DVT Flashcards
What is a DVT?
The formation of a thrombus (blood clot) in a deep vein
Partially or completely obstructs blood flow
What effect can a DVT have on the lung?
Thrombus can dislodge and travel in the blood to the pulmonary arteries
Causes a PE
Which other sites, apart from the deep vein of the legs or pelvis, can be affected by thrombosis?
- upper limb veins
- intracranial veins
- splanchnic veins
What is a provoked DVT?
A DVT associated with transient risk factors which can be removed hence reducing the risk of recurrence
Name the transient risk factors for a DVT
Anything that causes a hypercoagulable state and haemostasis e.g.,
Immobility
Recent major surgery
Pregnancy / puerperium
Long-haul flight (more than 4 hours)
COCP/HRT
Dehydration
Chemotherapy
Recent hospitalisation
What is an unprovoked DVT?
A DVT happening without transient risk factors
The person may not have an identifiable risk factor or have risk factors that aren’t easily correctable (e.g., malignancy, thrombophilia)
As risk factors cannot be removed the person is at an increased risk of DVT recurrence
Name the haematological conditions that cause thrombophilia
Antiphospholipid syndrome
Antithrombin deficiency
Factor V Leiden
Protein C&S deficiency
Hyperhomocysteinaemia
Prothrombin gene variant
Activated Protein C resistance
What are the antibodies that make up the antiphospholipid screening?
Cardiolipin antibodies
Anti-apolipoprotein antibodies
Lupus anticoagulant
Name the continuing / intrinsic risk factors of DVT?
Previous DVT
Acquired/familial thrombophilia
Malignancy
Aged over 60 years
Being overweight / obese
Male
Heart failure
Medical illness e.g., acute infection
Inflammatory disorder e.g., vasculitis, IBD
Varicose veins
Smoking
Name other complications of DVT apart from a PE
Post thrombotic syndrome
- affects up to 50% of people
- usually within 2 years of a lower limb DVT
- negatively impacts QoL
Bleeding associated with anticoagulation treatment
Heparin induced thrombocytopenia (HIT)
- may occur 5-7 days after initial exposure to heparin
- can occur in less than 1 day in people previously exposed to heparin
What is post thrombotic syndrome and what effect can it have on the limb?
A chronic venous HTN causing:
- limb pain
- swelling
- hyperpigmentation
- dermatitis
- ulcers
- venous gangrene
- lipodermatosclerosis
What are the typical signs and symptoms of a DVT?
Unilaterally localised pain - usually throbbing in nature made worse by walking or bearing weight
Calf swelling
Erythema
Tenderness
Oedema
Vein distension
Warm to touch
Which clinical examination is important to do in a DVT?
Measure the circumference of both the affected and unaffected calf 10cm below the tibial tuberosity
If difference is > 3cm DVT is highly likely
If a DVT is highly suspected which scoring tool can be used to confirm the diagnosis?
2-level DVT Wells score
Which Wells score indicates that a DVT is likely?
≥ 2 points
If the Wells score is ≥ 2 points, what should you do next?
Proximal leg vein USS within 4 hours
OR
D-dimer test (if not already done) THEN interim therapeutic anticoagulation AND scan within 24 hours
A proximal leg vein USS has been done and it is positive. What should you do next?
Diagnose DVT and offer/continue treatment
A proximal leg vein USS has been done and it is negative. What should you do next?
If the D-dimer is +ve and DVT unlikely then stop any anticoagulation and think about other diagnoses
OR
Do a D-dimer test if not already done
A proximal leg vein USS has been done and it is negative. The D-dimer is then done and it is positive. What should you do next?
Stop any anticoagulation and repeat scan 6-8 days later
A proximal leg vein USS has been done and it is negative. The D-dimer is then done and it is negative. What should you do next?
Stop any anticoagulation and think about other diagnoses
A proximal leg vein USS has been done and it is negative. The D-dimer is then done and it is positive. The repeat scan 6-8 days later is positive. What should you do next?
Diagnose DVT and offer/continue treatment
If the Wells score is ≥ 1 points, what should you do next?
Urgent D-dimer test with result within 4 hours
OR
Interim therapeutic anticoagulation while awaiting result
The Wells score is ≥ 1 points. A D-dimer has been done and it is positive. What should you do next?
Proximal leg vein USS within 4 hours
OR
D-dimer test (if not already done) THEN interim therapeutic anticoagulation AND scan within 24 hours
The Wells score is ≥ 1 points. A D-dimer has been done and it is negative. What should you do next?
Stop any anticoagulation and think about other diagnoses
What Tx should be given to people with a DVT (apart from those with antiphospholipid syndrome / pregnant)?
DOACs e.g., apixaban or rivaroxaban
Can be given in people with renal impairment if their CrCl is > 15ml/min
If neither apixaban or rivaroxaban is suitable as a treatment what should you offer instead?
LMWH for at least 5 days followed by dabigatran or endoxaban
OR
LMWH and a VKA for at least 5 days or until INR is 2.0 on 2 consecutive readings, then a VKA alone
For someone with renal impairment and CrCl < 15ml/min which Tx should you give them?
Don’t give DOACs. Can give one of the following:
- LMWH
- UFH
- LMWH/UFH and a VKA for at least 5 days, or until INR at least 2.0 on 2 consecutive readings then a VKA alone
What Tx should be given to people with antiphospholipid syndrome?
LMWH and a VKA for at least 5 days or until INR is at least 2.0 on 2 consecutive readings
Then VKA alone
What is the Tx duration for a provoked DVT?
3 months
Can be 3-6 months in cancer
What is the Tx duration for an unprovoked PE?
6 months
Sources
https://www.nice.org.uk/guidance/ng158/resources/visual-summary-pdf-11193380893
https://cks.nice.org.uk/topics/deep-vein-thrombosis/diagnosis/when-to-suspect-dvt/
https://cks.nice.org.uk/topics/deep-vein-thrombosis/diagnosis/when-to-suspect-dvt/
https://www.youtube.com/watch?v=POMdvRyxlFw
https://www.ouh.nhs.uk/immunology/diagnostic-tests/tests-catalogue/anti-phospholipid-antibodies.aspx
https://en.wikipedia.org/wiki/Antiphospholipid_syndrome
