Reply to M. Matsushita et al.

We would like to thank Dr. Matsushita and his colleagues for their interest in our article [1]. In their letter they mentioned that they too observed hyperamylasemia in 7 of 15 patients who underwent peroral double-balloon enteroscopy (DBE), and one of these patients developed acute pancreatitis. The percentage of post-peroral DBE hyperamylasemia was similar to that which we reported, supporting our point that hyperamylasemia occurs frequently after peroral DBE and that pancreatitis is attributable to the DBE procedure.

Dr. Matsushita and his colleagues carefully reviewed reported cases and raised an important issue on the mechanism of pancreatitis after peroral DBE. Since post-peroral DBE pancreatitis occurred predominantly in the pancreas body or tail in most of the reported cases [2] [3] and in their own case, they considered that traumatic injury or ischemia in the pancreas body or tail due to the procedure of shortening the proximal intestine is likely to be a cause of pancreatitis. We agree with their opinion. To date, we have observed three patients with pancreatitis after peroral DBE (two of these cases have been published [1] [4], and we observed one more case after these reports). In two of the three cases, the pancreatitis was localized to the pancreas body and tail. Another case revealed inflammation in the entire pancreas, but more severe in the body and tail than in the head of the pancreas. Therefore, we recently also came to consider that pancreatitis may be caused by the mechanical stress on the pancreas.

As mentioned in our previous paper [1], the duodenum and proximal small bowel are markedly shortened during peroral DBE due to the repeated procedure of pulling back the enteroscope and overtube to fold the proximal small bowel, and fluoroscopic guidance sometimes shows the duodenum to be nearly straight from the pyloric ring to the ligament of Treitz. In this situation, it is reasonable to consider that there is a mechanical stress on the pancreas body that induces traumatic injury or ischemia which may result in hyperamylasemia or pancreatitis. May et al. also hypothesized that traumatic injury or ischemia might play a role when the small bowel is threaded together onto the overtube, with removal of the loops exerting some torsion on parts of the mesentery [5]. They suggested that the length of the examination time may be an important factor as they have not observed pancreatitis in more than 500 DBE examinations and have a strict maximum limit of 2 h on the examination time. In our previous study, however, hyperamylasemia and pancreatitis also occurred in patients who had a short procedure time. We thus believe that it is the technique of DBE itself, with the shortening of the small bowel that it involves, that may be a factor in pancreatitis after peroral DBE, rather than the length of the examination time.

Today, it is certain that pancreatitis is one of the major complications of peroral DBE. The hypothesis made by Dr. Matsushita and his colleagues is reasonable and persuasive. However, the number of the accumulated cases so far is small and further studies with large numbers of patients are necessary to clarify the etiology of hyperamylasemia and pancreatitis after peroral DBE.

Competing interests: None

References

• 1 Honda K, Itaba S, Mizutani T. et al . An increase in the serum amylase level in patients after peroral double-balloon enteroscopy: an association with the development of pancreatitis.  Endoscopy. 2006;  38 1040-1043
• 2 Groenen M J, Moreels T G, Orlent H. et al . Acute pancreatitis after double-balloon enteroscopy: an old pathogenetic theory revisited as a result of using a new endoscopic tool.  Endoscopy. 2006;  38 82-85
• 3 Heine G D, Hadithi M, Groenen M J. et al . Double-balloon enteroscopy: indications, diagnostic yield, and complications in a series of 275 patients with suspected small-bowel disease.  Endoscopy. 2006;  38 42-48
• 4 Honda K, Mizutani T, Nakamura K. et al . Acute pancreatitis associated with peroral double-balloon enteroscopy: a case report.  World J Gastroenterol. 2006;  12 1802-1804
• 5 May A, Ell C. Push-and-pull enteroscopy using the double-balloon technique/double-balloon enteroscopy.  Dig Liver Dis. 2006;  38 932-938