DVT

Question 1

What is the definition of DVT?

Answer 1

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

Question 2

What is the aetiology 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)

Question 3

What are the risk factors associated with DVT?

Answer 3

COCP

Post-surgery

Prolonged immobility

Obesity

Pregnancy

Dehydration

Smoking

Polycythaemia

Thrombophilia (e.g. protein C deficiency)

Malignancy

Question 4

What is the epidemiology of DVT?

Answer 4

VERY COMMON

Especially in hospitalised patients

Question 5

What are the presenting symptoms of DVT?

Answer 5

Swollen limb

May be painless

Question 6

What are the signs of DVT upon physical examination?

Answer 6

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 7

What are the appropriate investigations for DVT?

Answer 7

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 8

What is the management plan for DVT?

Answer 8

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 9

What are the possible complications of DVT?

Answer 9

PE

Venous infarction (phlegmasia cerulea dolens)

Thrombophlebitis (results from recurrent DVT)

Chronic venous insufficiency

Question 10

What is the prognosis for patients with DVT?

Answer 10

Depends on extent of DVT

Below-knee DVTs have a GOOD prognosis

Proximal DVTs have a greater risk of embolisation