A pulmonary embolus is a blockage of an artery in the lungs by fat, air, a blood clot, or tumor cells.

Venous thromboembolism; Lung blood clot; Blood clot - lung; Embolus; Tumor embolus; Embolism - pulmonary

A pulmonary embolus is most often caused by a blood clot in a vein, especially a vein in the leg or in the pelvis (hip area). The most common cause is a blood clot in one of the deep veins of the thighs. This type of clot is called a deep vein thrombosis (DVT).

Less common causes include air bubbles, fat droplets, amniotic fluid, or clumps of parasites or tumor cells, all of which may lead to a pulmonary embolus.

Risk factors for a pulmonary embolus include:

• Burns
• Cancer
• Childbirth
• Family history of blood clots
• Fractures of the hips or femur
• Heart attack
• Heart surgery
• Long-term bed rest or staying in one position for a long time, such as a long plane or car ride
• Severe injury
• Stroke
• Surgery (especially orthopedic or neurological surgery)
• Use of birth control pills or estrogen therapy

People with certain clotting disorders may also have a higher risk.

Images

Lungs

Respiratory system

Pulmonary embolus

Review Date: 03/28/2010
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)