Definition

A sudden blockage of an artery (blood vessel) in the lung. A pulmonary embolism usually occurs when a blood clot in a deep vein in the leg or pelvis breaks loose and travels through the blood to the lungs. It may not cause any signs or symptoms, or it may cause shortness of breath, chest pain, a bloody cough, or a fast or abnormal heartbeat. A pulmonary embolism can be life-threatening, especially if the blood clot is large or there are many clots. It may be caused by surgery and by certain medical conditions, such as cancer, heart disease, or lung disease. It can also be caused by taking medicines that contain hormones, pregnancy and childbirth, not moving for long periods of time, older age, smoking, obesity, and having a family history of blood clots or pulmonary embolism.