Review Article: Respiratory Manifestations of GERD
Background: Respiratory manifestations represent one of the most prevalent and difficult-to-manage extra-oesophageal syndromes of gastro-oesophageal reflux disease.
Aims: To review the epidemiology, pathophysiological mechanisms and therapeutic outcomes of reflux-related respiratory disorders.
Methods: Search of the literature published in English using PubMed database.
Results: There is a discrepancy between the high prevalence of reflux in asthmatics and the limited efficacy of antireflux therapies. Asthma per se may cause reflux. Patients with difficult-to-treat asthma and/or nocturnal symptoms should be screened for reflux. Reflux can induce chronic cough through different mechanisms including micro-aspiration and both local and central reflexes. Cough and reflux may precipitate each other. A meta-analysis found no significant difference between placebo and proton pump inhibitors in the resolution of cough. Encouraging results have been reported, following antireflux surgery in patients selected on the basis of pH-impedance monitoring. Attention has been drawn to obstructive sleep apnoea syndrome.
Conclusions: The role of gastro-oesophageal reflux disease in the pathogenesis of miscellaneous respiratory disorders has been discussed for decades and established in asthma and cough. However, no major therapeutic advances have been reported recently. Future trials should concentrate on patient selection and the control of efficacy using recently developed technologies, such as pH-impedance monitoring.

Gastro-oesophageal reflux disease (GERD) is a common disorder caused by the reflux of gastric contents into the oesophagus. According to a recent global definition GERD can cause oesophageal and extra-oesophageal syndromes, which can co-exist or not in the same individual. Respiratory manifestations of GERD ( Table 1 ) represent one of the most prevalent and challenging of these extra-oesophageal syndromes. However, the relationship between reflux and respiratory symptoms is frequently difficult to establish with a high degree of certainty. Schematically, the causality of reflux in respiratory disorders can be supported by several different pieces of evidence, including (i) a significant epidemiological association between GERD and respiratory disorders, (ii) a temporal relationship between symptom occurrence and reflux episodes (as shown by pH or pH-impedance monitoring) and (iii) various plausible pathophysio-logical explanations, and (iv) efficacy of therapeutic interventions. Unfortunately, as far as reflux-associated respiratory manifestations are concerned, such a bulk of evidence is frequently missing and diagnostic as well as therapeutic management remains largely empirical. In this review of the recent literature, we have focused exclusively on true respiratory disorders (mainly asthma and chronic cough). We have excluded from the scope of the article, studies dealing only with laryngo-pharyngeal manifestations, although both types of symptoms are frequently associated in the same individual and thus are often combined in the same studies or therapeutic trials. We searched the PubMed database using the following MeSH topics and keywords: GERD; respiratory disorders; respiratory diseases; cough; asthma. The search was limited to articles published in English. We focused mainly on original works, clinical trials, meta-analyses, and reviews published during the last ten years.