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Can esophageal motility disorders be detected by esophagogastroduodenoscopy?

Esophageal motility disorders (EMDs) are diagnosed by esophageal manometry. Nowadays, high-resolution esophageal manometry (HREM) is a gold standard for evaluating esophageal motility, and the Chicago classification is widely used for diagnosing EMDs. Esophageal motility is evaluated based on esophageal body motility and swallow-related esophago-gastric junction (EGJ) relaxation, and EMDs are categorized into several diseases: Achalasia, EGJ outflow obstruction, distal esophageal spasm (DES), Jackhammer esophagus, absent contractility, fragmented peristalsis and ineffective esophageal motility (IEM). These EMDs, except fragmented peristalsis and IEM, are rarely observed in healthy individuals; therefore, they are called major disorders of peristalsis. In contrast, fragmented peristalsis or IEM can be seen in healthy people and are called minor disorders of peristalsis. Although HREM is necessary to diagnose these EMDs, the number of institutions in which HREM can be performed is limited. In diagnosing EMDs, organic diseases, such as esophageal carcinoma, eosinophilic esophagitis or infectious esophagitis, must be excluded by esophagogastroduodenoscopy (EGD). Typical endoscopic findings in achalasia have been reported, and they include a dilated or tortuous esophagus, food impaction and fluid pooling in the esophagus, and resistance to intubation of the EGJ. A corkscrew esophagus is also known as an endoscopic finding, indicating a spastic esophageal motility abnormality. In addition, several novel endoscopic findings indicating achalasia have been reported (e.g. esophageal rosette, pinstripe pattern, champagne glass sign, corona appearance and ginkgo leaf sign). Moreover, the presence of diverticula or candidiasis may suggest the presence of EMDs indirectly. Although esophageal motility can be observed directly during EGD, reports in which esophageal motility was evaluated during EGD are limited. Cameron et al. evaluated esophageal motility during EGD in patients with achalasia and systemic sclerosis and in control subjects from two aspects, contraction of the esophageal body and opening of the EGJ. This method is reasonable since these two factors are assessed when diagnosing EMDs on HREM. However, there were several limitations in that study. First, it was difficult to assess whether an esophageal contraction was peristaltic. Second, non-peristaltic esophageal contraction was seen frequently even in control subjects. Lim et al. reported on the usefulness of a novel disposable transnasal endoscopic device for evaluating esophageal motility. Although quantitative evaluation (e.g. strength of esophageal contraction or EGJ pressure) cannot be performed by transnasal EGD, patients can swallow during the procedure, which may allow evaluation of primary peristalsis and swallow-related EGJ relaxation appropriately. In addition, the amount of bolus in the esophagus may affect aptitude and velocity of esophageal contraction. Although the regular protocol for EGD can only assess dry swallows, wet swallows as well as dry swallows can be evaluated using transnasal EGD. Therefore, EGD can be useful to detect EMDs, although HREM is still necessary to diagnose EMDs. Matsubara et al. reported on an interesting study in which the prevalence and features of endoscopic findings in patients with EMDs were investigated. They found abnormal endoscopic findings in 64.4% of patients with EMDs and concluded that EGJ outflow obstruction and major disorders of peristalsis can be screened with EGD. In this study, the significant endoscopic findings related to EMDs were resistance during passage through the EGJ, residue in the esophagus, spastic contraction and non-occlusive contraction, of which the latter was the most frequent abnormal finding. However, non-occlusive contraction can also be found in subjects with normal esophageal motility, and it may be caused by deglutitive inhibition, in which processing a primary peristalsis is suppressed by a subsequent swallow. Since asymptomatic subjects were not enrolled in this study, findings on such individuals should be confirmed by further study. Endoscopic findings related to achalasia are frequently observed; therefore, achalasia can be screened by EGD. Although spastic contraction, such as the corkscrew esophagus, is a specific endoscopic finding indicating the presence of an EMD, the prevalence of the spastic contraction in