Concepts and controversies in disorders of upper gastrointestinal tract
The upper gastrointestinal tract is one part of the digestive system where tremendous innovations and advancements in knowledge have been recorded in the last several decades. The discovery of Helicobacter pylori by Warren and Marshal in 1983 and the introduction of Rome process for the classification, diagnosis and management of functional gastrointestinal disorders in 1990 set the stage for a plethora of research efforts which have culminated in improvements in the understanding of diseases of upper gastrointestinal tract.
However, there are still wide knowledge gaps and unresolved issues which should attract the attention of researchers. Some of these unresolved issues are highlighted in this review.
Till date, the term “dyspepsia” remains confusing to medical practitioners and physicians, including gastroenterologists. A consensus on the definition has been elusive. Some researchers hold the view that the term should encompass all symptoms emanating from the upper gastrointestinal tract, including symptoms of gastroesophageal reflux disease. Others (including proponents of Rome criteria) maintain that gastroesophageal reflux disease should be separated from dyspepsia. The recent discovery that functional dyspepsia and gastroesophageal reflux disease share a common pathophysiologic mechanism (impaired fundal accommodation) further confounds the argument.
Similarly, functional dyspepsia and gastroparesis are two entities that have more similarities in symptomatology, pathophysiology and response to treatment than differences. Idiopathic gastroparesis has all the signatures of conditions included as functional gastrointestinal disorders in the Rome criteria. Further revisions of Rome criteria are expected to address this.
One curious aspect of Rome IV is the inclusion of reflux hypersensitivity in functional gastrointestinal disorders. This entity is clearly part of gastroesophageal reflux disease. This calls for a new definition for GERD. Belching is grouped under gastroduodenal disorders rather than esophageal disorders for unclear reasons. This seeming misclassification needs to be revisited.
Gastroesophageal reflux disease and eosinophilic esophagitis (EoE) are two conditions that are also more similar than different, especially the variant of EoE that responds to proton pump inhibitors (PPIs). Finally, the geographic enigma in gastric cancer in relation to Helicobacter pylori remains unresolved, despite the plethora of explanations that have been advanced. By highlighting these unresolved issues, future researchers are expected to remain consistent and focused in the search for answers.