Pulmonary Embolism Flashcards
What are the causes of a PE?
- Most common - DVT from the pelvis/legs
- Right ventricular thrombus - Post MI
- Septic emboli - Right sided endocarditis
- Fat, air, amniotic fluid, neoplastic cells, parasites
What are the risk factors for PE?
- Recent surgery
- Thombophilia eg antiphospholipid syndrome
- Leg fracture
- Prolonged bed rest/reduced mobility
- Malignancy
- Pregnancy/postpartum, COCP, HRT
- Previous PE
What are the symptoms of PE?
Small emboli - May be asymptomatic
Large emboli - Acute breathlessness, pleuritic chest pain, haemoptysis, dizziness, syncope
What are the signs of PE?
Pyrexia, cyanosis, tachypnoea, tachycardia, hypotension, raised JVP, pleural rub, pleural effusion
- Look for signs of DVT
How would you investigate a suspected PE?
- Bloods - FBC, U+E, baseline clotting, D-dimers
- aBG - Low O2 and CO2
- Imaging - CXR may be normal. CTPA.
- ECG - Normal. may show tachycardia, RBBB, right ventricular strain, SI, QIII, TIII
What is the treatment for PE if haemodynamically unstable?
Thombolyse for massive PE - Alteplase 10mg IV over 1 min, then 90mg IVI over 2hrs, max 1.5mg/kg if <65kg
What is the treatment for PE if haemodynamically stable?
- Start LMWH/unfractionated heparin if renally impaired
- Start DOAC/warfarin. For warfarin, stop heparin when INR is 2-3 due to initial prothombotic effect of warfarin.
- Consider placement of vena caval filter if contra-indication to anticoagulation
What must you consider in unprovoked PE?
Consider underlying malignancy -
- Full history, examination, CXR, FBC, calcium, LFT’s, urinalysis
- If over 40, consider abomino-pelvic CT and mammography in women
- Consider antiphospholipid and thombophilia testing if family history positive
How can you prevent a PE?
- Give heparin to all immobile patients
- Stop HRT and COCP pre-op
How can you assess the clinical probability of a PE?
Well’s criteria
Clinical signs and symptoms of DVT - 3points
HR>100 - 15points
Recently bed ridden (>3days) or major surgery (<4weeks) - 15points
Previous DVT/PE - 15points
Haemoptysis - 1point
Cancer recieving treatment, treated in past 6/12, palliative - 1point
An alternate diagnosis is less likely than PE - 3points
Score <4 = PE unlikely Score>4 = PE likely
If Well’s score is over 4, what is your next step?
Immediate CTPA or treat empirically (LMWH) if delay
If Well’s score is under 4, what is your next step?
Do D dimer
If the patient is D dimer positive, what is your next step?
Immediate CTPA or empirical treatment LMWH
If the patient is D dimer negative, what is your next step?
Consider alternative diagnosis
What is the length of treatment in a provoked PE?
Three months and reassess risk to benefit profile
What is the length of treatment in an unprovoked PE?
Over 3 months even if no identifiable risk factor
What is the length of treatment in a malignancy related PE?
Continue treatment for LMWH for 6 months or until cure of cancer
What is the length of treatment in a pregnancy related PE?
Continued until delivery/end of pregnancy
What is a provoked PE?
A PE that occurs within 3 months of a transient major clinical risk factor eg trauma, surgery
What is unprovoked PE?
A PE that occurs with no major risk factor or with a risk factor that remains constant in a patient eg malignancy, family history of VTE, thrombophilia
What are the 3 main consequences of getting a PE pathophysiologically?
- Pulmonary infarction
- Impaired gas exchange - V/Q mismmatch
- Cardiac compromise - RV overload, causing right sided heart failure, leading to hypotension and tachycardia, then shock and cardiac arrest secondary to arrythmias
