DVT Flashcards
How do DVTs occur?
Starts with damage to the endothelium, which causes vasoconstriction and subsequent platelet activation (primary haemostasis) and of clotting factors (secondary haemostasis), which forms a fibrin plug
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What are risk factors for the development of DVT?
- Trauma
- Hormones - COCP, pregnancy
- Road traffic accidents
- Operations
- Malignancy
- Blood disorder - polycythaemia etc.
- Old age, obesity
- Serious illness
- Immobilisation
- S plenectomy
Others include dehydration and previous DVT
What are signs of DVT?
- Calf warmth
- Swelling
- Tenderness
- Erythema
- Pitting oedema
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What are symptoms of DVT?
Can be asymptomatic
If symptomatic
- Leg swelling
- Calf tenderness
- Persistent discomfort
What type of clot is a DVT?
Red clot - rich in fibrin and trapped erythrocytes (hence redness)
Important to remember for treatment - red clots are treated using heparins and warfarin, as they target fibrin production
If someone presented with suspected DVT, what is important to do when examining the leg?
Look at colour, feel warmth, feel for pulses, and MEASURE CALF CIRCUMFERENCE
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How would you determine what investigations to do on someone presenting with DVT?
Wells Score for DVT to assess risk
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If someone presented with features of a DVT, what else would be part of a differential diagnosis?
- Cellulitis
- Ruptured baker’s cyst
- Tumour
- Calf muscle haematoma
- Necrotising fasciitis - if really acute
How would distinguish a DVT from cellulitis?
Usually manifest redness, heat, and swelling in the dermis of the affected leg.
The affected area is likely to be smaller than in DVT (which may involve the entire foot, calf, or thigh), but the signs more pronounced.
What criteria are assessed in the DVT Wells score?
- Active cancer = +1
- Paralysis/plaster = +1
- Bed >3 days/surgery within 4 weeks = +1
- Tender veins = +1
- Entire leg swelling = +1
- Calf swelling >3 cm = +1
- Pitting oedema = +1
- Collateral veins = +1
- Alternative diagnosis likely = -2
What does a DVT Wells score of 0 indicate?
DVT unlikely
What does a DVT wells score of 1-2 indicate?
DVT moderately likely
What does a DVT wells score of >2 indicate?
DVT highly likely
What investigations would you do if someone had a Wells score of <2?
- D-dimer
What investigations would you do in someone with DVT Wells score of >2?
D-dimer and Doppler ultrasound