title: Increase of weakly acidic gas esophagopharyngeal reflux (EPR) and swallowing-induced acidic/weakly acidic EPR in patients with chronic cough responding to proton pump inhibitors.
abstract: BACKGROUND
  Gastro-esophageal reflux disease (GERD)-related chronic cough (CC) may have multifactorial causes. To clarify the characteristics of esophagopharyngeal reflux (EPR) events in CC patients whose cough was apparently influenced by gastro-esophageal reflux (GER), we studied patients with CC clearly responding to full-dose proton pump inhibitor (PPI) therapy (CC patients).
  
  
  METHODS
  Ten CC patients, 10 GERD patients, and 10 healthy controls underwent 24-h ambulatory pharyngo-esophageal impedance and pH monitoring. Weakly acidic reflux was defined as a decrease of pH by >1 unit with a nadir pH >4. In six CC patients, monitoring was repeated after 8 weeks of PPI therapy. The number of each EPR event and the symptom association probability (SAP) were calculated. Symptoms were evaluated by a validated GERD symptom questionnaire.
  
  
  RESULTS
  Weakly acidic gas EPR and swallowing-induced acidic/weakly acidic EPR only occurred in CC patients, and the numbers of such events was significantly higher in the CC group than in the other two groups (P < 0.05, respectively). Symptom association probability analysis revealed a positive association between GER and cough in three CC patients. Proton pump inhibitor therapy abolished swallowing-induced acidic/weakly acidic EPR, reduced weakly acidic gas EPR, and improved symptoms (all P < 0.05).
  
  
  CONCLUSIONS
  Most patients with CC responding to PPI therapy had weakly acidic gas EPR and swallowing-induced acidic/weakly acidic EPR. A direct effect of acidic mist or liquid refluxing into the pharynx may contribute to chronic cough, while cough may also arise indirectly from reflux via a vago-vagal reflex in some patients.
authors.affiliation: Department of Gastroenterology, Gunma University Hospital, Maebashi, Gunma, Japan. osamuk@med.gunma-u.ac.jp
authors.forename: O
authors.initials: O
authors.lastname: Kawamura
authors.forename: Y
authors.initials: Y
authors.lastname: Shimoyama
authors.forename: H
authors.initials: H
authors.lastname: Hosaka
authors.forename: S
authors.initials: S
authors.lastname: Kuribayashi
authors.forename: M
authors.initials: M
authors.lastname: Maeda
authors.forename: A
authors.initials: A
authors.lastname: Nagoshi
authors.forename: H
authors.initials: H
authors.lastname: Zai
authors.forename: M
authors.initials: M
authors.lastname: Kusano
mesh_terms: D000328:Adult; D000368:Aged; D002908:Chronic Disease; D003371:Cough / Q000150:complications*; D003679:Deglutition / Q000502:physiology*; D005260:Female; D005764:Gastroesophageal Reflux / Q000188:drug therapy* / Q000209:etiology* / Q000503:physiopathology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D054328:Proton Pump Inhibitors / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D054328:Proton Pump Inhibitors