Airway acidification and gastroesophageal reflux.

Although challenging to study, researchers recently recognized the relevance of airway pH to the pathophysiology of several respiratory diseases, ranging from asthma and cystic fibrosis to pneumonia. The airway epithelium is extraordinarily sensitive to acid. Gastroesophageal reflux can and does cause respiratory symptoms, through both neurally mediated pathways and direct aspiration. Direct aspiration has a variety of immunologic, biochemical, and physiologic effects that aggravate asthma and other respiratory diseases, yet strategies to diagnose and treat gastroesophageal reflux-related respiratory symptoms remain imprecise.