Enteric bacteriology, absorption, morphology and emptying after ileal pouch-anal anastomosis

Endoscopic assessment of the J pouch in ulcerative colitis: A narrative review

Patients with ulcerative colitis sometimes need a total colectomy with ileal pouch-anal anastomosis due to medically refractory disease or colitis-associated neoplasia. Up to 50% of patients with ulcerative colitis postoperatively develop pouchitis and the rate of chronic inflammatory pouch conditions requiring pouch excision or diverting ileostomy is reported to be 10%. In order to diagnose and monitor pouchitis, pouchoscopy is essential to assess endoscopic inflammatory findings of the J pouch and to survey neoplasia development, particularly in the remnant distal rectum. However, endoscopic protocols for the evaluation of the pouch may not be standardized worldwide and the reliability of existing disease activity indices for pouchitis has been questioned due to the lack of validation. Recently, reliable endoscopic scoring systems based on an observation of the anatomical location of the J pouch were reported and a significant association between the distribution pattern of endoscopic inflammation (i.e., endoscopic phenotype) and pouch outcomes was also uncovered. In this review, we discuss how to survey the J pouch using pouchoscopy, endoscopic indices for pouchitis disease activity, endoscopic phenotypes and classification, and the pathological mechanisms of pouchitis phenotype in patients with ulcerative colitis.

The aetiology of pouchitis in patients with inflammatory bowel disease

Restorative proctocolectomy with ileal pouch-anal anastomosis is a treatment option for patients with refractory ulcerative colitis. Pouchitis is the most common complication, representing a spectrum of diseases ranging from acute antibiotic-responsive type to chronic antibiotic-refractory. Early accurate diagnosis using a combined assessment of symptoms, endoscopy and histology is important for both treatment and prognostication. Most patients respond well to antibiotic therapy; however, management of chronic antibiotic-refractory pouchitis remains a challenge, and treatment options are based on small studies. Pouchitis is thought to be driven by the interaction between genetics, the immune system and the environment but as yet a causal relationship has yet to be identified. Further longitudinal assessment of the pouch integrating new technologies may help us understand the factors driving pouchitis. This review outlines the currently understood risk factors and aetiology of pouchitis.

Pouchitis in inflammatory bowel disease: a review of diagnosis, prognosis, and treatment

Patients with inflammatory bowel disease (IBD) occasionally need a restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) because of medically refractory colitis or dysplasia/cancer. However, pouchitis may develop in up to 70% of patients after this procedure and significantly impair quality of life, more so if the inflammation becomes a chronic condition. About 10% of patients with IBD who develop pouchitis require pouch excision, and several risk factors of the failure have been reported. A phenotype that has features similar to Crohn’s disease may develop in a subset of ulcerative colitis patients following proctocolectomy with IPAA and is the most frequent reason for pouch failure. In this review, we discuss the diagnosis and prognosis of pouchitis, risk factors for pouchitis development, and treatment options for pouchitis, including the newer biological agents.

Festschrift for Ronan O'Connell: pouchitis, ulcerative colitis and the microbiome

The hypothesis of altered bacterial communities contributing to the development of pouchitis began a scientific quest to link host mucosal factors, microbial metabolism and spatial structure of the colonic microbiome in ulcerative colitis, reaching its apotheosis with the integration of advanced spatial sampling with laser capture microdissection, mucin array profiling, molecular microbiology and next-generation sequencing technologies. This article, part of a festschrift, summarises the contributions of the O'Connell lab to the field of host-microbial interactions in inflammatory bowel disease.

Review article: the pathogenesis of pouchitis

BACKGROUND

A total proctocolectomy followed by ileal pouch-anal anastomosis is a potentially curative surgery for ulcerative colitis or familial adenomatous polyposis. About 5-35% of patients with ulcerative colitis and 0-11% of patients with familial adenomatous polyposis develop subsequent inflammation of the ileal pouch termed pouchitis.

AIM

To provide a comprehensive analysis of the research studying the possible pathogenesis of pouchitis. The goals were to identify promising areas of investigation, to help focus clinicians, researchers and patients on how to better understand and then potentially manage ileal pouchitis, and to provide avenues for future research investigations.

METHODS

This review examined manuscripts from 1981 to 2015 that discussed and/or proposed hypotheses with supportive evidence for the potential underlying pathogenic mechanism for pouchitis.

RESULTS

The pathogenesis of pouchitis is not definitively understood, but various hypotheses have been proposed, including (i) recurrence of ulcerative colitis, (ii) dysbiosis of the ileal pouch microbiota, (iii) deprivation of nutritional short-chain fatty acids, (iv) mucosal ischaemia and oxygen-free radical injury, (v) host genetic susceptibility and (vi) immune dysregulation. However, none of these alone are able to fully explain pouchitis pathogenesis.

CONCLUSIONS

Pouchitis, similar to inflammatory bowel disease, is a complex disorder that is not caused by any one single factor. More likely, pouchitis occurs through a combination of both dysregulated host inflammatory mechanisms and interaction with luminal microbiota.

Etiology of pouchitis

Restorative proctocolectomy with ileal-pouch anal anastomosis (RPC) is the operation of choice for ulcerative colitis (UC) patients requiring surgery. It is also used for patients with familial adenomatous polyposis (FAP). Pouchitis accounts for 10% of pouch failures. It is an idiopathic inflammatory condition that may occur in up to 50% of patients after RPC for UC. It is rarely seen in FAP patients after RPC. The etiology of pouchitis remains unclear. An overlap with UC is suggested by the frequency with which pouchitis affects patients with UC compared with FAP patients. There is significant clinical evidence implicating bacteria in the pathogenesis of pouchitis. Studies using culture and molecular methods demonstrate a dysbiosis of the pouch microbiota in pouchitis. Risk factors, genetic associations, and serological markers of pouchitis suggest that the interactions between the host immune responses and the pouch microbiota underlie the etiology of this idiopathic inflammatory condition. Here we present a detailed review of the data focusing on the pouch microbiota and the immune responses that support this hypothesis. We also discuss the contribution of luminal metabolic factors and the epithelial membrane in the etiology of this inflammatory process. The ileoanal pouch offers a unique opportunity to study the inter-relationships between the gut microbiota and host immune responses from before the onset of disease. For this reason the study of pouchitis could serve as a human model that significantly enhances our understanding of inflammatory bowel diseases in general.

Restorative Proctocolectomy with Ileo-anal Reservoir, a Histopathological, Histochemical, and Electron Microscopic Study

This study was conducted to investigate the nature of colonic metaplasia in ileo-anal pouches and incidence/frequency of pouchitis in the same. Biopsy specimens from 8 patients with functioning ileal pouches were studied using routine histology, mucin histochemistry and electron microscopy, over a 2 - year period. All 8 patients had villous abnormalities in the form of blunting of villi and sub total or partial villous atrophy. 6 patients had an increase in the goblet cell population and Paneth cell hyperplasia. These changes were supported by electron microscopic findings of a decrease in number and flattening of ileal type microvilli and their transformed morphologic resemblance to colonic type microvilli. All the ileal pouches also had acquired colorectal type sulphomucin, when sections stained with Alcian-blue and High Iron Diamine - Alcian blue, were studied. However, no case of pouchitis as defined in literature, was found in this study.

The bacterial pathogenesis and treatment of pouchitis

Restorative proctocolectomy (RPC) with ileal pouch-anal anastomosis is the operation of choice for patients with ulcerative colitis. Pouchitis is the most common cause of pouch dysfunction. Although the pathogenesis of this disease is not well understood, bacteria have been implicated in the disease process. Numerous bacterial studies have been reported over the last 25 years with few unifying findings. In addition, many different treatments for pouchitis have been reported with varying results. Antibiotic treatment remains the most studied and is the mainstay of treatment. In this article we review the aetiology of pouchitis and the evidenced-based treatment options.

Primary adenocarcinoma of ileostomy: case report with review of the literature

Primary adenocarcinoma is a rare and late complication following proctocolectomy and ileostomy for ulcerative colitis, familial adenomatous polyposis, Crohn's disease and multifocal colorectal cancer. We report a case of adenocarcinoma of the ileostomy occurring 48 years after proctocolectomy for ulcerative colitis. A review of the literature suggests that there are 39 cases reported in literature and this case reports the longest interval between formation of ileostomy and diagnosis of ileostomy adenocarcinoma. This case also reports lymph node metastasis to the adjacent mesenteric lymph node. The incidence of lymphnode metastasis is 15 percent as per literature. Onces diagnosis is confirmed by biopsy enblock excision with or without stomal relocation is the main stay of treatment. Patient education and regular surveillance of patients with long-standing ileostomy is recommended for early detection of this unusual cancer.

Bacterial community diversity in cultures derived from healthy and inflamed ileal pouches after restorative proctocolectomy

BACKGROUND

Pouchitis is believed to occur as a reaction to dysbiosis. In this study we assessed differences between mucosal bacterial communities cultured from noninflamed and inflamed ileal pouches.

METHODS

Thirty-two ileal pouch patients, 22 with ulcerative colitis (UC) and 10 with familial adenomatous polyposis (FAP), underwent symptomatic, endoscopic, and histological assessment. The Objective Pouchitis Score (OPS) and the Pouch Disease Activity Index (PDAI) were used to diagnose pouchitis. Seven UC patients had pouchitis (UC+), 15 had a noninflamed pouch (UC-), 9 had a noninflamed pouch (FAP-), and 1 FAP patient had pouchitis (FAP+). Biopsies taken from the ileal mucosa of the pouch were cultured under aerobic and anaerobic conditions. Following standardized DNA extraction a polymerase chain reaction (PCR) was performed to generate 16S rRNA gene products. A "fingerprint" of the bacterial community within each sample was created using terminal-restriction fragment length polymorphism (T-RFLP) profiling. Species richness and evenness were determined using T-RF band lengths and relative band intensities.

RESULTS

From the 64 DNA samples, 834 bands were detected, of which 179 represented different species (operational taxonomic units [OTUs]). The average species richness for the FAP-, FAP+, UC-, and UC+ groups was 26, 35, 23.9, and 29.6 per patient, with the average species diversity within the groups of 10.6, 29, 8.3, and 11.4, respectively. Similar trends were observed when the anaerobic and aerobic-derived bacterial groups were analyzed separately.

CONCLUSIONS

No significant differences were found between the bacterial cultures derived from any of the clinical groups or between pouchitis and nonpouchitis patients.

Pathogenesis of and unifying hypothesis for idiopathic pouchitis

Ileal pouch-anal anastomosis is the procedure of choice in the surgical management of refractory ulcerative colitis. Pouchitis affects up to 60% of patients following ileal pouch-anal anastomosis for ulcerative colitis. It overlaps significantly with ulcerative colitis such that improvements in our understanding of one will impact considerably on the other. The symptoms are distressing and impinge significantly on patients' quality of life. Despite 30 years of scientific and clinical investigation, the pathogenesis of pouchitis is unknown; however, recent advances in molecular and cell biology make a synergistic hypothesis possible. This hypothesis links interaction between epithelial metaplasia, changes in luminal bacteria (in particular sulfate-reducing bacteria), and altered mucosal immunity. Specifically, colonic metaplasia supports colonization by sulfate-reducing bacteria that produce hydrogen sulfide. This causes mucosal depletion and subsequent inflammation. Although in most cases antibiotics lead to bacterial clearance and symptom resolution, immunogenetic subpopulations can develop a chronic refractory variant of pouchitis. The aims of this paper are to discuss proposed pathogenic mechanisms and to describe a novel mechanism that combines many hypotheses and explains several aspects of pouchitis. The implications for the management of both pouchitis and ulcerative colitis are discussed.

Prevalence and outcome of anemia after restorative proctocolectomy: a clinical literature review

PURPOSE

Iron and/or vitamin B12 deficiency anemias, which have adverse effects on patients' quality of life, are commonly observed and often overlooked complications after restorative proctocolectomy. We performed a systematic review of publications on the prevalence of anemia as well as on the impact of anemia on a range of clinical, functional, quality of life, and economic outcomes in restorative proctocolectomy patients. This information is important to help healthcare providers through a comprehensive overview to increase awareness about a condition that could require therapy to improve patient healthcare and quality of life.

METHODS

We reviewed the English language publications on the incidence of anemia and its adverse effect after restorative proctocolectomy The United States National Library of Medicine database (MEDLINE), the Excerpta Medica database (EMBASE), the Cochran Library, and the Google search engine were searched for published articles on the prevalence and impact of anemia in post-restorative proctocolectomy surgical patients.

RESULTS

The long-term complication most frequently described after RPC is pouchitis. Pouchitis is significantly associated with iron deficiency anemia caused by pouch mucosal bleeding. Other causes are insufficient and/or impaired iron absorption. It has also been observed, however, that restorative proctocolectomy patients with underlying familial adenomatous polyposis rarely develop pouchitis yet show higher rates of iron deficiency anemia compared to those patients with underlying ulcerative colitis. Other causes shown as independent risk factors for iron deficiency anemia in restorative proctocolectomy patients are malignancy, desmoid tumors, and J-pouch configuration. Vitamin B12 deficiency anemia is also common after restorative proctocolectomy. About one-third of restorative proctocolectomy patients show abnormal Schilling test and 5 percent have low referenced serum cobalamin. It has been observed that the degree resection of the terminal-ileum, malabsorption, bacterial overgrowth, and dietary factors are among the known causes of cobalamin deficiency. Folate deficiency has not been reported in restorative proctocolectomy patients. Describing restorative proctocolectomy surgery and its outcomes, in patients without anemia, the quality of life is reported excellent regardless of operative technique.

CONCLUSIONS

Anemia is not uncommon following restorative proctocolectomy and has been shown to have negative effects on the patient's quality of life and the economy and may substantially increase healthcare costs. The treatment of anemia and its underlying causes is important to improving clinical and economic outcomes.

Free radical activity and lipid soluble anti-oxidant vitamin status in patients with long-term ileal pouch-anal anastomosis

OBJECTIVE

Ileal pouch-anal anastomosis (IPAA) is the operation of choice for patients with ulcerative colitis. Free radical activity and the status of lipid soluble antioxidant vitamins have not been previously assessed in patients with IPAA. The aim of the present study was to measure the plasma concentrations of lipophyllic antioxidants and free radical activity in IPAA patients and compare them with normal subjects.

METHOD

Forty-eight IPAA patients and 50 healthy controls were studied. A dietary assessment of vitamin E (alpha-tocopherol) and carotene was undertaken and plasma antioxidant status was assessed. Plasma malondialdehyde (MDA) was measured to assess the extent of free radical damage. In IPAA patients, association between the degree of inflammation in the pouch mucosa and the plasma concentration of lipophyllic antioxidants and extent of free radical activity was investigated.

RESULTS

The dietary intake of carotene was similar in both groups. Intake of vitamin E was significantly lower in patients than controls (P = 0.01). In the IPAA group plasma concentrations of alpha-carotene, beta-carotene and lycopene were significantly lower (P < 0.001) and alpha-tocopherol:cholesterol ratio significantly higher (P < 0.001). Free radical damage was significantly greater in patients than controls (P < 0.01). There were no significant correlations between the degree of inflammation in the pouch and plasma concentrations of MDA, carotenoids, alpha-tocopherol:cholesterol ratio or intake of vitamins.

CONCLUSION

Compared with normal subjects, patients with IPAA have significantly lower plasma concentrations of lipophyllic antioxidants alpha-carotene, beta-carotene and lycopene and higher free radical activity suggesting increased oxidative stress. These differences do not appear to be related to diet and do not correlate with histological severity of pouch inflammation.

Assessment of dietary intake and trace element status in patients with ileal pouch-anal anastomosis

PURPOSE

Panproctocolectomy and ileal pouch-anal anastomosis is the operation of choice for patients with ulcerative colitis and familial polyposis. The long-term nutritional consequences after pouch surgery are unknown. We have assessed the nutritional status of the essential trace elements-zinc, copper, manganese, and selenium-in patients several years (median, 10 (range, 2-15) years) after surgery.

METHODS

Fifty-five patients with uncomplicated ileal pouch-anal anastomosis and 46 healthy control subjects were studied. A dietary assessment of trace element intake was undertaken by using a semiquantitative food frequency questionnaire. The patients' trace elements status for zinc, copper, manganese, and selenium was assessed by measuring their concentrations in blood.

RESULTS

The dietary intake of individual trace elements was similar in both groups (all P values > 0.4). There was no significant difference in the concentrations of plasma copper, zinc, and selenium between patients and healthy control subjects (all P values > 0.07). The concentration of whole blood manganese was significantly higher (P = 0.004) in patients (median, 178.5 nmol/l; range, 59-478 nmol/l) compared with healthy control subjects (median, 140 nmol/l; range, 53-267 nmol/l). Four (7 percent) patients had manganese concentrations more than three standard deviations of the mean of control group (>255 nmol/l).

CONCLUSIONS

This study shows that patients who have had uncomplicated pouch surgery have a normal dietary intake of trace elements and do not develop deficiencies in copper, zinc, manganese, and selenium. However, these patients may be at increased risk of manganese toxicity.

Pouchitis atlas for objective endoscopic diagnosis

"Pouchitis" is a term for nonspecific mucosal inflammation of the pouch after total proctocolectomy and ileal pouch-anal anastomosis for ulcerative colitis. Pouchitis is the most frequent complication of the pelvic pouch at the late stage. To improve the accuracy of the pouchitis diagnosis, sets of clinical symptoms and endoscopic findings (with or without histology of biopsy samples) have previously been evaluated. Endoscopic findings are central to the diagnosis, and a universal consensus of various endoscopic findings must be the initial step toward an objective diagnosis of pouchitis. Since a proper signpost for the endoscopic evaluation of pouchitis has been absent, we developed this pouchitis atlas to minimize the diagnostic variation inherent among individual endoscopists. We also propose new criteria for the diagnosis of pouchitis: the Japanese criteria for diagnosis of pouchitis. These criteria are based on clinical symptoms and endoscopic findings that are clearly categorized in the atlas, and exclude infectious enteritis, anastomotic insufficiency, pelvic infection, anal dysfunction, and Crohn's disease. Advantages of the new criteria include ease of bedside diagnosis, without the calculation of points required by the other criteria for pouchitis. This pouchitis atlas, together with our new criteria, should contribute to the establishment of a clear-cut diagnosis for pouchitis and promote better evaluation and treatment of this novel intestinal inflammation.

Evolution of the restorative proctocolectomy and its effects on gastrointestinal hormones

Gastrointestinal (GI) peptide hormones are chemical messengers that regulate secretory, mechanical, metabolic, and trophic functions of the gut. Restorative proctocolectomy (RPC) or resection of the colon and rectum with maintenance of intestinal continuity through the construction of an ileal pouch reservoir and preservation of the anal sphincters has become the standard of care for the surgical treatment of ulcerative colitis and familial adenomatous polyposis. The manipulation of the digestive system to create the ileal pouch involves altering gut-associated lymphoid tissue among other anatomic changes that lead to changes in GI peptides. In addition, the ileal pouch epithelium responds to a wide variety of stimuli by adjusting its cellularity and function. These adaptive mechanisms involve systemic factors, such as humoral and neural stimuli, as well as local factors, such as changes in intestinal peristalsis and intraluminal nutrients. There have been conflicting reports as to whether the alterations in GI hormones after RPC have actual clinical implications. What the studies on alterations of GI peptides' response and behavior after RPC have contributed, however, is a window into the possible etiology of complications after pouch surgery, such as pouchitis and malabsorption. Given the possibility of pharmacologically modifying GI peptides or select components of adaptation as a therapeutic strategy for patients with ileal pouch dysfunction or pouchitis, a clear understanding of human pouch mucosal adaptation is of paramount importance. In this review, we summarize the evolution of the RPC and its effects on the GI hormones as well as their possible clinical implications.

Ileal pouch-anal anastomosis

BACKGROUND

Since 1977, restorative proctocolectomy with ileoanal anastomosis (IAA) has evolved into the surgical treatment of choice for most patients with intractable ulcerative colitis. Construction of an ileal pouch reservoir is now standard, usually in the form of J pouch (IPAA). The aim of this report is to review selection criteria for, and functional outcomes, follow-up and management of complications of IPAA after 30 years of widespread clinical application.

METHODS AND RESULTS

Literature published in English on the clinical indications, surgical technique, morbidity, complications and outcome following IAA and IPAA was sourced by electronic search, performed independently by two reviewers who selected potentially relevant papers based on title and abstract. Additional articles were identified by cross-referencing from papers retrieved in the initial search.

CONCLUSION

The functional results of IPAA are good. Pouchitis, irritable pouch syndrome and cuffitis are specific long-term complications but rarely result in failure. Pouch salvage is possible in selected patients with poor functional outcomes. One-stage operations are increasingly performed.

Vitamin B12 deficiency following restorative proctocolectomy

OBJECTIVE

Restorative proctocolectomy (RP) involves terminal ileal resection and formation of a small bowel reservoir that predisposes to bacterial overgrowth. It was anticipated that these patients would be at risk of vitamin B12 deficiency.

METHOD

Vitamin B12 levels were measured sequentially in 171 patients who underwent RP. Prospective results were obtained from all 20 patients undergoing pouch formation after the commencement of the study. Further results were obtained retrospectively from case notes and computerized laboratory records of the 151 patients who underwent RP prior to the commencement of the study and these were correlated with the results of follow-up samples taken prospectively from the same patients after the commencement of the study. The median age of the patients was 40 years (range: 13-67) and the median duration of follow up was 5.4 years (range: 1-12). Patients with an abnormally low serum B12 level underwent both a Schilling and a hydrogen breath test. Eight of these patients were then treated with oral vitamin B12.

RESULTS

Abnormally low serum B12 levels were found in 25% of patients. Forty per cent of our patient group had three or more sequential B12 measurements and of these, 66% showed steadily declining B12 levels. Ninety-four per cent of patients with low B12 had a normal Schilling test and were negative for bacterial overgrowth.

CONCLUSION

Subnormal vitamin B12 levels develop in almost one-quarter of patients after pouch surgery. The exact mechanism for B12 deficiency in these patients is uncertain. In the majority of patients undergoing RP, vitamin B12 levels fall on sequential measurement. Serum B12 levels should be measured during follow up and pouch patients with subnormal B12 levels, should see them successfully restored to a normal value after treatment with oral B12 replacement therapy.

Dysbiosis and pouchitis

BACKGROUND AND METHODS

The exact aetiology of pouchitis is unknown, but an association with dysbiosis has been suggested. This is a retrospective review of 17 studies published between 1985 and 2005, identified by a search of the Medline, Pubmed and Embase databases.

RESULTS

The methodology of the studies varied widely. Many were performed at a time when the distinction between a healthy and an inflamed pouch was vague; misclassification of patients makes the analysis of data difficult and conclusions uncertain.

CONCLUSION

The evidence that dysbiosis is a cause of pouchitis is poor. Nevertheless, available data allow the construction of an algorithm to aid management and suggest a structured approach for future research.

Pouchitis

Pouchitis is one of the commonest and most debilitating complications of a restorative proctocolectomy. The cause remains elusive, though a number of approaches have been shown to alleviate the condition. This review outlines current evidence relating to pouchitis, obtained from randomised and nonrandomised studies. Medline, the Bath Information Data Service (BIDS) and PubMed were searched using the keywords 'pouchitis' and 'inflammatory bowel disease'. In addition, articles were cross-referenced, and the abstracts of recent colorectal meetings studied.

A cost-effectiveness analysis of diagnostic strategies for symptomatic patients with ileal pouch-anal anastomosis

OBJECTIVE

Pouchitis is often diagnosed based on symptoms and empirically treated with antibiotics (treat-first strategy). However, symptom assessment alone is not reliable for diagnosis, and an initial evaluation with pouch endoscopy (test-first strategy) has been shown to be more accurate. Cost-effectiveness of these strategies has not been compared. The aim of this study was to compare cost-effectiveness of different clinical approaches for patients with symptoms suggestive of pouchitis.

METHODS

Pouchitis was defined as pouchitis disease activity index scores > or =7. The frequency of pouchitis in symptomatic patients with ileal pouch was estimated to be 51%; the efficacy for initial therapy with metronidazole (MTZ) and ciprofloxacin (CIP) was 75% and 85%, respectively. Cost estimates were obtained from Medicare reimbursement data.

RESULTS

Six competing strategies (MTZ trial, CIP trial, MTZ-then-CIP trial, CIP-then-MTZ trial, pouch endoscopy with biopsy, and pouch endoscopy without biopsy) were modeled in a decision tree. Costs per correct diagnosis with appropriate treatment were $194 for MTZ trial, $279 for CIP trial, $208 for MTZ-then-CIP trial, $261 for CIP-then-MTZ trial, $352 for pouch endoscopy with biopsy, and $243 for pouch endoscopy without biopsy. Of the two strategies with the lowest cost, the pouch endoscopy without biopsy strategy costs $50 more per patient than the MTZ trial strategy but results in an additional 15 days for early diagnosis and thus initiation of appropriate treatment (incremental cost-effectiveness ratio $3 per additional day gained). The results of base-case analysis were robust in sensitivity analyses.

CONCLUSIONS

Although the MTZ-trial strategy had the lowest cost, the pouch endoscopy without biopsy strategy was most cost-effective. Therefore, based on its relatively low cost and the avoidance of both diagnostic delay and adverse effects associated with unnecessary antibiotics, pouch endoscopy without biopsy is the recommended strategy among those tested for the diagnosis of pouchitis.

Electrolyte profiles within the ileoanal pouch: measurement by an in vivo equilibrium dialysis technique

BACKGROUND

Patients with an ileoanal pouch have high rates of fluid and electrolyte loss. These improve with pouch adaptation. There is limited information concerning secretion and absorption in the stable ileoanal pouch. A new method to measure and characterize electrolytes in the ileoanal pouch is described.

METHODS

Following an in vitro study, nine patients with a stable ileoanal pouch had consecutive placement of dialysis bags consisting of a semi-permeable membrane containing 5 ml of 10% dextran in normal saline into the ileoanal pouch. These were left in place for 15, 30, 60, and 120 min. After determining that 60 min was the optimal timing for measurement of electrolyte concentrations, 12 normal volunteers underwent a similar in vivo dialysis study with dialysis bags withdrawn at 60 min. Sodium, chloride, potassium, phosphorus, calcium and magnesium concentrations in the dialysis bags were compared between the two groups.

RESULTS

In the in vitro and in vivo studies, the measured electrolytes reached equilibrium within 60 min. Statistically significant differences between sodium concentrations (160.9 +/- 30.2 vs. 116.8 +/- 13.8 mmol/l, respectively) and phosphorus concentrations (6.8 +/- 5.2 vs. 1.8 +/- 0.7 mg/dl, respectively) at 60 min in ileoanal pouch patients and volunteers were found (p<0.001). There were no statistical differences in the other measured electrolytes between the two groups.

CONCLUSION

An in vivo dialysis technique is described for measuring electrolyte concentrations within the ileoanal pouch. Differences in sodium and phosphate concentrations may reflect incomplete adaptation of the ileoanal pouch, and are a potential explanation for increased stool frequency in these patients.

Pouchitis in Children: Therapeutic Options

Pouchitis is an unfortunate common complication of the ileal pouch-anal anastomosis procedure, an otherwise very attractive surgical option in patients with ulcerative colitis (UC). The fact that the same pouch in familial polyposis is hardly complicated by pouchitis suggests that the basic inflammatory process in UC might participate in the pathophysiology. We review the clinical features of pouchitis, the diagnostic approach, and the many therapeutic considerations, including more recent data on prebiotics and probiotics.

Irritable pouch syndrome: a new category of diagnosis for symptomatic patients with ileal pouch-anal anastomosis

OBJECTIVE

Pouchitis often is diagnosed based on symptoms alone. However, increased stool frequency, urgency, and abdominal pain could be due to a condition resembling irritable bowel syndrome. This study was designed to assess the etiology of bowel symptoms using the Pouchitis Disease Activity Index (PDAI).

METHODS

Symptoms, endoscopy, and histology were assessed in 61 consecutive symptomatic patients with ulcerative colitis after ileal pouch-anal anastomosis. Pouchitis was defined as a PDAI score of > or = 7, cuffitis was defined as endoscopic and histological inflammation of the rectal cuff and no inflammation of the pouch, and irritable pouch syndrome (IPS) was defined as symptoms with a PDAI of <7 and the absence of cuffitis.

RESULTS

Thirty-one patients (50.8%) had pouchitis, four (6.5%) had cuffitis, and 26 (42.6%) had IPS. Demographics were similar in the three groups. Increased stool frequency, urgency, and abdominal cramps were the most common symptoms in the three groups. Rectal bleeding was seen only in cuffitis (p < 0.001). No patient in the three groups had fever. Twenty-seven patients (87.1%) with pouchitis responded to a 2-wk course of ciprofloxacin or metronidazole with a reduction in PDAI scores of > or = 3. All four patients with cuffitis responded to topical hydrocortisone or mesalamine with a reduction in the PDAI symptom component score of > or = 1. Twelve patients with IPS (46.2%) responded to antidiarrheal, anticholinergic, and/or antidepressant therapies with a reduction in the PDAI symptom component score of > or = 1, whereas the remaining patients had persistent symptoms despite therapy.

CONCLUSIONS

A substantial number of symptomatic patients after ileal pouch-anal anastomosis do not meet the diagnostic criteria for either pouchitis or cuffitis and have been classified as having IPS. There is an overlap of symptoms among patients with pouchitis, cuffitis, and IPS, and endoscopic evaluation can differentiate among these groups. Distinction between these three groups has therapeutic implications.

Gut transit time after ileal pouch-anal anastomosis using a radiopaque marker

PURPOSE

The aim of this study was to determine the contribution of gastrointestinal motility to bowel function and the pathogenesis of pouchitis after ileal pouch-anal anastomosis.

METHODS

Gastrointestinal transit time was assessed by a radiopaque marker technique in 32 patients with ulcerative colitis.

RESULTS

Small intestinal transit time and pouch emptying time were 4.1 +/- 2 hours and 4.1 +/- 2.5 hours, respectively. There was no significant difference in pouch emptying time between patients with and without pouchitis. When only patients with acute pouchitis that responded to metronidazole were analyzed, there was a trend toward a prolonged pouch emptying time compared with those without pouchitis (P = 0.095). Whole gut transit time was inversely correlated with 24-hour stool frequency in patients without pouchitis (r = -0.63, P < 0.005). In the analysis of regional transit time, only small intestinal transit time was inversely correlated with 24-hour stool frequency (r = -0.472, P < 0.05). Significant prolongation of small intestinal transit time was demonstrated in patients over a period of 41 months (the median time) after ileostomy closure compared with those whose pouches had been functioning for 6 to 41 months (5.4 +/- 1.7 hours vs. 3.1 +/- 1.3 hours, P < 0.005).

CONCLUSIONS

There was an association between small intestinal motility and bowel frequency. Further investigation is necessary in the pathogenesis of acute pouchitis regarding the relationship between delayed pouch emptying and subsequent development of mucosal inflammation.

Expression of cytokines, inducible nitric oxide synthase, and matrix metalloproteinases in pouchitis: effects of probiotic treatment

OBJECTIVE

The efficacy of probiotic organisms in the treatment of pouchitis has been reported. In the present study, we evaluated the tissue levels of pro- and anti-inflammatory cytokines, nitric oxide synthase, and matrix metalloproteinases in control and inflamed pouches before and after antibiotic and probiotic treatment of patients with acute pouchitis.

METHODS

Pouch biopsy samples were obtained from seven patients with pouchitis before and after antibiotic and probiotic treatment. Tissue samples from five patients with normal pouches were used as controls. Cytokines were determined by ELISA, matrix metalloproteinase activity was evaluated by zymograms, and nitric oxide synthase activity was determined by measuring arginine to citrulline conversion.

RESULTS

Tissue levels of tumor necrosis factor a increased (p < 0.01) in pouchitis relative to uninflamed pouches and reduced after antibiotic and probiotic treatment. Also, interferon y and interleukin 1alpha (IL-1alpha) augmented in pouchitis, but their increase did not reach statistical significance. The latter, however, were lower (p < 0.05) after treatment with the antibiotics and probiotics. Tissue levels of IL-4 and IL-10 were unchanged in inflamed pouches and unaffected by antibiotic treatment. However, IL-10 increased (p < 0.05) after probiotic treatment. Moreover, inflamed pouches had higher levels of inducible nitric oxide synthase and gelatinase activities, which decreased after treatment.

CONCLUSIONS

The ability of antibiotic and probiotic treatments to increase tissue levels of IL-10, at a higher level than those observed in control pouches, and to decrease, to levels present in control pouches, proinflammatory cytokine, inducible nitric oxide synthase, and matrix metalloproteinase activity may suggest a mechanism of action to explain the efficacy of this therapeutic regime in pouchitis.

Endoscopic and histologic evaluation together with symptom assessment are required to diagnose pouchitis

BACKGROUND & AIMS

Pouchitis often is diagnosed based on symptoms alone. In this study, we evaluate whether symptoms correlate with endoscopic and histologic findings in patients with ulcerative colitis and an ileal pouch-anal anastomosis.

METHODS

Symptoms, endoscopy, and histology were assessed in 46 patients using Pouchitis Disease Activity Index (PDAI). Patients were classified as either having pouchitis (PDAI score > or =7; N = 22) or as not having pouchitis (PDAI score <7; N = 24).

RESULTS

Patients with pouchitis had significantly higher mean total PDAI scores, symptom scores, endoscopy scores, and histology scores. There was a similar magnitude of contribution of each component score to the total PDAI for the pouchitis group. Of note, 25% of patients with symptoms suggestive of pouchitis did not meet the PDAI diagnostic criteria for pouchitis. In both groups, the correlation coefficients between symptom, endoscopy, and histology scores were near zero (range, -0.26 to 0.20; P > 0.05).

CONCLUSIONS

The symptom, endoscopy, and histology scores each contribute to the PDAI and appear to be independent of each other. Symptoms alone do not reliably diagnose pouchitis.

Long-term follow-up after ileoanal pouch procedure: algorithm for diagnosis, classification, and management of pouchitis

PURPOSE

Inflammation of the ileoanal pouch (pouchitis) is one of the main complications after restorative proctocolectomy, yet its cause remains poorly understood. A standardized definition and diagnostic procedures in pouchitis are lacking.

METHOD

We analyzed all cases of pouchitis occurring in a group of 308 patients (210 with ulcerative colitis, 98 with familial adenomatous polyposis) who took part in a prospective long-term follow-up program. The severity of pouchitis was measured using a pouchitis activity score (Heidelberg Pouchitis Activity Score). An algorithm for the classification and management of pouchitis was established which enables the clinician: 1) to determine the severity of pouchitis, 2) to differentiate between primary pouchitis and pouchitis caused by surgical complications (secondary pouchitis), and 3) to evaluate the course (acute vs. chronic (> 3 months)).

RESULTS

The median duration of follow-up was 48 (range, 13-119) months. At least one episode of pouchitis was diagnosed in 29 percent of patients with ulcerative colitis and in 2 percent of familial adenomatous polyposis patients. Secondary pouchitis occurred in 6 percent of ulcerative colitis patients and was cured by surgical treatment in 13 (87 percent) of 15 cases. Primary pouchitis was diagnosed in 23 percent of ulcerative colitis patients, including 6 percent of all ulcerative colitis patients with chronic primary pouchitis. The latter showed poor response to medical treatment. In one case multifocal high-grade dysplasia occurred. Histologic examination of the excised pouch identified a carcinoma originating from the ileal mucosa.

CONCLUSIONS

Ulcerative colitis patients after restorative proctocolectomy face a high risk of developing pouchitis. The algorithm used in this study was highly efficient in identifying patients with a secondary pouchitis who require surgical treatment and patients with chronic primary pouchitis. For the latter, long-term surveillance seems mandatory because of the risk of malignant transformation of the pouch mucosa.

Simple gas chromatography analysis of faecal butyrate: application to patients at risk of pouchitis

In spite of the fact that pouchitis is the most frequently occurring and troublesome complication found in patients treated by ileo-anal anastomosis for ulcerative colitis, no biological marker currently exists to monitor the outcome of the disease. Since it has been noted faecal butyrate is reduced in patients with pouchitis, we developed a simple gas chromatography method to quantify butyrate in faecal water. This test is based on diethyl ether extraction with the use of methacrylic acid as an internal standard. We demonstrated that butyrate was effectively measured when this technique was applied to eleven patients with ileal-pouch anal anastomosis within the first year after the closure of their ileostomy. We also observed a noticeable reduction in the concentration of butyrate in patients who went on to develop a pouchitis.

Histological and macroscopic changes in the pelvic pouch: long-term follow up after restorative proctocolectomy for ulcerative colitis (UC)

OBJECTIVE

Our aim was to evaluate macroscopic and histological (inflammatory) changes in ileal pouch mucosa after restorative proctocolectomy with J-pouch-ileoanal anastomosis for UC during long-term follow up.

PATIENTS AND METHODS

Thirty-six (56%) out of 64 consecutive patients operated at our Institute during 1985-90 underwent endoscopy of the reservoir in the years 1994 and 1998. Functional outcome and macroscopic changes were recorded and histological samples taken from the three levels of the pelvic pouch. Acute and chronic inflammation were graded in accordance with a well-established histopathologic scoring system.

RESULTS

The functional outcome was unchanged in 26 (72%), became worse in eight (22%) and better in two (6%) cases during follow up. The number of macroscopic changes increased during follow up and there was a tendency for them to become more common in the distal pouch. Microscopic acute and chronic inflammation decreased during follow up. There were more severe inflammatory changes in the distal pouch. Both acute and chronic inflammatory scores were higher through the reservoir in the cases of chronic pouchitis. Chronic pouchitis occurred more often in males.

CONCLUSION

Macroscopic and inflammatory changes in the pelvic pouch seem to have separate progress during long-term follow up. In chronic pouchitis both acute and chronic inflammation are pronounced and spread over the entire pelvic pouch mucosa.

Functional and morphologic changes of the ileal mucosa after ileoanal pouch procedure

BACKGROUND

Restorative proctocolectomy is used widely for treatment of ulcerative colitis and familial polyposis coli. Limited information is available regarding the morphologic and functional adaptation of the mucosa in a functioning ileoanal pouch.

STUDY DESIGN

Ileal pouch specimens from patients who underwent pouch reconstruction (mean 7.5 years postcolectomy, n = 12) were compared with normal ileum (n = 15) and normal colon (n = 5). Amino-oligopeptidase (AOP) and maltase activity were measured as parameters of normal ileal function. Histologic samples were examined for the presence of neutrophils and plasma cells, the villus to crypt height ratio, and the degree of crypt hyperplasia, villus blunting, and goblet cell mass. Data were analyzed by analysis of variance.

RESULTS

The AOP activity in the normal ileum was 73 +/- 32 units of enzymatic activity per gram of mucosal protein; the AOP activities of the pouch and colon were 21 +/- 22 and 16 +/- 10, respectively. The maltase activity of the normal ileum measured 254 +/- 116 units of enzymatic activity per gram of mucosal protein, and the maltase activities of the pouch and colon were 57 +/- 71 units and 29 +/- 25 units, respectively. The ileal pouch mucosa demonstrated little acute inflammation and varying degrees of chronic inflammation. Morphologically, the ileal pouch mucosa demonstrated a range of adaptations, including villus blunting and crypt hyperplasia. Several specimens contained immature epithelial cells.

CONCLUSIONS

The AOP and maltase activities in mucosa from ileoanal pouches and colon were significantly lower than those in normal ileal mucosa. Ileoanal pouch mucosa from humans undergoes adaptive changes to resemble colonic mucosa both morphologically and functionally.

Bile acid metabolism, bacterial bowel flora and intestinal function following ileal pouch-anal anastomosis in dogs, with reference to the influence of administration of ursodeoxycholic acid

The pathophysiology following a total colectomy with ileal pouch-anal anastomosis (IPAA) has not been sufficiently clarified yet. We investigated bile acid metabolism, bacterial bowel flora and transit of the alimentary tract after IPAA, with reference to administration of ursodeoxycholic acid (UDCA) in dogs undergoing IPAA. Ten adult beagle dogs underwent IPAA at one stage, and were observed for 12 months. UDCA (100 mg/day) was administered orally to five dogs, and the other five did not. In the UDCA(+) group, UDCA replaced other bile acids, especially cholic acid, accounting for 16.5% of gallbladder bile at 12 months after surgery. Both plasma levels and postprandial increase of total bile acids remained unchanged in the UDCA(+) group, but decreased in the UDCA(-) group at 12 months. Fecal excretion of bile acids tended to be smaller in the UDCA(+) group, and the ratio of secondary to primary bile acids was larger in the UDCA(-) group. Almost all the bile acids were in free form in stool, and UDCA constituted 19% in the UDCA(+) group. The transit time of the whole alimentary tract was elongated by administering UDCA, especially at an early period after IPAA. Although both anaerobic and aerobic bacteria decreased after IPAA, the latter decreased more in stool, resulting in an increase in the ratio of total anaerobes/total aerobes, especially in the UDCA(-) group. The decrease in Bacteroidaceae and Lactobacillus after IPAA was slightly smaller in the UDCA(+) group. Administration of UDCA following IPAA was efficient to induce rapid intestinal adaptation and also to keep the bile acid fraction in the ileal pouch less harmful.

Pouchitis: extracolonic manifestation of ulcerative colitis?

Pouchitis is the most frequent complication of ileal pouch-anal anastomosis for treatment of ulcerative colitis. There are several possible explanations. Among them, we focus on the one that considers pouchitis as an extracolonic manifestation of ulcerative colitis. The aim of this study was to investigate the association between pouchitis and extra-intestinal manifestations (EIM), which are frequent in these patients. Sixty patients underwent restorative proctocolectomy with an ileal J pouch (IPAA) from September 1984 to December 1998. Pouchitis was defined by clinical, endoscopic, and histologic criteria. The following extra-intestinal manifestations were studied: articular, cutaneous, hepatobiliary, ocular, genitourinary, and growth failure. Thirteen patients, of which 10 were female (76.9%), developed one or more episodes of pouchitis. Twelve patients of this group (92.3%) presented some kind of extra-intestinal manifestation, 4 pre-operatively (exclusively), 2 post-operatively (exclusively), and 6 both pre- and post-operatively (1.7 per patient). Twenty patients (42.7%) of the 47 without pouchitis did not present extra-intestinal manifestations; 10/35 (28. 5%) of females had pouchitis, compared to 3/35 (12.0%) of men. Pouchitis was more frequent among females, though not statistically significant. EIM increases the risk of pouchitis. Pouchitis is related to EIM in 92.3 % of cases, corroborating the hypothesis that it could be an extracolonic manifestation of ulcerative colitis.

Surgical therapy for ulcerative colitis and Crohn's disease

Over the past 2 decades there has been considerable progress in the surgical management of inflammatory bowel disease. Crohn's disease is a chronic, nonspecific inflammatory disease of the gastrointestinal tract of unknown cause. It involves mainly the ileum, colon, and rectum, most often producing symptoms of obstruction or localized perforation with fistula. Although surgical treatment is palliative, operative excision in combination with strictureplasty, where appropriate, provides effective symptomatic relief and reasonable long-term benefit. Chronic ulcerative colitis is a diffuse inflammatory disease of the mucosal lining of the colon and rectum. Total removal of the colon and rectum provides a complete cure. Newer surgical alternatives, developed over the last 2 decades, have eliminated the need for a permanent ileostomy following definitive resection of the involved colon and rectum.

The physiology of ileo-anal pouch function

Even excellent clinical function after ileo-anal pouch construction is associated with a variety of physiological abnormalities. Small bowel intestinal motility is essentially normal but the ileal reservoir serves to markedly suppress the ileal motor response both to progressive distension by intestinal contents and to transmitted myoelectrical complexes. As a result, the healthy pouch can accommodate a large volume of intestinal content before the rising baseline pressure and the appearance of large isolated contraction waves produce an urge to defecate. Evacuation in the normal pouch patient is rapid and highly efficient and is achieved by means of the Valsalva maneuver without any evidence of significant intestinal propulsion. External anal sphincter function is fully preserved but internal anal sphincter function is significantly impaired in the immediate postoperative period. Recovery occurs over the next 6 to 12 months but is often incomplete. Bacterial overgrowth in the pouch and prepouch ileum is almost universal and results in the premature deconjugation of primary bile salts and accumulation of secondary bile salts within the pouch. These produce morphologic changes in the ileal mucosa, and their excretion in pouch effluent gradually depletes the bile salt pool. Anerobic organisms also bind with vitamin B12 and the vitamin B12-intrinsic factor complex, resulting in subtle but measurable reductions in vitamin B12 levels in pouch patients. Finally, anerobic fermentation of mucus and undigested carbohydrate results in excessive quantities of short chain fatty acids within the pouch lumen. The clinical significance of these substances is unclear, but they may have an adverse action on both ileal mucosal and smooth muscle function. In essence, however, the pouch surgeon can maximize the likelihood of good clinical function by constructing a large capacity pouch, by avoiding surgery in patients with clearly deficient anal sphincter mechanisms, and by careful attention to pouch-anal anastomotic technique.

Prospective study of morphologic and functional changes with time in the mucosa of the ileoanal pouch: functional appraisal using transmucosal potential differences

PURPOSE

This study was undertaken to investigate the morphologic and functional changes with time in the mucosa of the ileoanal pouch.

METHODS

A morphologic study by histopathologic analysis, mucosal morphometry, and mucin histochemistry and a functional study by analysis of transmucosal potential difference were performed in 27 patients with an ileoanal J-pouch after restorative proctocolectomy for ulcerative colitis. In 19 patients with a normal ileoanal pouch, two prospective follow-up analyses were performed after median functional pouch times of 14 and 39 months. We also evaluated eight patients with the diagnosis of pouchitis (median follow-up, 52.5 months).

RESULTS

In the normal ileoanal pouch group, some degree of chronic and acute inflammatory infiltration was identified in 100 percent and 63.2 percent of cases, respectively, with no significant differences being observed between the two follow-up analyses. The mean villous atrophy index at the first and second follow-up was 0.54 and 0.52, respectively, significantly lower (P < 0.001; an indication of a greater degree of villous atrophy) than the value obtained from the control group with a healthy terminal ileum (0.77). The group of patients with pouchitis exhibited statistically significant differences in the degree of acute and chronic inflammatory infiltration, the extent of ulceration, the crypt depth, and the villous atrophy index, compared with patients without pouchitis. In the normal ileoanal pouch group, the median percentage of sulfomucin with each degree of atrophy (1=mild; 2=moderate; and 3=severe) was 2.6, 4.5, and 20.9 percent, respectively. In patients with pouchitis, the median percentage of sulfomucin was 5.9 percent. The mean transmucosal potential difference at the first follow-up (-25.3 mV) was significantly lower (P=0.001) than at the second (-30.4 mV). Significant differences were apparent with respect to both the normal ileum (-8.9 mV) and the normal rectum (-40.2 mV).

CONCLUSION

These results suggest that the ileal pouch behaves as a neorectum, with different degrees of colonic metaplasia from a morphologic and a functional perspective.

Metabolic substrate utilization differs in ileal faecal and urinary reservoirs

BACKGROUND

Construction of an ileal faecal or urinary reservoir profoundly alters ileal luminal ecology and availability of mucosal metabolic substrates. The aims of this study were to measure mucosal metabolic flux of butyrate and glutamine in histologically normal (control) ileum and to determine the effect of reservoir construction on metabolic fluxes in patients with ileal pouch-anal anastomosis and ileocystoplasty.

METHODS

Endoscopic biopsy samples were obtained from normal ileum (n = 10), ileum of patients with ulcerative colitis (n = 10), ileal pouch-anal anastomosis (n = 7), ileocystoplasty (n = 7) and ileal conduit (n = 7). Using a closed microculture technique, biopsy utilization of 14C-labelled butyrate and glutamine was measured as [14C]carbon dioxide production. Biopsy DNA content was measured and [14C]carbon dioxide evolution expressed as picomoles [14C]carbon dioxide per microgram DNA per hour.

RESULTS

The metabolic flux of both butyrate and glutamine was reduced in ileal pouch mucosa compared with that of ileal mucosa in patients with ulcerative colitis. In contrast, the metabolic flux of buyrate alone was reduced in ileal mucosa from ileocystoplasty and ileal conduit compared with that in normal ileal mucosa, while the metabolic flux of glutamine remained unchanged.

CONCLUSION

Ileal mucosal metabolic fluxes measured in vitro are altered by changing luminal ecology in vivo. These changes may affect the health and mucosal integrity of ileum used to construct these reservoirs.

Pouchitis

Pouchitis is a major long-term complication of the continent ileostomy as well as the ileoanal pouch anastomosis. When diagnosed on the basis of clinical, endoscopic and histologic features, this syndrome has been demonstrated almost exclusively in patients with ulcerative colitis. The clinical course, the endoscopic findings and the histologic abnormalities resemble those of ulcerative colitis. The association with extra-intestinal manifestations further supports the hypothesis that pouchitis represents ulcerative colitis in the small bowel. All ileal reservoirs show bacterial overgrowth, especially of anaerobes. As a response to this altered intraluminal environment chronic inflammation and incomplete colonic metaplasia occur. The efficiency of metronidazole does suggest that bacteriological factors play an important role in the pathogenesis of pouchitis.

Crohn's-like complications in patients with ulcerative colitis after total proctocolectomy and ileal pouch-anal anastomosis

Total proctocolectomy with ileal pouch-anal anastomosis (IPAA) has become an established surgical procedure for ulcerative colitis. Occasional patients who have undergone IPAA develop persistent or recurrent episodes of pouchitis (chronic pouchitis), from which a subset also develop gastrointestinal and systemic complications that are identical to those seen in Crohn's disease. These complications include enteric stenoses or fistulas in the pouch or pouch inlet segment, perianal fistulas or abscesses, pouch fistulas, arthritis, iridocyclitis, and pyoderma gangrenosum. The development of Crohn's-like gastrointestinal complications in a patient with chronic pouchitis frequently engenders concern that the pathologist misinterpreted the proctocolectomy specimen as ulcerative colitis instead of Crohn's disease. We describe eight patients who developed chronic pouchitis and Crohn's-like complications after IPAA and total proctocolectomy. In each case, concern was voiced about misinterpretation of the proctocolectomy specimen as ulcerative colitis instead of Crohn's disease after the development of the Crohn's-like complications. Preoperatively, all eight patients had characteristic clinical, radiographic, and pathologic features of ulcerative colitis. Review of the pathology specimens indicated that all eight had ulcerative colitis. Crohn's-like complications are most likely related to chronic pouchitis, which probably is a form of recrudescent ulcerative colitis within the novel environment of the pouch. A diagnosis of Crohn's disease after IPAA surgery should only be made when reexamination of the original proctocolectomy specimen shows typical pathologic features of Crohn's disease, Crohn's disease arises in parts of the gastrointestinal tract distant from the pouch, pouch biopsies contain active enteritis with granulomas, or excised pouches show the characteristic features of Crohn's disease, including granulomas. There were no histologic differences in the total colectomy specimens between the eight ulcerative colitis study patients and 16 control ulcerative colitis patients who had a favorable clinical outcome after IPAA surgery groups. Crohn's-like complications and chronic pouchitis does not necessarily imply an incorrect original interpretation of ulcerative colitis by the pathologist.

Influence of bacterial overgrowth and intestinal inflammation on duration of parenteral nutrition in children with short bowel syndrome

OBJECTIVES

Massive intestinal resection results in short bowel syndrome and necessitates prolonged parenteral feeding. The purpose of this work was to assess the impact of late complications of short bowel syndrome, including intestinal bacterial overgrowth and enterocolitis, on the duration of parenteral nutrition (PN) in comparison with factors evident in the neonatal period.

METHODS

Retrospective chart review.

RESULTS

Of 49 children, 42 were weaned from parenteral nutrition after a treatment course of 17 +/- 14 months. In these 42, postresection small intestinal length equaled 81 +/- 65 cm; 45% had an ileocecal valve. Small intestinal length in the seven children who were PN dependent was 31 +/- 30 cm (p < 0.05); none had an ileocecal valve (p < 0.05). Bacterial overgrowth occurred in all seven PN-dependent children and in 23 of 42 children eventually weaned from PN (p < 0.05). When bacterial overgrowth was identified before weaning (n = 12), the duration pf PN was 28 +/- 17 months, but when bacterial overgrowth was first identified only after weaning (n = 11), the duration of PN was 16 +/- 13 months (p < 0.05). Small intestinal inflammation correlated with bacterial overgrowth (r = 0.69). Those children with severe enteritis identified before weaning remained on the PN regimen for 36 +/- 15 months, in comparison with 21 +/- 14 months in those with mild enteritis and 13 +/- 11 months in those without inflammation (p < 0.02).

CONCLUSIONS

Although the length of small intestine remaining after resection is the best immediate predictor of final success in terminating PN in children with short bowel syndrome, PN is prolonged by bacterial overgrowth and associated enteritis in those who will ultimately be weaned.

Ileal pouches: adaptation and inflammation

Ileal pouch-anal anastomosis (IPAA) has become the operation of choice following proctocolectomy for ulcerative colitis (UC) and familial adenomatous polyposis. Functioning ileal pouch mucosa undergoes histological changes resembling the colon (colonic metaplasia). The possible role of stasis and luminal factors--bile acids, short-chain fatty acids and bacteria--are discussed. It seems likely that colonic metaplasia is an adaptive response to the new luminal environment in IPAA. Inflammation in the ileal reservoir ('pouchitis') is the most significant late complication in IPAA. It occurs in 20-30% of patients and is virtually confined to those with prior UC. The clinical picture in pouchitis is highly variable; however, it can be easily categorized into three groups. Nevertheless, in most cases it is likely to represent recurrent UC in the ileal pouch. Current treatments and possible preventative strategies for pouchitis have been outlined.