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 of DVT

Answer 2

Deep veins in the legs are more prone to blood stasis, hence clots are more likely to form

(Virchow’s triad: Blood stasis, Blood hypercoagulability, Vessel wall injury)

Question 3

Risk factors for DVT

Answer 3

COCP
Post-op
Prolonged immobility (long haul flights/travel)
Obesity
Pregnancy
Dehydration
Smoking
Polycythaemia
Thrombophilia (protein C deficiency)
Malignancy

Question 4

Summarise the epidemiology of DVT

Answer 4

• VERY COMMON

* Especially in hospitalised patients

Question 5

Recognise the presenting symptoms of DVT

Answer 5

• Swollen limb

* May be painless

Question 6

Recognise the signs of DVT on physical examination

Answer 6

• Examination of the Leg
o Local erythema, warmth and swelling
o Measure the leg circumference
o Varicosities (swollen/tortuous vessels)
o Skin colour changes
o HOMANS SIGN - forced passive dorsiflexion of the ankle causes deep calf pain

• Examine for PE
o Check respiratory rate, pulse oximetry and pulse rate

Question 7

How is risk stratified in DVT patients

Answer 7

Risk is stratified using the WELLS CRITERIA
Score 2 or more = high risk

(NOTE: this is different from the PE Wells criteria)

Question 8

Identify appropriate investigations for DVT

Answer 8

• Doppler Ultrasound - GOLD STANDARD
• Impedance Plethysmography - changes in blood volume results in changes of electrical resistance

• Bloods
o D-dimer: can be used as a negative predictor
o Thrombophilia screen if indicated

Question 9

What extra investigations will you perform if a PE is suspected?

Answer 9

o ECG
o CXR
o ABG

Question 10

Generate a management plan for DVT

Answer 10

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

o DVTs that do NOT extend above the knee may be observed and anticoagulated for 3 months
o DVTs extending beyond the knee require anticoagulation for 6 months

o Recurrent DVTs require long-term warfarin

IVC FILTER
o May be used if anticoagulation is contraindicated and there is a risk of
embolisation

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

Question 11

What is INR?

Answer 11

The international normalised ratio (INR) is a laboratory measurement of how long it takes blood to form a clot.

Normal range: 2-3

Question 12

Identify possible complications of DVT

Answer 12

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

Question 13

Summarise the prognosis for patients with DVT

Answer 13

Depends on extent of DVT:

• Below-knee DVTs have a GOOD prognosis
• Proximal DVTs have a greater risk of embolisation