[Gastroesophageal reflux: new concepts on physiopathology and treatment].

Multiple factors through a complex interaction are involved in the pathophysiology of gastroesophageal reflux disease. The transient or permanent failure of the antireflux barrier located at the esophagogastric union (lower esophageal sphincter and diaphragmatic crura) and the presence of gastric content to be refluxed determine the occurrence of reflux from the stomach into the esophagus, according to the physiologic gastroesophageal pressure gradient. The activity and mechanism of damage of the injurious components of gastroduodenal refluxate (hydrochloric acid, pepsin, bile acids and trypsin) are determined by the pH of the refluxate. The esophagitis is the final consequence of a prolonged contact time between the epithelium and several injurious components of gastroduodenal refluxate, and is due to the impairment of esophageal volume and acid clearance as well as to the failure of the epithelial resistance mechanisms.