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Background: Olfactory dysfunction (OD) can occur from a variety of etiologies. However, there are few reports examining whether varying etiologies have unique profiles of psychophysical testing that may provide insight into the pathophysiology of OD. Methods: Adults with chronic rhinosinusitis with and without nasal polyps (CRSwNP/CRSsNP) and healthy control adults with no sinus complaints underwent olfactory assessment with Sniffin' Sticks. Profiles of identification and discrimination were compared between CRS and non-CRS subjects across the spectrum of OD. Results: Normosmics with or without CRS identified apple, pineapple, and turpentine less frequently than expected (range 52%-68% correct). Hyposmics with CRS correctly identified orange more frequently than control hyposmics (83%-93% vs 68% for controls) with similar findings for rose. Hyposmics of all cohorts were unable to identify apple (26%). Discrimination profiles were similar across the spectrum of OD and between diagnostic groups. Conclusions: Identification and discrimination rates of specific odorants may provide unique information regarding the etiology of OD, however psychophysical testing is a complex interplay of olfactory and trigeminal function, the strength of target odorant, distractor choices, and familiarity with odorants. [ABSTRACT FROM AUTHOR]

Respiratory tract viruses are the second most common cause of olfactory dysfunction. As we learn more about the effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with the recognition that olfactory dysfunction is a key symptom of this disease process, there is a greater need than ever for evidence-based management of postinfectious olfactory dysfunction (PIOD). Our aim was to provide an evidence-based practical guide to the management of PIOD (including post–coronavirus 2019 cases) for both primary care practitioners and hospital specialists. A systematic review of the treatment options available for the management of PIOD was performed. The written systematic review was then circulated among the members of the Clinical Olfactory Working Group for their perusal before roundtable expert discussion of the treatment options. The group also undertook a survey to determine their current clinical practice with regard to treatment of PIOD. The search resulted in 467 citations, of which 107 articles were fully reviewed and analyzed for eligibility; 40 citations fulfilled the inclusion criteria, 11 of which were randomized controlled trials. In total, 15 of the articles specifically looked at PIOD whereas the other 25 included other etiologies for olfactory dysfunction. The Clinical Olfactory Working Group members made an overwhelming recommendation for olfactory training; none recommended monocycline antibiotics. The diagnostic role of oral steroids was discussed; some group members were in favor of vitamin A drops. Further research is needed to confirm the place of other therapeutic options. [ABSTRACT FROM AUTHOR]

Objective Compare machine learning (ML)-based predictive analytics methods to traditional logistic regression in classification of olfactory dysfunction in chronic rhinosinusitis (CRS-OD) and identify predictors within a large multi-institutional cohort of refractory CRS patients. Methods Adult CRS patients enrolled in a prospective, multi-institutional, observational cohort study were assessed for baseline CRS-OD using a smell identification test (SIT) or brief SIT (bSIT). Four different ML methods were compared to traditional logistic regression for classification of CRS normosmics versus CRS-OD. Results Data were collected for 611 study participants who met inclusion criteria between 2011 April and 2015 July. Thirty-four percent of enrolled patients demonstrated olfactory loss on psychophysical testing. Differences between CRS normosmics and those with smell loss included objective disease measures (CT and endoscopy scores), age, sex, prior surgeries, socioeconomic status, steroid use, polyp presence, asthma, and aspirin sensitivity. Most ML methods performed favorably in terms of predictive ability. Top predictors include factors previously reported in the literature, as well as several socioeconomic factors. Conclusion Olfactory dysfunction is a variable phenomenon in CRS patients. ML methods perform well compared to traditional logistic regression in classification of normosmia versus smell loss in CRS, and are able to include numerous risk factors into prediction models. Several actionable features were identified as risk factors for CRS-OD. These results suggest that ML methods may be useful for current understanding and future study of hyposmia secondary to sinonasal disease, the most common cause of persistent olfactory loss in the general population. [ABSTRACT FROM AUTHOR]

Mucins are a key component of the surface mucus overlying airway epithelium. Given the different functions of the olfactory and respiratory epithelia, we hypothesized that mucins would be differentially expressed between these 2 areas. Secondarily, we evaluated for potential changes in mucin expression with radiation exposure, given the clinical observations of nasal dryness, altered mucus rheology, and smell loss in radiated patients. Immunofluorescence staining was performed to evaluate expression of mucins 1, 2, 5AC, and 5B in nasal respiratory and olfactory epithelia of control mice and 1 week after exposure to 8 Gy of radiation. Mucins 1, 5AC, and 5B exhibited differential expression patterns between olfactory and respiratory epithelium (RE) while mucin 2 showed no difference. In the olfactory epithelium (OE), mucin 1 was located in a lattice-like pattern around gaps corresponding to dendritic knobs of olfactory sensory neurons, whereas in RE it was intermittently expressed by surface goblet cells. Mucin 5AC was expressed by subepithelial glands in both epithelial types but to a higher degree in the OE. Mucin 5B was expressed by submucosal glands in OE and by surface epithelial cells in RE. At 1-week after exposure to single-dose 8 Gy of radiation, no qualitative effects were seen on mucin expression. Our findings demonstrate that murine OE and RE express mucins differently, and characteristic patterns of mucins 1, 5AC, and 5B can be used to define the underlying epithelium. Radiation (8 Gy) does not appear to affect mucin expression at 1 week. Level of Evidence N/A (Basic Science Research). IACUC-approved study [Protocol 200065]. [ABSTRACT FROM AUTHOR]

Key Points AI‐based CT sinus analysis may have advantages over visual based systems, for example, Lund–Mackay score. Here, we show multi‐institutional validation of an AI algorithm using novel OMC classification. Significant, robust correlations are seen between algorithm outputs and clinical outcomes. AI‐based CT sinus analysis may have advantages over visual based systems, for example, Lund–Mackay score.Here, we show multi‐institutional validation of an AI algorithm using novel OMC classification.Significant, robust correlations are seen between algorithm outputs and clinical outcomes. [ABSTRACT FROM AUTHOR]

• People with cystic fibrosis and sinus disease have impaired olfactory function. • These individuals have inflammation of the olfactory cleft on computed tomography. • Olfactory quality of life deficits were not prominently reported by people with CF. • Six months of CFTR modulator therapy did not lead to improvements in olfaction. • Future study will evaluate olfactory changes with greater duration of CFTR therapy. Elexacaftor-tezacaftor-ivacaftor (ETI) improves pulmonary health and chronic rhinosinusitis (CRS) for people with cystic fibrosis (PwCF), however its impact on olfaction has not been investigated. Olfactory dysfunction impairs quality-of-life (QOL). This study evaluated the impact of ETI on multiple olfactory metrics. Adult PwCF/CRS with CF transmembrane conductance regulator genotype F508del/F508del or F508del/minimal function who clinically initiated ETI participated in a prospective, observational study. Endpoints included changes after 6 months of ETI in quantitative olfactory function (Smell Identification Test, SIT), olfactory QOL (Questionnaire of Olfactory Disorders, QOD) and percent olfactory cleft opacification (%OCO), representing superior nasal cavity inflammation where afferent olfactory neurons are concentrated. 30 PwCF/CRS met inclusion criteria; 25 completed the study. Mean ETI adherence was 93%. At baseline, participants were hyposmic (mean SIT 31.3), had significant %OCO (mean 65.6%), yet reported non-impaired olfactory QOL (mean QOD 6.1). At follow-up, mean SIT worsened mildly (p=0.009), mean %OCO remained stable (p=0.46), and mean QOD improved modestly (p=0.008). No outcomes were impacted by prior modulator use, genotype, nasal polyps, or CF-related diabetes. Prior sinus surgery was associated with QOD improvement (p=0.04). Increased (worse) baseline QOD scores and %OCO were associated with greater improvements (p<0.003), but not SIT (p=0.44). ETI was not associated with improvement in quantitative olfaction or olfactory cleft opacification after 6 months. PwCF/CRS have hyposmia but do not report impairment in olfactory QOL. Further study to investigate mechanisms explaining olfactory dysfunction and whether olfaction improves with greater duration of ETI or in younger age groups is warranted. [ABSTRACT FROM AUTHOR]

Background: Multiple hypotheses are evolving that suggest several, potentially overlapping etiologies for olfactory dysfunction (OD) in chronic rhinosinusitis (CRS). Understanding inflammatory cytokine profiles of the olfactory cleft (OC) and their association with olfactory function is foundational for future clinical care and research. Methods: This cross‐sectional, case‐control study evaluates associations among OC mucus inflammatory proteins, psychophysical olfactory testing, and computed tomography (CT) analysis of the OC and sinuses. Normative reference intervals were determined for each protein and odds ratios (ORs) were used to compare proportions of altered expression between CRS without nasal polyposis (CRSsNP) and CRS without nasal polyposis (CRSwNP). Results: Case subjects with CRS (n = 151) and controls (n = 74) were evaluated. A majority of OC proteins tested were found within detectable ranges for cases and controls. The CRS cohort had significantly higher concentrations for 23 of 26 proteins. CRS cases with abnormal levels of C‐C motif chemokine ligand 2 (CCL2), CCL3, interleukin 5 (IL5), IL10, and IL13 associated with greater olfactory deficits. The prevalence of elevated IL5 and IL13 in anosmic patients was 64.6% and 62.5%, respectively (p < 0.004). CRS cases with the highest odds of elevated expression in CRSwNP were IL5 (OR = 10.83) and IL13 (OR = 8.36). However, both IL5 and IL13 were still elevated in approximately 14% of CRSsNP patients. The highest magnitude of correlation between the total percent of OC opacification was found to be with IL5 (r = 0.543; p < 0.001), whereas other moderate correlations were noted with immunoglobulin E (IgE), IL10, and IL13. Conclusion: This study confirmed that OC inflammatory proteins vary both by disease phenotype and in their association with OD. Type 2 inflammatory mediators are increased in CRS, especially within the CRSwNP group. However, a substantial proportion of CRSsNP also express type 2 inflammatory mediators. Further research is necessary to understand the complex roles OC mucous inflammatory proteins might play in defining endotype and in impacting CRS‐related OD. ©2021 ARSAAOA, LLC. [ABSTRACT FROM AUTHOR]

Background: Chronic rhinosinusitis (CRS) is one of the most common causes of olfactory loss, but the pathophysiology underlying olfactory dysfunction in CRS has not been fully elucidated. Previous studies found correlations between olfactory cleft (OC) inflammatory cytokines/chemokines and olfaction in CRS. The purpose of this study was to evaluate the relationship between OC mucus inflammatory proteins and olfaction in a multi‐institutional cohort. Methods: Adults with CRS were prospectively recruited. Demographics, comorbidities, olfactory assessment (Sniffin' Sticks), computed tomography (CT), and OC mucus for protein analysis were collected. Statistical analysis was performed to determine associations between olfactory function, OC mucus protein concentrations, and CT opacification. Results: Sixty‐two patients were enrolled in the study, with an average age of 48.2 (standard deviation, 16.2) years, and 56.5% were female and 59.7% were classified as CRS with nasal polyps (CRSwNP). Ten of 26 OC mucus proteins were significantly correlated with threshold, discrimination, and identification (TDI) scores and OC opacification. Subgroup analysis by polyp status revealed that, within the CRSwNP group, C‐C motif ligand 2 (CCL2), interleukin‐5 (IL‐5), IL‐6, IL‐13, IL‐10, IL‐9, tumor necrosis factor‐α (TNF‐α), CCL5, and CCL11 were significantly correlated with olfaction. For CRS without nasal polyps (CRSsNP), only C‐X‐C ligand 5 (CXCL5) showed a correlation. In CRSwNP, IL‐6, IL‐10, vascular endothelial growth factor‐A, and immunoglobulin E (IgE) correlated with OC opacification, whereas, in CRSsNP, only CXCL5 showed a correlation. OC mucus proteins and Lund‐Mackay score correlated only in the CRSsNP group (CXCL5, IL‐5, IL‐13, IgE). Conclusion: Several OC mucus proteins have been found to correlate with olfactory function and OC opacification. The profile of OC mucus proteins differs between CRSsNP and CRSwNP subgroups, suggesting different mechanisms between groups, but further study is required. [ABSTRACT FROM AUTHOR]

Background: Olfactory dysfunction (OD) in chronic rhinosinusitis (CRS) is common. It is likely that numerous factors such as sex, race, age, allergies, asthma, smoking, and other comorbidities play a role in CRS‐related OD. In order to determine which aspects of OD are due solely to CRS and which are associated with other confounders, control populations are needed to allow appropriate risk assessments. Methods: Prospective, multi‐institutional enrollment of patients with CRS and control subjects without CRS was performed. Demographic information, comorbidities, and olfactory testing (Sniffin' Sticks) of threshold (T), discrimination (D), and identification (I) scores (TDI) was collected. Results: A total of 224 patients with CRS and 164 control subjects were enrolled. Olfaction was worse in CRS patients compared to controls (mean ± standard deviation (SD) TDI = 22.4 ± 9.5 vs 28.8 ± 7.0, respectively, p < 0.001). Only 27% of CRS patients were normosmic compared to 49% of controls (p < 0.001). When stratifying by nasal polyp (NP) status, CRSwNP patients had significant impairments in TDI, T, D, and I compared to controls with mean differences of 11.2, 3.3, 3.5, and 4.4 points, respectively (all p < 0.001). In contrast, CRSsNP patients only had impaired T when compared to controls with a mean difference of 2.2 points (p < 0.001). Multivariate modeling of TDI scoring showed that OD was driven by polyps, asthma, diabetes, and age. CRSsNP was not independently associated with worse TDI scores. Conclusion: OD in CRS patients is multifactorial. Independent drivers appear to be polyp status, asthma, diabetes, and age. OD in patients with CRSsNP is similar to controls with the exception of impaired thresholds. [ABSTRACT FROM AUTHOR]

Background Olfactory loss is a cardinal symptom of chronic rhinosinusitis (CRS) and affects 40% to 80% of patients. However, common sinus-specific quality-of-life (QOL) instruments include only single questions related to olfaction. Few studies have explored olfactory outcomes after surgery utilizing validated, olfaction-specific QOL questionnaires. Methods Patients with CRS were enrolled from 3 centers across North America into a prospective cohort study. Patients completed the short modified version of the Questionnaire of Olfactory Disorders (QOD-NS) and the 40-item Smell Identification Test (SIT-40) before and at least 6 months after endoscopic sinus surgery (ESS). Multivariate linear regression was used to determine whether specific demographic, comorbidity, or disease severity measures were independently associated with QOD scores at baseline or predicted change after surgery. Results A total of 121 patients, equally split between genders, were enrolled with an average age of 47.9 years (range, 18-80 years). Baseline total QOD-NS scores were significantly associated with SIT-40 scores, with a moderate strength of correlation ( Rs = 0.400; p < 0.001). The average QOD-NS score improved after ESS (35.7 ± 13.0 vs 39.7 ± 12.2; p = 0.006). Allergy, polyps, and steroid-dependent conditions were found to be independently associated with worse preoperative QOD-NS scores, whereas septal deviation was associated with better QOD-NS scores. Baseline computed tomography (CT) scores were the only variable that significantly predicted change in QOD-NS after surgery. Conclusion Olfaction-specific QOL is worse in patients with polyps and comorbid allergy. Significant improvements in olfaction-specific QOL are seen after ESS, with the greatest gains seen in those with worse CT scores at baseline. [ABSTRACT FROM AUTHOR]