The importance of smell in patients with bronchiectasis

Abstract

Background: The aim of the study was to evaluate the sense of smell in patients with bronchiectasis.

Methods: Prospective controlled study was performed on 91 patients with bronchiectasis. Bronchiectasis patients were sub-classified depending on: the presence of chronic rhinosinusitis, with or without nasal polyps, and the bronchiectasis ethiology. Olfactory function was evaluated by means of the Barcelona Smell Test (BAST-24) olfactometry for detection, identification, and forced choice for the first and fifth cranial nerve dependent odours in comparison to a group of 120 healthy volunteers.

Results: Most patients with bronchiectasis (80.2%) satisfied EP(3)OS criteria of chronic rhinosinusitis (CRS), and 26.4% presented nasal polyps (NP). Smell detection, identification, and forced choice tests were significantly (p < 0.001) worse in bronchiectasis patients than healthy controls for both the 1st and 5th CN. Among subgroups, patients with CRS presented a significant (p < 0.05) reduction in smell detection compared to both healthy controls and patients without CRS. Patients with both CRS and NP presented a significant (p < 0.01) reduction in both smell detection and forced choice compared to patients with CRS and without NP. Patients with bronchiectasis and primary humoral immunodeficiency had a poorer smell detection (p < 0.001) and forced choice (p < 0.001) compared with post-infective and idiopathic bronchiectasis patients.

Conclusions: Patients with bronchiectasis have a moderate loss of smell with a higher impairment in patients with CRS, being maximal in patients with NP. Patients with immunodeficiency bronchiectasis showed high prevalence of CRS, and therefore marked impairment on the sense of smell. The mechanism could be explained through a mixed ethiology (obstruction/inflammation).