The utilitiy of FENO for the diagnosis of hypersensitivity pneumonitis

Abstract

IntroductiOn: There is very few evidence of the utility of the oxide exhaled fraction (FeNO) in interstitial lung disease (ILD) and nearly all of it, it´s related with connective tissue disease. A recent study showed that patients with hypersensitivity pneumonitis (HP) had significantly higher levels of FeNO that patients with other ILD. The objective of the present study was to investigate the levels of FeNO before and after de specific inhalation challenge (SIC) in patients diagnosed of HP and to value its utility for the diagnosis of HP. Material and Methods: It was a prospective study of 25 patients that had been submitted under the suspicion of presenting HP. Eleven patients received the diagnosis of HP due to avian o fungi antigens, based on the past medical history, pulmonary function testing, IgGs, thorax CT scan, bronchoalveolar lavage and biopsy. FeNO was measured before and after performing SIC. Results: Out of the 25 patients that were studied, 11 were diagnosed of HP, 6 patients that had been exposed to avian proteins and 5 that had been exposed to fungi. Differences were not observed between the FENO values, before and after the SIC. There were not differences in the basal levels of FENO between patients that had been diagnosed of HP and the 14 patients that had ILD other than HP. ![Figure][1] ConclusiOn: FENO not seems to be useful for the diagnosis of HP. Further studies with larger number of patients would be needed to confirm these results. [1]: pending:yes