title: Is impedance pH monitoring superior to the conventional 24-h pH meter in the evaluation of patients with laryngorespiratory symptoms suspected to be due to gastroesophageal reflux disease?
abstract: OBJECTIVE
  Cough and laryngo-pharyngeal symptoms (LPS) are associated with gastroesophageal reflux disease (GERD). The role of acid reflux (AR) and non-acid reflux (NAR) in atypical GERD pathogenesis is controversial. The aims of the study were to determine the prevalence of high esophageal acid exposure time (AET) in patients presenting with cough or LPS and determine the incremental yield of multichannel intraluminal impedance-pH (MII-pH) monitoring.
  
  
  METHODS
  We undertook a prospective study of patients with cough or LPS referred for GERD evaluation between January 2009 and May 2011. All patients underwent esophageal manometry, gastroscopy and MII-pH. Patients' characteristics, gastroscopy findings, distal esophageal AET, bolus exposure (BE) time and numbers of AR and NAR episodes in the proximal and distal esophagus were studied.
  
  
  RESULTS
  Overall 50 patients (22 male, mean age 47.5 ± 14.2 years) were evaluated for unexplained chronic cough (n = 23, 46.0%), and LPS symptoms including globus (n = 10, 20.0%), sore throat (n = 12, 24.0%) and hoarse voice (n = 5, 10.0%). A normal gastroscopy, Los Angeles grade A and B esophagitis occurred in 44 (88.0%), 5 (10.0%) and 1 (2.0%) patient, respectively. Seven (14.0%) recorded elevated AET (chronic cough, 4; sore throat, 2; and hoarse voice, 1). Nine patients recorded abnormal impedance characteristics (raised BE time and/or increased reflux numbers) despite a normal AET leading to an incremental diagnostic yield of 18%.
  
  
  CONCLUSIONS
  An isolated high AET is uncommon in patients with cough or LPS. Combined MII-pH improves the diagnostic yield in patients with atypical GERD manifestations.
authors.affiliation: Department of Gastroenterology, Changi General Hospital, Singapore. ang_daphne@yahoo.com
authors.forename: Daphne
authors.initials: D
authors.lastname: Ang
authors.forename: Tiing Leong
authors.initials: TL
authors.lastname: Ang
authors.forename: Eng Kiong
authors.initials: EK
authors.lastname: Teo
authors.forename: Pon Poh
authors.initials: PP
authors.lastname: Hsu
authors.forename: Augustine
authors.initials: A
authors.lastname: Tee
authors.forename: Choo Hean
authors.initials: CH
authors.lastname: Poh
authors.forename: Jessica
authors.initials: J
authors.lastname: Tan
authors.forename: Jeannie
authors.initials: J
authors.lastname: Ong
authors.forename: Kwong Ming
authors.initials: KM
authors.lastname: Fock
mesh_terms: D000328:Adult; D000368:Aged; D002908:Chronic Disease; D003291:Conversion Disorder / Q000209:etiology; D003371:Cough / Q000209:etiology*; D017097:Electric Impedance; D050782:Esophageal pH Monitoring; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis*; D006685:Hoarseness / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010612:Pharyngitis / Q000209:etiology*; D011446:Prospective Studies