Pulmonary embolism

Question 1

How does a patient with PE typically present?

Answer 1

Sudden-onset, pleuritic CP w/ SOB +- haemoptysis

Massive PE can present as cardiac arrest

Should be suspected in all breathless patients with RF for DVT or proven DVT

Question 2

What would you expect to find on examination?

Answer 2

Tachycardia + tachypnoea

Signs of raised right heart pressure + cor pulmonale

Cyanosis –> large PE

Pleural rub or effusion

Lower limbs –> thrombophlebitis

Mild fever can be present

Question 3

What are some causes of PE?

Answer 3

Secondary to DVT

Septic emboli

Fat embolism

Air embolism

Amniotic fluid

Neoplastic cells

Foreign materials

Question 4

What are some risk factors for DVT?

Answer 4

Procoagulant states:

1. Congenital –> Factor V Leiden, Protein C/S deficiency
2. Acquired –> malignancy, APS, OCP, nephrotic syndrome, myeloproliferative disorders

Venous stasis –> immobility, surgery, pregnancy, obesity

Miscellaneous –> hyperviscosity syndromes, previous DVT, FHx

Question 5

What general investigations would you order for someone with suspected PE?

Answer 5

ECG –> sinus tachycardia, non-specific ST/T changes in anterior leads, classical changes of acute cor pulmonale (rare)

ABG –> can be normal, likely red. PaO₂, mild resp alkalosis

CXR –> can be normal, in fact a normal CXR with severe respiratory signs is v telling (signs = Westermark’s)

Bloods –> FBC, CK, trop? kinda useless

Question 6

What investigations could you order to look for underlying cause for PE?

Answer 6

USS deep veins of legs

USS abdomen and pelvis –> ? occult malignancy

Procoagulation screen

Autoimmune screen –> anticardiolipin antibody, ANA

Biopsy of suspicious LN / masses

Question 7

What are some specific investigations for pulmonary embolism?

Answer 7

D-dimer –> negative has 95% accuracy in excluding PE

VQ scan –> should be performed in all suspected cases. Normal scan rules out significant-sized PE, therefore low probability for PE

Question 8

What is the ‘gold-standard’ and recommeded lung imaging modality for PE?

Answer 8

‘gold-standard’ –> pulmonary angiography + can give direct thrombolysis (evidence is suggesting MRPA as good)

CTPA –> recommended with non-massive PE, has >90% S+S

Question 9

What are the key points in management of PE?

Answer 9

Oxygen

PE suspected –> start LMWH

PE confirmed –> start warfarin, continue LMWH until INR is 2-3

Analgesia

Hypotensive –> IV fluids

Evidence haemodynamic instability –> thrombolysis

Question 10

What are some indiciations for an inferior vena cava filter?

Answer 10

Tbh, not often used as little to suggest improved mortality

1. Anticoagulation is contraindicated
2. Anticoagulation failure despite OMT
3. Prophylaxis in high-risk pt

Question 11

What thrombolytic agents would you use for PE?

Answer 11

Refer to local hospital protocol and consult the BNF + senior etc etc

ALTEPLASE –> 100mg over 2h or 0.6mg/kg over 15 min (max 50mg), followed by heparin

STREPTOKINASE –> 250 000U over 30min, followed by 100 000U/h infusion for 24h