A pulmonary embolism is a blood clot that affects the lungs. Typically, a blood clot travels from another area in the body before becoming lodged in one of the arteries that supply blood to the lungs.
A pulmonary embolism can damage part of the lung due to restricted blood flow, decrease oxygen levels in the blood, as well as damage other organs (NHLBI). Large or multiple blood clots can be fatal.
The blockage can be life threatening, but immediate emergency treatment greatly increases your chances of avoiding permanent lung damage.
Blood clots can form for a variety of reasons. Pulmonary embolisms are most often caused by deep vein thrombosis, a condition in which blood clots form in veins deep in the body. The blood clots that most often cause pulmonary embolisms typically begin in the legs or arms.
Factors that increase a person’s risks of deep vein thrombosis and pulmonary embolism include:
- a close family member with a history of embolisms
- fractures of the leg or hip
- genetic blood clotting disorders (hypercoagulable states), including Factor V Leiden, prothrombin gene mutation, and elevated levels of homocysteine
- a history of heart attack or stroke
- major surgery
- a sedentary lifestyle
Symptoms of a pulmonary embolism depend on the size of the clot and the location in your lung where it becomes lodged.
The most common symptom of a pulmonary embolism is shortness of breath. This may be gradual or sudden. If you experience sudden shortness of breath, you should seek medical attention immediately.
Other symptoms of a pulmonary embolism include:
- clammy or bluish skin
- chest pain that may extend into your arm, jaw, neck, and shoulder
- irregular heartbeat
- rapid breathing
- rapid heartbeat
- spitting up blood
- weak pulse
If you notice one or more of these symptoms, especially shortness of breath, you should seek medical attention immediately.
In some cases, a pulmonary embolism can be difficult to diagnose. This is especially true if you have an underlying lung or heart condition, such as lung disease or high blood pressure.
When you first see your doctor about your symptoms, he or she will ask about your overall health and any pre-existing conditions you may have as part of a complete health profile.
Your doctor will typically perform one or more of the following tests to discover the cause of your symptoms:
- chest X-ray: this standard, noninvasive test allows doctors to see your heart and lungs in detail, as well as any problems with the bones around your lungs.
- electrocardiography (ECG): this test measures your heart’s electrical activity.
- magnetic resonance imaging (MRI): this scan uses radio waves and magnetic field to produce detailed images
- computed tomography (CT) scan: this scan gives your doctor the ability to see cross-sectional images of your lungs
- pulmonary angiography: this test involves making a small incision so your doctor can guide specialized tools through your veins. A special dye is injected so that the vessels of the lung can be seen.
- duplex venous ultrasound: this test uses radio waves to visualize the flow of blood and to check for blood clots in your legs.
- venography: this is a specialized X-ray of the veins of your legs..
Your treatment for a pulmonary embolism depends on the size and location of the blood clot. If the problem is small and caught early, your doctor may opt for medication as the primary treatment. Some drugs can break up small clots.
Drugs your doctor may use include:
- anticoagulants: also called blood thinners, the drugs heparin and warfarin prevent new clots from forming in your blood. These can save your life in an emergency situation.
- clot dissolvers (thrombolytics): these drugs speed up the breakdown of a clot. These are typically reserved for emergency situations because side effects may include dangerous bleeding problems.
Surgery may be required to remove problematic clots, especially those that restrict the blood flow to the lungs or heart. Some surgical procedures your doctor may use in the case of a pulmonary embolism include (Mayo):
- vein filter: a small incision is made to use a thin wire to install a small filter in your inferior vena cava—the main vein that leads from your legs to the right side of your heart. The filter prevents blood clots from traveling from your legs to your lungs.
- clot removal: large clots may need to be suctioned out of your artery using a thin tube called a catheter. It isn’t an entirely effective method because of the difficulty involved, so it’s not always a preferred method of treatment.
- open surgery: open surgery is used only in emergency situations when a person is in shock or medications aren’t working to break up the clot.
After you’ve been properly treated for a pulmonary embolism at the hospital, you’ll be advised to treat the underlying cause. This is typically deep vein thrombosis.
You’ll most likely be put on anticoagulant medications, such as heparin and warfarin to prevent blood clots from returning. You may also be given compression stockings—similar to really tight socks—or another device to prevent clots from forming in your legs.
Regularly exercising your legs will also be a key component of therapy after a pulmonary embolism. Your doctor will give you complete instructions on how to care for yourself to prevent future blood clots.