Pulmonary Embolism (PE)
Background and Definition
A pulmonary embolism (PE) is a life-threatening acute condition where one or more emboli become lodged in the pulmonary arterial system, causing severe respiratory dysfunction and obstructed blood flow.
In the vast majority of cases, these emboli arise from a blood clot (thrombus) formed in the deep veins-most commonly a deep vein thrombosis (DVT) in the lower limbs. Left untreated, PE has a high mortality rate and a generally poor prognosis. Even following treatment, patients may develop long-term complications, such as chronic thromboembolic pulmonary hypertension (CTEPH).
Key Risk Factors
PE should be heavily suspected if a patient presents with symptoms and possesses one or more of the following major risk factors:
- History of DVT or previous PE
- Recent surgery or lower limb trauma
- Significant immobility (e.g., bedridden for >3 days)
- Active cancer (ongoing treatment, palliative, or diagnosed within the last 6 months)
- Pregnancy and the postpartum period (specifically up to 6 weeks postpartum)
- Increasing age or family history of DVT
- Medical conditions like Antiphospholipid antibody syndrome or recent myocardial infarction
- Other factors: Combined oral contraception, hormone replacement therapy (HRT), smoking, obesity, and long-duration travel.