The acid pocket and its relevance to reflux disease

Fletcher and his colleagues also reported that the acid pocket extended above the squamocolumnar junction and suggested that this may be a factor underlying inflammation, intestinal metaplasia and carcinoma at the gastro-oesophageal junction. 8 In this issue of Gut (page 10.1136/gut.2006.109421 ) the team from Glasgow extend their earlier observations to patients with severe reflux oesophagitis and/or Barrett's oesophagus. 9 Refinements to the earlier methodology included use of concurrent manometry to identify the LOS and closely timed radiology to assess the position of the pH electrode relative to the squamo-columnar junction and LOS. [...]there is emerging interest in patterns of acid reflux in the region 1-2 cm immediately above the LOS, a site where the earliest and most severe mucosal damage typically occurs in reflux disease. pH monitoring has shown over double the rate of detection of acid reflux in this region compared with 5 cm, and up to six times higher within the LOS segment itself. 17 The rate of reflux episodes detected in the most distal oesophagus is also higher in patients with reflux disease than in controls. 18 19 Given the proximity of the acid pocket to the distal border of the LOS, and evidence that it might even extend into the distal LOS segment because of meal-induced opening of the distal segment of the LOS, it is possible that continued high levels of acidity at the cardia might have a greater impact on acid exposure in the very distal oesophagus than more proximally.