24-HOUR AMBULATORY ESOPHAGEAL PH MONITORING IN THE DIAGNOSIS OF ACID REFLUX-RELATED CHRONIC COUGH

To define the role of ambulatory pH monitoring in evaluating chronic c ough, we studied esophageal pH values of patients referred to a gastro enterology laboratory. Chronic cough was evaluated in 31 patients, who were grouped based on response to treatments; 11 patients (35.5%) had gastroesophageal reflux (GER)-related cough, 11 (35.5%) had pulmonary /otorhinolaryngolic-related cough (1 bronchitis, 6 asthma, 2 postnasal drip, 1 pneumonia), and 9 patients (29%) had cough of unknown etiolog y. Esophageal pH values of groups were compared. Excessive acid reflux distally (upright and supine) and proximally (upright) and cough symp tom frequency related to acid reflux were significantly higher in pati ents with GER. Esophageal pH monitoring had good sensitivity (91%), sp ecificity (82%), and positive (83%) and negative (90%) predictive valu es in identifying GER-related cough. In summary, ambulatory pH monitor ing is an excellent test for identifying patients with GER-related cou gh.