Causes and Risk Factors
Clots form when blood flow slows, vessel walls are injured, or the blood clots more easily than normal. Common risk factors include:- Prolonged immobility: Long flights or car trips, bed rest, or recovery after surgery — especially hip, knee, or abdominal operations.
- Cancer and its treatment: Many cancers increase clotting tendency.
- Hormones: Estrogen-containing birth control, hormone therapy, and pregnancy raise clot risk.
- Inherited clotting disorders: Conditions such as the factor V Leiden mutation and other hypercoagulable states make clots more likely, particularly when combined with other risks.
- Other factors: Obesity, smoking, heart failure, and a previous DVT or PE.
Symptoms
Symptoms depend on the size of the clot and can appear suddenly:- Shortness of breath: Often abrupt and worse with exertion.
- Chest pain: Typically sharp and worse with a deep breath or cough.
- Rapid heart rate, lightheadedness, or fainting: Signs the heart is under strain.
- Cough: Sometimes with blood-streaked sputum.
- Leg swelling or pain: A warm, swollen calf may signal the DVT that produced the embolism.
When to Seek Immediate Care
Pulmonary embolism is a medical emergency. Call 911 or go to the nearest emergency department for sudden unexplained shortness of breath, chest pain with breathing, coughing up blood, or fainting.Diagnosis
Doctors combine a risk assessment with testing. A D-dimer blood test can help rule out clots in lower-risk patients, while a CT pulmonary angiogram — a contrast CT scan of the chest — is the standard imaging test. Ultrasound of the legs, an electrocardiogram, and an echocardiogram may also be used to find the source of the clot and assess strain on the heart.Treatment
Treatment prevents the clot from growing and stops new clots while the body dissolves the old one.- Anticoagulants (blood thinners): Direct oral anticoagulants such as apixaban, rivaroxaban, dabigatran, or edoxaban are used for most patients; warfarin with regular blood-test monitoring is an alternative, and injectable enoxaparin is often used in the hospital or during cancer treatment. Treatment usually lasts at least three months, and sometimes indefinitely if risk factors persist.
- Clot-dissolving therapy or procedures: Reserved for massive, life-threatening clots, when medication is delivered directly to the clot or the clot is removed with a catheter.
- Oxygen and monitoring: Many patients with smaller clots and stable vital signs can now be treated at home, while larger clots are observed in the hospital.
Prevention and Recovery
After a first clot, your doctor will look for the reason it happened — surgery, immobility, hormones, or an underlying clotting tendency — because that determines how long blood thinners should continue. Practical prevention includes getting up and moving every hour or two on long flights and car trips, staying well hydrated, resuming activity promptly after surgery as advised, and taking prescribed blood thinners exactly as directed. Most people recover fully over weeks to months, though it is common for stamina to return gradually. Some patients develop lasting breathlessness from pulmonary hypertension after a PE, so follow-up matters. The internal-medicine team at Zimmer Medical Group manages anticoagulation, monitors recovery, and evaluates clotting risk — schedule a visit if you have had a clot or are concerned about your risk.Recovering From a Pulmonary Embolism
Most of the danger passes in the first days; the decisions that matter come in the months after: how the blood thinner is taken, how long it continues, and what the breathlessness that lingers actually means.
Taking a blood thinner so it protects you
Apixaban is taken twice daily and rivaroxaban once daily with food, and both stop working within a day of a missed dose; a missed dose is taken when remembered unless the next one is close, and never doubled. Warfarin remains the right choice for people with antiphospholipid syndrome, and enoxaparin injections are used in pregnancy and some cancers. NSAIDs such as ibuprofen and aspirin taken on top of a blood thinner multiply bleeding risk; acetaminophen is the pain reliever of choice. Some antibiotics, antifungals, seizure medicines, and St. John's wort change blood thinner levels, so every new prescription is checked.
How long treatment lasts depends on why it happened
A clot provoked by surgery, a cast, or a long period of immobility is treated for three months and then stopped, because the cause is gone. A clot with no clear trigger, a second clot, or one tied to active cancer or a persistent clotting disorder is usually treated indefinitely, because the risk of recurrence when stopping outweighs the bleeding risk of continuing. Estrogen-containing contraception and hormone therapy are stopped after a clot. Testing for the factor V Leiden mutation or a lupus anticoagulant is done selectively, because most results do not change the plan.
Breathlessness that does not resolve
Stamina returns gradually over weeks to months, and graded walking speeds it. Breathlessness that is unchanged or worsening three to six months later is not accepted as normal: an echocardiogram and a ventilation-perfusion scan look for chronic thromboembolic pulmonary hypertension, a rare, treatable form of pulmonary hypertension in which the clot has scarred into the artery. Our pulmonary team arranges that evaluation.
Travel, storms, and procedures
Snowbird flights and the long drive down are classic triggers, and after a clot they call for aisle seats, walking every hour, water rather than alcohol, and compression stockings if a deep vein thrombosis left the leg swollen; our blood clots and snowbird travel guide covers the details. Keep at least two weeks of blood thinner on hand during hurricane season. Dental work and colonoscopies are usually done without stopping the medication; surgery needs a written plan for pausing and restarting it.
The warning signs while on treatment
Sudden worsening breathlessness, chest pain, fainting, or coughing blood means a new clot or bleeding into the lung and needs 911. Black or bloody stools, red urine, vomiting blood, a severe headache, or a fall with a blow to the head on a blood thinner needs same-day evaluation. Bruising and minor gum or nose bleeding are expected and are not reasons to stop treatment. NHLBI and MedlinePlus publish patient guidance on anticoagulation and recovery.
If you had a pulmonary embolism and no one has told you how long your blood thinner should continue, or you are still short of breath months later, schedule a visit.