Overlap of GERD and gastrointestinal functional disorders

The functional gastrointestinal disorders (FGIDs) are common conditions with an overall prevalence burden estimated at approximately one-third of the population. These represent a heterogeneous group of conditions which may include both abnormal symptom perception and functional causes and seems to share similar trigger factors as food, lifestyle and psychological factor. GERD develops when the reflux of gastric contents into the esophagus leads to troublesome symptoms, with or without mucosal involvement. Functional heartburn (FH) represents a subcategory of patients who refers with heartburn but without abnormal esophageal acid exposure, abnormal number of reflux events or any temporal correlation between symptoms and reflux events, on the same hands these patients do not report any symptom relief during antisecretory treatment with proton pump inhibitors. To date, several studies have reported a certain degree of overlap between GERD and FGIDs that it is only partially explained solely by chance. This review evaluated the overlap between GERD but especially FH and different FGIDs as: functional non-cardiac chest pain, irritable bowel syndrome, functional dyspepsia, gastric belching and supragastric belching and pharyngeal globus. A large number of mechanisms have been proposed to elucidate the connection between these numerous conditions. When pathophysiologic tests to subgroup GERD have been performed, FH seems overlap more frequently than GERD with FGIDs. From a therapeutic point of view visceral hypersensitivity, that characterize these functional disorders might be modulated by antidepressant therapy even if there are limited evidences. More studies and especially randomized controlled trials should consider these agents for future agenda researches.