Pulmonary Embolism

Question 1

What is a PE and where do they most commonly derive from?

Answer 1

A blood clot in the lung vasculature

- 75% derived from DVT

Question 2

Presentation of PE?

Answer 2

Acute-onset pleuritic chest pain + SoB

- also commonly features fever and tachycardia

Question 3

CXR findings in PE?

Answer 3

Wedge-shaped opacity due to consolidation associated with pulmonary infarction (Hampton hump)

Question 4

What is the Westermark sign?

Answer 4

A focus of oligaemia (hypovolaemia) in x-ray distal to an occluded blood vessel - visual loss of obvious blood vessels on CXR

Question 5

ECG findings in PE?

Answer 5

Sinus tachycardia is most common
S1Q3T3 is characteristic
- S-wave in lead I, Q-wave and inverted T-wave in lead III

Question 6

ABG findings in PE?

Answer 6

Type 1 respiratory failure

- V/Q mismatch, reduced perfusion with normal ventilation

Question 7

What are D-dimers and what are the findings relevant to investigation of PE?

Answer 7

D-dimers are breakdown products of clots

• low D-dimer excludes PE
• high D-dimer does not confirm it

Question 8

How is the next investigation in PE indicated?

Answer 8

CXR findings

Question 9

CXR findings and their corresponding next investigations?

Answer 9

CXR clear - perform V/Q scan to look for areas receiving air but not blood

CXR not clear and/or V/Q scan inconclusive - spiral CT (CT pulmonary angiography CTPA)

Question 10

How do V/Q scan results affect management?

Answer 10

Normal V/Q scan excludes PE in patients with low clinical probability
Will either show the above, be inconclusive, or identify the PE so no need for further tests

Question 11

How do CTPA results affect management?

Answer 11

Good negative CTPA do not require any further investigation/treatment for PE
- may also offer an alternative diagnosis when PE is excluded

Obviously will show the PE otherwise thus being diagnostic

Question 12

Treatment of PE?

Answer 12

Heparin/LMWH in the short-term

Moved onto warfarin for 6 months, aiming for an INR of 2 to 3

Question 13

What investigation is useful in identifying a massive PE and what is seen?

Answer 13

Echocardiography

• acute dilatation of right heart
• visible thrombus

Question 14

How does management change in massive PE from normal one?

Answer 14

Urgent thrombolysis is needed

- once stabilised, on to warfarin for prophylaxis