Thromboembolic disease: PE (R1)

Question 1

Pathophysiology of PE?

Answer 1

• Usually arises from embolisation of DVT
• Blockage in the pulmonary arteries –> capillaries
• Impaired gas exchange leads to hypoxia and hypercapnia. This stimulates drive to breathe (SOB)
• Also leads to pulmonary infarction

Question 2

Complications
- 3 acute complications?
- Is there a high risk of recurrence?

Answer 2

Shock: less blood reaches left ventricle –> reduced CO
Acute cor pulmonale: increased resistance in pulmonary arteries …
Death

Yes, there is a high risk of recurrence.

Question 3

History:
- Symptoms of PE?

Answer 3

Pleuritic chest pain
SOB (may only be exertional!)
Cough +- haemoptysis
Palpitations
Syncope/fainting

Question 4

Exam
- Vitals?
- Importance of taking exertional vitals in PE?
- Are there additional exam findings in your notes?

Answer 4

↑HR, ↑ RR, ↓BP, ↓ PO2
Potentially ↑ temperature - if infection related

Yes - some people may only show vitals on exertion

Yes

Question 5

Investigations
- Bedside: supportive test?

Answer 5

ECG

Question 6

Investigations
- Bedside: ECG
What may it show?

Answer 6

• Most common: sinus tachycardia
• May be normal
• Signs of right heart strain
• S1 Q3 T3 (uncommon):
  
  • S1: deep S waves in lead I
  • Q3: deep Q waves in lead III
  • T3: T wave inversion in lead III

Question 7

Investigations: labs
- Smoking gun?

Answer 7

D dimer

Question 8

Investigations: D dimer
- When should it be used?
- What to do if you get a positive result?

Answer 8

If there is a moderate to high probability of PE
Go straight to imaging

Question 9

Investigations: labs
- What supportive tests?

Answer 9

Baseline FBC, UEC, LFT, coagulation studies

Troponin: may be a low grade rise

ABG: if low PO2

Question 10

Investigations: imaging
- What are the 2 modalities?

Answer 10

CT pulmonary angiogram
VQ scan

Question 11

Investigations: imaging
- What is the finding of PE in each?
- Why might a VQ scan be used instead of a CT PA?

Answer 11

CT PA: filling defects
VQ scan: area of ventilation that is not perfused

VQ scan would be used if:
- The patient has poor lung function (smoker, COPD etc)
- Pregnant
- Renal impairment or contrast allergy

Question 12

Management
- If hemodynamically unstable?

Answer 12

Question 13

Management
- Ongoing management?

Answer 13

Anticoagulants
- DOACs: apixaban and rivaroxaban (factor Xa inhibitors)
- LMWH : enoxaparin (Clexane) - if contraindicated to the above

Question 14

Management: ongoing
- Timing of anticoagulation if the PE is unprovoked versus provoked?

Answer 14

Provoked: can usually stop anticoagulants after 3 months
Unprovoked: ongoing

Question 15

Management:
Treatment if contraindicated to anticoagulants, or recurrent VTE despite adequate anticoagulation therapy?

Answer 15

IVC filter

Question 16

Explaining a PE to a patient

Answer 16

Question 17

Explaining to a patient
- Anticoagulation
- Thrombolysis
- Percutaneous catheter directed thrombolysis
- Surgical embolectomy

Answer 17

Anticoagulation: stop the clot from growing, so it can naturally break down.
Thrombolysis: dissolving the clot; given via IV
Percutaneous catheter directed thrombolysis: via a thin tube (catheter) to the clot directly
Surgical embolectomy: surgery to remove the clot