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SBL Exam 2 > Bleeding and Clotting - Hubbard > Flashcards

Bleeding and Clotting - Hubbard Flashcards

1
Q

platelet adhesion is dependent on glycoproteins on platelet surface and is mediated by vonWillebrand factor

  • activated platelets have storage granules and secrete factors (ADP, serotonin) which recruit other platelets
  • end result is the formation of a platelet plug which blocks egress of blood from the site of vascular injury
A

primary hemostasis

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2
Q

involves the serum coagulation factors which ultimately catalyze the devlpment of fibrin latticework which braces and supports the platelet plug
- serum coagulation factors also function to recruit platelets and amplify both primary and secondary hemostasis

A

secondary hemostasis

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3
Q

what ROS are important to ask in a pt with bleeding disorder?

A
  • bleeding
  • bruising
  • abnormal clotting
  • recurrent DVT
  • hx of PE/stroke
  • fatigue
  • fever
  • enlargement of spleen/LN/liver
  • weight loss
  • GO bleed
  • GU bleed -> beware beeturia!
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4
Q

what should always be considered a cause of petechiae/thrombocytopenia?

A

medications:

  • abx (cephalosporin)
  • H2 blockers
  • heparin
  • digoxin
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5
Q

complication of medical, surgical, obstetrical situations

  • intrinsic and extrinsic coagulation system are activated with resulting local and general escape of thrombin into the circulatory system, resulting in initial thrombosis
  • a platelets and clotting factors are depleted, bleeding ensues -> major factor of dz
A

disseminated intravascular coagulation (DIC)

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6
Q

what is the tx for DIC?

A
  • correction of underlying dz: sepsis, bowel obstruction
  • heparin (only if thrombosis occurs)
  • supportive care
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7
Q

generalized disorder of microcirculation characterized by thrombocytopenic purpura, microangiopathic hemolytic anemia (schistocytes), fluctuating neurological signs, febrility

A

thrombotic thrombocytopenic purpura (TTP)

- hyaline thrombi which occlude the capillaries of virtually every organ in the body

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8
Q

MAHA + thrombocytepenia (<50k) + fever + neurologic symptoms

A

TTP

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9
Q

MAHA + thrombocytopenia (<50k) + fever + neurologic symptoms + RENAL FAILURE

A

hemolytic uremic syndrome (HUS)

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10
Q

what are the two major forms of TTP?

A
  1. hereditary: ADAMTS13 mutation
  2. acquired: autoAb against ADAMTS13 (linked to infection, malignancy, immune disorders)

No ADAMTS13 = too much clumping

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11
Q

what is the tx for TTP?

A
  • treat the underlying cause
  • plasmapharesis
  • nearly 100% mortality if not treated
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12
Q

very large group of related disease that have decreased platelet adhesion as their hallmark

A

vonWillebrand disease

- pathologic lesion is decreased or absent vWF

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13
Q

what is the tx for vonWillebrand disease?

A
  • cryoprecipitate (replaces vWF)

- DDAVP (causes release of vWF from endothelium

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14
Q

defects in platelet function may be seen in what 3 diseases?

A
  1. uremia: impaired platelet adhesion
  2. dysproteinemias: interference with platelet membrane function
  3. autoimmune disorders: multiple abnormalities
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15
Q

the only endothelial syndrome associated with hemostatic complications

  • caused by thinning of vessel walls with telangiectatic formations, AV malformations, and aneurysmal dilations throughout the body
  • AD inheritance
  • telangiectasias gradually appear throughout life
  • epistaxis MC sx
A

hereditary hemorrhagic telangiectasia

- aka Osler-Weber-Rendu syndrome

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16
Q

hereditary hemorrhagic telangiectasia is caused by a defect in what gene?

A

endoglin (CD105) on xsome 9

- membrane glycoprotein strongly expressed on endothelial cells

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17
Q

what is the tx for hereditary hemorrhagic telangiectasia?

A

surgery and laser photoablation of telangiectasias of some value
- usually benign clinical course, recurrent bleeds frequent, but death from exsanguination is rare

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18
Q

recurrent LE thrombophlebitis and DVT, venous insufficiency, chronic leg ulcers
- significantly increased risk DVT in pregnant women (due in part to pregnancy-induces hypercoagulability)

A

AT-III deficiency

- diagnosed by decreased levels AT-III in serum (<50%)

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19
Q

what is the tx for AT-III def?

A
  • prophylactic w/ anticoagulants
  • pts w/ DVT should receive heparin, HIGH doses
  • AT-III replacement therapy is available for pts w/DVT
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20
Q

protein that inactivates factors V and VIII

A

protein C

21
Q

protein that is a cofactor for protein C

A

protein S

22
Q

MCC of hypercoagulable state from deficiency of protein C and S is caused by what?

A

initiation of warfarin therapy

- protein C and S are depleted prior to the other factors, resulting in temporary increase in coagulability

23
Q

abnormality of what factor, at the binding site for activated protein C

A

factor V leiden

  • heterozygotes at increased risk for thromboembolic disease
  • homozygotes have excessively high risk for thromboembolism
24
Q

what is the tx for factor V leiden mutation?

A
  • no prior episodes: DVT prophylaxis

- prior episodes: consider lifelong anticoagulation

25
Q

mutation resulting in increased activity for prothrombin and inability to de-activate prothrombin
- risk of thrombosis very high!

A

prothrombin 20210

  • aka factor II
  • combined with facor V leiden, may account for most cases of hereditary thrombophilia
26
Q

what is the tx of prothrombin 20210 mutation?

A

same as factor V:

  • no prior episodes: DVT prophylaxis
  • prior episodes: consider lifelong anticoagulation
27
Q
  • anticardiolipin Ab syndrome
  • lupus anticoagulant
  • false positive VDRL Ab syndrome
A

antiphospholipid syndrome

28
Q

what are the assoc features of antiphospholipid syndrome?

A
  • thromboembolic phenomena
  • miscarriage
  • thrombocytopenia
  • cerebral ischemia and recurrent stroke
29
Q

connective tissue disease (present in >50%, but not required for dx)

  • prolonged PTT
  • valvular heart disease
  • coronary artery disease
A

antiphospholipid synd

30
Q

what are the three diagnostic tests that Hubbard wants us to know for antiphospholipid syndrome?

A
  1. prolonged PTT
  2. lack of correction in mixing studies using NL plasma
  3. neutralization of inhibitor with excess phospholipid

NOTE: multiple positive tests over 3-12months required to make dx

31
Q

what test may be more specific than PTT for antiphospholipid syndrome?

A

dilute Russell Vwhatiper venom time (DRVVT)

32
Q

what is the tx for antiphos synd?

A

lifelong anticoagulation

  • heparin in pregnancy
  • hydroxychloroquine in pts w/ APS and SLE
33
Q

anticoagulation during pregnancy may be accomplished with what in pt with antiphospholipid syndrome?

A

subQ heparin KNOW this

34
Q

what are the 3 elements of virchows triad?

A
  1. vessel wall damage
  2. altered blood flow (stasis)
  3. hypercoagulability
35
Q

what are the 4 main INHERITED thrombotic disorders that Hubbard wants us to know?

A
  • antithrombin III def
  • protein C and S def
  • factor V leiden mutation
  • prothrombin 20210 mutation
36
Q

what are the 3 main ACQUIRED thrombotic disorders that Hubbard wants us to know?

A
  • protein C and S def
  • dysfribrinogenemias
  • antiphospholipid synd
37
Q

PE finding, pain in calf or popliteal area on dorsiflexion of foot
- **beware lots of false positives and negatives

A

Homans sing

38
Q

PE finding, pain typically caused with compression of the calf against the tibia but not when squeezing the calf itself
- neither sensitive not specific for DVT

A

Moses sign

- aka Bancrofts sign

39
Q

pain with percussion of the anteromedial tibia

- not sen/specific for DVT

A

Lisker’s sign

40
Q

BP cuff applied to mid-calf and pain elicited with inflation to 80mmHg
- not sen/specific for DVT

A

Lowenberg’s sign

41
Q

veins of affected leg distended in comparison to non-affected leg
- not sen/specific for DVT

A

unilateral superficial venous distention

42
Q
  • clinical sx/sy of DVT
  • alternative dx less likely than DVT
  • HR 100bpm
  • immobilization (>3 days) or surgery in last 4 weeks
  • previous hx DVT
  • hemoptysis
  • active cancer w/in last 6 months
A
  • *modified wells criteria for DVT**

- KNOW this

43
Q
  • previous PE or DVT
  • HR 100bpm
  • recent surgery/immobilization
  • clinical signs of DVT
  • alternative dx less likely that PE
  • hemoptysis
  • cancer
A
    • modified wells criteria for PE**

- KNOW this

44
Q

what is the scoring range for well criteria?

A 
0-1 = low probability
2-6 = intermediate probability
7+ = high probability
45
Q

medical sign involving episodes of vessel inflammation due to blood clot (thrombophlebitis) which are recurrent or appearing in different locations over time (thrombophlebitis migrans or migratory thrombophlebitis)

A

trousseau’s syndrome

46
Q

what are the 3 main causes of drug-induced hypercoagulability?

A
  1. tamoxifen: SERM that increases risk DVT/PE/stroke
  2. bevacizumab: VEGF inhibitor may cause both arterial and venous thromboembolic issues
  3. thalidomide, lenalidomide: angiogenesis inhibitors that cause arterial and venous thromboembolic issues
47
Q

what are the “other” causes of hypercoagulability?

A
  • prolonged sitting
  • extended travel
  • heart failure -> major RF for intracardiac thrombi
48
Q

what are the two examples of synnergistic risk factors for DVT?

A
  • oral contraceptives + heterozygous factor V leiden

- hyperhomocystinemia + heterozygous factor V leiden

49
Q

what are the pharmacologic and non-pharmacologic therapies that prevent DVT/PE?

A
  • stop smoking

- stop meds that increase risk (oral contraceptives, tamoxifen, megestrol acetate)

SBL Exam 2 (13 decks)

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