Coag review

Question 1

PTT or aPTT evaluates for which pathway? Used to monitor what therapy

Answer 1

• intrinsic and common pathways
• used to monitor unfractionated heparin therapy

Question 2

PT evaluates for which pathway? Used to monitor what therapy

Answer 2

• extrinsic and common
• used to monitor Warfarin (coumadin) therapy
  
  • vitamin K dependent clotting factors

Question 3

which factors are part of the intrinsic pathway

Answer 3

• 8, 9, 11, 12

Question 4

which factors are part of the extrinsic pathway

Answer 4

• tissue factor
• VII

Question 5

what is present in common pathway

Answer 5

• prothrombin (II)
• Thrombin (IIa)
• fibrinogen (I)
• V
• X

Question 6

target INR therapy for DVT (prophylaxis)

Answer 6

1.8-2.5

Question 7

target INR therapy for venous thromboembolism and AFIB

Answer 7

2-3

Question 8

target INR therapy for mechanical heart valves

Answer 8

2.5-3.5

Question 9

hemophilia A

Answer 9

factor VIII deficiency

Question 10

how does liver cirrhosis cause thrombocytopenia

Answer 10

• liver cirrhosis -> portal HTN -> splenomegaly -> splenic sequestration -> thrombocytopenia

Question 11

What is platelet dysfunction and what causes it? Treatment?

Answer 11

• impaired adherence or aggregation of platelets
• acquired: more common
  
  • liver disease, von willebrand disease, myeloproliferative disease, drugs
• treatment:
  
  • treat underlying cause
  • platelet transfusion

Question 12

Name conditions that cause increased destruction of platelets

Answer 12

• ITP
• DIC
• heparin-induced thrombocytopenia (HIT)
• thrombotic microangiopathies
  
  • TTP
  • HUS

Question 13

what is heparin-induced thrombocytopenia (HIT)

Answer 13

• new onset thrombocytopenia/thrombus while on heparin therapy
• will occur 5-10 days after putting someone on heparin; patient develops antibodies that bind to platelets

Question 14

thrombotic thrombocytopenic purpura (TTP) is more common in males or females

Answer 14

females

Question 15

etiology of thrombotic thrombocytopenic purpura (TTP)

Answer 15

• inherited or idiopathic
  
  • deficiency or antibodies ADAMST-13
• drugs, pregnancy, HIV infection

Question 16

explain what happens in thrombotic thrombocytopenic purpura (TTP)

Answer 16

• ADAMTS-13 is responsible for cleaving vWF into a smaller molecule, so without it, platelets aggregate around huge vWF and leads to clots and low platelet levels in blood
• microthrombi are formed throughout the body

Question 17

Name the Pentad of symptoms associated with thrombotic thrombocytopenic purpura (TTP)

Answer 17

• microangiopathic hemolytic anemia
• thrombocytopenia
• acute kidney injury
• neurologic defects
• fever

Question 18

treatment of thrombotic thrombocytopenic purpura (TTP)

Answer 18

plasma exchange

Question 19

hemolytic uremic syndrome typically seen in what patient population

Answer 19

children

Question 20

etiology of hemolytic uremic syndrome

Answer 20

Ecoli O157:H7

Question 21

name Triad of symptoms seen in hemolytic uremic syndrome

Answer 21

• microangiopathic hemolytic anemia
• thrombocytopenia
• acute kidney injury
• **most cases preceeded by bloody diarrhea

Question 22

treatment of hemolytic uremic syndrome in adults

Answer 22

plasma exchange

Question 23

treatment of hemolytic uremic syndrome in children

Answer 23

• IV fluid and electrolyte repletion
• dialysis if indicated

Question 24

typical of what conditions

• microangiopathic hemolytic anemia
  
  • fragmented RBC: schistocytes: helmet cells

Answer 24

TTP and HUS

Question 25

clinical findings are associated with this condition * increased indirect biliruben * decreased serum haptoglobin (binds to iron to preserve it) * negative coombs test * thrombocytopenia * PT and aPTT are normal * acute kidney injury * microangiopathic hemolytic anemia

Answer 25

* TTP * HUS

Question 26

name nutritional causes of impaired production of platelets

Answer 26

* Vitamin B12, folate deficiency * alcohol * direct toxicity to bone marrow * hypersplenism secondary to liver disease

Question 27

List the anticoagulants that are available for use

Answer 27

* IV unfractionated heparin (UFH) * LMWH * oral warfarin * factor Xa inhibitors * oral direct thrombin inhibitors

Question 28

Contraindications to anticoagulation

Answer 28

* pregnancy * risk of hemorrhage \> than the potential clinical benefits of therapy

Question 29

function of warfarin

Answer 29

* inhibits conversion of vitamin K to active form * depletion of vit K dependent clotting factors (2, 7, 9, 10) * inhibits Protein C and Protein S * inhibits propagation - does not remove thrombus

Question 30

indications for use of warfarin

Answer 30

* prophylaxis/treatment * VTE * AFIB * prosthetic heart valve * stroke * post MI

Question 31

when should warfarin treatment by initiated? Initial dose?

Answer 31

* initiated on **day 1 or day 2 of heparin** * initial dose: \< or = **5 mg/day**

Question 32

lower initiation doses of warfarin are recommended for

Answer 32

* elderly * liver disease * malnourished

Question 33

warfarin requires on average how many days before full anticoagulation effect in achieved? peak effect of warfarin occurs when?

Answer 33

* requires 2-3 days before full effect * peak effect of drug: after 48 hours

Question 34

Treatment for patients with acute DVT of leg requires warfarin **bridge therapy**. describe this

Answer 34

* parental therapy (heparin) should overlap with warfarin for a minimum of **5 days** AND until the INR is 2.0 or above for at least 24 hours

Question 35

what is a normal INR for a patient who is NOT anticoagulated

Answer 35

1.0

Question 36

patients on warfarin should be monitored how often?

Answer 36

* daily and then weekly * once stabilized, every 2-4 weeks

Question 37

hemorrhagic risk becomes dominant at an INR greater than

Answer 37

4

Question 38

no warfarin efficacy below INR of ? Efficacy diminished when INR is ?

Answer 38

* no efficacy: \< 1.5 * diminished efficacy: \< 2.0

Question 39

what common drug can cause decreased warfarin effect

Answer 39

oral contraceptive

Question 40

food sources of vit K

Answer 40

* cauliflower * green leafy vegetables * spinach

Question 41

what is given for supratherapeutic INR (non urgent)

Answer 41

vitamin K (oral, SC, or IV) * will take 6-24 hours to correct INR

Question 42

what is given for supratherapeutic INR ( urgent)

Answer 42

* 10 mg vitamin K (IV) * fresh frozen plasma * prothrombin complex concentrate (PCC) * recombinant factor VII

Question 43

time to anticoagulation reversal following discontinuation of warfarin

Answer 43

5-14 days