Review article: the role of pH monitoring in extraoesophageal gastro-oesophageal reflux disease.

Gastro-oesophageal reflux disease is associated with several extraoesophageal disease states including laryngitis, asthma, chronic cough and non-cardiac chest pain. Currently, the exact role reflux of gastric contents play in the pathogenesis of extraoesophageal symptoms remain controversial. Twenty-four hours pH monitoring is often considered the 'gold standard' in the diagnosis of gastro-oesophageal reflux disease and is increasingly utilized in patients with extraoesophageal symptoms. The use of this test is aimed at improving the association between patients' extraoesophageal symptoms and oesophageal or hypopharyngeal acid reflux events. However, the clinical utility of pH monitoring in this patient population remains controversial. Important clinical questions in this area include: does the presence of abnormal oesophageal acid reflux suggest a causal association between patients' extraoesophageal symptoms and gastro-oesophageal reflux disease? Conversely, does the absence of abnormal acid exposure in the oesophagus suggest lack of such an association? Should the test be performed on or off therapy and does it matter? In this study, the role of pH monitoring in laryngitis, asthma, chronic cough and non-cardiac chest pain is examined and answers to the above questions are addressed based on current data.