A pulmonary embolism is a sudden blockage in a lung artery, usually due to a blood clot that traveled to the lung from a vein in the leg. A clot that forms in one part of the body and travels in the bloodstream to another part of the body is called an embolus.

Pulmonary embolism is a serious condition that can cause:

• Permanent damage to part of your lung from lack of blood flow to lung tissue
• Low oxygen levels in your blood
• Damage to other organs in your body from not getting enough oxygen

If the blood clot is large, or if there are many clots, pulmonary embolism can cause death.
At least 100,000 cases of pulmonary embolism occur each year in the United States. Pulmonary embolism is the third most common cause of death in hospitalized patients.
In most cases, pulmonary embolism is a complication of a condition called deep vein thrombosis.

Symptoms

Signs and symptoms of pulmonary embolism include unexplained shortness of breath, difficulty breathing, chest pain, coughing, or coughing up blood. An arrhythmia (a rapid or irregular heartbeat) also may indicate pulmonary embolism.

In some cases, the only signs and symptoms are related to deep vein thrombosis. These include swelling of the leg or along the vein in the leg, pain or tenderness in the leg, a feeling of increased warmth in the area of the leg that's swollen or tender, and red or discolored skin on the affected leg.

Treatment

The main goals of treating pulmonary embolism (PE) are to stop the blood clot from getting bigger and keep new clots from forming.

Treatment may include medicines to thin the blood and slow its ability to clot. If your symptoms are life threatening, the doctor may give you medicine to dissolve the clot more quickly. Rarely, the doctor may use surgery or another procedure to remove the clot.

Several types of medicine may be used to treat and/or prevent deep vein thrombosis:

• Anticoagulants to decrease your blood's ability to clot
• Thrombolytics to quickly dissolve a blood clot
• Thrombin inhibitors to interfere with the clotting process

If you have had blood clots before, you may need a longer period of treatment. If you're being treated for another illness, such as cancer, you may need to take anticoagulants as long as risk factors for pulmonary embolism are present.

In some cases, the doctor may use a catheter to reach the blood clot. A catheter is a flexible tube placed in a vein to allow easy access to the bloodstream for medical treatment. The catheter is inserted into the groin (upper thigh) or arm and threaded through a vein to the clot in the lung. The catheter may be used to extract the clot or deliver medicine to dissolve it.

Vena cava filters are used when you can’t take medicines to thin your blood, or when you are taking blood thinners but continue to develop clots anyway. The filter is inserted inside a large vein called the vena cava. The filter catches clots that break off in a vein before they move through the bloodstream to the lungs (pulmonary embolism). The filter doesn’t prevent new clots from developing.

Graduated compression stockings can reduce the chronic swelling that can occur after a blood clot has developed in a leg. These stockings are tight at the ankle and become looser as they go up the to the knee. This causes a gentle compression (or pressure) up the leg. The pressure keeps blood from pooling and clotting.