Smell in cystic fibrosis

Abstract

In cystic fibrosis (CF), the most frequent life threatening inherited disease in Caucasians, sinonasal mucosa is regularly affected by defective mucociliary clearance. This facilitates pathogen colonization into CF airways and causes frequent symptoms of rhinosinusitis, including an impaired sense of smell. Despite probable effects on nutrition and overall health, CF-rhinosinusitis is little understood: CF-associated smelling deficiencies reported in literature vary between 12 and 71 %. The aim of this study was to assess olfactory and gustatory function in relation to sinonasal symptoms and sinonasal colonization, and lung function and nutrition. Thirty-five CF patients of different ages were compared to 35 age-matched healthy controls. Olfactory function was assessed by 'Sniffin'Sticks', gustatory qualities by "Taste-strips", and symptoms by sino-nasal outcome test 20 (SNOT-20). Normosmia was found in 62.8 % of healthy controls but only in 28.6 % of CF patients. In contrast the majority of CF patients exhibited a smell loss; almost 62.9 % of them were hyposmic, and 8.6 % functionally anosmic. Importantly, reduced olfactory function only affected odor thresholds, which were significantly increased in CF, not odor identification. This suggests that the olfactory dysfunction in CF results from the olfactory periphery due to either problems in conduction and/or a functional lesion due to the inflammatory process. SNOT-20 scores increased continuously from normosmic to hyposmic and anosmic CF patients (means 7.2/11.1/28.3 points). Neither sinonasal pathogen colonization, gender, pulmonary function, nor allergy or sinonasal surgery appeared to have significant effects on olfactory function and taste. Olfactory disorders are considerably more frequent in CF patients than in age-matched healthy controls. Assessing these parameters within CF-routine care should be considered because of their importance to nutrition and, thus, overall therapy outcome.

Effect of ionic compositions in nasal irrigations on human olfactory thresholds

“…Cystic fibrosis (CF) provides another prominent example of a genetic mutation involving a specific TCNIC that classically results in CRS through abnormal mucociliary clearance. Although CF pathophysiology involves mutations of a transmembrane chloride ion transporter, CF patients, whose nasal liquid also consists of increased potassium concentrations, often report olfactory loss . In patients with these single‐gene defects, the dysfunctional ionic regulation within the upper and lower airways certainly extends to the olfactory cleft and increases the likelihood of olfactory impairment as a part of CRS symptomatology.…”

Longitudinal improvement and stability of olfactory function in the evaluation of surgical management for chronic rhinosinusitis

“…Data were excluded from final analyses if study participants failed to complete preoperative study evaluations as well as postoperative olfactory evaluations at 6 months, 12 months, and 18 months. Additionally, participants with either ciliary dyskinesia and/or corticosteroid dependent conditions were excluded from final analyses due to variations in global health, differential treatment considerations surrounding standard of care, and potential confounding of olfactory status …”

Medical and Surgical Advancements in the Management of Cystic Fibrosis Chronic Rhinosinusitis

“…84 When administered via nebulized inhalation, the major advantage of this medication rests in its ability to reduce mucus viscosity by cleaving extracellular, long-chain DNA that accumulates in CF airways as a result of extensive neutrophil degradation. 60,85 In CF patients over age 5, dornase alfa has demonstrated significantly improved lung function as measured by forced expiratory volume in one second (FEV1) 86 , as well as decreased incidence of pulmonary exacerbations. 85,86 Moreover, bronchial inhalation of dornase alfa has been shown to reduce the annual rate of pulmonary deterioration in a number of trials.…”

“…60,85 In CF patients over age 5, dornase alfa has demonstrated significantly improved lung function as measured by forced expiratory volume in one second (FEV1) 86 , as well as decreased incidence of pulmonary exacerbations. 85,86 Moreover, bronchial inhalation of dornase alfa has been shown to reduce the annual rate of pulmonary deterioration in a number of trials. 86–91 A recent double-blind, placebo-controlled cross-over trial concluded that vibrating sinonasal inhalation of dornase alfa results in symptom and QOL improvement in patients with CF-related CRS.…”