Distinction between patients with non-erosive reflux disease and functional heartburn

Non-erosive reflux disease (NERD) and functional heartburn (FH) are two different clinical entities and the clear distinction between the two forms is actually possible thanks to the use of impedance-pH monitoring. NERD is the more common manifestation of gastro-esophageal reflux disease (GERD), one of the most widespread chronic gastrointestinal disorders in Western countries. The absence of visible lesions on endoscopy and the presence of troublesome reflux-associated (to acid, weakly acidic or non-acid reflux) symptoms are the two key factors for the definition of NERD. FH is an exclusive diagnosis and is defined by the Rome III criteria as a burning retrosternal discomfort, excluding GERD and esophageal motility disorders as a cause of the symptom. FH does not have any type of reflux underlying symptoms and psychological factors seem to be more expressed in FH patients than in patients with reflux-provoked disturbances. The aim of our review is to report the state-of-the-art knowledge about NERD and FH, to clarify their features and differences and to stimulate new research in this field.