Pulmonary embolism Flashcards
Where do most thrombi originate?
Deep veins of calf or pelvis
How common are PEs?
Fairly common - 12% of PMs show PEs
Predisposing factors for a PE
- Immobile
- Contraceptive pill
- Malignancy (pancreas, uterus, breast and stomach)
- Heart failure
- Post operative
- Fractures of pelvis or lower limb
- Hypercoagulable states e.g. pregnancy
Clinical features of PE
- Dyspnoea
- Tachypnoea
- Pleuritic pain
- Apprehension
- Tachycardia
- Cough
- Leg pain
Discuss clinical presentation of a massive PE
- Sudden onset severe chest pain and dyspnoea
- Onset often occurs when patient goes for a poo 💩 - the idea that the act of defecation is a trigger acute embolism in patients with DVTs
- If patient has had surgery, classically occurs around a week after the op
- Signs of shock
- Right ventricular heave, prominent A wave in JVP
Why would a PE cause a prominent A wave on JVP?
Saddle PE blocks blood from leaving the right ventricle therefore there is nowhere for blood from the right atria to pump into meaning that when the atria contract there is a marked increase in the A-wave which indicates atrial contraction
What is an infarct?
Area of dead tissue/ necrosis secondary to ischaemia
What are the causes of PE other than thromboemboli?
- Fat emboli after injury to subcut fat or fatty marrow following fracture
- Air
- Tumour cells in capillary bed
- Amniotic fluid (very rare, amniotic fluid enters mother’s blood stream and causes a reaction, disseminated intravascular coagulation occurs followed by massive bleeding due to the fact that all clotting factors have been used up)
Which patients are admitted immediately when PE is suspected?
- If they are showing signs of haemodynamic instability: pallor, tachycardia, hypotension, shock and collapse
- They are pregnant or had a baby in the past 6 weeks
**If neither of the above apply but PE suspected - use the PE Wells score
What is the PE Wells score?
Used to predict clinical probability of PE
Criteria:
- Clinical signs of DVT: +3
- HR >100bpm: +1.5
- Immobilisation for 3 days or surgery in last 4 wk: +
- Previous DVT/ PE: +1.5
- Haemoptysis: +1
- Cancer: +1
- Alternative diagnosis is less likely than PE: +3
SCORE OF 5 OR MORE - PE LIKELY 😬
SCORE OF 4 OR LESS - PE UNLIKELY
What if a patient has a PE Wells score of 5+?
This means a PE is likely - admit them for an immediate CTPA (CT pulmonary angiography)
**If CTPA cannot be carried out straighaway, give therapeutic anticoagulant and arrange admission
What if your patient has a PE Wells score of 4 or less?
This means a PE in unlikely (but not impossible!)
- Offer a D-dimer test with a result within 4hrs
- If you can’t get a result within 4hrs, give anticoagulant
- D-dimer result positive - DO CTPA
- D-dimer result negative - stop any anticoagulant and consider a differnt diagnosis
Which anticoagulants are given to patients with suspected PE?
ApiXaban and RivaroXaban
What are D-dimers?
They are degradation products of cross-linked fibrin and are released into the circulation when a thrombus begins to dissolve
Is the presence of D-dimers in the blood diagnostic of PE?
No because they can be elevated in infection, malignancy and post surgery
But if a patient is suspected to have a PE, a Wells score of <4 and a + D-dimer result - arrange a CTPA
What is a ventilation perfusion scan?
Nuclear medicine scan that uses radioactive material to examine ventilation and perfusion of the lungs
Radioactive material is breathed in and pictures or images are taken to look at the airflow in the lungs. In the second part, a different radioactive material is injected into a vein in the arm, and more images taken to see the blood flow in the lungs
Image of saddle embolus
