Mechanisms of Barrett's oesophagus (clinical): LOS dysfunction, hiatal hernia, peristaltic defects

Abstract

Summary Barrett’s esophagus, with the potential to develop into esophageal adenocarcinoma (EAC), is a major complication of gastroesophageal reflux disease (GERD). However, about 50% of patients developing EAC had no known GERD beforehand. Hence, while GERD symptoms, esophagitis, and Barrett’s have a number of common determinants (esophagogastric junction (EGJ) incompetence, impaired esophageal clearance mechanisms, hiatus hernia) they also have some independent determinants. Further, although excess esophageal acid exposure plays a major role in the genesis of long-segment Barrett’s esophagus there is minimal evidence supporting this for short-segment Barrett’s. Hence, these may have unique pathophysiological features as well. Long-segment Barrett’s seems to share most, if not all, of the risk factors for esophagitis, particularly high-grade esophagitis. However, it is uncertain if EGJ function and acid clearance are more severely impaired in patients with long-segment Barrett’s compared to patients with high-grade esophagitis. With respect to short-segment Barrett’s, the acid pocket may play an important pathogenic role. Conceptually, extension of the acid pocket into the distal esophagus, also known as intra-sphincteric reflux, provides a mechanism or acid exposure of the distal esophageal mucosa without the occurrence of discrete reflux events, which are more likely to prompt reflux symptoms and lead to the development of esophagitis. Hence, intra-sphincteric reflux related to extension of the acid/no acid interface at the proximal margin of the acid pocket may be key in the development of short segment Barrett’s. However, currently this is still somewhat speculative and further studies are required to confirm this.

Esophageal Hypocontractile Disorders and Hiatal Hernia Size Are Predictors for Long Segment Barrett’s Esophagus

“…7,18 The presence of hiatal hernia is highly prevalent among patients with BE (up to 96.0%). 19 The close relationship between hiatal hernia and BE has been previously described in the literature as well as the correlation between LSBE and hiatal hernia length. A meta-analysis has shown that the presence of hiatal hernia is associated with an increased risk of developing BE (OR, 3.94; 95% CI, 3.02-3.96).…”

Hiatus hernia in healthy volunteers is associated with intrasphincteric reflux and cardiac mucosal lengthening without traditional reflux

“…However, unlike oesophageal adenocarcinomas, these cardia and junctional cancers have only a very weak association with a previous history of reflux symptoms 7 8. These observations suggest that the mechanism of acid exposure inducing these junctional cancers may be different from traditional transsphincteric reflux 9 10…”

The management of hiatal hernia: an update on diagnosis and treatment

“…Prokinetic drugs are not recommended in guidelines neither as monotherapy nor as add-on treatment as there is no evidence supporting their efficacy in the treatment of hiatal hernia associated with GERD [20,23].…”