Possible image finding is
Case 332
【Progress】
He was advised to take regular medicines of Tamiful and Caronal since his symptoms were getting improved.
【Discussion】
I dare to say influenza-positive pneumonia for usually reported post-influenza pneumonia because pneumonia demonstrated on CT does not always occur after or by influenza virus infection. In 2015-2016 season, when influenza epidemic prevailed nationwide, I investigated CT images of influenza-positive pneumonia because I was not familiar about influenza pneumonia and eager to keep in mind a typical image of influenza pneumonia. After collection of CT images in six patients with positive influenza infection, I realized and embarrassed to realize that these images are not different from those with community acquired pneumonia; 3, bronchopneumonia; 1, pneumonia;1, centrilobular pneumonia:1, ground glass pneumonia. At that time, influenza vaccination was prevailed. It is reported that post-influenza pneumonia is associated with bacterial pneumonia in 30-50% (1-4). Then, our data was not contractive with other reports.
In 2019, Corona virus pandemic emerged worldwide, and typical CT images with ground glass opacity in marginal area due to Corona 19 virus were often found. As vaccination with mRNA vaccination prevailed in 2023, the typical CT images for COVID-19 were less found, instead, those for positive COVID-19 are becoming to be indistinct from community-acquired pneumonia such as bacterial infection or aspiration pneumonia.
The typical images of virus infection are reported to be ground glass opacity histologically composed of virus itself, IgA, surfactant, Ig G and immune cells of macrophages and lymphocytes (5, 6). The defense volume is probably greater than offensive volume. Ground glass opacity is a common CT images of pneumonia with Influenza and COVID-19. The difference is the site for ground glass opacity: centrilobular for influenza versus marginal for COVID-19 (4,5). Influenza virus and COVID-19 virus are common RNA viruses. They own spike proteins surrounding RNA for invades to host cells. One of the spike proteins of influenza virus, hemagglutinin spike protein is more familiar to bronchial epithelial cells, that might indicate to be more aggressive or more susceptible to bronchial cells for Influenza virus (7). As Corona virus evolves, acquiring HA spike protein for COVID-19 as well as influenza virus indicates COVID-19 is becoming more difficult to be differentiated from influenza virus on symptoms and CT images.
【Summary】
We presented a twenty-two-year-old male for high fever and pharyngeal pain, positive influenza infection. Chest CT images showed centrilobular ground glass opacity at left lower lobe S6. It is borne in mind that typical CT images of COVID-19 infection are marginal ground glass opacity, while those of influenza infection are centrilobular ground glass opacity. As vaccination of both viruses prevailed and evolution of both viruses acquire protein spikes that brings them more easily invade to bronchial epithelial cells, it indicates that symptoms and CT images would be becoming more alike each other although, to date, CT images of influenza and COVID-19 look distinct.
【References】
1.O'Brien KL, et al. Severe pneumococcal pneumonia in previously healthy children: the role of preceding influenza infection. Clin Infect Dis 2000;30:784–789.
2.Marchiori E, et al. High-resolution computed tomography findings from adult patients with Influenza A (H1N1) virus-associated pneumonia. Eur J Radiol. 2010 Apr;74(1):93-8.
3.Nicolini A, et al. Influenza A (H1N1)-associated pneumonia. J Bras Pneumol. 2011;37(5):621–7
4.Rello J, et al. Clinical review: Primary influenza viral pneumonia. Crit Care. 2009; 13(6): 235.
5.Sambit K Mohanty, et al. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and coronavirus disease 19 (COVID-19) - anatomic pathology perspective on current knowledge. Diagn Pathol 2020 Aug 14;15(1):103
6.Mehta H, et al. Cigarette smoking and innate immunity. Inflamm. res. 2008; 57:497–503
7.Boschi C, et al. SARS-CoV-2 Spike Protein Induces Hemagglutination: Implications for COVID-19 Morbidities and Therapeutics and for Vaccine Adverse Effects. Int J Mol Sci. 2022 Dec; 23(24): 15480.
2024.4.19