DVT Flashcards
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What is a deep vein thrombosis (DVT)?
A thrombus (clot) formed in deep venous circulation, resulting from venous thromboembolism
Where do DVTs most commonly form?
In venous valve pockets and other sites of stasis, most commonly below the knee
What are the two types of DVT?
- Distal vein thrombosis
= DVT of the calf, distal to the popliteal vein. - Proximal vein thrombosis
= DVT of the popliteal or femoral vein, is more likely to embolise
What are the common symptoms of DVT?
Calf warmth
Tenderness
Swelling
Erythema (unilateral)
Mild fever
What are the common signs of DVT?
Pitting oedema
Localised swelling
What investigations are used to diagnose DVT?
1 - D-dimer blood test
= useful for ruling out DVT in low-risk patients
2 - Ultrasound (Doppler)
= First-line diagnostic test if D-dimer or Wells score is high
What is the first-line treatment for acute DVT?
Anticoagulation with DOACs (e.g., apixaban or rivaroxaban)
What are second-line anticoagulants for DVT treatment?
1 - LMWH followed by dabigatran or edoxaban
2 - If dabigatran or edoxaban are contradicted then vitamin K antagonist (e.g., warfarin)
What is the goal of secondary prevention for DVT?
Inhibit clot formation with long-term anticoagulation (e.g., warfarin, DOACs, or LMWH) for at least 3 months
How does anticoagulation prevent DVT complications?
It inhibits the clotting cascade, preventing further clot formation but does not dissolve existing clots
What is the duration of treatment with warfarin for patients with an unprovoked DVT/PE?
They should be treated with 6 months DOAC therapy
What is the next best step in the management of a patient with suspected DVT with a Well’s score of more than 2?
Venous duplex ultrasound is the first line investigation
How long should patients with a deep vein thrombosis be anticoagulated for?
Anticoagulation should continue for at least 3 months. In unprovoked DVT most patients carry on for 6 months
What is the next best step in the management of a patient with suspected DVT with a Well’s score of less than 2?
D-dimer
What is the target INR for patients with recurrence of VTE (Venous Thromboembolism) while on warfarin?
Note that for patients with recurrence of a VTE whilst on warfarin
= Target INR should be increased from 2-3 to 3-4
What are the factors that increase the DVT Wells score by one point?
(1) Active cancer
(2) Paralysis, paresis, or recent plaster immobilisation of the legs
(3) Recently bedridden for 3+ days or major surgery in the last 12 weeks
(4) Localised tenderness along the deep venous system
(5) The entire leg is swollen
(6) Calf swelling at least 3 cm larger than the asymptomatic side
(7) Pitting oedema confined to the symptomatic leg
(8) Collateral superficial veins
(9) Personal history of DVT
If a patient has a DVT Wells score of 2 or more, what is the next step in management?
(1) DVT is likely
= perform an ultrasound Doppler of the proximal leg veins within 4 hours.
(2) If not possible, do a D-dimer test, start interim anticoagulation, and arrange the Doppler within 24 hours
What should be done if a patient has a Wells score of 1 or less?
(1) DVT is unlikely
= send a D-dimer.
(2) If results can’t be obtained within 4 hours, offer interim anticoagulation while awaiting results.
(3) If the D-dimer is positive, perform an ultrasound Doppler of the proximal leg veins.
(4) If negative, stop anticoagulation and consider an alternative diagnosis
A 40-year-old woman presents to her GP with left leg swelling. She returned three days ago from a vacation. She is normally fit and well, with no medical conditions, and is physically active. She has visible superficial veins on the left leg and left calf swelling of 1 cm compared with the right. She has pitting oedema up to her shin on her left leg and is tender along the deep venous system.
A deep venous thrombosis (DVT) is suspected, and a Well’s score is calculated. What would her Well’s score be?
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