What are the causes of pulmonary embolism? Can it be treated?

1 Answer

When clots from deep venous system break off and travel to the lungs, Pulmonary Embolism (PE) occurs.

Most emboli arise from Ileo-femoral thrombosis, may also come from pelvic and upper extremity veins.

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Risk Factors:

  • Lower extremity venous disease
  • Cancer
  • Congestive Heart Failure (CHF)
  • Recent surgery
  • Immobilization
  • Family history
  • Pregnancy
  • Paraplegia
  • Previous Deep Venous Thrombosis (DVT)
  • Oral Contraceptive Pills (OCP) use
  • Trauma
  • Hypercoagulable state (factor V Leiden, antiphospholipid antibody, protein C and S deficiency)

Non-thrombotic PE:

  • Fat embolus
  • Air embolus
  • Amniotic fluid embolism


  • > 50% of PE are undiagnosed
  • 90% of PE arises from a lower extremity DVT
  • 50% of patients presenting with DVT have concomitant PE

Virchow’s triad indicates increased the risk of thrombus formation, endothelial trauma, stasis, and hypercoagulability.

Signs and Symptoms:

  • Dyspnoea
  • Pleuritic chest pain
  • Tachypnoea
  • Tachycardia
  • Anxiety
  • A cough
  • Crackles
  • Fever
  • Haemoptysis due to pulmonary infarction
  • Edema
  • Calf tenderness
  • Homan’s sign (pain with plantar flexion)
  • Hypotension
  • Signs of acute right heart dysfunction


  • Pulmonary Angiogram
  • Ventilation-Perfusion Ratio (V/Q) scan
  • Helical (Spiral) CT
  • D-Dimer
  • Lower Extremity Venous Duplex Scanning
  • Arterial Blood Gas (ABG)
  • Chest X-Ray
  • ECG: normal or tachycardia, may see S1Q3T3 or RV strain.


  • Oxygen therapy.
  • Anti-coagulation: IV Heparin or LMWH (less bleeding, improved mortality) when PE is clinically suspected; coumadin therapy should follow for at least 6 months and may need to be continued indefinitely depending on the underlying cause.
  • IVC filter: consider if anticoagulants are contraindicated, recurrent embolism despite anticoagulation, massive PE, or poor baseline cardiac or pulmonary status.
  • Systemic Thrombolytic Therapy: consider in massive PE with Hypotension or refractory hypoxemia
  • Pulmonary Embolectomy: occasionally used in refractory hypotension and proven pulmonary emboli.
  • IV Fluids, Norepinephrine, consider thrombolysis or surgery.
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