LAUSR

Background E-cigarette or vaping has become an increasingly popular alternative to smoking tobacco. In September 2019 multiple cases of confirmed E-cigarette or vaping product use associated lung injury were published. However, there is limited knowledge regarding the pathologic mechanism of this condition. Methods We performed a systematic literature review in PubMed and EMBASE aiming to obtain additional clinical data on confirmed E-cigarette or vaping product use associated lung injury cases with lung biopsy results. With this information we hope to determine whether this condition is related to a histopathological pattern of acute lung injury instead of lipid deposits. Results Seven articles were reviewed and a total of 27 cases were included. Imaging findings predominantly showed presence of diffuse bilateral ground glass opacities. A majority of patients had complete resolution of the disease. The most common histopathological pattern was organizing pneumonia present in almost half of the patients. Other frequently occurring patterns included diffuse alveolar damage and acute fibrinous pneumonitis; lipoid pneumonia was found in one case. Conclusion The underlying pathophysiological mechanism in E-cigarette or vaping product use associated lung injury is most likely acute lung injury related to direct inhalant-mediated parenchymal inflammation.