T2 L7: Thrombosis Flashcards
Order from abdomen to foot: Femoral vein, Tibial vein, Popliteal vein and Iliac vein
Iliac vein, femoral vein, popliteal vein and Tibial vein
What is Virchows triad?
3 factors that are critically important in the development of venous thrombosis: venous stasis, activation of blood coagulation, and vein damage.
Why is pregnancy a thrombotic risk factors?
It causes a hypercoagulative state
What is a baker’s cyst (popliteal cyst)?
A fluid-filled swelling that develops at the back of the knee.
What are the 5 clinical presentations of a deep vein thrombisis?
Unilateral calf swelling, heat, pain, redness, hardness
How is an ultrasound used as a diagnosis for deep vein thrombosis?
The veins will be non-compressible and this is visible with an ultrasound
What is a venogram?
A dye is injected into the vein and then x-rays are taken
What is the Wells score?
It measures the risk of developing an acute pulmonary embolism. Can be used for deep vein thrombosis too
What is a D-dimer test?
Looks for D-dimer in the blood (a protein fragment that’s made when a blood clot dissolves in your body)
What does a high Wells score and positive D-dimer test indicate?
Likelihood of deep vein thrombosis so ultrasound is needed to confirm
What type of drug is Tinzaparin?
A LMW Heparin
What type of drug is Enoxaparin?
A LMW Heparin
When is IV unfractionated heparin given?
When other heparin can’t be given because the patient has insufficient kidney function
What is the adequate EGFR for kidney function?
> 30ml/min
What is EGFR?
Estimated glomerular filtration rate
Why is someone given Heparin when being switched to Warfarin first as treatment for deep vein thrombosis?
When the INR is >2.0 for 2 days. Heparin is only used to start the patient of anticoagulants
What is INR?
International normalised ratio (INR) is the prothrombin time. It’s used to see how long blood takes to clot
What is the treatment when someone is having their first DVT?
Anticoagulants for 6 months
What is the treatment when someone is having their second DVT?
Lifelong coagulants
What should the INR normally be?
2-3
What are the classic symptoms of a medium PE?
Pleuritic pain, dyspnoea, and haemoptysis
What is dyspnoea?
Uneasy breathing which can cause shortness of breath
What are the classic symptoms of a massive PE?
Syncope and death
What is haemoptosis?
Coughing up blood
What are the presentations of a PE on examination?
Tachycardia, tachypnoea, and hypotension
What is Tachycardia?
Fast heart rate
What is Tachypnoea?
Rapid breathing
What is a V/Q mismatch?
A ventilation/ perfusion mismatch. The lung receives O2 without the blood or the other way around. It means that perfusion is not efficient
What is a V/Q scan?
A ventilation/perfusion radio-isotope scan. Not done anymore
What are the classic indication of a PE on and ECG?
Sinus tachycardia, atrial fibrillation and/or right heart strain (RBBB (Right bundle branch block)). Most common pattern is S1Q3T3 pattern
What would a CXR look like when someone has a PE?
Usually normal. There might be linear atelectasis and small effusions
Why won’t a blood clot show up on an R-ray?
Because the clot is radiolucent. A CT will show blood clots
What is a atelectasis?
A complete or partial collapse of the entire lung or
a lobe of the lung
What is the mortality rate for PE despite treament?
5%
What is tPA?
Alteplase (A thrombolytic drug)
How does Alteplase work?
It’s a tissue plasminogen activator. A fibrinolytic drug
What is an inferior Vena Cava filter and what is it used for?
A small device put into the vein to catch blood clots
What type of drug has been shown to give better outcomes to cancer patients?
LMW Heparin
What is a DOAC?
Direct oral anticoagulant
What type of drug is Dabigatran and how does it work?
An anticoagulant that directly inhibits thrombin
What type of drug is Rivaroaxaban and how does it work?
An anticoagulant that directly inhibits Xa
What do anti-thrombin, protein s and protein c have in common?
They help regulate coagulation
What is lupus?
An autoimmune disease that causes inflammation throughout the body. It’s partly genetic and environmental
What disease is DRVVT used to diagnose?
Dilute Russell viper venom time is used to diagnose lupus
What type of drug is apixaban and how does it work?
An anticoagulant that directly inhibits factor Xa
How does Warfarin work?
It’s a Vitamin K antagonist that prevents the gamma-carboxylation of factors II, VII, IX, and X which is required for those factors to mature. This all prolongs the prothrombin time
How long does it take for Warfarin to achieve therapeutic effects?
> 3 days
What is the half life of prothrombin (Factor 2)?
60 hours
Which anticoagulant inhibits Protein C and S?
Warfarin so the patient becomes prothrombotic
What is meant by prothrombotic?
Promote blood clotting
What is the interaction of Warfarin with cytochrome P450?
Enzyme inhibitors will potentiate Warfarin and enzyme inhibitors will inhibit Warfarin
What is meant by potentiate?
Increase power of effect
What is the interaction between Warfarin and alcohol?
Binge drinking tends to potentiate Warfarin. Chronic alcoholism inhibits Warfarin (alcohol upregulates inhibitors)
What is meant by teratogenic?
Affect embryo and causes developmental issues
Why can’t Warfarin be used during pregnancy?
Its teratogenic. LMW Heparin is used instead
What are the 5 main side effect of Warfarin?
It’s teratogenic, Increases risk of haemorrhage, causes minor bleeding, skin necrosis, and Alopecia
What is Alopecia?
Hairloss
What is the drug Octaplex used for?
It’s an activated prothrombin complex that reverses Warfarin effects
What is the drug Beriples used for?
It’s an activated prothrombin complex that reverses Warfarin effects
What are the steps to reversing the effect of Warfarin?
Give an activated prothrobmin complex and Vitamin K
What is the dose of activated prothrombin complex?
25-50 units pew kg depending on the INR level
What dose of vitamin K is given to reverse Warfarin effects?
2-10 mg depending on INR level
Why may a patient become refractory when they are being reloaded with Warfarin after the effects were previously reversed?
Because clotting factors sometimes have long half lives
When is FFP (Fresh frozen plasma) given to reverse Warfarin effects?
In an emergency
What is Heparin and how does it work?
A Mucopolysaccharide that potentiates anti-thrombin by irreversibly inactivating factor IIa and factor Xa
What’s another name for factor IIa?
Thrombin
Why is unfractionated Heparin not used much?
It’s usually given by IV which is inconvenient
What is a bolus infusion?
Not gradual, all the drug is given at once
What dosage is unfractionated heparin at and how?
Given IV with 5000u bolus and then about 10000/hour infusion
Where is unfractionated heparin metabolised?
In the liver
What does the APTT test for?
Intrinsic pathway
What does PT test for?
Extrinsic pathway
What does TT test for?
Common pathway
