Review article: Supra-oesophageal manifestations of gastro-oesophageal reflux disease and the role of night-time gastro-oesophageal reflux
Gastro-oesophageal reflux disease (GERD) has been associated with a variety of supra-oesophageal symptoms, including asthma, laryngitis, hoarseness, chronic cough, frequent throat clearing and globus pharyngeus. GERD may be overlooked as the underlying mechanism for these symptoms because typical GERD symptoms may be absent, despite abnormal oesophageal acid exposure. Two basic mechanisms linking GERD with laryngeal symptoms have been proposed: direct contact of gastric acid with the upper airway, in some cases due to micro-aspiration, and a vagovagal reflex triggered by acidification of the distal portion of the oesophagus. Gastro-oesophageal reflux (GER) during sleep is believed to be an important mechanism for the development of supra-oesophageal complications of GERD, such as asthma and idiopathic pulmonary fibrosis (IPF). Several physiological changes during sleep, including prolonged oesophageal acid contact time, decreased upper oesophageal sphincter pressure, increased gastric acid secretion, decreased salivation, decreased swallowing and a decrease in conscious perception of acid, render an individual more susceptible to reflux-induced injury. Supra-oesophageal symptoms often improve in response to aggressive acid-suppressive therapy. However, many unanswered questions remain regarding the appropriate approach to diagnosis and treatment of patients with GERD-related supra-oesophageal symptoms. In this article we review the relationship between supra-oesophageal symptoms and GERD and, where possible, highlight the evidence supporting the role of night-time reflux as a contributing factor to these symptoms.