Diagnosis of pulmonary embolism

Pulmonary embolism (PE) is often unrecognized or misdiagnosed because of the lack of specificity of clinical signs and symptoms. PE shares many of the clinical features of pneumonia and is therefore often unrecognized in elderly patients who present with low-grade fever, modest leukocytosis, and pulmonary infiltrates. Assessment of clinical risk factors increases the usefulness of diagnostic tests. The accuracy of diagnosis is improved if specific tests are performed. Ventilation-perfusion lung scans, noninvasive or contrast venography, and pulmonary angiography increase the likelihood of correct diagnosis. Since pulmonary angiography is a relatively low-risk procedure, it should be performed in most patients suspected of having PE who have nondiagnostic lung scans and negative lower extremity venous studies.