Chronic Cough Due to Gastroesophageal Reflux Disease: Pathophysiology
Physicians who manage patients with cough should be aware of these differences. While there is much that has been learned about a variety of esophageal and extraesophageal manifestations of GERD, this section will focus solely on chronic cough. Literature on screening for and managing complications of esophageal GERD, such as Barrett epithelium and esophageal cancer, can be found elsewhere., This section reflects an Ovid MEDLINE literature review (through March 2004) for all studies published in the English language and selected articles published in other languages such as French since 1963 using the medical subject heading terms “cough,” “gastroesophageal reflux,” and “gastroesophageal reflux disease.”
When the diagnosis of chronic cough due to GERD is based on a favorable response (eg, elimination of or improvement in cough) to specific GERD treatment, prospective before-and-after intervention studies have revealed that GERD, singly or in combination with other conditions, is one of the most common causes of chronic cough in adults in the world. The prevalence in these studies ranged from 5 to 41%. While it is not clear what accounts for the variation in prevalence, multiple factors likely contribute to it, such as differences in the populations referred and studied. For example, in three prospective studies published by Irwin et al over a period of 17 years, the prevalence and relative commonness of GERD as the cause of chronic cough increased from a low of 10% and being the fourth most common cause in 1981, to 21% and the third most common cause in 1990, to 36% and the second most common cause in 1998. my canadian pharmacy
Knowledge of what is known about where and how GERD can cause cough provides a framework for understanding what has been learned about diagnosis and treatment. Although GERD can stimulate the afferent limb of the cough reflex by irritating the upper respiratory tract without aspiration (eg, the larynx) and by irritating the lower respiratory tract by microaspiration or macroaspiration, there is evidence from a randomized and controlled study by Ing and colleagues that strongly suggests that GERD also can cause chronic cough by stimulating an esophageal-bronchial cough reflex. By this neural reflex mechanism, refluxate into the distal esophagus alone is thought to be a sufficient stimulus to cause cough.