Transnasal ultrathin esophagogastroduodenoscopy (N-EGD) with less gagging reflexes under non-sedation is likely suitable for the diagnosis of gastroesophageal reflux disease (GERD), however, N-EGD might have drawbacks, including its low image resolution. Limited information is available regarding the diagnosability of N-EGD for GERD. We compared the utility and gagging reflexes of three different endoscopies, including N-EGD, ultrathin transoral EGD (UTO-EGD) and conventional oral EGD (CO-EGD), in the diagnosis of GERD. We performed screening endoscopy in 1580 patients (N-EGD n=727, UTO-EGD n=599, CO-EGD n=254) and compared the frequency distributions of the severity of reflux esophagitis, hiatus hernia, and Barrett's epithelium to estimate the diagnostic performance of each endoscopy. We also analyzed patients' tolerability of endoscopy by the subjective evaluation of gagging reflexes. In the diagnosis of reflux esophagitis and Barrett's epithelium, there was no significant difference in the frequency distributions of the severity of the diseases among three EGDs. However, the incidence of Barrett's epithelium was higher than that in the previous nationwide survey of GERD in Japan. The evaluated size of hiatus hernia was smaller in N-EGD than in two other peroral endoscopies. The size of hiatus hernia correlated significantly with severity of gagging reflexes that was also lowest when diagnosed with N-EGD. N-EGD had an equivalent performance in the diagnosis of reflux esophagitis and Barrett's epithelium compared with CO-EGD. Enlargement of hiatus hernia induced by gagging reflexes was minimal in N-EGD, resulting in its better performance in the diagnosis of Barrett's epithelium.

Background and study aims: l-Menthol (LM), sprayed on the distal gastric mucosa, is a safe antispasmodic agent used during esophagogastroduodenoscopy (EGD). However, it seems to affect gastric mucosal endoscopic findings. Therefore, we evaluated whether LM causes specific changes and impacts the endoscopic morphology of gastric lesions. Patients and methods: A total of 98 patients scheduled to undergo EGD were randomly assigned to receive LM solution (160 mg of 0.8 % LM added to 2.5 mL of indigo carmine [IC]; n = 49; LM group) or decuple-diluted IC solution without LM (n = 49; placebo group). We compared the incidence of specific mucosal changes and the difference in the endoscopic findings of several gastric lesions between these groups. Results: Annular-reticular – like mucosal changes appeared immediately after the administration of LM solution. This change was observed in 71.4 % of the LM group compared with 12.2 % of the placebo group (P < 0.01). In the placebo group, this change was observed in 14.7 % of subjects with atrophic gastritis compared with 6.7 % of those without atrophic gastritis (P = 0.39), whereas in the LM group, this change was observed in 84.8 % of subjects with atrophic gastritis compared with 43.8 % of those without atrophic gastritis (P < 0.01). Most early gastric cancers, erosions, and ulcers observed in this study became well demarcated after LM administration, although the incidence of gastric lesions did not differ significantly between the two groups. Conclusion: LM changes the gastric mucosa into edematous mucosa, and this occurs more frequently in atrophic gastric mucosa than in pathologic lesions. LM may facilitate the demarcation of pathologic gastric lesions without intestinal metaplasia.