Improved Diagnosis of GERD in Patients With Unexplained Chronic Cough
Improved Diagnosis of GERD in Patients With Unexplained Chronic Cough
Background: Symptoms, oesophageal pHmetry and proton pump inhibitor treatment are used for diagnosing gastro-oesophageal reflux-related cough. Weakly acidic reflux is now increasingly associated with reflux symptoms such as regurgitation or chest pain.
Aim: To study the association between weakly acidic reflux and cough in a selected, large group of patients with unexplained chronic cough.
Methods: A total of 100 patients with chronic cough (77 'off' and 23 'on' a proton pump inhibitor) were studied using impedance-pHmetry for reflux detection and manometry for objective cough monitoring. Symptom Association Probability (SAP) Analysis characterized the reflux–cough association.
Results: Acid reflux could be a potential mechanism for cough in 45 patients (with either heartburn, high acid exposure or +SAP for acid reflux). Weakly acidic reflux could be a potential mechanism for cough in 24 patients (with either increased oesophageal volume exposure, increased number of weakly acidic reflux or +SAP for weakly acidic reflux). Reflux could not be identified as a potential mechanism for cough in 31 patients.
Conclusion: A positive association between cough and weakly acidic reflux was found in a significant subgroup of patients with unexplained chronic cough. Impedance-pH-manometry identified patients in whom cough can be related to reflux that would have been disregarded using the standard diagnostic criteria for acid reflux.
Chronic cough, defined as cough lasting more than 8 weeks, has a high socio-economic impact and can significantly impair the quality of life. Gastro-oesophageal reflux (GER), in addition to asthma and postnasal drip syndrome (PNDS), is considered a common cause of chronic cough in all age groups. Because only a minority of patients with GER-related cough have typical reflux symptoms such as heartburn or regurgitation, other tests are frequently used to establish a possible GER–cough association. Empirical treatment with proton pump inhibitors (PPI), aiming to reduce gastric acid secretion, and oesophageal pH monitoring have been incorporated in the diagnostic routine of patients with unexplained chronic cough. If heartburn and regurgitation are absent, if pH monitoring does not show an increased oesophageal acid exposure and/or if the response to PPI treatment is inconclusive, the diagnosis of GER-related cough is discarded. It is possible, however, that these criteria are still insufficient to disregard GER as the cause of cough in some of these patients. It is known, for example, that a subgroup of patients with gastro-oesophageal reflux disease (GERD) may have heartburn with normal oesophageal acid exposure and incomplete response to PPI treatment. One of the mechanisms that have been proposed to explain symptoms and refractoriness to PPI in these patients is the occurrence of oesophageal distension by weakly acidic (WA) reflux. A similar mechanism might be present in patients with unexplained chronic cough.
Oesophageal impedance-pH monitoring is a new technique that improves detection and quantification of acid GER and incorporates the possibility to assess WA reflux. An objective detection of cough, using simultaneous gastro-oesophageal manometry, allows both quantification and precise analysis of the temporal association between cough and reflux.
We hypothesized that a number of patients with unexplained chronic cough might still have their cough associated with GER even if they do not have heartburn or regurgitation, their pH monitoring is normal or they do not respond to standard PPI treatment.
The aim of this study was to further characterize the reflux–cough association in a large number of thoroughly selected patients with unexplained chronic cough using combined 24-h impedance-pH-manometry.
Background: Symptoms, oesophageal pHmetry and proton pump inhibitor treatment are used for diagnosing gastro-oesophageal reflux-related cough. Weakly acidic reflux is now increasingly associated with reflux symptoms such as regurgitation or chest pain.
Aim: To study the association between weakly acidic reflux and cough in a selected, large group of patients with unexplained chronic cough.
Methods: A total of 100 patients with chronic cough (77 'off' and 23 'on' a proton pump inhibitor) were studied using impedance-pHmetry for reflux detection and manometry for objective cough monitoring. Symptom Association Probability (SAP) Analysis characterized the reflux–cough association.
Results: Acid reflux could be a potential mechanism for cough in 45 patients (with either heartburn, high acid exposure or +SAP for acid reflux). Weakly acidic reflux could be a potential mechanism for cough in 24 patients (with either increased oesophageal volume exposure, increased number of weakly acidic reflux or +SAP for weakly acidic reflux). Reflux could not be identified as a potential mechanism for cough in 31 patients.
Conclusion: A positive association between cough and weakly acidic reflux was found in a significant subgroup of patients with unexplained chronic cough. Impedance-pH-manometry identified patients in whom cough can be related to reflux that would have been disregarded using the standard diagnostic criteria for acid reflux.
Chronic cough, defined as cough lasting more than 8 weeks, has a high socio-economic impact and can significantly impair the quality of life. Gastro-oesophageal reflux (GER), in addition to asthma and postnasal drip syndrome (PNDS), is considered a common cause of chronic cough in all age groups. Because only a minority of patients with GER-related cough have typical reflux symptoms such as heartburn or regurgitation, other tests are frequently used to establish a possible GER–cough association. Empirical treatment with proton pump inhibitors (PPI), aiming to reduce gastric acid secretion, and oesophageal pH monitoring have been incorporated in the diagnostic routine of patients with unexplained chronic cough. If heartburn and regurgitation are absent, if pH monitoring does not show an increased oesophageal acid exposure and/or if the response to PPI treatment is inconclusive, the diagnosis of GER-related cough is discarded. It is possible, however, that these criteria are still insufficient to disregard GER as the cause of cough in some of these patients. It is known, for example, that a subgroup of patients with gastro-oesophageal reflux disease (GERD) may have heartburn with normal oesophageal acid exposure and incomplete response to PPI treatment. One of the mechanisms that have been proposed to explain symptoms and refractoriness to PPI in these patients is the occurrence of oesophageal distension by weakly acidic (WA) reflux. A similar mechanism might be present in patients with unexplained chronic cough.
Oesophageal impedance-pH monitoring is a new technique that improves detection and quantification of acid GER and incorporates the possibility to assess WA reflux. An objective detection of cough, using simultaneous gastro-oesophageal manometry, allows both quantification and precise analysis of the temporal association between cough and reflux.
We hypothesized that a number of patients with unexplained chronic cough might still have their cough associated with GER even if they do not have heartburn or regurgitation, their pH monitoring is normal or they do not respond to standard PPI treatment.
The aim of this study was to further characterize the reflux–cough association in a large number of thoroughly selected patients with unexplained chronic cough using combined 24-h impedance-pH-manometry.
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