Reply to Souza et al.

Reply to Souza et al.

We have read the letter by Souza et al. published in the current issue [1]. Authors attributed new cases of mucosal changes to the use of electrolyzed acid water (EAW) after disinfection.

We reported the appearance of mucosal changes during colonoscopy, with changes characteristic of pseudolipomatosis seen on endoscopic examination [2]. These findings were presumably due to the direct toxic effect of peracetic acid, which had been used as a disinfectant, and to an inadequate cleaning of a channel during the disinfection procedure.

In their letter, Souza et al. found the endoscopic and pathological images highly suggestive of mucosal pseudolipomatosis induced by EAW. This condition is characterized histologically by the presence of optically empty, unlined spaces within the colorectal lamina propria, grossly similar to fat but actually accounted for by the presence of intramucosal gas [3].

Peracetic acid is well known to induce toxicity on mucosa or skin. Colonic pseudolipomatosis is a rare entity, reported in only 0.3 % to 1.7 % of all colonoscopies performed [3] [4]. Prevalence is likely underestimated due to the lack of clinical expression.

EAW has never been described as an etiology of pseudolipomatosis. EAW has been used since 1999 as a disinfection agent in certain countries. Acidic electrolytic water is generated by electrolysis of water that contains 0.05 % of NaCl. EAW has a strong oxidizing ability. Bacteria are unlikely to survive in this solution. Thus, EAW may be useful as a potent disinfectant. Tsuji et al. showed that EAW does not irritate the skin and eyes and appears to be safe for both patients and endoscopes [5].

Souza et al. reported no modification of the mucosal appearance during withdrawal. Also, lesions were evidenced at the insertion point of the colonoscope. Those findings suggest that lesions were not caused by EAW.

The pathogenesis of colonic pseudolipomatosis remains unclear. Gas invasion or lymphatic extravasation into the chorion could be influenced by the presence of colonic mucosal lesions resulting in barotraumas subsequent to insufflation during the colonoscopic procedure, peracetic acid, or hydrogen peroxide. Brevet et al. reported nine cases of pseudolipomatosis in 2099 colonoscopies [6]. They used 3 % hydrogen peroxide to disinfect endoscopes and the endoscopes were rinsed manually. Lesions were discovered when ascending the endoscope in eight out of nine patients, suggesting rinsing was not the origin of these lesions.

Therefore, we recognize that hydrogen peroxide or peracetic acid can induce colitis, but we do not believe that EAW is responsible for the findings reported by Souza et al. Lesions evidenced at the insertion point, along with the absence of an incriminating agent, undermine their assertion that chemical colitis is the cause of the appearance described.

Competing interests: None

References

• 1 Souza J, Ribeiro T, Borgnes L, da Silva J. Electrolyzed acid water can cause colitis?.  Endoscopy. 2008;  40 627
• 2 Coriat R, Chaput U, Ismaili Z, Chaussade S. What induces colitis? Hydrogen peroxide or peracetic acid.  Endoscopy. 2008;  40 231
• 3 Snover D C, Sandstad J, Hutton S. Mucosal pseudolipomatosis of the colon.  Am J Clin Pathol. 1985;  84 575-580
• 4 Waring J P, Manne R K, Wadas D D, Sanowski R A. Mucosal pseudolipomatosis: an air pressure-related colonoscopy complication.  Gastrointest Endosc. 1989;  35 93-94
• 5 Tsuji S, Kawano S, Oshita M. et al . Endoscope disinfection using acidic electrolytic water.  Endoscopy. 1999;  31 528-535
• 6 Brevet M, Chatelain D, Bartoli E. et al . Colonic pseudolipomatosis: clinical, endoscopical and pathological features in nine cases.  Gastroenterol Clin Biol. 2006;  30 9-13