Lung diffusion capacity in children with respiratory symptoms and untreated GERD

BACKGROUND: Gastroesophageal reflux disease (GERD) is associated with many respiratory disorders, among which, chronic cough, laryngitis, and asthma are among the most common. We investigated lung function, including gas diffusion capacity, in children with poor asthma control or chronic laryngitis with untreated GERD. MATERIAL/METHODS: A total of 71 children, aged 6–17 years, with chronic respiratory and other symptoms suggestive for GERD, were enrolled and divided into 2 groups: chronic laryngitis and asthma. Participants underwent 24-hour pH monitoring and lung function assessment, measurement of single-breath diffusing capacity of the lung for carbon monoxide (DL(CO)), and fraction of exhaled nitric oxide (F(E)NO) measurement. RESULTS: 24-hour pH monitoring was positive for GERD in 92.1% of preselected children with asthma and 90.1% of children with chronic recurrent laryngitis. All flows (PEF, MEF(75), MEF(50), and MEF(25)) were significantly lower in the asthma group, while F(E)NO and DL(CO) were significantly lower in the laryngitis group. A significant inverse relationship was found between DL(CO) and all reflux indexes in the laryngitis group. Each unit change of Johnson-DeMeester score and Boix-Ochoa score increased the odds for significantly lower DL(CO) in laryngitis patients by 3.9% and 5.5%, respectively. CONCLUSIONS: In children with uncontrolled asthma and chronic laryngitis, the regurgitation of gastric contents due to GERD contributes to poor asthma control and aggravation of chronic laryngitis. Despite having normal lung function, the gas diffusion capacity should be controlled in patients with GERD and chronic laryngitis, and it might be the very first abnormality in distal airways.