Haem - DVT and VTE Flashcards
What is a VTE?
Thrombus develops in circulation, it embolises from deep vein
When can a VTE cause a stroke?
If the patient has a septal defect, the thrombus can pass to the left side of the heart and travel to the systemic circulation and go to the brain
What are the risk factors for developing a VTE?
Immobility
Recent surgery
Long haul travel
Pregnancy
Hormone therapy (with oestrogen)
Malignancy
Polycythaemia
SLE
Thrombophilia
What should you ask if a patient presents with features of a DVT or PE?
Risk factors e.g. immobility, surgery and long-haul flights
What are some examples of thrombophilias?
Antiphospholipid syndrome
Factor V Leiden
Antithrombin defieciency
Protein C or S deficiency
Hyperhomocysteinaemia
Prothrombin gene variant
Activated protein C resistance
When should you suspect antiphospholipid syndrome?
Recurrent miscarriage
Diagnose with blood test for antiphospholipid antibodies
What VTE prophylaxis is used in hospital?
Given to patients with increased risk
- Low molecular weight heparin e.g. dalteparin
Contraindicated in active bleeding or existing warfarin or DOAC use - Anti-embolic compression stockings
Contraindicated in peripheral arterial disease
How do DVTs present?
Unilateral
- Calf or leg swelling
- Dilated superficial veins
- Calf tenderness
- Oedema
- Colour changes in leg
What does a bilateral DVT suggest?
Rare
More likely due to chronic venous insufficiency or heart failure
How is the calf circumference measured?
10cm below tibial tuberosity
More than 3cm difference is significant
What is used to predict risk of a patient having a DVT or PE?
Wells Score
How is a DVT diagnosed?
Wells score is used to guide next steps
Likely - perform a leg vein utlrasound
Unlikely - perform d-dimer, if positive leg vein ultrasound
USS of the leg is required to diagnose DVT
Why is a D-dimer sensitive but not specific?
If there is a raised D-dimer it will be detected with high precision
May be multiple reasons for a raised d-dimer
- Pneumonia
- Malignancy
- Heart failure
- Surgery
- Pregnancy
If there is a negative USS and the patient has a positive D-dimer and likely Wells score when should an USS be repeated?
6-8 days later
What is the first-line imaging for pulmonary embolisms?
CT pulmonary angiogram (CTPA)