Interstitial Lesions in Both Lungs Finally Diagnosed as a Rare Coinfection of Influenza A Virus and Pneumocystis Jiroveci.

Background: Influenza is an acute respiratory infection caused by influenza viruses, with influenza A virus (IAV) being the most common and most likely to progress to critically ill cases leading to death. Pneumocystis jiroveci is an opportunistic lung-causing fungus that occurs most often in immunocompromised individuals and can cause Pneumocystis jiroveci pneumonia (PJP). It is rare for both diseases to occur in the same patient. Methods: Appropriate laboratory tests, chest computed tomography (CT), bronchoalveolar lavage fluid, secondgeneration macro gene sequencing, and pathogenetic tests to clarify the diagnosis. Results: G test and LDH were high, and chest CT showed rapidly progressive interstitial pneumonia, which was confirmed by bronchoalveolar lavage fluid and macrogenomic second-generation sequencing (mNGS) to be a mixed infection of H. influenzae type A virus and Pneumocystis jiroveci. Conclusions: In rapidly progressive interstitial pneumonia, bronchoalveolar lavage and mNGS should be done early to clarify the presence of infection with specific pathogenic organisms. [ABSTRACT FROM AUTHOR]