deficiency
  3. factor V deficiency
25
Q

what happens in vitamin K deficiency?

A

leads to the production of inactive vitamin K dependent coagulation factors: factors II, VII, IX, X, protein C&S

leads to prolonged aPTT and PT

26
Q

what is the most common cause of vitamin K deficiency?

A

warfarin/coumadin

both blood thinners/anticoagulants

27
Q

are acquired or inherited coagulation disorders more common?

A

acquired disorders are more common than inherited

usually involve multiple factor deficiencies

28
Q

what is the half life of factor VII?

A

4-10 hours

29
Q

what is the half life of protein C?

A

4-10 hours

30
Q

what is the half life of factor IX?

A

1 day

31
Q

what is the half life of factor X?

A

1-2 days

32
Q

what is the half life of factor S?

A

2-3 days

33
Q

what is the half life of factor II?

A

2-3 days

34
Q

where is von willebrand factor produced and stored?

A

vascular endothelial cells

all other coagulation factors are produced in the liver!

35
Q

what lab values would you expect in someone with liver disease?

A

except for vWF, all other coagulation factors are produced in the liver

so liver diseases is associated with reduction in the levels of many coagulation factors

this would cause:

  • elevated PT, aPTT, TCT
  • reduced levels of fibrinogen
  • low platelet count
  • poor bone marrow function
  • splenomegaly
  • increased bleeding risk
  • increased clotting risk because of reduced levels of antithrombin III and proteins C&S
36
Q

what are acquired inhibitors of coagulation factors?

A

antibodies directed at coagulation factors

can be caused by malignancy, pregnancy, and other autoimmune disorders

most are spontaneous or idiopathic

factor VIII inhibitors are the most common

37
Q

what is DIC?

A

disseminated intravascular coagulation

an acquired thrombohemorrhagic disorder due to excess thrombin and plasmin generation in the circulation

ALWAYS associated with an underlying disorder like sepsis that triggers that coagulation pathway and leads to thrombin generation

initially, there is lots of microvascular thrombosis but it’s followed by tons of bleeding as the coagulation factors and platelets get rapidly consumed

38
Q

what are the lab results that you get in a patient with DIC?

A

increased aPTT, PT and TCT

low platelet and fibrinogen levels

elevated FDP/FSP and D-Dimer

may be fragmented RBCs = microangiopathic hemolytic anemia

39
Q

what causes hyperfibrinolysis?

A

excessive activation of plasminogen to plasmin or reduced inhibition of the pathway

the most common cause of increased activation is thrombolytic therapy using TPA to lyse clots like in patients with strokes

the most common cause of reduced inhibition is liver disease and DIC

TPA = tissue plasminogen activator

40
Q

what would the lab results be for a patient with hyperfibrinolysis?

A

normal platelet count

normal D-dimer

increased FDP/FSP

reduced fibrinogen

**D-dimer is normal because there’s no antecedent thrombosis in hyperfibrinolytis as there is in DIC

HemOnc Week 2 (14 decks)

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