Primary Motility  Disorders of the  Esophagus
 The Esophageal
 Mucosa
 The
 Esophagogastric  Junction
 Barrett's
 Esophagus

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OESO©2015
 
Volume: Barrett's Esophagus
Chapter: Pathophysiology
 

Is there a correlation between the detrimental effects of bile reflux and the value of the pH in the refluxate?

W.K.H. Kauer, H.J. Stein, J.R. Siewert (Munich)

The recognition of duodenal contamination of the refluxed gastric juice using the time pH is greater than 7 on pH monitoring has been a subject of controversy [1-3]. The pooled nature of the reflux aspirates study does not allow for a direct temporal analysis of the association between alkaline reflux episodes on pH monitoring and the presence of bile acids in the refluxed gastric juice. Nevertheless, the significant correlation between the overall time pH is greater than 7 and the bile acid concentration in the aspirates of patients with gastroesophageal reflux disease suggests that alkaline episodes on pH monitoring reflect reflux of duodenal contents into the esophagus. However, several precautions need to be taken when assessing the time esophageal pH is greater than 7 on pH monitoring. The diet of patients during the test need to be restricted to foods with a pH below 7. Each patient should also be inspected for dental caries, which may cause a rise in salivary pH. Strictures need to be dilated prior to pH monitoring to prevent pooling of saliva. Finally, glass rather than antimony pH electrodes should be used [4], and accurate calibration at pH 7 before and after each test must to be ensured. Reflux of gastric contents into the esophagus will result in an increased esophageal exposure to pH above 7 only in situations of excessive duodenogastric reflux. Smaller amounts of duodenogastric reflux will mix with gastric acid and result in a pH of the refluxed gastric juice indistinguishable from the normal luminal pH of the esophagus. An increased time pH is greater than 7 on esophageal pH monitoring, therefore, reflects the extreme of duodeno-gastroesophageal reflux. As shown in a study by Stein et al. [5], an increased bile acid concentration may also be present in the refluxed gastric juice of patients with a normal-time pH above 7 on esophageal pH monitoring. For this situation, the term "biliary reflux" is therefore more appropriate than the commonly used misnomer "alkaline reflux."

The prevalence of increased esophageal alkaline exposure in this study was greatest in patients with previous foregut surgery. In patients with a destroyed gastroduodenal barrier for example, after pyloroplasty or distal gastric resection it is easy to imagine excessive duodenogastric reflux and, consequently, contamination of the refluxed gastric juice with bile acids. Excessive duodenogastric reflux may also occur after cholecystectomy, and 15 of 35 patients with an increased time that pH was greater than 7 on esophageal pH monitoring had undergone a previous cholecystectomy in the present study. An increased bile acid concentration in esophageal aspirates was, however, also observed in a substantial number of patients without previous foregut surgery, although this did not usually result in an increase in the time that the pH was greater than 7.

References

1. Stein HJ, Barlow AP, DeMeester TR, et al. Complications of gastroesophageal reflux disease. Ann Surg 1992;216:3543.

2. Mittal RK, Reuben A, Whitney JO, et al. Do bile acids reflux into the esophagus? Gastroenterology 1987;92:571-575.

3. Singh S, Bradley LA, Richter JE. Determinants of esophageal "alkaline" pH environment in controls and patients with gastroesophageal reflux disease. Gastroenterology 1992;102:A166.

4. Sjoberg F, Gustafsson U, Tibbling L. Alkaline esophageal reflux. Scand J Gastroenterol 1992;27:1084-1088.

5. Stein HJ, Feussner H, Kauer WKH, et al. Alkaline gastroesophageal reflux:Assessment by ambulatory esophageal aspiration and pH monitoring. Am J Surg 1994;167:163-168.


Publication date: August 2003 OESO©2015