Deep vein thrombosis Flashcards
Define DVT
Formation of a thrombus within the deep veins (most commonly in calf or thighs)
Aetiology of DVT
Deep veins in the legs are more prone to blood stasis, hence clots are more likely to form (Virchow’s triad)
Risk factors for DVT
10
COCP Post surgery Prolonged immobility Obesity Pregnancy Dehydration Smoking Polycythaemia Thrombophilia (e.g. protein C deficiency) Malignancy
Epidemiology of DVT
prevalence, group
VERY COMMON
Especially in hospitalised patents
Presenting symptoms of DVT
2
Swollen limb
May be painless
Signs of DVT on physical examination
5
Local erythema, warmth & swelling Measure leg circumference Varicosities (swollen/tortuous veins) Skin colour changes Homan’s sign = forced passive dorsiflexion of ankle causes deep calf pain
Signs of DVT on physical examination - risk stratification
2
WELLS CRITERIA
Score 2 or more is high risk
Signs of DVT on physical examination - examine for PE
Check resp rate, pulse oximetry & pulse rate
Investigations for DVT
4 groups
Doppler US
Impedance plethysmography
Bloods
If PE suspected
Investigations for DVT - doppler US
GOLD STANDARD
Investigations for DVT - impedance plethysmography
Changes in blood volume result in changes of electrical resistance
Investigations for DVT - bloods
2
D-dimer - can be used as negative predictor
Thrombophilia screen if indicated
Investigations for DVT - if PE suspected
3
ECG, CXR, ABG
Management of DVT
3 groups
Anticoagulation
IVC filter
Prevention
Management of DVT - anticoagulation
4
Heparin whilst waiting for warfarin to increase INR to target range of 2-3
DVTs that do not extend above the knee may be observed & anticoagulated for 3 months
DVTs extending beyond the knee require anticoagulation for 6 months
Recurrent DVTs require long term warfarin
