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GK F3 E6 Heme/Onc > Clotting Disorders > Flashcards

Clotting Disorders Flashcards

1
Q

Platelets and clotting factors circulate normally in an _________ form.

A

Platelets and clotting factors circulate normally in an inactive form.

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2
Q

Vascular injury disrupts endothelium and leads to what 3 things?

A
  1. Vascular spasm
  2. Platelet adhesion mediated by Von Willebrand factor
  3. Coagulation cascade
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3
Q

What does PT represent?

A

time in seconds for plasma to clot after addition of calcium and an activator of extrinsic pathway (thromboplastin)

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4
Q

What leads to a prolonged PT?

A

Deficiencies or inhibitors of clotting factors within extrinsic or final common pathways

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5
Q

Why was INR created?

A

PT results for identical patients vary with different labs

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6
Q

What is INR?

A

mathematical conversion of patient’s PT compared to geometric mean of PT of at least 20 healthy subjects of males and females at THAT lab

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7
Q

What does PTT (Partial Thromboplastin Time) measure?

A

integrity of intrinsic and final common pathways of coag cascade

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8
Q

What does PTT represent?

A

time in seconds for patient’s plasma to clot after the addition of phospholipid, an intrinsic pathway activator- calcium

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9
Q

if clotting times remain prolonged what should you think?

A

inhibitor

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10
Q

if clotting times normalize or decrease to near-normal what should you think?

A

factor-deficiency

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11
Q

What does PTT correct?

A

Factor DEFICIENCY of intrinsic pathway like factors VIII, IX, XI, or XII

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12
Q

How can you determine which clotting factor is involved with an abnormal PTT?

A

clotting factor assay

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13
Q

PTT stays prolonged with what?

A

an inhibitor: heparin, LMWH, AIH/Factor 8 inhibitor

Lupus anticoagulant

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14
Q

What do you see in pts w/LAC (lupus anticoag)?prolonged PTT

A

prolonged baseline PTT

Seen more in young females

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15
Q

When would you suspect LAC?

A

pt w/no bleeding hx

pt w/clot w/baseline prolonged PTT before Ant-coag was started

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16
Q

What should you think if a PT corrects with normal PTT?

A

DEFICIENCY of factors II, VII, and X or fibrinogen (2, 7, 10)

Liver dz (prolonged PT)

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17
Q

What should you think if PT is still prolonged with prolonged PTT?

A

Factor 5 inhibitor

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18
Q

PT and PTT MIxing study:

deficiencies caused by what?

A

supratherapeutic warfarin or rat poison

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19
Q

what inhibitors will you see in lymphoproliferative d/o or monoclonal protein d/o?

A

LAC

nonspecific factor inhibitors

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20
Q

Pts with what 2 disorders can develop antibodies against self (have autoimmune characteristics)?

A

lymphoproliferative d/o

monoclonal protein d/o

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21
Q

Warfarin:

What can supratherapeutic INR lead to?

A

elevated PTT

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22
Q

every 1.0 increase of PT is what of PTT?

A

16-17 sec PTT

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23
Q

3 MC reasons to use Warfarin

A

1) A-Fib INR 2-3
2) VTE INR 2-3
3) Mechanical valve replacement- INR 2.5-3.5

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24
Q

Warfarin interferes with what factors and proteins?

A

factors VII, IX, X and proteins C & S

25
Can you use warfarin in pregnancy?
No: Preggo X
26
UFH inhibits which factors?
IIa (thrombin) Xa
27
UFH PK and risk
PK: large molecule: 30 units long and not well absorbed subcutaneously risk of HIT
28
What does LMWH inhibit?
More of Xa some of IIa
29
LMWH benefits
smaller so well absorbed subcutaneously predictable 1/2 life Ex: Enoxaparin, Dalteparin Risk of HIT Can give with preggos
30
**T/F:** No need to draw blood tests to see if anticoag is therapeutic unless pt. is **very obese or very thin** ## Footnote **What would you draw if you had to?**
TRUE anti-factor Xa levels 3-4 hrs post LMWH administered
31
**synthetic pentasaccharide** that i**nhibits factor Xa** and **binds to antithrombin III** causing antithrombin III to go through **conformational change inhibiting coag cascade** **_Half-life 17 hrs. long and NO reversal agent_** Which med?
Fondaparinux
32
Direct Xa inhibitors
Rivaroxaban Apixaban
33
ex of DOAC
dabigatran
34
what are **fondaparinux, rivaroxaban/apixaban and dabigatran** used for?
A-fib & VTE
35
What agents should be used to reverse overdose in the following meds? 1. Heparin 2. Enoxaparin 3. Pradaxa 4. Xarelto 5. Fondaparinux
1. Heparin: **Protamine** 2. Lovenox/Fragmin: **Protamine** 3. Pradaxa: **Dialysis** (if bleeding in brain) or **Idarucizumab** (if no bleeding) 4. Xarelto/Eliquis- **PCC** 5. Fondaparinux (Arixtra)- **Novo 7, DDAVP**
36
RF for VTE & hypercoagulable state
stasis recent trauma/surgery and hypercoagulable state increased risk for venous thromboembolism (VTE) CA (Trousseau's syndrome) pregnancy smoking estrogen
37
**Protein C & S along with antithrombin III deficiencies** **Factor V Leiden mutation** Prothrombin gene mutation **Lupus anticoagulant** Hyperhomocysteinemia **Anticardiolipin antibody** **Paroxysmal nocturnal hemoglobinuria** These are all...
hypercoagulable states
38
what 3 things prevent **overclotting**?
Protein C, Protein S, and Antithrombin III
39
Both are **vitamin K dependent proteins** Both can be **low in nephrotic syndrome**
Protein C &S
40
Can be **low d/t liver disease, nephropathy or heparin** Mutations **reduce levels or decrease its functional capacity**
AT III deficiency
41
essential cofactor to allow conversion of **prothrombin to thrombin**, which then converts **fibrinogen to fibrin --\> clot** **This is inactivated by protein C** What Factor?
Favtor Va
42
single AA substituted allowing **resistance to inactivation** or **activated protein C resistance** so **continues to clot d/t high levels of prothrombin --\> thrombin (factor IIa)** WHat mutation?
Mutation Arg506Gln
43
Mutation of nucleotide substitution in 3’-untranslated region of prothrombin gene which results in **greater function of prothrombin (factor II)** **What mutation?**
Prothrombin Gene G20210A Mutation
44
High levels of homocysteine lead to what?
Vascular injury Intimal thickening Elastic lamina disruption **Platelet aggregation** Smooth muscle hypertrophy **Impairs nitric oxide activity**
45
**MTHFR deficiency**- alanine to valine substitution at **677 amino acid position** ## Footnote **Deficiencies of vitamins B6, B12 and folic acid** **Fibrates and nicotinic acid increase** **What condition?**
Hyperhomocysteinemia
46
What do you treat Hyperhomocysteinemia with?
Vit B12 & folate
47
Recurrent arterial or venous thrombosis, pregnancy morbidity/fetal loss and presence of antiphospholipid antibodies including Lupus anticoagulant (LAC) Anticardiolipin antibody Anti-Beta 2 glycoprotein What dz?
**Antiphospholipid Ab Syndrome (APS)**
48
body forms **IgG or IgM antibodies against phospholipids** Phospholipids are involved in coag cascade **More arterial clotting** **Sneddon syndrome** (livedo reticularis and neurologic abnormalities) What dz?
LAC and Anticardiolipin Ab
49
Best test to evaluate VTE?
Doppler US: can be falsely negative with DVT below the knee fi high suscpicion = repeat in 2-3 day
50
Dx test for PE
CT angiogram
51
If pt has renal insufficiency, pregnancy or anaphylaxis to iodine, what dx test would you do if they have VTE?
VQ scan
52
How do you approach a pt with VTE?
1. Find out if they have risk factors: **Surgery, pregnancy,** cancer, HRT, travel 2. **Start UFH or LMWH first and then warfarin**: Sounds paradoxical but warfarin **initially will drop protein c & s** levels placing pt. at higher risk of VTE before actually taking effect to **“thin” blood out** _Can start with DOAC_ If pt. started on UFH, LMWH, or warfarin, recommended **not to run hypercoagulable panel because some tests will be falsely low** _**Wait until off warfarin for at lease 3 weeks before running tests\*\***_
53
VTE & AC duration: 1st VTE
AC for 3-6 mos
54
VTE & AC duration: 1st VTE and hypercoagulable
no need for lifelong AC
55
Recurrent VTE & hypercoagulable
lifelong AC
56
Who is tPA indicated for?
pts who have extensive clot burden PE causing significant hemodynamic instability & RV strain
57
When would you use an IVC filter?
pts who cannot take AC and have or are at risk for lower extremity DVT to prevent propogation of clot. pt that had a BIG PE to avoid possible future lung injury pts with high risk of bleeding complications
58
SF thrombophlebitis TX
**NSAIDS/ASA + warm compresses** **Consider AC if:** _\>5cm_ very symptomatic clot is within 2 cm of where SF vein enters the deep vein _if pt had SF vein thrombosis while on ASA_
59

GK F3 E6 Heme/Onc (6 decks)

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