Deep Vein Thrombosis Flashcards
Define DVT?
Formation of a thrombus within the deep veins (most commonly in the calf or thigh)
What are the causes of DVT?
Deep veins in the legs are more prone to blood stasis, hence clots are more likely to form
What are the risk factors for DVT?
COCP (combined oral contraceptive pill) Post-surgery Prolonged immobility Obesity Pregnancy Dehydration Smoking Polycythaemia Thrombophilia Malignancy
What is the epidemiology of DVT?
Very Common
Especially in hospitalised patients
What are the presenting symptoms of DVT?
Swollen limb
May be painless
What are the signs of DVT on physical examination?
Local Erythema, Warmth and swelling Measure the leg circumference Varicosities (swollen/tortuous vessels) Skin colour changes Homan's sign
What is Homan’s sign?
Forced passive dorsiflexion of the ankle causes deep calf pain
How is risk stratified for DVT?
Using the Wells Criteria
If the score is 2 or more it is classifed as high risk
What would you do to examine for PE?
Check resp rate
Pulse oximetry
Pulse rate
What is the gold standard investigation for DVT?
Doppler Ultrasound
How does Impedance Plethysmography work for DVT?
Changes in blood volume results in changes of electrical resistance
What bloods would you do for a DVT?
D-Dimer which can be used as a negative predictor
Thombophilia screen if indicated
What bloods would you do if PE is suspected?
ECG
CXR
ABG
What is the management plan for DVT?
Anticoagulation
IVC Filter
Prevention
What do you do for anti-coagulation in DVT?
Heparin whilst waiting for warfarin to increase INR to the target range of 2-3
DVTs that don’t extend above the knee may be observed and anticoagulated for 3 months
DVTs that extend beyond the knee require anticoagulation for 6 months
Recurrent DVTs require long-term warfarin
When would you use an IVC filter?
If anticoagulation is contraindicated and there is a risk of embolism
What would you do to prevent DVTs?
Graduated compression stockings
Mobilisation
Prophylactic heparin (if high risk e.g. hospitalised patients)
What are the possible complications of DVT?
PE
Venous infarction (phlegmasia cerulea dolens)
Thrombophlebitis (results from recurrent DVT)
Chronic venous insufficiency
What is the prognosis for patients with DVT?
Depends on extent of DVT
Below-knee DVTs have a good prognosis
Proximal DVTs have a greater risk of embolisation
