The CT pulmonary angiogram reveals a filling defect, which is visualized within the segmental pulmonary artery suspicious for a pulmonary embolus. Incidental small bilateral pleural effusions with total collapse of the right lower lobe are noted, and subsegmental atelectasis of the right middle and left lower lobes is observed. The patient is transferred to the ICU for monitoring and started on heparin.
Pulmonary emboli usually arise from thrombi that originate in the deep venous system of the lower extremities but can also originate in the pelvis, upper extremity veins, renal system, and right heart chambers. After traveling to the lung, large thrombi can lodge at the bifurcation of the main pulmonary artery or the lobar branches and cause hemodynamic compromise.
Three primary influences predispose a patient to thrombus formation. These form the Virchow triad, which consists of the following:
Stasis or turbulence of blood flow
Certain patients are at higher risk of developing deep venous thrombosis and, subsequently, pulmonary embolism. These include patients with venous stasis, hypercoagulable states, immobilization, surgery, trauma, pregnancy, malignancy, and those taking hormones or oral contraceptives medications.[2,3,4]
Clinical signs and symptoms for pulmonary embolism are nonspecific, and thus the differential diagnosis for patients with similar symptoms is broad. The "classic" presentation with abrupt onset of pleuritic chest pain, shortness of breath, and hypoxia is rarely seen. The clinical presentation of acute pulmonary embolism ranges from shock or sustained hypotension to mild dyspnea. Pulmonary embolism may even be asymptomatic and diagnosed by imaging procedures performed for other purposes. Depending on the clinical presentation, the case fatality rate for acute pulmonary embolism ranges from about 60% to less than 1%.
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Cite this: Jason Chang, Linda Chun. Chest Pain and Shortness of Breath in a 33-Year-Old Man - Medscape - Jul 20, 2020.