Introduction Chronic cough and GERD are very common and prevalent diseases. It is known that GERD is one of the three most common causes of chronic cough. During the last years, new methods have been introduced to study the temporal and causal association between reflux and cough. pH-impedance monitoring has been proposed as the most sensitive method for detection of acid and non acid reflux whereas either manometric or acoustic methods have been used for objective detection of cough. During these studies, a sequence of association of “reflux-cough” has been used to establish a positive diagnosis. The sequence cough-reflux has also been described but controversy still exist about its prevalence and clinical relevance. One potential factor for such controversy could be due to different methodology for cough detection. The aim of this study was to assess the contribution of cough to pathologic GER in patients with chronic cough and increased esophageal acid exposure.
Methods Simultaneous 24h ambulatory reflux and cough monitoring was performed in 17 patients with suspected reflux-related chronic cough. Reflux episodes were detected by pH-impedance monitoring and coughs by a) manometric detection and b) acoustic detection (independent listening of complete 24hs sound recordings). Manometric cough detection was performed with a two-channel pressure catheter with sensors in the oesophagus and stomach. Cough was manually declared when simultaneous abdomino-thoracic pressure bursts occurred of at least 2 peaks within 3 seconds. Acoustic detection was performed using 3 sound surface sensors. Cough events were identified and inserted into the reflux tracing. We measured total esophageal acid exposure and bolus exposure (by impedance). We calculated the time of acid exposure and bolus exposure after manometrically and acoustic detected cough events.
Results 6/17 patients had pathological esophageal acid exposure. In these patients the total number of reflux events/24hs was 38 (29–70). From that total number, 7.4% (0–25) reflux episodes occurred within 2 minutes after a cough episodes. Total acid exposure was 9.7% ± 4.7. From the acid exposure, 3.5% (0- 8)% occurred after cough detected by manometry or audio. The median total bolus exposure was 2.1 ± 0.6%. From total bolus exposure, 6.3% (0–20) occurred after manometric cough detection and 6.8% (0–50) after acoustic detected cough. Only 1/6 patients had a significant increase in acid and bolus exposure after cough.
Conclusion In patients with chronic cough and pathological acid GER, cough was followed by reflux in a minority of cases regardless of the method for cough detection. In only 1/6 patients the sequence cough-reflux could be considered as causal of pathological GER.
Disclosure of Interest None Declared
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