Pulmonary Embolism

Question 1

When does a pulmonary embolism classically occur?

Answer 1

10-12 days after a DVT

Question 2

Define embolism

Answer 2

The movement of material from one part of the circulation to another

Question 3

What is a pulmonary embolism?

Answer 3

Material has passed through the R side of the heart and has lodged in the pulmonary arteries

Question 4

Name some embolic material

Answer 4

Thrombus

Air

Fat

Amniotic fluid

Tumour

Bullet

Question 5

What is the primary cause of pulmonary embolism?

Answer 5

90% arise from DVT in popliteal vein and more proximal veins including the pelvic veins

Question 6

What are the risk factors for DVT and PE?

Answer 6

Age >40

Surgery >30 mins (trauma) = blood shift toward prothrombotic

Obesity

Cancer

Prolonged immobilisation

Previous thromboembolism

Heart failure

Contraceptive pill

Preg

HRT

Question 7

Outline the possible outcomes of PE

Answer 7

Sudden death

Asymptomatic

Question 8

How are pts categorised with regards to PE

Answer 8

Shock/hypotension present?

Yes = high-risk (20%)

No = low risk (80%)

Question 9

Outline the pathophysiology of PE

Answer 9

1) R ventricular overload = pulmonary artery pressure increases = R ventricle dilation = inotropes released to maintain systemic BP = pulmonary artery vasoconstriction = exacerbates the situation = main cause of death
2) respiratory failure = ventilation perfusion mismatch, low R ventricle output
3) pulmonary infarction = small distal emboli = alveolar haemorrhage = haemoptysis, pleuritis, pleural effusion

Question 10

What is a paradoxical embolism?

Answer 10

1/3 of pts = patent foramen ovale = R to L shunting of emboli

Can cause stroke

Question 11

What is pleuritic pain?

Answer 11

Pain on inspiration

Pathology in pleura = pneumonia, PE

Question 12

What are the possible symptoms of PE?

Answer 12

Dyspnoea

Pleuritic chest pain

Cough

Substernal chest pain (heart struggling to pump)

Fever

Haemoptysis

Syncope

Unilateral leg pain

Question 13

What is a differential diagnosis of sudden onset pleuritic chest pain?

Answer 13

MI

Pneumothorax

Pneumonia/pleurisy

Question 14

What physical signs can be identified in PE?

Answer 14

Pleural rub

Raised JVP = reflect R ventricular failure

Question 15

What investigations can be used to identify PE?

Answer 15

CXR = normal in PE, used to exclude other diagnoses

ECG = may show signs of right ventricular strain, S1 Q3 T3

Blood gases = hypoxaemic and hypocapnia due to hyperventilation

D-dimer = normal d-dimer rules out PE

CT pulmonary angiography

Question 16

What is d-dimer?

Answer 16

Fibrin degradation product

Not normally present

Question 17

How is PE treated?

Answer 17

Oxygen

Immediate heparinisation = stop thrombus propagation, fibrinolytic system then dissolves clot clot away

Haemodynamic support

Exogenous fibrinolytics

Percutaneous catheter directed thrombectomy

Surgical pulmonary embolectomy

Warfarinise pt for 3 months

Those that cant be warfarinised = inferior vena cava filter