Most important pathophysiological cause of GERD is:

Ans is 'b' i.e. transient LES relaxation "Transient LES relaxations account for at least 90% of reflux in normal subjects or GERD patients without hiatus hernia HarrisonTransient lower esophageal sphincter relaxations account for essentially all reflux events in individuals with a normal LES pressure at the time of reflux Pathogenesis of gastroesophageal reflux disease (GERD)The primary event in the pathogenesis of gastroesophageal reflux disease (GERD) is movement of gastric juice from the stomach into the esophagus.The three dominant pathophysiologic mechanisms causing gastroesophageal junction incompetence are:Transient lower esophageal sphincter relaxations (tLESRs)A hypotensive lower esophageal sphincter (LES)Anatomic disruption of the gastroesophageal junction, often associated with a hiatal herniaThe latest concept is that the dominant mechanism varies as a function of disease severity with tLESRs predominating with mild disease and mechanisms associated with a hiatus hernia and/or a weak sphincter predominating with more severe disease Transient LES relaxations are different from swallow-induced LES relaxation: tLESRs occur without an associated pharyngeal contraction, are unaccompanied by esophageal peristalsis, and persist for longer periods (>10 sec) than do swallow-induced LES relaxations. tLESRs are the physiological mechanism of belching.