Role of gastroesophageal reflux in children with unexplained chronic cough

The relation between respiratory symptoms and gastroesophageal reflux (GER) is a matter of contention and debate, with limited data in children to substantiate or refute cause and effect. Moreover, there are few data on the relation between nonacid reflux and chronic cough in childhood. We aimed to describe the type and physical characteristics of reflux episodes in children with unexplained chronic cough.

Forty-five children with chronic cough underwent 24-hour multichannel intraluminal impedance-pH monitoring (MII-pH monitoring). Symptom association probability (SAP) characterized the reflux-cough association. Twenty children with erosive reflux disease (ERD) served as controls.

Twenty-four children had cough-related reflux (CRR), with 19 having no gastrointestinal symptoms. Twenty-one had cough-unrelated reflux (CUR). CRR and ERD had increased acid (AR), weakly acidic (WAc), and weakly alkaline (WAlk) reflux. Esophageal acid exposure time and acid clearance time were higher in ERD than in CRR and CUR. In the CRR group, of 158 cough episodes related to reflux episodes, 66% involved AR, 18% WAc, and 16% WAlk. Seventeen children had positive SAP, 7 for AR, 5 for both AR and WAc, 4 for both WAc and WAlk, and 1 for WAlk.

In children with unexplained chronic cough, asymptomatic acid and nonacid GER is a potential etiologic factor. The increased acid exposure time and delayed acid clearance characteristic of ERD are absent in cough-related GER. MII-pH monitoring increases the likelihood of demonstrating a temporal association between the cough and all types of reflux.