COUGH AND GASTROESOPHAGEAL REFLUX: THE MECHANISMS

Abstract

Cough is the most common presenting complaint in adults seeking medical treatment in an ambulatory setting. Gastro-esophageal reflux (GER) of gastric contents into the esophagus occurs in virtually all normal subjects and most often causes no symptom or discomfort. However, when GER is accompanied by symptoms or discomfort, it becomes non-physiological and is termed gastro-esophageal reflux disease. It seems therefore that the coexistence of reflux and cough in many patients can likely be plained on the basis of different mechanisms some of which are obvious (i. e. aspiration) whilst others require confirmatory investigations. There is no doubt that aspiration or micro-aspiration of gastric content represent an effective cause of cough in a well-delineated minority of patients. In other instances, neurogenic mechanisms reflexly acting in response to esophageal acidification may result in airway changes and respiratory symptoms including cough. Central sensitization of the cough reflex in response to “chronic” acid or non-acid exposure of the esophageal mucosa in refluxers may represent an unifying mechanism that, although not causative, exerts an important facilitatory effect on the genesis of a hypertussive state.