Deep vein thrombosis (DVT)

Question 1

Define DVT

Answer 1

Formation of a thrombus within the deep veins (most commonly in the calf or thigh)

Question 2

Explain the aetiology/risk factors of DVT

Answer 2

Deep veins in the legs are more prone to blood stasis, hence clots are more likely to form (look up Virchow’s triad)

Risk Factors
COCP
Post-surgery
Prolonged immobility
Obesity
Pregnancy
Dehydration
Smoking
Polycythaemia
Thrombophilia (e.g. protein C deficiency)
Malignancy

Question 3

Summarise the epidemiology of DVT

Answer 3

VERY COMMON

Especially in hospitalised patient

Question 4

Recognise the presenting symptoms of DVT

Answer 4

Swollen limb

May be painless

Question 5

Recognise the signs of DVT on physical examination

Answer 5

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

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

Question 6

Identify appropriate investigations for DVT

Answer 6

Doppler Ultrasound-GOLD STANDARD

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

Question 7

Generate a management plan for DVT

Answer 7

ANTICOAGULATION

Heparin whilst waiting for warfarin to increase INR to the target range of 2-3

DVTs that do NOT extend above the knee may be observed and anticoagulated for 3 months

DVTs extending beyond the knee require anticoagulation for 6 months

Recurrent DVTs require long-term warfarin

IVC Filter - May be used if anticoagulation is contraindicated and there is a risk of embolisation

Prevention
Graduated compression stockings
Mobilisation
Prophylactic heparin (if high risk e.g. hospitalised patients)

Question 8

Identify possible complications of DVT

Answer 8

PE
Venous infarction (phlegmasia cerulea dolens)
Thrombophlebitis (results from recurrent DVT)
Chronic venous insufficiency

Question 9

Summarise the prognosis for patients with DVT

Answer 9

Depends on extent of DVT
Below-knee DVTs have a GOOD prognosis
Proximal DVTs have a greater risk of embolisation