Challenges to Unravel Mechanisms of GERD

Gastroesophageal reflux disease (GERD) encompasses a spectrum of disorders caused by a reflux of gastric contents into the esophagus or complications of gastroesophageal reflux. Although depending on the definition, the prevalence of GERD is higher in the West than in the East, and the prevalence has been slightly increasing, so that the clinicians, even though they are not gastroenterologists, must encounter GERD patients and treat them. However, the clinicians do feel difficulty in treating GERD patients, since prescription of acid neutralizing agents, such as proton pump inhibitors (PPIs), sometimes fail to resolve their complaints. This may be partly explained by the discrepancies between clinical complaint and endoscopic findings; some patients present endoscopic esophagitis while some do not, and be partly explained by the potentially wide spectrum of pathophysiological etiologies than has been thought. This chapter describes current knowledge on heterogeneous mechanisms of GERD development. Clarifying the mechanisms of GERD on the individual basis may realize conceptual shift from uniform prescription of acid neutralizing agents to establishment of patient-oriented therapies.