Nomenclature of dyspepsia, dyspepsia subgroups and functional dyspepsia: clarifying the concepts.

There is international agreement that dyspepsia refers to pain or discomfort centered in the upper abdomen. However, the term 'discomfort' has been variably defined. While other symptoms may often be simultaneously present, gastro-oesophageal reflux disease can usually be clearly distinguished by the presence of predominant heartburn. Dyspepsia is a frequent reason for consultation in primary care and in gastrointestinal practice. With the widespread availability and utilization of endoscopy, it has become evident that a structural (or organic) explanation is found in only a minority of patients presenting with dyspepsia. Operationally, functional dyspepsia is defined as persistent or recurrent dyspepsia for 3 or more months in the absence of a clinically identifiable structural disease causing the symptoms. It has been proposed, based on symptoms, that functional dyspepsia be subdivided into symptom subgroups to promote patient homogeneity. The initially proposed 'clustering' of symptoms into ulcer-like and dysmotility-like functional dyspepsia has proved a dismal failure because of the considerable overlap observed, the lack of stability over time and the failure to identify robust pathophysiological abnormalities or responses to therapy. A subcategorization based upon the most bothersome symptom is theoretically more attractive but needs to be prospectively and rigorously tested.