| Theme | GERD in Clinical Practice 2018 -- Current Status and Issues | |
|---|---|---|
| Title | Pathophysiology of Gastroesophageal Reflux Disease (GERD) | |
| Publish Date | 2018/03 | |
| Author | Eriko Koizumi | Department of Gastroenterology, Nippon Medical School, Graduate School of Medicine |
| Author | Katsuhiko Iwakiri | Department of Gastroenterology, Nippon Medical School, Graduate School of Medicine |
| [ Summary ] | Gastroesophageal reflux disease (GERD) can be categorized into 2 types, each with a distinct pathology : reflux esophagitis (RE) which is associated with esophageal mucosal breaks and non‒erosive reflux disease (NERD) without any esophageal mucosal breaks. The cause of RE is attributable to excessive esophageal acid exposure. Acid reflux and esophageal acid clearance after acid reflux are important factors related to excessive esophageal acid exposure. The primary mechanism associated with acid reflux is transient lower esophageal sphincter relaxation (TLESR), which refers to LES relaxation that is not associated with swallowing. It must be noted that acid reflux caused secondary to a low LES pressure is a rare condition. The frequency of TLESR during the postprandial period does not significantly differ between healthy individuals and patients with GERD ; however, the incidence of acid reflux episodes occurring during TLESR is significantly higher in patients with GERD. The layer of acid that appears above the layer of food in the stomach immediately below the esophagogastric junction (acid pocket) has been gaining increasing attention as a possible factor that determines the difference between the groups in terms of acid reflux during TLESR. Regarding NERD it must be noted that approximately 60‒70 % of reflux symptoms are attributable to acid reflux and the remaining to non‒acid reflux secondary to esophageal hypersensitivity, esophageal motility disorders, eosinophilic esophagitis, and functional heartburn, among other such conditions. A study analyzing esophageal motor function demonstrated that patients with NERD showed defective triggering of secondary peristalsis compared to that observed in healthy individuals. Persistence of reflux symptoms after the completion of standard‒dose proton pump inhibitor (PPI) therapy, warrants evaluation of the pathophysiology associated with this condition using esophageal multi‒channel impedance testing and pH monitoring and/or esophageal manometery to determine the relationship between symptoms and esophageal pathophysiology. | |