Pulmonary embolus

Alternative Names

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

Definition of Pulmonary embolus

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

Causes, incidence, and risk factors

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 (DVT).

Signs and tests

The following lab tests may be done to see how well your lungs are working:


Emergency treatment and a hospital stay are often necessary. The goal is to stabilize your cardiovascular system and to prevent new clots from forming. Oxygen therapy may be required to maintain normal oxygen levels.

Expectations (prognosis)

It is difficult to predict how well a patient will do. Often, the outlook is related to what put the person at risk for pulmonary embolism (for example, cancer, major surgery, or trauma).


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. – 3/28/2010

Respiratory system
Pulmonary embolus

ADAM Medical Encyclopedia

Article written by

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability.