Inability to belch syndrome: what the gastroenterologist needs to know.

PURPOSE OF REVIEW To review recent publications on the inability to belch syndrome. RECENT FINDINGS Five recent retrospective case series indicate that the inability to belch syndrome usually starts in early childhood and is often accompanied by gurgling noises in the chest, pain in the chest or upper abdomen, bloating, and excessive flatulence. Currently, the vast majority of patients who have been identified with inability to belch have self-diagnosed the syndrome on the basis of information available on the internet. A favorable response to injection of botulinum toxin in the cricopharyngeus muscle is regarded as confirmation of the diagnosis. In a mechanistic study in eight patients, absence of reflexogenic relaxation of the upper esophageal sphincter upon rapid gaseous esophageal distension was confirmed to play a pivotal role in the pathogenesis of the syndrome. SUMMARY The inability to belch syndrome, caused by failure of the upper esophageal sphincter to relax when the esophageal body is distended, clearly exists and may not be as rare as thought hitherto. However, overdiagnosis is also likely to occur because the diagnosis is usually made on the basis of symptoms only. The efficacy of botulinum toxin injection in the upper sphincter needs to be assessed in double-blind placebo-controlled studies.