[Therapy resistance of gastro-oesophageal reflux symptoms: acid reflux, non-acid reflux or no reflux].

The introduction of proton pump inhibitors (PPIs) was a huge step forward in the treatment of gastric acid-related disorders such as reflux disease and gastric ulcers. Despite the strong effectiveness of PPIs, in a small number of patients reflux symptoms are not adequately relieved by these drugs. The amount of acid inhibition that can be achieved using a PPI depends on a number of different factors, such as Helicobacter pylori infection, genetic variation in metabolizing enzymes, and lack of compliance. Nocturnal gastric acid breakthrough does not appear to be important in the pathogenesis of therapy-resistant reflux symptoms. Not all reflux from the stomach into the oesophagus appears to be acidic. Episodes of non-acid reflux may also elicit typical reflux symptoms. This can be established by impedance measurements of the oesophagus. However, most patients whose symptoms do not respond satisfactorily to PPI therapy appear not to have reflux disease but instead be suffering from other conditions such as functional dyspepsia, aerophagy or rumination. Careful history-taking is pivotal in patients with reflux symptoms and should always precede additional investigations such as upper endoscopy and if necessary 24-hour reflux monitoring.