Cystic Fibrosis: the sense of smell.

Background: Cystic Fibrosis (CF) consists of multiorgan manifestations that include chronic rhinosinusitis (CRS) with or without nasal polyposis. The principal symptoms of CRS are nasal congestion, rhinorrea, mouth breathing, facial pain, and olfactory dysfunction (anosmia/hyposmia). A large percentage of CF patients present CRS therefore we evaluated the olfactory performance in: i) CF patients with CRS without polyps; ii) age-matched healthy controls. Materials and Methods: We enrolled: - group I: 29 CF patients with CRS without polyps with different mutations (mean age: 30.1±9.3 years); - group II: 29 age-matched healthy volunteers (mean age: 29.7±5.9 years). All cases were not smokers. They did not assume food or beverages other than water within 6 hours previous test. Subjects with acute nasal infection, facial trauma and/or nasal polyps were excluded. All subjects underwent the Sniffin’Sticks (Burghart Medical Technology) (SS) to assess the olfactory performance. Results: Group I: 7% of CF patients were normosmic, 69% hyposmic, 10% anosmic, 14% borderline. They presented mean odor identification of 10.55±2.99, mean odor discrimination of 10.28±2.67, mean odor threshold of 2.14±2.63, mean TDI score of 22.97±6.07. All these olfactory evaluations were statistically different to healthy controls (Group II) (p<0.001). Conclusions: The impairment of olfaction influences the quality of life in CF patients, decreasing appetite, aggravating nutritional problems and playing a significant role in social interactions. We found a significant frequency of smelling disorders in CF patients and a major impairment of odor threshold. Our data suggest that CF olfactory impairment can result from olfactory periphery dysfunction due to either conduction problems by CRS and impaired mucociliary clearance owing to thickened mucus. So therapies improving the mucociliary clearance might recover olfactory performance in CF patients with CRS. Moreover this olfactory test could represent a new clinical tool in the follow-up of CF patients.