Abstract:Objective To investigate the clinical characteristics of idiopathic pulmonary embolism for better diagnosis and treatment. Methods Thirty-three cases with identified pulmonary embolism but without acquired high-risk factors for embolism formation who admitted to Chinese PLA General Hospital from July 2010 to February 2012 were enrolled in this study. Their clinical data including general information, clinical signs and symptoms, examinations, mal-diagnosis and treatment were collected and retrospectively analyzed. Results There was no significant difference between male and female patients in the incidence of idiopathic pulmonary embolism. The cohort was at a mean age of (57.6±14.1) years and a mean body mass index of (26.4±3.2). Dyspnea (97.0%) and chest pain (30.3%) were the most common symptoms. In laboratory examination, 30 cases (90.9%) had D-Dimer over 0.5mg/L, 15 cases (57.7%) had BNP exceeding 150ng/L, and 15 cases (51.7%) had PaO2 lower than 75 mmHg. V1–V4 ST-T wave changes were common in electrocardiogram (60.6%), and elevated pulmonary arterial pressure was common in ultrasonic cardiogram. Vascular spiral computed tomography and pulmonary angiography showed filling defects at different degrees. The most common misdiagnosis of first visit was acute myocardial infarction and pneumonia, with a misdiagnosis rate of 69.7%. Anticoagulation was carried out for all the patients. Some patients accepted thrombolysis and/or interventional therapy. Conclusion Idiopathic pulmonary embolism is prone to be misdiagnosed because of lacking predisposing factors. Suspicious patients should be decided by combined consideration in terms of clinical manifestations, D-Dimer and imaging, and pulmonary angiography should be conducted as soon as possible to confirm the diagnosis .