VTE and PE

Question 1

Where are the common anatomic locations of deep venous thrombosis?

Answer 1

• Occur in the deep veins of the leg, orginating around the valves
• The most common veins to thrombose are the:
  
  • anterior tibial
  • posterior tibial
  • perineal
  • superficial femoral
  • popliteal vein

Question 2

What are risk factors for venous thrombosis?

Answer 2

Venous thrombosis often occurs in normal vessels, thus statsis and hypercoagulability factors are the main risk factors:

• Age/immobility
• Pregnancy/OCP
• Malignancy
• Obesity
• Surgery
• Previous DVT

Question 3

What is the Well’s score?

Answer 3

The Well’s score can refer to either:

• DVT probability scoring for diagnosing deep vein thrombosis OR
• Pulmonary embolism probability scoring for diagnosing pulmonary embolism

Wells criteria include the major risk factors and symptoms associated, and ask if another diagnosis is likely, to sort patients into high and low risk groups. Criteria include: active cancer, bedridden >3 days/major surgery, calf swelling >3cm compared to other leg, visible collateral veins, entire leg swollen, localised tenderness, pitting oedema (greater in symptomatic leg); paralysis/paresis/recent cast and previously documented DVT.

The maximum score is 9. A Wells’ score higher than one should raise clinical suspicion of DVT.

Question 4

What are the clinical features of a deep vein thrombosis?

Answer 4

Most DVTs are silent.

Classical clinical features:

• Calf tenderness & firmness
• Oedema
• Erythema & Calor
• Distension of superficial veins
• Superficial thrombophlebitis (tender, erythematous, palpable superficial vein)
• Homan’s sign (pain on dorsiflexion of the ankle, however this is unreliable and should not be tested for as it may dislodge the thrombus)

Some atypical presentations: ilio-femoral thrombosis can prevent severe pain, complete occlusion of a large vein can lead to cyanotic discolouration

Question 5

What investigations would you do for a patient with a suspected DVT?

What do they show?

Answer 5

• D-dimer:
  
  • D-Dimers are breakdown products of fibrin – and therefore formed by the process of fibrinolysis.
  • Highly sensitive - 80% (although not specific for DVT - increased in infection, pregnancy, malignancy and post-op)
  • Used to rule out DVT if negative combined with a low pretest clinical probability
• Compression USS
  
  • Non-collapsing veins indicate presence of DVTs
• Thrombophilia screen
  
  • Do prior to commencing anticoagulant therapy if there are no predisposing factors

Question 6

How can acute arterial ischaemia be differentiated from chronic venous insufficiency?

How can they both be differentiated from cellulitis?

Answer 6

Acute arterial ischaemia

• may be identified by the 6 Ps (pain, pallor, parasthesia, paralysis, pulseless, cold)

Chronic venous insufficiency

• will show VVV LAPS (varicose veins, venous ulcers, venous stars, lipodermatosclerosis, atrophy blanche, pitting oedema, scars).

Cellulitis

• an infection of the skin and underlying soft tissue, presenting with the four signs of inflammation: pain, heat, swelling, redness.

However, all should be considered in the patient presenting with the acute limb.

Question 7

What is a pulmomary embolism?

How are pulmonary emboli caused?

Answer 7

• A pulmonary embolism is a blockage in the pulmonary artery, the blood vessel that carries blood from the heart to the lungs
• Generally caused by DVTs in the legs

Question 8

How do PEs classically present?

What can they lead to?

When do they commonly occur?

Answer 8

• Present with
  
  • Sudden onset breathlessness
  • Pleuritic pain
  • Haemoptysis
  • (however should be included in almost any respiratory differential as they are so common and variable in presentation)
• They lead to increased pulmonary artery pressure (right heart strain) and ischaemia of the lung, with a ventilation/perfusion mismatch
• They often occur 10 days post-surgery

Question 9

How are pulmonary embolisms classified?

Answer 9

Massive PE (5%)

• >60% of the pulmonary circulation is blocked, leading to rapid cardiovascular collapse

Major PE (10%)

• middle-sized pulmonary arteries are blocked leading to breathlessness, pleuritic chest pain and haemoptysis

Minor PE (85%)

• small peripheral vessels are blocked, and patients may be aysmptomatic, or present as above (haemoptysis rare)
• Massive PE may ensure following a minor PE, which is known as the ‘premonitory embolus’

Question 10

What clinical signs would you see for a patient with a PE?

Answer 10

• Evidence of DVT
• Raised JVP
• Cyanosis if the embolus is large