Pathophysiology, clinics and diagnostics of non-thrombotic pulmonary embolism

Non-thrombotic pulmonary embolism (NTPE) is commonly defined as the partial or total occlusion of the pulmonary circulation caused by a variety of non-thrombotic embolic agents. Although its prevalence is much lower than that of pulmonary thromboembolism, this life-threatening pathology is often underestimated due to the low specificity of signs and symptoms and because it might be frequently overlooked in the differential diagnosis of the chest pain. The main sources of non-thrombotic pulmonary emboli include cancers, fat, infective agents, amniotic fluid, a variety of foreign materials and gases. The diagnosis is particularly challenging. The spectrum of imaging findings using imaging techniques such as computed tomography is unpredictable and typically heterogeneous, whereas laboratory tests can only be helpful for establishing the cause but not the presence of the disease (i.e., D-dimer testing is frequently negative). As such, the clinical history along with the identification a potential underlying disease are the often the mainstay for the differential diagnosis. The aim of this article is to provide an overview of the pathophysiology, clinics and diagnostic approach to NTPE.