Deep Vein Thrombosis Flashcards
What happens in a pulmonary embolism?
Thrombus embolises from deep veins through right side of the heart into the lungs
Thrombus then becomes lodged in the pulmonary arteries, blocking blood flow to areas of the lungs
How can a thrombus lead to a stroke?
Thrombus embolises and travels to the heart
If the patient has a cardiac septal defect the thrombus can pass through to the left side of the heart and into systemic circulation
If the embolus travels to the break it can lead to a large stroke
What are the risk factors of developing a DVT or PE?
- Immobility
- Recent surgery
- Long haul travel
- Pregnancy
- Hormone therapy with oestrogen
- Malignancy
Less common:
- Polycythaemia
- SLE
- Thrombophilia
What are thrombophilias?
Conditions that predispose the patient to develop blood clots
What are some examples of thrombophilias?
- Antiphospholipid syndrome
- Factor V Leiden
- Antithrombin deficiency
- Protein C or S deficiency
- Hyperhomocysteinaemia
- Prothrombin gene variant
- Activated protein C resistance
What is a key indicator of antiphospholipid syndrome?
Recurrent miscarriage
Diagnosis via blood test for antiphospholipid antibodies
What VTE Prophylaxis is used in hospital?
Low molecular weight heparin e.g. dalteparin
(contraindicated with warfarin or a DOAC)
Anti-embolic compression stockings
(contraindicated with peripheral arterial disease)
How do DVTs present?
Unilateral
Bilateral DVT is rare, much more likely to be chronic venous insufficiency or heart failure
- Calf or leg swelling
- Dilated superficial veins
- Tenderness to the calf
- Oedema
- Colour changes to the leg
How do you examine the leg for signs of swelling?
Measure circumference of the calf 10 cm below the tibial tuberosity
3cm difference between calves is significant
What is a Wells Score used for?
Predicts the risk of a patient presenting with symptoms of DVT or PE
How is a DVT diagnosed?
D-dimer
High sensitivity but not specific
Useful for excluding VTE when there is low suspicion
Doppler ultrasound
Required to diagnose DVT
NICE recommends repeating negative ultrasound scan after 6-8 days if positive D-dimer and Wells score suggests DVT is likely
What conditions can cause a raised d-dimer?
Pneumonia
Malignancy
Heart failure
Surgery
Pregnancy
DVT
How is a pulmonary embolism diagnosed?
CT pulmonary angiogram
(Preferred unless patient has significant renal impairment or contrast allergy)
or
VQ scan
How is a DVT managed?
Initial management is with anticoagulation
Treatment dose of apixaban or rivaroaxaban
Start immediately in patients where DVT or PE is suspected and there is delay in getting scan
How is a symptomatic iliofemoral DVT managed?
Catheter-directed thrombolysis if symptoms lasting less than 14 days
