Pulmonary Embolism
Also known as PE, Blood clot on the lung
This article is general health information for the selected condition. It is not a diagnosis and does not replace clinical judgement. If you have questions or need treatment advice, please consult a qualified healthcare professional.
What is pulmonary embolism?
A pulmonary embolism occurs when a blood clot, usually travelling up from a deep vein in the leg, lodges in an artery in the lungs. It blocks blood flow and strains the right side of the heart. It is a common and frequently missed emergency, and it should be considered in anyone with sudden breathlessness or sharp chest pain, particularly after surgery, immobility or a long flight.
Causes
- Clot travelling from a deep vein thrombosis in the leg or pelvis
- Immobility after surgery, illness or long travel
- Cancer and its treatments
- Pregnancy and the period after birth
- Combined hormonal contraception or hormone therapy
- Inherited clotting disorders
Symptoms
- Sudden breathlessness
- Sharp chest pain that is worse on breathing in
- Coughing, sometimes with blood
- Rapid heartbeat
- Light headedness or fainting
- Anxiety and sweating
- Leg swelling or calf pain from the original clot
Risk factors
- Recent surgery, especially hip or knee replacement
- Prolonged immobility or hospital admission
- Previous clot
- Active cancer
- Pregnancy and postpartum period
- Obesity and smoking
- Oestrogen containing medicines
Diagnosis
- Clinical probability scoring such as the Wells score
- D dimer blood test to exclude clot in low risk patients
- CT pulmonary angiogram, the definitive test
- Ventilation perfusion scan where CT is unsuitable
- Leg ultrasound to look for the source clot
- Echocardiogram to assess right heart strain
Treatment
- Anticoagulation, usually a direct oral anticoagulant
- Low molecular weight heparin in pregnancy and cancer
- Thrombolysis for large clots causing shock
- Oxygen and supportive care
- Treatment for at least three months, longer if risk persists
- Inferior vena cava filter where anticoagulation is contraindicated
Self care
- Take anticoagulation exactly as prescribed and never skip doses
- Move and walk regularly on long journeys
- Stay hydrated and avoid excess alcohol when travelling
- Wear compression stockings if advised
- Carry an anticoagulant alert card
- Report unusual bruising or bleeding promptly
- Build activity back gradually, breathlessness can take weeks to settle
When to see a doctor
Book an appointment if:
- A swollen, painful calf
- Breathlessness that is new or worsening
- Bleeding or heavy bruising on anticoagulation
- Before any surgery or dental work while anticoagulated
- Planning pregnancy with a history of clots
- Persistent breathlessness months after treatment
Some symptoms need emergency care rather than an appointment. See the warning signs listed above.
Prevention
- Move regularly during long flights and after surgery
- Take prescribed preventive anticoagulation after operations
- Use compression stockings when advised
- Stay well hydrated when travelling
- Stop smoking and keep to a healthy weight
- Discuss clot risk before starting oestrogen containing medicines
Outlook
With prompt anticoagulation most people recover well, though breathlessness and reduced exercise tolerance can persist for weeks to months. Large clots causing circulatory collapse carry significant mortality, which is why speed of diagnosis matters. A small proportion develop chronic thromboembolic pulmonary hypertension and need specialist assessment for ongoing breathlessness.
Common questions
Why is pulmonary embolism so often missed?
Symptoms overlap with chest infection, anxiety and asthma, and examination can be normal. This is why clinicians use structured probability scoring and D dimer rather than relying on how well someone looks.
How long will I need anticoagulation?
Usually at least three months. If the clot followed a temporary trigger such as surgery, treatment often stops there. If it was unprovoked or you have ongoing risk such as cancer, longer or indefinite treatment is common.
Can I fly after a pulmonary embolism?
Usually yes once you are stable on anticoagulation, though advice depends on how recent the clot was. Discuss timing with your doctor and take standard precautions such as moving regularly and staying hydrated.
References
Important: Dard AI is not a medical device and does not diagnose, treat, or replace clinician judgement. This article is general information only. Always consult a qualified healthcare professional about diagnosis and treatment, and seek emergency care for severe or rapidly worsening symptoms.