Upregulation of the esophago-UES relaxation response: a possible pathophysiological mechanism in suspected reflux...

Inappropriate or excessive, non-swallow related, reflexive relaxation of the upper esophageal sphincter (UES) in response to esophageal distension may be the principal mechanism permitting retrograde trans-sphincteric flow during acid regurgitation. The neural pathways mediating reflexive UES relaxation in the human have received little attention. Patients with laryngitis demonstrate an increased acid reflux in the proximal esophagus. Such events, combined with an increased tendency for UES relaxation, might precipitate regurgitation into the pharynx. The aim was to determine whether the esophago-UES relaxation reflex induced by rapid esophageal distension is upregulated in patients with posterior laryngitis.

In 21 healthy volunteers and 14 patients with posterior laryngitis, UES responses to rapid air insufflation were examined. UES responses were monitored with perfused manometry catheter with a oval sleeve sensor.

The probability of triggering UES relaxation in response to the rapid esophageal air distension, for all volumes of insufflation, was higher in laryngitis (45%) than in health (17%). The minimum distension volume required to elicit an UES relaxation response was significantly lower in laryngitis patients when compared with controls. Patients who demonstrated a laryngoscopic response to a trial of omeprazole, were less likely to generate a distension-induced UES contractile response (5%) than patients who did not respond (23%).

The threshold for esophageal distension-induced UES relaxation is reduced in patients with laryngitis when compared with controls. This finding supports the hypothesis that in this population, a hypersensitive belch-like response may be one contributory mechanism of regurgitation when triggered by an abrupt spontaneous gastro-esophageal reflux event.