257 - Acquired Coagulopathies Flashcards

1
Q

Which coagulation/anticoagulation proteins are Vitamin K dependent?

A
  • Pro-coagulant
    • II
    • VII
    • IX
    • X
  • Anti-coagulant
    • Protein C
    • Protein S
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2
Q

What two molecules are required for the action of coagulation factors?

A

Phospholipids

Calcium

Anti-phospholipid antibodies! Can interfere with clotting times, but more associated with clotting than bleeding

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3
Q

What is the treatment for DIC?

A

Treat the underlying cause

(ex: sepsis)

Only give blood products if necessary

  • Give:
    • platelets if <20k or <50k with active bleeding
    • FFP if bleeding and elevated PT/PTT
    • Fibrinogen if <100 (or <200 in obstetric cases)
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4
Q

What is a key difference in the lab values of DIC and TTP?

A

DIC will have prolonged PT and PTT

TTP (and HUS) will have normal PT and PTT

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5
Q

How is a Bethesda assay performed?

A

Serial dilutions of pt plasma incubated with normal plasma

VIII activity measured at each dilution

1 Bethesda Unit (BU) = amount of antibody that inhibits 50% of FVIII in a normal sample

Low titier inhibitor is ≤ 5 BU

Bethesda Assay = used to test how much FVIII antibody (inhibitor) is present in the sample

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6
Q

What is the treatment for vitamin K deficiency?

A
  • If no bleeding
    • Oral vitamin K
    • Give subcutaneous only if malabsorption or NPO
  • If bleeding
    • IV vitamin K
    • Plasmaproducts (FFP or prothrombin complex concentrates)
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7
Q

What kind of inhibitors are present in congenital vs. acquired hemophilia?

A

Congenital hemophilia has alloantibodies

Acquired hemophilia has autoantibodies

Not exactly sure why this is - lmk if you have any ideas!

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8
Q

List 2 key differences between antiphospholipid antibody syndrome and F VIII inhibitor (acquired hemophilia A)

(bleed or clot? and what level of FVIII?)

A
  • Anti-phospholipid antibody
    • Thrombosis
    • Normal FVIII
  • F VIII inhibitor
    • Bleeding
    • Low FVIII
  • Neither will correct on mixing study;*
  • APA will correct when phospholipid is added*
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9
Q

What are the criteria for diagnosing anti-phospholipid syndrome?

A
  • 1 clinical outcome
    • Thrombosis
    • Adverse pregnancy outcome
  • 1 laboratory criteria (phospholipid antibody) on 2 or more occasions, 12 weeks apart
    • Lupus anticoagulant
    • Anticardiolipin
    • Beta-2 glycoprotein
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10
Q

List 4 ways that liver disease can predispose somebody to bleeding

A
  • Decreased platelets/platelet function (decreased TPO?)
  • Decreased synthesis of coagulation factors
  • Decreased fibrinogen (produced in the liver)
  • Decreased vitamin K absorption
    • Due to decreased bile acid production
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11
Q

How will these labs change in DIC?

  • PT/PTT
  • D-Dimer
  • Fibrinogen
  • Platelets
A
  • PT/PTT - High
  • D-Dimer - High
  • Fibrinogen - Low
  • Platelets - Low

Will also see MAHA; elevated LDH + schistocytes on blood smear

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12
Q

List 3 clinical manifestations of anti-phospholipid syndrome

A

Venous thrombosis

Arterial thrombowiss

Adverse pregnancy outcomes

May also see thrombocytopenia, hemolytic anemia, livedo reticularis, cognitive deficits, cardiac valvular disease…

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13
Q

Describe the pathophysiology of DIC

A
  • Trigger (often sepsis)
    • Widespread clotting factor activation
    • Consumes platelets and clotting factors
  • Deficiency in clotting factors –> bleeding state

Result is bleeding AND microthrombi that cause organ damage

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14
Q

Which newborns are at risk of vitamin K deficiency?

A

All of them!

Usually given vitamin K shot

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15
Q

List the causes of DIC (8)

A

SSTOP Making New Thrombi

  • Sepsis
  • Snake bite
  • Trauma
  • Obstetric complication
  • Pancreatitis (acute)
  • Malignancy
  • Nephrotic syndrome
  • Transfusion
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16
Q

What clot-based assays will be abnormal in a patient with an acquired FVIII inhibitor?

A

aPTT is prolonged

Mixing study:

  • aPTT shortens and then proglongs
    => presence of VIII inhibitor
17
Q

What is the difference in presentation of acute vs. chronic DIC?

A
  • Acute
    • Clotting factors depleted rapidly
    • More bleeding -> shock
    • MAHA
  • Chronic
    • Liver and bone marrow can compensate
    • More clotting
    • More often seen in malignancy
18
Q

What is the treatment for acquired FVIII inhibitors?

A
  • Prevent bleeding
    • Low titer: vasopressin + FVIII concentrate
    • High titer: Prothrombin complex concentrate + recombinant FVIIa
  • Get rid of the antibody
    • Immunosuppressant
    • Rituximab
19
Q

Are hemarthroses more common in congenital or acquired hemophilia?

A

Congenital

Hemarthroses = blood within a joint

20
Q

How can liver disease can predispose someone to clotting?

A

Decreased anticoagulants

  • Protein C
  • Protein S
  • Antithrombin
21
Q

Describe the pathophysiology of how anti-phospholipid syndrome leads to clotting

A
  • Antiphospholipid antibody recognizes B2GP1 antigen bound to endothelium
  • Binds
  • Activates endothelium
    • ​Increased adhesion molecules, tissue factor
  • Monocyte activation (upregulator of tissue factor and cytokines)
  • Platelet activation –> clotting
22
Q

What is the dietary source of vitamin K?

Where is it absorbed?

A

Leafy green vegetables

Terminal ilium

Vitamin K deficiency can result from severe malnutrition

23
Q
A

C. prothrombin time

  • D dimer is not specific*
  • Everything else will be low in liver disease*