What are the esophageal defense mechanisms involved in gastroesophageal reflux disease (GERD)?

Updated: May 23, 2019
  • Author: Marco G Patti, MD; Chief Editor: BS Anand, MD  more...
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Answer

Esophageal defense mechanisms can be broken down into 2 categories (ie, esophageal clearance and mucosal resistance). Proper esophageal clearance is an extremely important factor in preventing mucosal injury. Esophageal clearance must be able to neutralize the acid refluxed through the lower esophageal sphincter. (Mechanical clearance is achieved by esophageal peristalsis; chemical clearance is achieved with saliva.) Normal clearance limits the amount of time the esophagus is exposed to refluxed acid or bile and gastric acid mixtures. Abnormal peristalsis can cause inefficient and delayed acid clearance.

Whether peristaltic dysfunction is secondary to esophageal exposure to acids or a primary defect is not understood clearly. In a review by Kahrilas et al, peristaltic dysfunction was progressively more common in patients with greater degrees of esophagitis. [16] Abnormal peristalsis was identified in 25% of patients with mild esophagitis and 48% of patients with severe esophagitis.

Buttar and associates described the importance of esophageal mucosal resistance as a protective mechanism. [17] They classified the factors into pre-epithelial, epithelial, and postepithelial defenses. When the defenses fail, esophagitis and other complications of reflux disease arise.


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