A series of patients with purging type anorexia nervosa who do "tube vomiting".

Background: It is important for clinicians to assess their patients' purging behavior. Various methods of purging, such as self-induced vomiting are well-known. Because patients do not always report their purging behavior, knowing the clinical signs that indicate the behavior is useful. However, we have experienced patients who did not have the reported physical signs of self-induced vomiting because they used hoses instead of their fingers to purge their stomach contents, which they call "tube vomiting". No other previous studies have reported the use of hoses as a purging tool.

Case Presentation: We present as our main case a 20-year-old Japanese woman with anorexia nervosa who engaged in "tube vomiting." Although she recovered well under medical treatment in our hospital, she began to lose weight and blood potassium soon after discharge. We found that she used a garden hose instead of her fingers to perform self-induced vomiting,. She inserted the hose into her stomach and evacuated the stomach contents through it, without pain. She learned this technique through a blog about eating disorders. We also present two other similar cases. In fact, many patients discuss "tube vomiting" on the internet.

Conclusion: Our experience suggests that a sudden decrease in the weight and blood potassium level could indicate "tube vomiting". In addition, because many information resources are available on the internet, medical practitioners should be aware of these sites.