Chemical colitis due to endoscope cleaning solutions: a mimic of pseudomembranous colitis

Endoscope disinfectant-induced colonic pseudolipomatosis: case series of a rare condition

Aim: Colonic mucosal pseudolipomatosis is a rare and benign endoscopic finding with distinct macroscopic and histological characteristics. Case series: We observed a form of unprecedented colitis in eight patients in a 3-month period. Operators have found, during colonoscopy, flat or slightly raised whitish-yellow plaques, in the colonic mucosa of all patients. Histological examination concluded to pseudolipomatosis. After investigation, the disinfectant machine was found to have technical malfunctioning of the rinse cycle of the endoscope during this period. No other cases were observed after the machine was fixed. Conclusion: Pseudolipomatosis is more an endoscopically induced lesion than a true pathological condition. A careful check of the disinfection process should be carried out when such lesions are detected.

Reductively modified albumin attenuates DSS-Induced mouse colitis through rebalancing systemic redox state

Albumin (Alb) is the most abundant plasma protein with multiple biological functions, including antioxidative property through its thiol activity. Given that inflammatory bowel disease is associated with a decreased level of Alb and an increased level of Alb oxidation, we asked whether Alb could have a therapeutic effect on colitis. Here we tested this possibility. Bovine serum albumin (BSA) was reductively modified with dithiothreitol (DTT) and administrated via gavage or intraperitoneal injection. Dextran sulfate sodium (DSS)-induced mice colitis was associated with massive oxidative stress, as indicated by the elevated sulfenic acid formation in blood, colon tissues, and feces. Treatment of mice with the reductively modified albumin (r-Alb) attenuated the oxidative stress and reduced local inflammation and tissue injury. These effects of r-Alb were only partially achieved by unmodified Alb and wholly lost after blocking the -SH groups with maleimide. In cultured colon epithelial cells, r-Alb prevented DSS- and H2O2-induced ROS elevation and barrier dysfunction, preceded by inhibition of sulfenic acid formation and P38 activation. Further analysis revealed that Alb was susceptible to H2O2-induced oxidation, and it detoxified H2O2 in a -SH group-dependent way. Moreover, Alb reacted with GSH/GSSG via thiol-disulfide exchange and reciprocally regulated the availability of -SH groups. Collectively, our study shows that r-Alb effectively attenuates DSS colitis via -SH group-mediated antioxidative action. Given that the oxidative stress underlies many life-threatening diseases, r-Alb, functioning as a potent antioxidant, could have a wide range of applications.

Cytomegalovirus Colitis Followed by Colonic Pseudolipomatosis and Gastric Emphysema in a Post-resuscitation Patient

A 64-year-old Japanese man suffered cardiopulmonary arrest, which may have resulted from sepsis and/or hyperosmolar hyperglycemic non-ketonic coma, and was admitted after successful resuscitation. He had watery diarrhea on day 18 and was diagnosed with cytomegalovirus enterocolitis. In addition, computed tomography performed on day 27 and colonoscopy revealed gastric emphysema and intestinal pseudolipomatosis, respectively. This report is the first to describe a patient with cytomegalovirus enterocolitis and subsequent gastric emphysema and pseudolipomatosis. Gastrointestinal cytomegalovirus infection may underlie gastric emphysema and intestinal pseudolipomatosis, particularly in patients with relative or obvious immune dysfunction.

Hydrogen Peroxide Enema-induced Proctitis in a Young Female: A Case Report

Hydrogen peroxide is a disinfectant commonly used for cleansing superficial wounds due to its oxidizing capacity. In the past, it has also been used for the management of meconium ileus in children as the oxidizing action of hydrogen peroxide potentiates peristalsis that relieves ileus or fecal impaction. The potential dangers were unknown till Pumphrey, in 1951, described the harmful effects of its use as an enema. We present a case of a 32-year-old female who was admitted for complaints of perianal pain. She used an enema, consisting of water and hydrogen peroxide, for constipation. It improved her symptoms but subsequently, she developed a burning sensation in her rectum. The patient had a colonoscopy which revealed severe proctitis up to 15 cm from the anal verge manifested by superficial mucosal ulceration, marked erythema, and edema with friable mucosa and hemorrhage. The patient was subsequently given mesalamine, and the symptoms resolved.

An Emergency Department Presentation of Severe Colitis After a Home Hydrogen Peroxide Enema

BACKGROUND

Health information found on open access Internet platforms is often unscrutinized, unreliable, and can lead to considerable morbidity for patients and their presentation to the emergency department. Currently, home treatments for constipation and other gastrointestinal ailments featuring the use of hydrogen peroxide (H₂O₂) enemas are readily available.

CASE REPORT

We present a case of a 48-year-old female with a history of fibroids who presented to the emergency department with acute abdominal pain after self-administering a 3% H₂O₂ enema, which she learned about on the Internet as a treatment for constipation. She subsequently developed a severe colitis with evidence of pneumatosis and focal perforation. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Although toxicity from oral ingestions of H₂O₂ is well described in the literature, there are few reports of the sequelae related to rectal administration. Due to its significant morbidity and the public health concerns related to this mechanism of toxicity, emergency physicians are at the frontlines for diagnosing and properly managing these patients. This case report reviews the patient's presentation, findings, and management.

Pseudolipomatosis of the Colon and Cecum Followed by Pneumatosis Intestinalis

A 74-year-old Japanese woman was diagnosed with pseudolipomatosis of the cecum and ascending colon. Colonoscopy was performed, which revealed the presence of slightly elevated white lesions, while a magnifying observation showed microbubbles within the mucosa. A month after colonoscopy, the patient was diagnosed with pneumatosis intestinalis. Although the exact pathogenesis is unclear, pneumatosis intestinalis may arise secondary to pseudolipomatosis. This case also indicates that a magnifying observation during colonoscopy may aid in the diagnosis of pseudolipomatosis of the large intestine, since it shows microbubbles within the mucosa, which may be a distinctive feature reflecting the pathology of this disease.

Chemical colitis caused by hydrogen peroxide enema in a child: case report and literature review

A 2-year-old girl, previously healthy, was brought to the emergency department because of significant cramping abdominal pain with recurrent hematochezia after an accidental hydrogen peroxide enema (35%, 5 mL) by her caregiver. She was hospitalized to the pediatric department and treated with nothing per mouth, intravenous fluid and parenteral antibiotic therapy. Laboratory, radiologic and endoscopic evaluation was performed during the admission period. She was discharged in a fully recovered state on the tenth hospital day, and this is the first case report of acute chemical colitis by accidental hydrogen peroxide enema in children.

Colonic mucosal pseudolipomatosis: Are we aware of it?

OBJECTIVE

Colonic mucosal pseudolipomatosis is rare, and its pathogenesis is controversial. A number of mechanisms, including mechanical injury during an endoscopic procedure or chemical injury by disinfectant, seem to contribute to its pathogenesis.

MATERIAL AND METHODS

This retrospective study examined the colonic biopsies of 1370 patients. These biopsies were preserved at the Department of Pathology of Istanbul Training and Research Hospital between January 2012 and June 2013.

RESULTS

We found pseudolipomatosis in 14 of 1370 colonoscopy cases (1.02%). Of these 14 patients, 8 were male and 6 were female. The male patients were between 24 and 66 years, with a mean of 39; the female patients were between 26 and 58 years, with a mean of 42.

CONCLUSION

Many endoscopists are unaware of the lesion, and the diagnosis is generally possible only after pathological assessment of multiple biopsies taken from suspect lesions. Here we report and discuss colonic pseudolipomatosis incidentally found in a series of patients undergoing routine colonoscopy, and we underline the endoscopic pattern and diagnostic difficulties.

A review of current disinfectants for gastrointestinal endoscopic reprocessing

Gastrointestinal endoscopy is gaining popularity for diagnostic and therapeutic purposes. However, concerns over endoscope-related nosocomial infections are increasing, together with interest by the general public in safe and efficient endoscopy. For this reason, reprocessing the gastrointestinal endoscope is an important step for effective performance of endoscopy. Disinfectants are essential to the endoscope reprocessing procedure. Before selecting an appropriate disinfectant, their characteristics, limitations and means of use must be fully understood. Herein, we review the characteristics of several currently available disinfectants, including their uses, potency, advantages, and disadvantages. Most disinfectants can be used to reprocess gastrointestinal endoscopes if the manufacturer's guidelines are followed. The selection and use of a suitable disinfectant depends on the individual circumstances of each endoscopy suite.

Colonic mucosal pseudolipomatosis: disinfectant colitis?

Colonic pseudolipomatosis is rare and its pathogenesis is still unclear. A number of mechanisms, including mechanical injury during an endoscopic procedure or chemical injury by disinfectant, seem to contribute to its pathogenesis. In our endoscopy unit, pseudolipomatosis occurred in an epidemic pattern after changing the endoscopic disinfectant from 2% glutaraldehyde to peracetic acid compound to decrease the length of endoscope reprocessing time. We assumed that pseudolipomatosis could be a type of chemical colitis produced by the residual disinfectant solution that remained on the surface or in a channel of the endoscope after reprocessing. The aim of this report was to highlight a series of 12 cases of colonic pseudolipomatosis in order to describe the endoscopic and pathological features and discuss the harmful effect of disinfectants as a possible cause of pseudolipomatosis. To identify the cause of the lesions, we systematically reviewed each patient history and the endoscopic and histological features. From March 2004 to February 2005, 1276 colonoscopies were performed and 12 cases (0.94%) of colonic pseudolipomatosis were diagnosed at the Kangnam Sacred Heart Hospital of Hallym University. The pathogenesis of colonic pseudolipomatosis is not well-known, but our experience indicates the endoscopic disinfectant as the probable cause of pseudolipomatosis rather than either mechanical traumatic injury or intraluminal air pressure-related injury.

[A case of chemical colitis caused by hydrogen peroxide enema]

Hydrogen peroxide is commonly used as a disinfectant that has been reported to cause chemical colitis. We report a case of 49 year-old man who presented with chemical colitis caused by self-inflicted hydrogen peroxide enema. In the sigmoidoscopic examination, diffuse erythematous and edematous mucosal change with multiple ulcerations and easy touch bleeding was noted from the rectum to the proximal sigmoid colon. Abdominal computed tomography showed diffuse wall thickening of the rectum and the sigmoid colon with inflammatory and reactive change at surrounding. The patient was treated with NPO, intravenous fluid, and antibiotic therapy. On 5th hospital day, abdominal pain and bloody stool disappeared, and the patient started oral feeding. He discharged on 6th hospital day with fully recovered state.

Automated endoscope reprocessors

The ASGE Technology Committee provides reviews of existing, new, or emerging endoscopic technologies that have an impact on the practice of GI endoscopy. Evidence-based methodology is used, with a MEDLINE literature search to identify pertinent clinical studies on the topic and a MAUDE (U.S. Food and Drug Administration Center for Devices and Radiological Health) database search to identify the reported complications of a given technology. Both are supplemented by accessing the "related articles" feature of PubMed and by scrutinizing pertinent references cited by the identified studies. Controlled clinical trials are emphasized, but in many cases data from randomized, controlled trials are lacking. In such cases, large case series, preliminary clinical studies, and expert opinions are used. Technical data are gathered from traditional and Web-based publications, proprietary publications, and informal communications with pertinent vendors. Technology Status Evaluation Reports are drafted by 1 or 2 members of the ASGE Technology Committee, reviewed and edited by the committee as a whole, and approved by the Governing Board of the ASGE. When financial guidance is indicated, the most recent coding data and list prices at the time of publication are provided. For this review, the MEDLINE database was searched through February 2010 for articles related to automated endoscope reprocessors, using the words endoscope reprocessing, endoscope cleaning, automated endoscope reprocessors, and high-level disinfection. Technology Status Evaluation Reports are scientific reviews provided solely for educational and informational purposes. Technology Status Evaluation Reports are not rules and should not be construed as establishing a legal standard of care or as encouraging, advocating, requiring, or discouraging any particular treatment or payment for such treatment.

Glutaraldehyde-induced colitis: three case reports

Glutaraldehyde (2% solution) is an effective and widely used disinfecting solution for cold sterilization of endoscopic instruments. Direct contact of glutaraldehyde solution with colonic mucosa can cause self-limited colitis. As it rarely occurs as a complication of colonoscopy, glutaraldehyde-induced colitis is generally reported only as case reports in the literature. We report three cases of glutaraldehyde-induced colitis after colonoscopy. All lesions resolved with supportive treatment. We stress the need for thorough rinsing of the surface and channels of the endoscope with water to avoid the occurrence of this complication.

Chemical colitis due to glutaraldehyde: case series and review of the literature

Chemical colitis can occur as a result of accidental contamination of endoscopes or by intentional/accidental administration of enemas containing various chemicals.We present three cases of glutaraldehyde induced colitis and review the cases in the literature. Glutaraldehyde induced colitis presents clinically with severe abdominal pain, bloody and mucoid diarrhea, rectal bleeding, and tenesmus 48-72 h after colonoscopy. Endoscopic findings are nonspecific and mimic ischemic colitis, inflammatory bowel disease, and infectious colitis. The timing of symptoms and the knowledge that glutaraldehyde is a chemical irritant to colonic mucosa is important for the diagnosis. The treatment is mainly supportive but sometimes necessitates mesalamine, prednisolone, or metronidazole and the resolution is rapid. In endoscopy units, strict adherence to published disinfection protocols is very important and the cleaning, rinsing and drying protocols also deserve the same attention.

Acute rectocolitis following endoscopy in health check-up patients--glutaraldehyde colitis or ischemic colitis?

PURPOSE

Acute rectocolitis is a rare complication that follows endoscopy. It could be caused by glutaraldehyde or ischemic injury. The clinical, endoscopic, radiological, and pathological features of glutaraldehyde-induced colitis may mimic those of ischemic colitis. We reported our experiences regarding this problem.

METHODS

The medical records of patients with acute rectocolitis following endoscopy treated at Kaohsiung Veterans General Hospital since 2001 were reviewed. The indication of endoscopy was health check-up for all patients. Published English-language studies regarding acute rectocolitis following endoscopy were also reviewed.

RESULTS

An outbreak of six patients occurred in April 2002 and one cirrhotic patient was admitted in July 2008. All patients developed a self-limited syndrome of abdominal pain and bloody diarrhea within 48 h of uncomplicated endoscopy. One severely ill patient required hospitalization to receive intravenous fluid and antibiotics. After the investigation in April 2002, glutaraldehyde-induced colitis was diagnosed due to a defect in the endoscope-cleansing procedure. There were no any deficiencies in the cleansing procedure in July 2008. Considering the patient's concomitant disease, we postulated that ischemic colitis with cirrhosis-related intestinal inflammation and endotoxemia was the possible diagnosis in this sporadic case.

CONCLUSIONS

Endoscopists should be aware of this iatrogenic complication in patients presenting with acute rectocolitis, especially in those who have undergone recent endoscopic examination. An outbreak of acute rectocolitis following endoscopy should be considered glutaraldehyde-induced and should lead to an investigation of cleansing and equipment-disinfection procedures. In the absence of strong evidence of an outbreak, an infectious disease, or contamination of glutaraldehyde, a sporadic case should be considered ischemic colitis especially in patients with relevant concomitant diseases or predisposing factors.

Chemical colitis

Chemical colitis can occur as a result of accidental contamination of endoscopes or by intentional or accidental administration of enemas containing various chemicals. Most cases have occurred after accidental contamination of endoscopes with glutaraldehyde and/or hydrogen peroxide. There have been multiple case reports of chemical colitis resulting from unintentional administration of caustic chemicals. Intentional administration of corrosive enemas has been implicated in sexual practices, bowel cleansing, or in suicide attempts. Patients present with nonspecific symptoms including abdominal pain, rectal bleeding, and/or diarrhea. As chemical colitis remains rare, the literature consists of scattered case reports and small series. Agents implicated in chemical colitis that are covered in this review include alcohol, radiocontrast agents, glutaraldehyde, formalin, ergotamine, hydrofluoric acid, sulfuric acid, acetic acid, ammonia, soap, sodium hydroxide, hydrogen peroxide, herbal medicines, chloro-m-xylenol, and potassium permanganate. Clinical, endoscopic, and histologic features are outlined for each agent in addition to the existing literature. Given the nonspecific presentation of many cases of chemically induced colitis, the diagnosis can be challenging if the pertinent history is not obtained. Most patients demonstrate the resolution of chemical-induced colitis after conservative or medical therapy. Depending on the depth and extent of injury, patients rarely require colectomy for ischemic colitis and/or peritonitis. Other postingestion complications include colonic strictures and rectovaginal fistulae. The benefits of medical therapy compared with conservative therapy are not known, as comparative clinical management trials have not been performed.

Noninfectious colitides: collagenous colitis, lymphocytic colitis, diversion colitis, and chemically induced colitis

Approximately 10% of patients with chronic diarrhea carry a diagnosis of microscopic colitis. The endoscopic appearance of both collagenous colitis and lymphocytic colitis may be normal; however, biopsies confirm the diagnosis. Available treatments include antidiarrheals, bismuth salicylate, and budesonide. Although most patients with fecal diversion may have endoscopic evidence of colitis, a much smaller percentage of patients are symptomatic. Some cases of diversion colitis respond to treatment with short-chain fatty acid enemas; however, return of the fecal stream is the most successful therapy. A variety of oral, intravenous, and per rectum chemicals may cause colitis; symptoms usually abate when chemical exposure is discontinued.

Exogenous endoscopy-related infections, pseudo-infections, and toxic reactions: clinical and economic burden

OBJECTIVES

The objective of this study was to analyze the characteristics and costs of exogenous endoscopy-related infections, pseudo-infections, and toxic reactions in the US.

METHODS

A systematic review of the scientific literature published between 1966 and 2005 was conducted in Medline. Data collection was based on a prospective protocol developed by the authors.

RESULTS

The literature review included 70 outbreaks described in 64 scientific articles. Bronchoscopy accounted for half of all reported outbreaks. Inadequate decontamination practices were the leading cause of contamination; equipment malfunction became the second leading cause of contamination during the period 1990-2004. More than 91% of the infections identified could be prevented by health care providers if quality control systems are improved and implemented. The available economic information concerning exogenous endoscope related events is very limited. A model for the analysis of the economic burden of exogenous endoscopy-related events is proposed.

CONCLUSIONS

Proper decontamination practices, the use of protective sheaths, and the improvement of surveillance systems could reduce the clinical and economic burdens associated with exogenous endoscopy-related events.

Colonic pseudolipomatosis: clinical, endoscopical and pathological features in nine cases

Colonic pseudolipomatosis is a rare and benign condition. It is not well known by gastroenterologists and its pathogenesis is still unclear.

METHODS

All cases of colonic pseudolipomatosis seen between February 2002 and June 2004 at the Amiens Universisty Hospital were identified and analyzed.

RESULTS

During this period, 2099 colonoscopies were performed and 9 cases of colonic pseudolipomatosis were diagnosed (0.4%). Patients were all males aged from 41 to 67 (median age 52 years). They consulted for rectal bleeding (two patients), diarrhea (two patients) or abdominal pain (two patients). In three patients, colonic pseudolipomatosis was a fortuitous discovery during colonoscopy for polyp surveillance. The lesions presented as whitish and yellowish slightly elevated plaques ranging in size from a few millimeters to 4 cm. They extended over a two to 20 cm-long area, located in the right (two patients), transverse (four patients) or left colon (three patients). Microscopic examination showed empty spaces in the lamina propria measuring from 50 to 600 microm. They were negative for anti-CD31, CD34 and PS100 antibodies at immunohistochemistry and negative for Sudan black in three cases. The ultrastructural study showed in two cases round spaces containing small fibrillary protein-like deposits that might be lymph.

CONCLUSION

Colonic pseudolipomatosis is rare. Its pathogenesis is not well-known but could be due to gas invasion or extravasation of lymph into lamina propria, maybe induced by mucosal lesions related to barotrauma or certain colonoscope cleaning solutions.

Colonic pseudolipomatosis, microscopically classified into two groups

BACKGROUND

Colonic pseudolipomatosis is rare and the pathogenesis is controversial. The purpose of the present paper was to clarify endoscopic and histological characteristics of colonic pseudolipomatosis and to discuss the etiology.

METHODS

A total of 15 lesions from 14 patients was reviewed. They were able to be histologically classified into two groups on the basis of variety in size of the vacuoles: Group A, the ratio of largest vacuole to smallest vacuole in size is less than three, Group B, the ratio is more than four.

RESULTS

Four of 15 lesions were group A, and were endoscopically polypoid or flat lesions covered with normal-looking mucosa. They were microscopically characterized by (i) predominant location in the upper portion of the lamina propria; (ii) no submucosal involvement; (iii) less variation in vacuolar size; and (iv) no association with lymph follicles. The vacuoles of group A contained proteinaceous materials in two of four lesions. Group B (11 lesions) had small elevated mucosa with normal-looking surface or non-elevated reddish mucosa. Microscopically, the lesions were mainly located in the lower portion of the lamina propria, occasionally also in the submucosa, had variable-sized vacuoles, and were related to lymph follicles.

CONCLUSION

It is suggested that the vacuoles in group A contain fluid, and may indicate an abnormal stagnation of interstitial fluid. Microscopic appearance of group B is essentially similar to that of pneumatosis coli. It is thought that group B probably results from penetration of gas from the crypts into the mucosa during colonoscopy. It is unclear why group B had a preference for ileocecal valve and an association with lymph follicles.

Colite hémorragique avec choc après une coloscopie

We report the case of a 43-year-old woman with an acute haemorrhagic colitis after colonoscopy with ambulatory anaesthesia. The diagnosis is likely to have been glutaraldehyde induced colitis (used for disinfection of the endoscope). The patient recovered spontaneously completely.

Reprocessing endoscopes: United States perspective

Endoscopes are used frequently for the diagnosis and therapy of medical disorders. For example, greater than 10000000 gastrointestinal endoscopic procedures are performed each year in the United States. Failure to employ appropriate cleaning and disinfection/sterilization of endoscopes has been responsible for multiple nosocomial outbreaks and serious, sometimes life-threatening, infections. Flexible endoscopes, by virtue of the site of use, have a high bioburden of microorganisms after use. The bioburden found on flexible gastrointestinal endoscopes following use has ranged from 10(5) to 10(10)CFU/ml, with the highest levels being found in the suction channels. Cleaning dramatically reduces the bioburden on endoscopes. Several investigators have shown a mean log(10) reduction factor of 4 (99.99%) in the microbial contaminants with cleaning alone. Cleaning should be done promptly following each use of an endoscope to prevent drying of secretions, allow removal of organic material, and decrease the number of microbial pathogens. Because the endoscope comes into intimate contact with mucous membranes, high-level disinfection is the reprocessing standard after each patient use. High-level disinfection refers to the use of a disinfectant (e.g., FDA-cleared chemical sterilant or high-level disinfectant) that inactivates all microorganisms (i.e., bacteria, viruses, fungi, mycobacteria) but not high levels of bacterial spores. The disinfection process requires immersion of the endoscope in the high-level disinfectant and ensuring all channels are perfused for the approved contact time (e.g., for ortho-phthaladehyde this is 12 min in the US). Following disinfection, the endoscope and channels are rinsed with sterile water, filtered water, or tapwater. The channels are then flushed with alcohol and dried using forced air. The endoscope should be stored in a manner that prevents recontamination. A protocol that describes the meticulous manual cleaning process, the appropriate training and evaluation of the reprocessing personnel, and a quality assurance program for endoscopes should be adopted and enforced by each unit performing endoscopic reprocessing.

Toxicological, medical and industrial hygiene aspects of glutaraldehyde with particular reference to its biocidal use in cold sterilization procedures

Aqueous solutions of > or =5% glutaraldehyde (GA) are of moderate acute peroral toxicity and those of < or =2% are of slight toxicity. By single sustained skin contact, aqueous GA solutions of > or =45% are of moderate acute percutaneous toxicity, those of 25% are of slight toxicity and those of </=15% do not present an acute percutaneous hazard. Vapor generated at ambient temperature may cause sensory irritant effects to the eye and respiratory tract, but not acute respiratory tract injury. The 50% decrease in respiratory rate (rd(50)) is 13.86 ppm. A 0.1% solution of GA is not irritating to the eye; the threshold for conjunctival irritation is 0.2% and for corneal injury it is 1.0%. Eye injury is moderate at 2% and severe at > or =5%. Primary skin irritation depends on the duration and contact site, occlusion and solvent. By sustained contact, the threshold for skin irritation is 1%, above which erythema and edema are dose related. With 45% and higher, skin corrosion may occur. There is a low incidence of skin sensitizing reactions, with an eliciting threshold of 0.5% aqueous GA. However, GA is neither phototoxic nor photosensitizing. Subchronic repeated exposure studies by the peroral route show only renal physiological compensatory effects, secondary to reduced water consumption. Repeated skin contact shows only minor skin irritant effects without systemic toxicity. By subchronic vapor exposure, effects are limited to the nasal mucosa at 1.0 ppm, with a no-effect concentration generally at 0.1 ppm. There is no evidence for systemic target organ or tissue toxicity by subchronic repeated exposure by any route. A chronic drinking water study showed an apparent increase, in females only, of large granular cell lymphocytic leukemia but this was not dosage related. This is most likely the result of a modifying effect on the factor(s) responsible for the expression of this commonly occurring rat neoplasm. A chronic (2-year) inhalation toxicity/oncogenicity study showed inflammatory changes in the anterior nasal cavity but no neoplasms or systemic toxicity. In vitro genotoxicity studies--bacterial mutagenicity, forward gene mutation (HGPRT and TK loci), sister chromatid exchange, chromosome aberration, UDS and DNA repair tests--have given variable results, ranging from no effect through to weak positive. In vivo genotoxicity studies--micronucleus, chromosome aberration, dominant lethal and Drosophila tests--generally have shown no activity but one mouse intraperitoneal study showed bone marrow cell chromosome aberrations. Developmental toxicity studies show GA not to be teratogenic, and a two-generation study showed no adverse reproductive effects. Percutaneous pharmacokinetic studies showed low skin penetration, with lowest values measured in vitro in rats and human skin. Overexposure of humans produces typical sensory irritant effects on the eye, skin and respiratory tract. Some reports have described an asthmatic-like reaction by overexposure to GA vapor. In most cases this resembles reactive airways dysfunction syndrome, and the role of immune mechanisms is uncertain. Local mucosal effects may occur if medical instruments or endoscopes are not adequately decontaminated. Protection of individuals from the potential adverse effects of GA exposure requires that there be adequate protection of the skin, eyes and respiratory tract. The airborne concentration of GA vapor should be kept below the recommended safe exposure level (e.g. the threshold limit value) by the use of engineering controls. Those who work with GA should, through a training program, be aware of the properties of GA, its potential adverse effects, how to handle the material safely and how to deal with accidental situations involving GA. If effects develop in exposed workers, the reasons should be determined immediately and corrective methods initiated. (c) 2001 John Wiley & Sons, Ltd.

Digestive System 1

This chapter deals with the digestive system. The major and minor salivary glands and their secretions also represent and integral part of the protective mechanism of the oral cavity, and derangement of saliva production may lead to loss of integrity of the oral mucosa. Drug-induced abnormalities of taste sensation are also well-described phenomena occurring in man although human studies are necessary for the detection of these effects. Inflammation of the oral cavity may involve the buccal mucosa, the gingiva (gingivitis), the tongue (glossitis), and the peridontal tissues (peridontitis). Therapeutic agents can induce inflammatory lesions in the tongue. Moreover, a protective layer of mucus, a visco-elastic material containing high molecular weight glycoproteins produced by the major and minor salivary glands, covers the stratified squamous mucosa of the oral cavity. Salivary secretions also possess digestive enzyme activity although in herbivores and carnivores, it is usually low in contrast to high digestive enzyme activity in omnivorous species.

Disinfection of endoscopes: review of new chemical sterilants used for high-level disinfection

Chemical sterilants are used to high-level disinfect heat-sensitive semicritical items such as endoscopes. Most endoscopes have been reprocessed between each patient use with glutaraldehyde (>2%) or the Steris System 1. Several new chemical sterilants have been developed recently, including 7.5% hydrogen peroxide, 0.08% peracetic acid plus 1.0% hydrogen peroxide, and 0.55% orthophthalaldehyde. In order to aid the infection control professional in choosing the appropriate disinfection methodology, this article reviews the characteristics, advantages, and disadvantages of high-level disinfectants intended for reprocessing endoscopes.

Glutaraldehyde as a possible cause of diarrhoea after sigmoidoscopy

BACKGROUND

An outbreak of proctitis at the start of a colorectal cancer screening programme utilizing flexible sigmoidoscopy prompted scrutiny of the incidence of this complication and the role of glutaraldehyde in its aetiology.

METHODS

Questionnaires completed 1 day and 3 months after sigmoidoscopy were reviewed for 388 patients, and glutaraldehyde levels in the recycled rinse water of the endoscope washing machine were measured. The incidence of symptoms in the subsequent 612 patients after installation of a washer that does not recycle rinse water was examined.

RESULTS

Five patients (1.3 per cent) presented to hospital with bloody diarrhoea occurring immediately after a normal flexible sigmoidoscopy. Repeat examination confirmed the presence of proctitis. Symptoms subsided rapidly with either no treatment or steroid enemas. Eight additional patients (2.1 per cent) recorded similar problems but received no treatment and the symptoms settled spontaneously. Glutaraldehyde levels rose progressively in the rinse water after each wash cycle with 2 per cent glutaraldehyde solution. Only one possible case of proctitis (0.2 per cent) was identified from the questionnaires completed by 612 patients after changing to a washer that did not recycle the rinse water.

CONCLUSION

These observations should prompt the careful assessment of cleaning techniques. The use of washing machines that do not recycle rinse water may avoid this complication.

Disposable, sheathed, flexible sigmoidoscopy: a prospective, multicenter, randomized trial. The Disposable Endoscope Study Group

A new fiberoptic sigmoidoscopic system has been developed that utilizes a disposable sheath to cover and protect all working surfaces of the endoscope from contamination. The reusable part of the endoscope has no air, water, or suction/biopsy channels. These are incorporated in the disposable sheath, which is easily removed after use to provide each patient with a contamination-free endoscope. A prospective, randomized, controlled trial was performed to compare the disposable, sheathed, flexible sigmoidoscope with standard sigmoidoscopes. Clinical evaluations of the new sigmoidoscope system were performed at 15 facilities. Visual analog rating scales were used to record evaluations of endoscope performance and reprocessing by endoscopists and reprocessing personnel. The time to perform procedures, depth of insertion, and total instrument downtime were also recorded. One hundred forty-three procedures (70 standard, 73 sheathed) were performed. No significant difference was found for overall depth of insertion (50 versus 48 cm), although fewer sheathed endoscopes reached to 60 cm than did standard endoscopes (51% versus 30%). The sheathed system had a slightly longer mean procedure time than the standard (5.6 versus 6.7 minutes), but a significantly shortened overall downtime (32.8 vs 8.1 minutes). The standard system was preferred by the endoscopists. Reprocessing personnel preferred the disposable system. The disposable sigmoidoscope system has important advantages of decreased instrument turn-around time and potentially increased staff and patient safety, and future models should be improved to meet physicians' concerns.

Glutaraldehyde colitis following endoscopy: clinical and pathological features and investigation of an outbreak

Although potentially noxious compounds are used routinely to disinfect endoscopes, reports of their inadvertent introduction to the gastrointestinal tract, usually attributed to the retention of disinfectant within endoscope channels, are rare. This case report describes the clinical features of glutaraldehyde-induced colitis and the pathology of the mucosal injury in four patients, in at least one of whom the disinfectant was not retained in the endoscope itself. Within 3 months, three patients experienced severe acute proctocolitis < 6 hours after a sigmoidoscopy showing no abnormalities, performed in a small endoscopy unit. Investigation of the unit's protocols suggested that the most likely cause was retention of 2% glutaraldehyde disinfectant in the endoscope channels, and changes were made to prevent this. When a fourth case occurred 5 months later, the source of the glutaraldehyde was found to be the tubing connecting water bottles to the endoscopes, which was disinfected rigorously but flushed inconsistently between cases. Glutaraldehyde-induced colitis seems similar to ischemic colitis in biopsy specimens and cannot be diagnosed by histological analysis alone. Acute colitis occurring within 24 hours of a colonoscopy showing no abnormalities should be considered iatrogenic and should lead to an investigation of procedures in use for cleaning and disinfecting endoscopic equipment.