Upper sphincter function during transient lower oesophageal sphincter relaxation (tLOSR); it is mainly about microburps

Transient lower oesophageal sphincter relaxations (tLOSRs) are both a dominant mechanism of reflux and an element of the belch reflex. This study aimed to analyse the interplay between reflux and upper oesophageal sphincter (UOS) activity during meal-induced tLOSRs. Fifteen normal subjects were studied with a solid-state high-resolution manometry assembly positioned to record from the hypopharynx to the stomach and a catheter pH electrode 5 cm above the LOS. Subjects ate a 1000-calorie high-fat meal and were monitored for 120 min in a sitting posture. The relationship among tLOSRs, common cavities, pressure changes within the oesophagus and UOS contractile activity were analysed. A total of 218 tLOSRs occurred among the 15 subjects. The majority (79%) were coupled with UOS relaxation and 84% (145/173) of these occurred in association with a common cavity. Upper oesophageal sphincter relaxation was usually preceded by a pressure change in the oesophagus; however, some relaxations (16%) occurred without a discernable increase in pressure or before the pressure increase began. Acid reflux did not appear to play a role in determining UOS response to tLOSRs. The majority of post-prandial tLOSRs were associated with brief periods of UOS relaxation, likely permissive of gas venting (microburps). Intraoesophageal pressure changes likely modulate this UOS response; however, an anticipatory characteristic was evident in some subjects. Whether or not GORD patients with extra-oesophageal symptoms exhibit an exaggeration of the UOS relaxation response during reflux is yet to be determined.     

Transient lower oesophageal sphincter relaxation in achalasia: everything but LOS relaxation

Abstract  In conducting clinical high-resolution oesophageal pressure topography (HROPT) studies we observed that after subjects sat upright between series of supine and upright test swallows, they frequently had a transient lower oesophageal sphincter relaxation (TLOSR). When achalasia patients were studied in the same protocol, they exhibited a similar HROPT event leading to the hypothesis that achalasics had incomplete TLOSRs. We reviewed clinical HROPT studies of 94 consecutive non-achalasics and 25 achalasics. Studies were analyzed for a TLOSR-like event during the study and, when observed, that TLOSR-like event was characterized for the degree and duration of distal oesophageal shortening, the degree of LOS relaxation, associated crural diaphragm (CD) inhibition, oesophageal pressurization and upper oesophageal sphincter (UOS) relaxation. About 64/94 (68%) non-achalasics and 15/24 (63%) of achalasics had a pressure topography event after the posture change characterized by a prolonged period of distal oesophageal shortening and/or LOS relaxation. Events among the non-achalasics and achalasics were similar in terms of magnitude and duration of shortening and all were associated with CD inhibition. Similar proportions had associated non-deglutitive UOS relaxations. The only consistent differences were the absence of associated LOS relaxation and the absence of HROPT evidence of reflux among the achalasics leading us to conclude that their events were incomplete TLOSRs. Achalasic patients exhibit a selective defect in the TLOSR response suggesting preservation of all sensory, central and efferent aspects of the requisite neural substrate with the notable exception of LOS relaxation, a function of inhibitory (nitrergic) myenteric plexus neurons.     

Eosinophilic oesophagitis in adults

Abstract  Previously considered a rare condition, eosinophilic oesophagitis (EoE) has become increasingly recognized as an important cause of dysphagia and food impactions in adults. This is likely attributable to a combination of an increasing incidence of EoE and a growing awareness of the condition. EoE may occur in isolation or in conjunction with eosinophilic gastroenteritis. However, the burgeoning field is likely attributable to the variant that uniquely affects the oesophagus. Adults classically present with symptoms of dysphagia, food impactions, and heartburn. Typical endoscopic features include concentric mucosal rings, linear furrowing, white plaques or exudates and a narrow caliber oesophagus. In some cases, the endoscopic features may appear normal. For years, EoE went unrecognized because eosinophilic infiltration was accepted as a manifestation of reflux, which continues to be a confounding factor in some patients. Current consensus is that the diagnosis of EoE is established by 1) the presence of symptoms, especially dysphagia and food impactions in adults, 2) ≥15 eosinophils per high power field in oesophageal tissue, and 3) exclusion of other disorders with similar presentations such as GERD. Current understanding of EoE pathophysiology and natural history are limited but the entity has been increasingly linked to food allergies and aeroallergens. The main treatment options for EoE are proton pump inhibitors, dietary manipulation, and topical or oral glucocorticoids. This review highlights recent insights into EoE in adults although, clearly, much of the available data overlap with pediatrics and, occasionally, with eosinophilic gastroenteritis.