Coagulation Studies Flashcards by Lauren F

Which clotting pathways are evaluated by PTT or aPTT?

Intrinsic and common

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Which drug therapy is monitored by PTT or aPTT?

Unfractionated heparin

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Which clotting pathways are monitored by PT?

Extrinsic and common

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What drug therapy is monitored with PT?

Warfarin

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What is INR?

It’s a more accurate reflection of PT.

Its the ratio of the patient’s PT to a control PT, and it’s independent of the individual lab used

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What is a normal INR/

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What is the target INR for prophylaxis?

1.5-2.0

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What is the target INR for DVT/PE?

2-3

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What is the target INR for afib?

2-3

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What is the target INR for mechanical mitral valve?

2.5-3.5

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What is the target INR for a mechanical aortic valve?

2-3

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What is an inhibitor screen (mixing test)?

Coagulation factor deficiency vs inhibitor problem

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What is thrombin time (TT)?

Measures the final step of coagulation, the conversion of fibrinogen to fibrin.

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What can low fibrinogen levels cause?

Impaired clot formation and increased bleeding risk

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What is on the hypercoagulable panel?

Antithrombin

Factor V-Leiden

Protein C

Protein S

Prothrombin gene mutation

Lupus anticoagulant (Antiphospholipid antibodies)

MTHFR gene

(I know this card sucks and idk if its important or not, but i thought I’d make it just in case)

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What are the 3 congenital coagulation disorders?

Hemophilia A (Factor VIII deficient)

Hemophilia B (Factor IX deficient)

Von Willebrand disease

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What kind of drugs can cause acquired platelet dysfunction?

Chemo

Antibiotics

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What is the management of platelet dysfucntion?

Treat the underlying cause

Platelet transfusion

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What efffect will splenomegaly have on platelet levels?

Decrease

That big old spleen eats them all up

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What effect will cirrhosis have on the spleen and therefore the platelets?

It causes vascular congestion, causing splenomegaly, and then low platelet levels

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What 4 things can cause increased destruction of platelets?

Immune thrombocytopenia (ITP)

Disseminated intravascular coagulation (DIC)

Heparin-induced thrombocytopenia (HIT)

Thrombotic microangiopathies (TTP and HUS)

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What are the two types of thrombotic microangiopathy (TMA)

TTP

HUS

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What is thrombotic microangiopathy?

Low platelets due to the incorporation of platelets in the micro vasculature and microangiopathic hemolytic anemia.

(Microangiopathic hemolytic anemia is anemia caused by the shearing of RBCs as they pass through the little thrombi in the micro vasculature)

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Is Thrombotic Thrombocytopenic purpura (TTP) a medical emergency?

Yes

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What are the 2 ways you can wind up with TTP?

Acquired: developing antibodies against ADAMTS-13 Inherited: ADAMTS-13 mutations

Who is more likely to get TTP?

Black females

What might cause you to develop antibodies against ADAMTS-13?

Pregnancy

What happens with TTP?

Microthrombi are formed throughout the entire body. Purpura/petechiae appear on skin. Results in this CLASSIC PENTAD** - microangiopathic hemolytic anemia - thrombocytopenia - acute kidney injury (uncommon) - neurological defects**** - fever

What happens with hemolytic uremic syndrome?

Someone, usually a CHILD, eats SHIGA toxin from E. Coli O157:H7**** and then they have BLOODY DIARRHEA. After that, they get microangiopathic hemolytic anemia, thrombocytopenia, and ACUTE KIDNEY INJURY. Do yourself a favor https://youtu.be/U3VbjS7WqOE Don’t 5 this card until you watched that

What will you see on the blood smear of someone with microangiopathic hemolytic anemia (TTP or HUS)?

Schistocytes aka HELMET CELLS** (Remember the RBCs get sheared by all the little thrombi forming in the tiny vasculature, and the schistocytes/helmet cells are the carnage left behind)

Will a Coombs test be positive or negative in someone with microangiopathic hemolytic anemia (TTP or HUS)?

Negative | Coombs test tests for antibodies that destroy RBCs. The RBCs are being destroyed by thrombi, not attack by antibodies

Will PT and aPTT be normal or elevated with thrombotic microangiopathy (TTP or HUS)?

Normal

What do you do to treat thrombotic microangiopathy?

Plasma exchange Supportive care (give antibiotics and fluids for the kid with e.coli HUS)

Which one is TTP and which one is HUS: Neurological deficits Acute kidney injury

TTP: neurological deficits HUS: acute kidney injury (Yes, kidney injury is part of the classic Pentad for TTP, but its not as bad as it is in HUS)

What kinds of things can impair the production of platelets?

Bone marrow failure Chemo/radiation Bone marrow infiltration (neoplasmic/infections) Nutritional deficiencies- B12, folate, iron Too much alcohol 🍺

What is the other name for Warfarin (Coumadin)?

Vitamin K antagonist (VKA)

What are the 4 Factor Xa Inhibitors?

Fondaripinux (Arixtra) Rivaroxaban (Xarelto) Apixaban (Eliquis) Edoxaban (Savaysa, Lixiana)

Which drug is an oral direct thrombin inhibitor?

Dabigatran (Pradaxa)

What are the 4 drugs that are DOACs (Direct Oral Anticoagulants)

Dabigatran (Pradaxa) Apixaban (Eliquis) Rivaroxaban (Xarelto) Edoxaban (Savaysa, Lixiana) (They spell DARE. And the 3 that are Xa inhibitors have “Xa” in their name. Then dabigatran is the direct thrombin inhibitor)

Everybody knows that warfarin takes a few days to kick in. What should we use to get our patients anticoagulated in the meantime?

Heparin or LMWH

What is the preferred anticoagulant for patients with kidney disease

Warfarin aka VKA | vitamin K antagonist

What is the preferred anticoagulant for pregnant women?

LMWH | None of the others are OK.

Which anticoagulants are contraindicated in patients with kidney diseae?

Direct oral anticoagulants LMWH

Which baseline labs are necessary when you start a pt on unfractionated heparin?

aPTT PT/INR CBC

What labs need to be monitored when your pt is on unfractionated heparin?

aPTT OR Factor Xa

What are the baseline labs required if you start a pateitn on LMWH?

PT/INR aPTT CBC Creatinine* (risk of kidney injury)

What labs do you need to monitor while your patient is on LMWH?

Usually none

What are the preferred anticoagulants for patients with DVT or PE as long as they don’t have cancer?

DOACs >> Warfarin > LMWH

If your patient has cancer, what is the preferred anticoagulant?

LMWH

What is the MOA of Warfarin?

It inhibits the conversion of vitamin K to its active form, and therefore depletes all clotting factors that depend on vitamin K. It also inhibits protein C. ~inhibits propagation, does not remove thrombi!~

Will warfarin dissolve a thrombus?

What are some indications for using warfarin?

VTE (PE or DVT) Inherited thrombophilia AFib Prosthetic heart valve Stroke

When starting a patient on warfarin, should we give a “loading dose”?

No, won’t help. Only increases risks of bleeds

Ok i know i have to start heparin at the same time i start warfarin. Should i start them together at the same time?

Warfarin should be initiated on day 1 or 2 of heparin. The heparin and warfarin should then overlap for at least 5 days and until the INR is therapeutic for 24 hours or 2 consecutive days (?)

What is the initial dose of warfarin we should give?

5mg/day and then tweak it until you get to the target INR

How often do we need to monitor the patients INR when they are on Warfarin?

Daily for first 6 days, then weekly. Once stabilized, every 2-4 weeks

It seems like every drug interacts with warfarin! Which ones were in red boxes on the UpToDate chart that was lazily pasted into this half ass lecture?

Tylenol Aspirin Cephalosporins Diclofenac Macrolides Bactrim Oral contraceptives

Well shit your patient took way too much of his warfarin and his INR is now way too high. What should you do?

If his INR is 4.5-10 and he’s not bleeding out, don’t do anything. If his INR is over 10 and he’s still not bleeding, you need to give him PO vitamin K If he’s having a major bleed, you need to give PCC and IV Vitamin K (5-10mg)********

Your patient took too much warfarin and he’s having a major bleed. What do you do? **this is probably a test question***

IV Vitamin K 5-10mg PCC (prothrombin complex concentrate) Stop the warfarin too lol

What is the reversal agent for heparin? | either type

Protamine Andexanet$$$ PER977$$$

What is the reversal agent for Warfarin?

4Factor PCC (prothrombin complex concentrate) Vitamin K

What is the reversal agent for dabigatran (Pradaxa)?

Idarucizumab (Praxbind) Supportive care for bleeding

What is the reversal agent for the direct thrombin inhibitors that are not Pradaxa?

Supportive care for bleeding (good luck!)

What is the reversal agent for Direct Xa Inhibitors? | Xarelto, Eliquis, Lixiana, Savaysa

Supportive care for bleeding 😃 Andexanet$$$ PER977$$$$

Coagulation Studies Flashcards

(64 cards)