Pulmonary embolism Flashcards
List 9 non-modifiable risk factors for PE
DVT
Recent surgery
Immobility
Previous DVT/ PE
Malignancy
Anti phospholipid syndrome
Recent MI
Age
Pregnancy + 6w postpartum
List 4 modifiable risk factors for PE
Long duration travel
Obesity
COCP
Smoking
What occurs in a PE?
1 or more emboli (usually from clot in veins) lodges in + obstructs the pulmonary arterial system causing severe resp dysfunction
What are 3 broad causes of PE
Hypercoagulability (e.g. increased platelet adhesion, thrombophilia).
Venous stasis (e.g., varicosis, immobilization)
Endothelial damage (e.g., inflammation, trauma)
List 4 symptoms of PE
Dyspnoea
Pleuritic/ retrosternal chest pain
Syncope
Haemoptysis.
List 6 signs of PE
Tachypnoea + Hypoxia
Crackles
Tachycardia.
Fever
Elevated JVP
Systemic hypotension + cardiogenic shock.
What is the textbook triad of PE S/S? (only ~10% present like this)
Pleuritic chest pain
Dyspnoea
Haemoptysis
What is performed to determine next steps in suspected PE?
Well’s Score
Low Probability ,<4: use D-dimer
High Probability > 4: required imaging (CTPA)
What initial investigations should be performed in suspected PE?
ECG
CXR
What may CXR show in PE?
Usually normal (r/o other ddx)
May see wedge-shaped opacification
What may you see on an ECG in PE?
May be normal
Sinus tachycardia, RAD or RBBB
S1Q3T3 pattern (less common)
Which bloods would you perform?
ABG: reduced PaO2, reduced PaCO2 due to hyperventilation
Thrombophilia screen
What is the S1Q3T3 pattern?
S wave in lead 1
Q wave in lead 3
T-wave inversion in lead 3
How can a PE cause RBBB on ECG?
Increased pressure from the lung results in RV overload, leading to poorer perfusion of the right bundle
What is the preferred first investigation used for PE?
CT Pulmonary angiogram
Poor sensitivity for small emboli
VERY sensitive for medium to large emboli
If low clinical suspicion of PE, what assessment can be used?
PERC (PE r/o criteria)
What mneumonic can be used to remember the PERC criteria?
H- hormone use (oestrogen)
A- Age >50
D- DVT or PE hx
C- Coughing blood
L- Leg swelling disparity
O- O2 <95%
T- Tachycardia >100bpm
S- Surgery or Trauma (recent)
What assessment tool can be used to estimate clinical probability of PE? What do the results indicate?
2-level Wells Score
,< 4: PE unlikely
>4: PE likely
7 features of the 2-level Wells score
C- Clinical features of DVT (3)
A- Alternative dx less likely (3)
T- Tachycardia (1.5)
P- Previous DVT or PE (1.5)
I- Immobilisation >3 days (1.5)
C- Cancer (1)
H- Haemoptysis (1)
What is the initial management of a patient with a Wells score >4?
Admit + immediate CTPA
(if NA immediately, anticoagulant in interim)
If CTPA is negative in a patient with a Wells score >4, what should be performed?
Proximal leg vein USS
In a patient with renal impairment and a Wells score >4, what investigation is preferred?
V/Q scan
(doesn’t require contrast)
How should patients be further assessed with a Wells score of 4 or less?
D-dimer with results available within 4h (if >4 anticoagulate)
D-dimer +ve: CTPA
D-dimer -ve: consider alternative dx (+ stop interim anticoagulant)
What should be offered as interim anticoagulation if appropriate?
Apixaban
or
Rivaroxaban
(if unsuitable- 5 days LMWH, then Dabigatran)
