Background: The increasing prevalence of GERD has become a major concern due to its major health and economic impacts. Beyond the typical unpleasant symptoms, reflux can also be the source of severe, potentially life-threatening complications, such as aspiration.
Aim: Our aim was to support our hypothesis that the human body may in some cases develop various protective mechanisms to prevent these conditions.
Methods: Based on our experiences and review of the literature, we investigated the potential adaptive nature of seven reflux complications (hypertensive lower esophageal sphincter, achalasia, hypertensive upper esophageal sphincter, Zenker's diverticulum, Schatzki's ring, esophageal web, and Barrett's esophagus).
Results: Patients with progressive GERD may develop diverse structural and functional esophageal changes that narrow the lumen of the esophagus and therefore reduce the risk of regurgitation and protect the upper aerodigestive tract from aspiration. The functional changes (hypertensive lower esophageal sphincter, achalasia, hypertensive upper esophageal sphincter) seem to be adaptive reactions aimed at easing the unpleasant symptoms and reducing acid regurgitation. The structural changes (Schatzki's ring, esophageal web) result in very similar outcomes, but we consider these are rather secondary consequences and not real adaptive mechanisms. Barrett's esophagus is a special form of adaptive protection. In these cases, patients report significant relief of their previous heartburn as Barrett's esophagus develops because of the replacement of the normal squamous epithelium of the esophagus by acid-resistant metaplastic epithelium.
Conclusion: We believe that GERD may induce different self-protective reactions in the esophagus that result in reduced acid regurgitation or decreased reflux symptoms.
Keywords: Adaptive change; Aspiration; Barrett’s esophagus; Esophageal motility disorder; Gastroesophageal reflux disease.