pulmonary embolism Flashcards
What is a pulmonary embolism? What causes it?
blood clot (thrombus) forms in the pulmonary arteries. usually the result of a deep vein thrombosis (DVT) that developed in the legs and travelled (embolised) through the venous system and the right side of the heart to the pulmonary arteries in the lungs.
How do PE’s cause symptoms?
they block the blood flow to the lung tissue and create strain on the right side of the heart
What are the risk factors for PE’s? 9
- Immobility 2. Recent surgery 3. Long haul flights 4. Pregnancy 5. Hormone therapy with oestrogen 6. Malignancy 7. Polycythaemia 8. Systemic lupus erythematosus 9. Thrombophilia
How do PE’s present?
top 3 = triad chest pain - typically pleuritic dyspnoea haemoptysis tachycardia tachypnoea respiratory examination - classically the chest will be clear
What is the PERC criteria and when is it used?
Used when probability of PE is low (<15%)
What is the criteria in the wells score?
When is a PE likely?
If PE is likely after Well’s what should you do?
Arrange a CTPA
If PE is likely according to Well’s score but CTPA has been delayed what is the next step?
Start on anticoagulant - one that can be continued if positive = DOAC
Epixiban or Rivaroxoban
If CTPA is negative what can you do?
consider a proximal leg vein ultrasound scan if DVT is suspected
What is the investigations protocol for PE?
When is V/Q scan preferable to CTPA?
If renal impairment - does not require contrast
What should you do with D-dimer for those over 50?
Age adjust
Besides D-dimer/ CTPA what other investigations are needed?
CXR for all - typically normal in PE
ECG
What are ECG findings in PE?
S1Q3T3
Large S wave in Lead I
Large Q wave in Lead III
Inverted T wave in Lead III
Right bundle branch block and left axis deviation also associated
sinus tachycardia may be seen
What ABG finding is seen in PE?
How does it differ from the other cause of this finding?
Respiratory Alkalosis
(tachycardia means they blow of C02)
one of the few causes, another being hyperventilation syndrome
Difference: 02 is low in PE
02 is high in Hyperventilation syndrome
When is LMWH followed VKA used instead of DOAC in PE?
Severely impaired kidney function
Antiphospholipid syndrome
How long should anticoagulants be continued for?
All patients should have 3 months
If provoked - stopped
If unprokoed or active cancer - continue to 6 months
HASBLED score can be used to assess bleeding risk
When is thrombolysis recommended?
What does it involve?
When there is a massive PE leading to haemodynamic comrpomise e.g hypotension
injecting fibrinolytic med which breaks down fibrin which dissolves the clot
When is thrombolysis used?
What is an example of a thrombolytic agen?
Where there is a massive PE where benefit outweighs risk (i.e bleeding)
Alteplase
streptokinase
What may someone be offered if they have repeated PE’s despite anticoagulation?
IVC filter
prevent clots formed in deep vein of the legs moving to the pulmonary arteries
