Cough reflex sensitivity in children with suspected and confirmed gastroesophageal reflux disease

Experimental and clinical studies performed in adults revealed that gastresophageal reflux disease (GORD) is associated with an appreciable increase in cough reflex sensitivity (CRS). The association between respiratory diseases and GORD is also present in children, but there is little evidence that GORD without aspiration of refluxate (proximal reflux) is a frequent cause of cough in children. The aim of this study was to find out whether CRS in children with GORD will be changed compared with healthy children, and if so, to determine the role of proximal vs. distal reflux in these changes. CRS and 24-h esophageal pH monitoring were performed in 20 children of whom 13 had confirmed GORD and 7 were suspected to have GORD. The control group consisted of 27 healthy children. For assessing the CRS, each subject inhaled 12 capsaicin aerosol concentrations (0.61-1250 micromol/l) at 1 min intervals. CRS was defined as the lowest capsaicin concentration that evoked minimally 2 coughs (C2). CRS in the group of children with suspected GORD [C2: 17.0 micromol/l (6.4-45.6 micromol/l)] and with confirmed GORD [C2: 13.4 micromol/l (3.6-50.9 micromol/l)] were significantly elevated (P<0.05) compared with healthy children [C2: 72.1 micromol/l (25.5-203.9 micromol/l)]. According to the parameters of 24-h pH monitoring, a significantly higher exposure to acid was present in the distal compared with proximal oesophagus. CRS changes correlated negatively with the distal, but not proximal, esophageal acid exposure. In conclusion, CRS changes in children suffering from GORD are similar to those described in adult patients with GORD. It is plausible that the main role in increased CRS in children with GORD play episodes of distal acid refluxes.