Document Detail

Precise role of acid in non-erosive reflux disease.
MedLine Citation:
PMID:  18832838     Owner:  NLM     Status:  MEDLINE    
The fundamental abnormality in gastroesophageal reflux disease is exposure of the esophageal epithelium to acidic gastric contents, resulting in histopathologic injury and/or symptoms. With increasing understanding of gastroesophageal reflux disease, non-erosive reflux disease (NERD) is found to account for >50% of cases involving gastroesophageal reflux. There is a good correlation between esophageal acid exposure (EAE) and endoscopic changes. Duration of EAE correlates with severity of erosive esophagitis (EE), and the number of prolonged acid reflux episodes and esophageal exposure to acid and pepsin is increased in more severe reflux. However, there is no convincing evidence to support a significant difference in the acid secretory capacity between patients with NERD or EE. Although acid reflux gives rise to similar symptoms in both NERD and EE patients, the underlying mechanism of acid injury may be different. Dilated intercellular spaces may be responsible for the enhanced perception of proximal acid reflux and dilated intercellular spaces are a feature of NERD patients, irrespective of EAE, and can be considered an objective, structural marker of reflux symptoms. Three different mechanisms have been proposed to explain the occurrence of heartburn in endoscopy-negative patients: esophageal visceral hypersensitivity, sustained esophageal contractions, and abnormal tissue resistance. Impaired esophageal mucosal resistance or increased sensitivity, even to small amounts of acid reflux, plays a key role in the pathophysiology of NERD. Moreover, hyperalgesia may be a predominant mechanism in eliciting symptoms in NERD patients. Increasingly seen are patients with a poor response to acid suppression treatment. Moreover, even double proton pump inhibitor dosing does not completely inhibit gastric acid secretion and relieve all symptoms. Thus, current definitions of acid reflux require review to increase the sensitivity to determine the frequency and implication of short periods of acidity in the esophagus. Analysis such as analysis of the area under the H(+) activity time curve is one alternative approach for evaluating acid secretion. The precise role of acid in NERD needs further clarification.
Changcheng Wang; Richard H Hunt
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Publication Detail:
Type:  Journal Article; Review     Date:  2008-10-02
Journal Detail:
Title:  Digestion     Volume:  78 Suppl 1     ISSN:  1421-9867     ISO Abbreviation:  Digestion     Publication Date:  2008  
Date Detail:
Created Date:  2008-10-03     Completed Date:  2009-02-26     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0150472     Medline TA:  Digestion     Country:  Switzerland    
Other Details:
Languages:  eng     Pagination:  31-41     Citation Subset:  IM    
Copyright Information:
2008 S. Karger AG, Basel
Division of Gastroenterology, McMaster University Medical Centre, Hamilton, Ont., Canada.
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MeSH Terms
Esophageal pH Monitoring
Gastric Acid / secretion
Gastroesophageal Reflux / drug therapy,  etiology,  pathology*,  physiopathology*
Heartburn / etiology
Intestinal Mucosa / injuries*
Proton Pump Inhibitors / therapeutic use
Severity of Illness Index
Reg. No./Substance:
0/Proton Pump Inhibitors

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