Electrolyzed acid water can cause colitis?

We read with great interest the article by Cammarota et al. [1] and the letter of Coriat et al. [2] on the endoscopic finding of chemical colitis (pseudolipomatosis). Cammarota et al. attributed these mucosal changes to the use of hydrogen peroxide flushes following high-level disinfection with automatic machines using peracetic acid, mainly in examinations performed with Fujinon colonoscopies. Coriat et al. thought the cause was inadequate rinsing of endoscopic channels and surfaces with water after immersion in peracetic acid, presumably causing direct irritation of the mucosa.

We carry out nearly 3000 colonoscopies per year, both diagnostic and therapeutic. In the same year we had two similar cases: a 67-year-old male patient who underwent colonoscopy for screening for colorectal cancer, and an 80-year-old male who presented with iron deficiency anemia. In both patients, the pseudolipomatous lesions presented as slightly elevated whitish-yellowish plaques, measuring from 1 cm to 4 cm for the longest dimension, and were adherent and confluent in some areas ([Fig. 1]). The lesions were located in the descending colon and in the rectum, respectively. Lesions were visualized at colonoscope insertion and there was no change in their appearance during withdrawal. Microscopic study showed empty spaces irregularly distributed in the mucosa down as far as the muscularis mucosa layer, and measuring 5 – 300 µm ([Fig. 2]). Sudan-black stain did not reveal the presence of lipid deposits in the vacuoles, and immunohistochemistry was negative for anti-CD34 in both cases. Stool culture for enteric pathogens and Clostridium difficile toxin showed negative results. The first patient had a well-differentiated adenocarcinoma of the ascending colon and was submitted to a 6-month follow-up colonoscopy after surgery, which showed no lesion suggestive of pseudolipomatosis. The other patient had no follow-up.

Fig. 1 Endoscopy appearance of colonic pseudolipomatosis presented as adherent, irregular, and elevated whitish plaques in the descending colon.

Fig. 2 Microscopic appearance of the colonic pseudolipomatosis showing empty spaces irregularly distributed in the mucosa (hematoxylin and eosin stain, original magnification × 40).

All examinations at our center are performed using Olympus endoscopes. We do not use either hydrogen peroxide or peracetic acid in any stage of the disinfection of the scopes. All colonoscopes are submitted to high-level disinfection using an automatic disinfecting machine, which uses electrolyzed acid water (EAW). Electrolysis of a low concentration of NaCl in water produces Cl₂, HClO, H⁺Cl^–, O₂ and O₃ at the anode. The bactericidal effect of EAW is explained by the low pH (< 2.7), oxidization–reduction potential exceeding 970 mV, and the presence of Cl₂, and these factors have synergic effects [3]. The use of EAW does not produce hydrogen peroxide. All channels of the scope are rigorously irrigated with distilled water after the cycle is finished.

It seems that either the compounds of the EAW could also cause pseudolipomatosis of the colon and rectum, or that this was only a coincidence, and that pseudolipomatosis, in fact, has various etiologies that are yet poorly understood.

Competing interests: None

References

• 1 Cammarota G, Cesaro P, Cazzato A. et al . Hydrogen peroxide-related colitis: a series of cases occurring in an epidemic pattern.  Endoscopy. 2007;  39 916-919
• 2 Coriat R, Chaput U, Ismaili Z, Chaussade S. What induces colitis? Hydrogen peroxide or peracetic acid.  Endoscopy. 2008;  40 231
• 3 Tagawa M, Yamaguchi T, Yokosuka O. et al . Inactivation of a hepadnavirus by electrolyzed acid water.  J Antimicrob Chemother. 2000;  46 363-368