Chronic cough as the sole presenting manifestation of gastroesophageal reflux

Nine patients complaining only of chronic cough of unknown cause were prospectively studied with prolonged esophageal pH monitoring (EPM) before and after cough had disappeared as a complaint in order to determine if and why gastroesophageal reflux (GER) was causing their coughs. Coughs disappeared as a complaint an average of 161 +/- 75 days after medical therapy for GER. Comparisons of pretreatment and post-treatment EPM data revealed the following: numbers of coughs (p = 0.029), total refluxes (p = 0.001), refluxes greater than or equal to 5 min (p = 0.019), and reflux-induced coughs (p = 0.005) had significantly decreased in the distal esophagus, and total refluxes (p = 0.05) had significantly decreased in the proximal esophagus. During the entire study period, the number of coughs were significantly correlated with the number of total refluxes (p = 0.039), longest reflux (p = 0.019), number of refluxes greater than or equal to 5 min (p = 0.006), and percent of total time that pH was less than 4 (p = 0.017) in the distal esophagus. On the basis of these results, we conclude that (1) cough can be the sole presenting manifestation of GER, and it gradually responds to standard GER therapy; (2) prolonged EPM is safe, well-tolerated, and extremely useful in diagnosing clinically silent GER; (3) the mechanism by which GER causes cough is related to a critical number and/or duration of reflux episodes in the distal and/or proximal esophagus.