DVT Flashcards
Define DVT
DEFINITION: formation of a thrombus within the deep veins (most commonly in the calf or thigh)
Explain the aetiology
Deep veins in the legs are more prone to blood stasis, hence clots are more likely to form Virchow's triad -stasis -hypercoagulability -endothelial injury
Risk Factors
COCP
Post-surgery
Prolonged immobility
Obesity
Pregnancy
Dehydration
Smoking
Polycythaemia
Thrombophilia (e.g. protein C deficiency)
Malignancy
Summarise the epidemiology of DVT
VERY COMMON
Especially in hospitalised patients
Recognise the presenting symptoms of DVT
Swollen limb
May be painless
Recognise the signs of DVT on physical examination
Examination of the Leg
Local erythema, warmth and swelling
Measure the leg circumference
Varicosities (swollen/tortuous vessels)
Skin colour changes
NOTE: Homan’s Sign - forced passive dorsiflexion of the ankle causes deep calf pain
Recognise the signs of DVT on physical examination
Risk is stratified using the WELLS CRITERIA (NOTE: this is different from the PE Wells criteria)
Score 2 or more = high risk
Examine for PE
Check respiratory rate, pulse oximetry and pulse rate
Identify appropriate investigations for DVT
Doppler Ultrasound - GOLD STANDARD
Impedance Plethysmography
Bloods
Impedance Plethysmography
changes in blood volume results in changes of electrical resistance
Bloods
D-dimer: can be used as a negative predictor
Thrombophilia screen if indicated
If PE suspected
ECG
CXR
ABG
Management plan for DVT- ANTICOAGULATION
Heparin whilst waiting for warfarin to increase INR to the target range of 2-3
DVTs that do NOT extend above the knee=anticoagulated for 3 months
DVTs extending beyond the knee= anticoagulation for 6 months
Recurrent DVTs require long-term warfarin
Management plan for DVT- IVC Filter
May be used if anticoagulation is contraindicated and there is a risk of embolisation
Management plan for DVT- Prevention
Graduated compression stockings
Mobilisation
Prophylactic heparin (if high risk e.g. hospitalised patients)
