What Is a Pulmonary Embolism?
A pulmonary embolism occurs when a blood clot (usually from a DVT in the leg) travels through the bloodstream and lodges in the pulmonary arteries of the lungs, blocking blood flow. It ranges from mild to immediately life-threatening.
Emergency — Call 999/911 If:Sudden shortness of breath | Sharp chest pain (worse on breathing in) | Rapid heart rate | Coughing up blood | Collapse or loss of consciousness.
Symptoms of PE
- Sudden, unexplained breathlessness
- Pleuritic chest pain (sharp, worse on breathing in)
- Haemoptysis (coughing up blood)
- Rapid heart rate (tachycardia)
- Low oxygen levels
- Feeling faint or actually fainting
- Signs of DVT in one leg (swelling, pain)
Diagnostic Tests
| Test | Purpose |
|---|---|
| D-dimer blood test | A negative result in low-probability cases rules out PE |
| CT Pulmonary Angiogram (CT-PA) | Gold standard — directly visualises clots in pulmonary arteries |
| Oxygen saturation | Low SpO2 raises suspicion |
| ECG | Shows sinus tachycardia or classic S1Q3T3 pattern |
| Arterial blood gas (ABG) | Hypoxia and hypocapnia in PE |
| Troponin + BNP | Right heart strain markers — gauge severity |
| Echocardiogram | Right ventricular strain in massive PE |
Treatment
- Anticoagulation immediately — DOACs or LMWH
- Massive PE: thrombolysis (clot-busting drugs) or surgical embolectomy
- Oxygen supplementation
- Pain relief
- Duration of anticoagulation: 3–6 months minimum
FAQs
Is a PE the same as a heart attack?
No — heart attack is a blocked coronary artery supplying the heart muscle. PE is a blocked pulmonary artery supplying the lungs. Both are emergencies.
Can PE occur without DVT symptoms?
Yes — up to 50% of PE patients have no obvious leg symptoms. The clot may have dissolved by the time PE develops.
What is a Wells score?
A clinical probability score used to estimate likelihood of PE and guide whether D-dimer testing or CT-PA is appropriate.
Medical Disclaimer: Pulmonary embolism is a medical emergency. Seek immediate emergency care if you have sudden breathlessness and chest pain.