Gastro-oesophageal reflux, eosinophilic airway inflammation and chronic cough.

Abstract

BACKGROUND AND OBJECTIVE:

Patients with eosinophilic airway inflammation (EAI) often show a therapeutic response to corticosteroids. Non-invasive methods of diagnosing EAI are potentially useful in guiding therapy, particularly in conditions such as chronic cough, for which corticosteroids may not be the first-line treatment.

METHODS:

The value of exhaled nitric oxide (ENO) in the diagnosis of EAI was prospectively investigated in a cohort of 116 patients with chronic cough of varying aetiology. An optimum cut-off value was derived for differentiating between EAI and non-EAI causes of chronic cough. As the diagnosis was gastro-oesophageal reflux in 70 patients (60.3% of the total), the possible relationship between ENO and EAI in the presence or absence of reflux was subsequently investigated.

RESULTS:

The optimum value of ENO for differentiating EAI (32% of patients) from non-EAI causes of cough was 33 parts per billion (sensitivity 60.5%, specificity 84.6%). In the subgroup of patients with reflux, ENO was highly specific for the diagnosis of EAI (sensitivity 66%, specificity 100%). Conversely, in the patients without reflux, ENO did not discriminate between cough due to EAI or other causes (sensitivity 100%, specificity 28.9%).

CONCLUSIONS:

These results suggest that the presence or absence of reflux should be taken into consideration when interpreting ENO measurements in the diagnosis of chronic cough associated with EAI.

• Authors: Adalberto Pacheco, Vicenta Faro, Ignacio Cobeta, Ana Royuela, Ian Molyneux, Alyn H Morice
• Journal: Respirology (Carlton, Vic.) (Respirology) Vol. 16 Issue 6 Pg. 994-9 (Aug 2011) ISSN: 1440-1843 [Electronic] Australia
• PMID: 21651646 (Publication Type: Journal Article)
• Copyright: © 2011 The Authors. Respirology © 2011 Asian Pacific Society of Respirology.

Chemical References

• Nitric Oxide

Topics

• Asthma (diagnosis)
• Breath Tests
• Bronchitis (diagnosis)
• Chronic Disease
• Cohort Studies
• Cough (diagnosis)
• Eosinophilia (diagnosis)
• Female
• Gastroesophageal Reflux (diagnosis)
• Humans
• Male
• Middle Aged
• Nitric Oxide (analysis)
• Prospective Studies
• Sensitivity and Specificity