Introduction: Mannitol challenge testing can be useful in asthma diagnosis, to demonstrate objective evidence of airways hyperreactivity (AH). Aim: To review mannitol testing locally, identify characteristics of those with positive and negative tests, and look at outcomes in terms of diagnosis and clinical improvement. Methods: We reviewed all tests in our Trust between 2009 and 2011, compared baseline spirometry between positive and negative tests, and looked at immunological evidence of atopy. We reviewed clinic letters for change in diagnosis or management, as well as symptomatic improvement and whether patients were discharged from follow-up (representing clinical stability). Results: Tests were performed on 177 patients between April 2009 and October 2011. The positive and negative groups were compared in terms of spirometry and immunological evidence for atopy (total IgE and IgE to inhaled allergen mix and aspergillus). The test was positive in 40 patients (22.6%). Of these, immunological evidence of atopy was greater than in those with negative tests (mean total IgE 275 vs. 132; IgE to IAM 5.48 and 4.73; IgE to aspergillus 0.6 and 0.25 respectively). Baseline spirometry tended towards more airflow obstruction in the positive group though the means were both within normal range (89% and 97% predicted). Of the 126 patients for whom we had data the mannitol challenge resulted in changes in treatment and improved symptoms in 115 (91.2%). Conclusion: Bronchial provocation testing is useful in identifying those with AH, and for guiding treatment leading to symptomatic improvement.
Full conference title:
European Respiratory Society Annual Congress
- ERS 22nd (2012)