Pulmonary embolism

Question 1

What is a pulmonary embolism?

Answer 1

Pulmonary artery circulation blocked by blood clot, typically embolism from DVT

Question 2

RF for PE

Answer 2

Virchows triad and fHx
Venous stasis, endothelial damage, hypercoagulability

Question 3

What causes Endothelial damage?

Answer 3

smoking, htn, trauma, vascular catheters

Question 4

What causes venous stasis?

Answer 4

Immobility (eg. long haul flight)
Post surgery
Varicose veins
AF

Question 5

What causes hypercoagulability?

Answer 5

Acquired = pregnancy, obesity, Malignancy, COCP (high oestrogen)

Inherited = Factor V Leiden, Anti phospholipid syndrome, Protein C+S deficiency

Question 6

How does a DVT go to develop a PE and the effects of a PE?

Answer 6

DVT embolisms and enters right heart via IVC

Occluding pul artery small vessels causes:
Increase A-a gradient (alveoli-arterial) - typically 1
V/Q decrease (ventilation with no perfusion)
Reactive bronchoconstriction therefore high dyspnoea + smaller airways

Embolus increases Pul BP = Pul htn which causes RV strain = COR PULMONALE + RHS HEART FAILURE

Question 7

Sx of DVT + PE?

Answer 7

Classically = Sudden onset SOB + Chest pain (pleuritic) with swollen calf (ie. DVT) + Hx of immobility (eg. after a flight/surgery)

Haemophysis (streaky bloody sputum often seen)
High JVP
tachypnoea
dyspnoea

Question 8

What are some signs of RHS heart failure?

Answer 8

hypotensive
tachy
peripheral oedema

Question 9

What is used to diagnose a PE/DVT?

Answer 9

wells score

<4 PE unlikely = D Dimer
Low = PE unlikely
High >500 = PE likely then CTPA

> 4 PE likely = CTPA (GS)
Normal = exclude PE
Clot diagnosed as PE

Question 10

If CTPA is CI, then what do you use?

Answer 10

V/Q scan

Question 11

What other tests would be used?

Answer 11

ECG
S1Q3T3
S waves deep In lead 1
Q waves very deep in lead 3
T waves inverted in lead 3
RBBB V1-3 = RSR pattern due to right axis deviation

Doppler USS = shows DVT (Vein doesn’t compress when squeezed)

Chest X ray = Usually NORMAL
Ddx = pleural effusion + pneumothorax - visible on chest x ray)

Question 12

Tx for PE?
If haemodynamically stable

Answer 12

haemodynamically stable = Anti coags
1st line = DOAC (Rivaroxaban, apixaban)
1st line if DOAC CI = LMWH
2nd line = warfarin

Question 13

Tx for PE?
If haemodynamically unstable

Answer 13

Thrombolysis
Clot buster = ALTEPLASE
If fails = catheter embolectomy

Question 14

Prophylaxis for DVT/PE?

Answer 14

compression stocking
regular walks
SC LMWH