title: Predominant nocturnal acid reflux in patients with Los Angeles grade C and D reflux esophagitis.
abstract: OBJECTIVE
  Nocturnal gastric acid breakthrough (NAB) is defined as an intragastric pH < 4.0 lasting more than 1 h during the night in patients taking a proton pump inhibitor (PPI). Gastroesophageal reflux disease (GERD) patients with nocturnal gastroesophageal acid reflux accompanied by NAB are thought to be refractory to PPI treatment. The aim of this study was to endoscopically identify the patients with predominant nocturnal gastroesophageal acid reflux.
  
  
  METHODS
  The subjects were 37 patients with erosive reflux esophagitis (Los Angeles classification (LA) grade A, 12; B, 10; C, eight; and D, seven cases) and a control group of 20 patients without esophagitis. The results of ambulatory 24 h gastric and esophageal pH monitoring were compared among different grades of esophagitis.
  
  
  RESULTS
  Gastroesophageal reflux during 24 h in patients with high-grade esophagitis was more frequent than for patients with low-grade esophagitis or no esophagitis. Although the length of esophageal acid exposure (percentage time with pH < 4.0) in patients with grade A or without esophagitis was longer in the daytime, that in patients with grades C and D was longer during the night. The reason for the delayed nocturnal acid exposure was the longer nocturnal acid clearance in high-grade reflux esophagitis.
  
  
  CONCLUSIONS
  Nocturnal exposure of the esophagus to acid occurs frequently in patients with LA grades C and D esophagitis. Thus, the existence of NAB with resulting nocturnal acid reflux should be considered when the patient with high-grade esophagitis shows resistance to PPI treatment.
authors.affiliation: Department of Internal Medicine II, Shimane Medical University, Izumo-shi, Shimane, Japan. kadachi@shimane-med.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Adachi
authors.forename: H
authors.initials: H
authors.lastname: Fujishiro
authors.forename: T
authors.initials: T
authors.lastname: Katsube
authors.forename: M
authors.initials: M
authors.lastname: Yuki
authors.forename: M
authors.initials: M
authors.lastname: Ono
authors.forename: A
authors.initials: A
authors.lastname: Kawamura
authors.forename: M A
authors.initials: MA
authors.lastname: Rumi
authors.forename: M
authors.initials: M
authors.lastname: Watanabe
authors.forename: Y
authors.initials: Y
authors.lastname: Kinoshita
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002940:Circadian Rhythm; D004942:Esophagitis, Peptic / Q000209:etiology / Q000503:physiopathology*; D004945:Esophagoscopy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index