[Pathogenesis of gastroesophageal reflux]

Abstract

Gastro-oesophageal reflux (GOR) is common. Nearly all healthy individuals experience occasional or frequent reflux episodes, with or without symptoms, which occur during spontaneous relaxations of the lower oesophageal sphincter, predominantly after meals. It is not known how neural, hormonal and muscular factors contribute to this. A proportion of the patients with reflux disease have normal lower oesophageal sphincter pressures, and their reflux episodes occur during spontaneous sphincter relaxations following the pattern of normals. Nevertheless, most patients with reflux disease have decreased lower oesophageal sphincter pressure, and manoeuvres which increase the intraabdominal pressure provoke "stress" reflux. If the sphincter pressure is very low, "free" reflux occurs; the cause of decreased sphincter pressure is not known. Pharmacological and gastric factors also facilitate GOR. The noxious potency of reflux material on the oesophageal epithelium depends on its components [( H+], pepsin, bile salts, trypsin) and the contact time, which is prolonged during supine and nocturnal reflux episodes, i.e. when clearance function is impaired. In complicated reflux disease it is necessary to consider this multifactorial model of the pathogenesis of reflux disease, and to go on to more sophisticated diagnostic procedures (manometry, scintiscanning, prolonged pH-monitoring) in order to identify an individual patients' predominant pathogenetic factor.