Pulmonary Embolism Flashcards
What are the symptoms of a PE?
1) Sudden-onset SOB
2) Pleuritic chest pain (sharp pain when breathing deeply or coughing)
3) Haemoptysis
What additional symptoms can a massive PE present with?
Syncope, shock
What are the signs of a PE?
1) Tachycardia
2) Tachypnoea
3) Hypoxia
4) Low grade pyrexia
What are the additional signs in a massive PE?
1) Hypotension (esp. despite fluid resus) - clinical instability
2) Cyanosis
3) Raised JVP, parasternal heave, loud P2 (signs of RH strain)
How does a DVT present?
Unilateral swollen, tender calf
ECG findings in a PE?
Sinus tachycardia or normal
ECG findings in massive PE?
Evidence of RH strain:
1) P pulmonale
2) Right axis deviation
3) Right bundle branch block
4) Non-specific ST/T wave changes
What is the classic PE ECG pattern that is relatively uncommon < 20% of patients?
S1Q3T3
1) Deep S waves in lead I
2) Pathological Q waves in lead III
3) Inverted T waves in lead III
ABG results in a PE?
1) Type 1 respiratory failure (hypoxia without hypercapnia)
2) Respiratory alkalosis
What does respiratory alkalosis occur in a PE?
Hyperventilation secondary to hypoxia
Abnormal blood results in a PE?
1) Anaemia (if haemoptysis)
2) Raised CRP
Which blood tests need to be done if you suspect a PE?
1) U&E
2) Clotting function
Why do you need to do U&Es in a PE?
To assess renal function before CTPA
Why do you need to do clotting function blood tests in a PE?
Important if patient will be started on LMWH or Warfarin
What type of test is a D-dimer?
Blood test
When is a D-dimer useful?
Useful in ruling out PE if negative (95% negative predictive value) but highly non-specific - useful if clinical suspicion of a PE is low
What is the key diagnostic test for PE?
CTPA
What will a CTPA show in PE?
Filling defect in the pulmonary vasculature
What is the alternative diagnostic test for PE if CTPA is contraindicated?
V/Q scan
When is a V/Q scan preferred for diagnosing a PE?
1) Renal impairment
2) Contrast allergy
3) Pregnant
What imaging other than CTPA is done in PE diagnostic work up?
1) CXR
2) Lower limb duplex
2) Bedside echo
What are possible findings on a CXR in a PE?
1) Fleischner sign - enlarged pulmonary artery
2) Hampton’s hump - peripheral wedge shaped opacity
3) Westermark’s sign - regional oligaemia
Why is a CXR useful in PE diagnostic workup?
To rule out differentials e.g. pneumonia, PTX (typically normal in PE)
What is the first line investigation for PE in pregnancy (before a CTPA)?
Lower limb duplex
When is a lower limb duplex helpful in PE diagnosis?
If a DVT is thought to be the cause of the PE
When is a bedside echo used in PE diagnostic workup?
If the patient is thought to have a massive PE (signs of RH strain/hypotension)
Why is a bedside echo used in PE diagnosis?
To assess suitability for thrombolysis
Which scoring system is used in PE?
Well’s score
What is the Well’s score useful for in PE?
Risk stratifying patients with suspected PE
How are points allocated using the Well’s score?
3, 1.5 or 1 points
What scores 3 points on the Well’s score?
1) Clinical signs and symptoms of a DVT
2) If no alternative diagnosis is more likely than a PE
What scores 1.5 points on the Well’s score?
1) Tachycardia (HR > 100 bpm)
2) Patient has been immobile for > 3 days or has had major surgery within the last month
3) Previous PE or DVT
What scores 1 point on the Well’s score?
1) Haemoptysis
2) Active malignancy
What is the cut off point for the Well’s score?
4 points
If Well’s score is ≤ 4?
D-dimer should be measured
If D-dimer is low?
Exclude PE
If D-dimer is raised?
Indication for diagnostic imaging - CTPA or V/Q scan
If Well’s score > 4?
1) Further diagnostic imaging is required (CTPA)
2) LMWH typically administered in the interim if the clinical suspicion of PE is high (and defo administer if delay in performing CTPA)
How should a PE be acutely managed in the ED (short answer)?
Assessed using ABCDE
Describe the ABCDE findings in a PE
A - patent
B - tachypnoeic and hypoxic, oxygen should be administered
C - tachycardic, signs of RH strain suggest sub-massive PE, hypotension suggest massive PE, consider IV fluids if systolic BP < 90
D - nil
E - low grade pyrexia, signs of DVT, consider analgesia at this stage if required
What acute treatment is indicated in a massive PE (features of haemodynamic instability/cardiovascular compromise)?
Thrombolysis - IV bolus of alteplase
What is the key medical management of PE?
Anticoagulation
What method of anticoagulation is first line medical management of PE in the inpatient/emergency setting?
LMWH
What medical management should be started for PE in the outpatient setting?
Direct oral anticoagulants (DOACs) e.g. apixaban, rivaroxaban
Why is LMWH used for medical management of PE vs DOACs in inpatient/emergency setting?
Bc it is shorter acting
Which anticoagulation options can be considered for PE if neither LMWH or DOACs are suitable?
Dabigatran, edoxaban or warfarin
How long should LMWH be continued for when treating a PE?
At least 5 days
How long should warfarin be continued if using warfarin to treat a PE?
Until 48h of therapeutic INR (>2) has been achieved
If using dabigatran or edoxaban to treat a PE then how long should LMWH be used for?
5 days prior
What does the duration of anticoagulation treatment depend on?
The aetiology of the PE - provoked or unprovoked
What is a provoked PE?
A PE with identifiable risk factors e.g. surgery, peri-partum
How long should a provoked PE be treated for?
3 months
How long should an unprovoked PE be treated for?
6 months
What is an example of an ongoing cause of PE?
Thrombophilia
How long should a patient be treated for PE if there is an ongoing cause?
For life
How does recurrence of a VTE in a patient already on warfarin change their treatment?
It requires an increase in the target INR to 3-4
What are the two interventional management options for a PE?
1) Embolectomy
2) Inferior vena cava filter
When may an embolectomy be considered for management of a PE?
In patients with a massive PE when thrombolysis is contraindicted
When may an inferior vena cava filter be considered for management of a PE?
1) Patients with recurrent DVTs on warfarin
2) Patients in which anticoagulation is contraindicated
How can a massive PE appear on bedside echo?
Massive saddle PE
How does LMWH work in PE?
Anticoagulation - prevents any further clot from forming thus encouraging, but not directly causing, clot breakdown (can take longer to see clinical improvement than thrombolysis)
Why do patients with a massive PE that are clinically unstable require thrombolysis?
1) Important to treat these patients quickly, without delay, as there is high risk of further deterioration
2) Breakdown the clot and restore perfusion more rapidly than is possible with treatment dose LMWH
How are patients with a massive PE treated after thrombolysis is started?
Once thrombolysis has been performed the patient would then be started on treatment dose LMWH for a minimum of 3 months
What drugs are used as thrombolytic agents to treat massive PE?
Fibrinolytic drugs e.g. alteplase
What are contraindications to thrombolysis?
1) Any previous bleed within the CNS
2) Recent trauma or surgery
3) Known bleeding disorders
What is the first step in managing massive PE after diagnosing it on a bedside echo?
Thrombolysis - CTPA done later to confirm diagnosis but don’t delay treatment when clinically unwell and high suspicion (high risk of deterioration)
When is a prophylactic dose of LMWH used?
To prevent clots from forming in medical/surgical inpatients experiencing a period of reduced mobility
What are risk factors for PE?
Malignancy, immobility, leg swelling and tenderness (signs of DVT)
Why is alteplase (thrombolysis) only used in massive PE?
Bc of massive risk of bleeding and haemorrhagic stroke
Which drug can cause VTE?
Tranexamic acid - used in prevention of excessive blood loss (binds plasminogen preventing fibrin degradation)
