Functional disorder of the proximal gastrointestinal tract

Functional gastrointestinal disorders (FGIDs), although highly common, are relatively poorly understood and difficult to manage in clinical practice. The Rome consensus has classified these disorders into organ regions (i.e., esophageal, gastroduodenal, bowel, biliary, anorectal), presuming that there are unifying features underlying diagnosis and management that relate to these organ locations. Individual disorders are diagnosed based on symptom groupings. The link between symptoms and organ location is mainly based on expert consensus. The previous Rome I-III consensus documents generated authorative criteria for diagnosing, studying and treating FGIDS. The latest iteration of this process is the Rome IV consensus on diagnostic criteria for FGIDS, just presented last May 2016. As a general important innovation, thresholds for frequency of symptoms in Rome IV now have a scientific basis: the Rome foundation conducted a Normative Symptom Study to allow the development of thresholds for symptoms based on evidence.

In a first part, the major changes with Rome IV will be highlighted. The functional esophageal disorders were thoroughly revised taking into account new diagnostic entities that need to be excluded (eosinophilic esophagitis) and new technological developments to detect other diseases (high resolution manometry and esophageal pH impedance monitoring). In addition, in Rome III, "Functional Heartburn" defined heartburn symptoms in the absence of evidence that the symptom is associated with gastroesophageal reflux. However, there are also patients who have normal acid reflux levels, but who are sensitive to this physiological reflux and so develop heartburn. For Rome IV, "Reflux Hypersensitivity" characterizes this entity and is to be differentiated from functional heartburn and from classic non-erosive reflux disease with pathological acid exposure. Since the Rome III consensus, FD was subdivided into epigastric pain syndrome (EPS) and postprandial distress syndrome (PDS). PDS is characterized by postprandial fullness and early satiation) while EPS is characterized by epigastric pain and burning. The Rome IV subdivision has used the same principles for defining EPS and PDS, but aimed at decreasing the overlap by taking into account postprandial occurrence of EPS symptoms and nausea. Current evidence shows that this has a favorable impact on the overlap issue. For Rome IV the new diagnosis "Chronic Nausea Vomiting Syndrome" combines the previous Rome III entities "Chronic Idiopathic Nausea" and "Functional Vomiting." The rationale for combining the two diagnoses relates to the paucity of data delineating differences in diagnostic approach and management of nausea compared to vomiting, and the clinical observation that these symptoms are commonly associated.

In the second part, clinical application in diagnostic-therapeutic algorithms will be illustrated for several of these disorders.