Pulmonary embolus is a blockage of an artery in the lungs by fat, air, tumor tissue, or blood clot.
Pulmonary emboli are caused by clots from the venous circulation, from the right side of the heart, from tumors that have invaded the circulatory system, or from other sources such as amniotic fluid, air, fat, bone marrow, and foreign substances. A pulmonary embolism affects as many as 5 out of 10,000 people in the U.S. each year, and sudden death can occur as a result of pulmonary embolism. The risk factors include prolonged bed rest or inactivity, oral contraceptive use, surgery, child birth, cancer, stroke, heart attack, heart surgery, and fractures of the hips or femur. Other clot-preventive measures include leg exercises and elastic support stockings as appropriate. Definitive treatment consists of dissolving the clot by thrombolytic therapy.