To evaluate whether the proportion of acid and weakly acidic refluxes preceding cough bursts could be different in infants, preschool- and school-aged children with chronic, unexplained cough.Patients and Methods:
One hundred six children with unexplained chronic cough, not receiving acid suppressive therapy, underwent impedance–pH monitoring. They were divided into Group A: <2 years (21 pts), Group B: ≥2 to ≤6 years (41 pts), and Group C: >6 years (44 pts). Reflux was defined as acid (pH <4), weakly acidic (WA; pH 4–7), and weakly alkaline (pH >7).Cough episodes were considered temporally associated with gastroesophageal reflux (GER) when occurring within 2 min after a GER episode.Results:
Impedance–pH detected 55.50 (39.00–76.00) reflux episodes/patient with an acid-to-WA reflux event ratio of 3.31 (1.55–8.33). This parameter was significantly lower in Group A (1.33 [0.41–3.40]) than in Group B (3.06 [2.00–6.50];P< 0.05] and Group C (5.09 [2.34–12.43;P< 0.001]). No cough episode was preceded by weakly alkaline refluxes in any patient. During impedance–pH recording, 93 patients (87.7%) had at least one cough episode that had been preceded by impedance refluxes in 83 patients. In this latter group (83 pts), the median number of cough episodes was 12.0 (5.0–25.5), of which 48.15% (30.15–71.43%) were preceded by refluxes; GER-preceded cough episodes were similar in the three groups. The majority of children had cough episodes preceded by acid refluxes in the total population (78.3%), in Group B (80.5%) and in Group C (93.7%), but not in Group A (40.0%;P< 0.001).Conclusions:
In addition to acid, also a significant proportion of WA GER may precede cough episodes in young children with persistent cough, possibly explaining the inconstant effects of anti-acid treatment on respiratory symptoms.