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Medical Author:

Benjamin Wedro, MD, FACEP, FAAEM

Benjamin Wedro, MD, FACEP, FAAEM

Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.

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Medical Editor:

George Schiffman, MD, FCCP

George Schiffman, MD, FCCP

Dr. Schiffman received his B.S. degree with High Honors in biology from Hobart College in 1976. He then moved to Chicago where he studied biochemistry at the University of Illinois, Chicago Circle. He attended Rush Medical College where he received his M.D. degree in 1982 and was elected to the Alpha Omega Alpha Medical Honor Society. He completed his Internal Medicine internship and residency at the University of California, Irvine.

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Medical Editor:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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In this Article

• Pulmonary embolism facts
• What is a pulmonary embolism?
• What are the causes and risk factors for pulmonary embolism?
• What are the signs and symptoms of pulmonary embolism?
• How is pulmonary embolism diagnosed?
• History and physical examination
• Basic testing (CBC, electrolytes, BUN, creatinine blood test, chest x-ray, EKG)
• Pulmonary angiogram
• d-Dimer blood test
• CT Scan
• Ventilation-perfusion scans
• Venous Doppler study
• Echocardiography (EKG, ECG)
• What is the treatment for pulmonary embolism?
• Anticoagulation
• Thrombolytic therapy
• What is the prognosis for pulmonary embolism?
• Can pulmonary embolism be prevented?
• Patient Comments: Pulmonary Embolism - Symptoms
• Patient Comments: Pulmonary Embolism (Blood Clot in the Lung) - Treatments
• Pulmonary Embolism Index

If the healthcare provider's suspicion for pulmonary embolism is low, a d-Dimer blood test can be used. The d-Dimer blood test measures one of the breakdown products of a blood clot. If this test is normal, then the likelihood of a pulmonary embolism is very low. Unfortunately, this test is not specific for blood clots in the lung. It can be positive for a variety of reasons including pregnancy, injury, recent surgery, or infection. D-dimer is not helpful if the potential risk for a blood clot is high.

If there is greater suspicion, then computerized tomography (CT scan) of the chest with angiography can be done. Contrast dye is injected into an intravenous line in the arm while the CT is being taken, and the pulmonary arteries can be visualized. There are some limitations of the test, especially if a pulmonary embolism involves the smaller arteries in the lung. However similar problems are seen with the more invasive pulmonary angiogram. As CT scan has become more and more sophisticated, not identifying significant emboli is unusual. It is very important that the dye used during the CT angiogram be timed appropriately so that the bolus of dye is not diluted too much by blood as it travels through the lungs.

There are risks with this test since some patients are allergic to the dye, and the contrast dye can be harsh on kidney function especially if the patient's kidney function (as measured by blood tests) is marginal. It may be wise to limit the patient's exposure to radiation, especially in pregnant patients. However, since pulmonary embolus can be fatal, even in pregnancy this test can be performed, preferably after the first trimester.