xRead - Nasal Obstruction (September 2024) Full Articles

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International consensus statement on rhinosinusitis

factors associated with increased severity of CRS, are both implicated in epigenetic modification. Evidence of epige netics in-vivo is still limited, but nevertheless, the con cepts suggested by these studies are intriguing and hold promise for the future. 853,966–969 Most studies assessing blood and/or nasal epithelia have identified that epigenetic changes are more pronounced in epithelium than in cir culating blood, supporting the importance of contact with the external environment for their development. This sug gests that pathogens might be playing a role in adapting the environment for evolutionary advantage. In summary, the current knowledge base in the genetics of CRS is still very limited. However, as our understand ing and appreciation of interactions of the immune sys tem, microbiome, and epithelial barrier improve, it offers the promise of further identification of novel pathogenic mechanisms and markers that identify predisposing fac tors and predict disease evolution. This could then eluci date optimal response to therapy and allow customization of therapy to a patient’s disease profile, improving clinical care. IX.C.16 Contributing Factors for CRS: Viruses Because of limited data, CRSsNP and CRSwNP are com bined in this analysis. Beyond the role of acute respiratory infection-related inflammatory edema, the pathogenic roles of respiratory viruses in the development of CRS or CRS exacerbations are largely unknown. Several cross-sectional or case-control studies have examined the prevalence of respiratory viruses in patients with CRS. Most commonly, nasal swabs, nasal lavage, or mucosal scrapings were collected and screened for multiple viruses, frequently including: parainfluenza 1, 2, and 3; respiratory syncytial virus; human metap neumovirus; adenovirus; rhinovirus (RV); coronavirus; bocavirus; cytomegalovirus; and influenza A and B. Several studies found an increase in viral detec tion in CRS patients compared to control 753,754,1006 or high viral prevalence in CRS in cross-sectional studies. 1007,1008 However, several studies did not replicate these findings. 1009–1013 Many of the studies which did not show increased viral detection were limited by small patient numbers or seasonal sample collection. This is important, as many respiratory viruses have seasonal increases in prevalence. Goggin et al. in 2019 was the largest study, reporting results from 288 patients. Nasal brushings were taken, and PCR was utilized to evaluate for adenovirus, bocavirus, coronavirus, enterovirus, influenza, metapneumovirus,

parainfluenza 1-4, respiratory syncytial virus, and rhi novirus. Viral species were isolated from 7% of controls, 20% of CRSsNP, and 15% of CRSwNP. RV species and coro navirus species were the most frequently isolated viruses. Peak viral isolation was found in samples collected in win ter and spring. Only 20% of CRSsNP patients were posi tive for viral DNA/RNA at time of sampling; however, this group had significantly worse objective measures of dis ease severity compared to CRSsNP patients who were neg ative for a virus. Viral presence was not associated with increased objective disease severity in CRSwNP or virus positive controls. Among the epidemiologic studies which showed differential viral recovery in CRS vs control patients, 753,754,1006,1007 a consistent finding was that RV is either the most prevalent or one of the most preva lent viruses. A recent systematic review 1014 identified 5 studies that met a multi-component quality review for potential bias. Three studies reported an association between RV and CRS, 1006,1015,1016 while 2 studies reported no association. 1009,1010 Three additional epidemiologic studies evaluated RV in CRS (among other respiratory viruses) since this systematic review. Two of these 753,1013 found no association of RV with CRS status, but the largest 754 found that RV species and coronavirus species were the 2 most commonly isolated viruses from CRS samples. One epidemiologic study 1016 sequenced RV to determine the species. Only RV-A was detected in the control group. Both RV-A and RV-B were detected in CRS patients. The results may have been skewed, however, because subjects with active URI symptoms were excluded from their analyses. These studies suggest a trend toward greater prevalence of viral infections, particularly RV, in CRS patients. How ever due to the heterogeneity of the studies and mixed results, the relationship of viral infection to CRS is unclear. One possibility is that CRS patients may have persistent viral infections with chronic local inflammation. Further longitudinal studies and repeated samplings of positive viral infections are necessary to test this hypothesis. Several factors may explain the heterogeneity of epi demiologic findings. Viral detection rates in CRS patients may vary seasonally. 1008 This could lead to seasonality of sample collection influencing viral prevalence rates in CRS, even if the patient is asymptomatic. Collection of specimens over at least 1 full year may minimize any potential bias. Differences in sampling technique may also explain some observed differences, as various methodolo gies were used. Additionally, the site of collection may influence viral recovery, demonstrated by the lack of con cordance between viruses recovered from the inferior and middle meatus of individuals. 1013 While studies uti lizing prospective viral challenges have been useful in