Incidence and prevalence of pouchitis

Pouchitis significantly affects patients’ quality of life and long-term surgical outcome. Reported cumulative frequencies of pouchitis 10 to 11 years after IPAA surgery range from 23% to 46%. It is estimated that approximately 50% of patients who have undergone IPAA surgery for UC develop at least 1 episode of pouchitis. The estimated incidence within the first 12 months after ileostomy closure was as high as 40%, as reported in a clinical trial. In patients with pouchitis, 70% had the initial episode during the first 12 months after ileostomy closure. As the incidence of inflammatory bowel disease (IBD), including UC, seems to be increasing, the authors expect a growing number of patients with pouchitis or other pouch disorders in clinical practice.

Etiology and pathogenesis of pouchitis

Pouchitis occurs almost exclusively in patients with underlying UC, not in patients with FAP who undergo the same surgical procedure. It is generally believed that pouchitis results from alternations in luminal microflora (ie, dysbiosis), leading to abnormal mucosal immune response in genetically susceptible hosts. Attempts have been made to identify true pathogenic microbes. In a subset of patients with pouchitis, pathogenic factors may be identified. A recent study showed that 18% of patients seen in a specialty pouchitis clinic tested positive for Clostridium difficile toxins A or B. Cytomegalovirus (CMV) and fungi (such as Candida albicans ) have also been implicated in pouchitis, particularly in patients with chronic antibiotic-refractory pouchitis.

Although microbiological investigation of the bacterial communities in the gut failed to demonstrate consistently the existence of pathogens in pouchitis, a large body of evidence suggests that alteration in the bacteria community, ie, dysbiosis, of the human gut likely plays a key role in the initiation and development of pouchitis. In a culture-based study of fecal specimens in patients with UC pouches or FAP pouches, viable sulfate-reducing bacteria were exclusively detected in pouches of UC patients, but not in patients with FAP. Sulfate-reducing bacteria were detected in higher numbers in active pouchitis than in those without a history of pouchitis, past episode(s) of pouchitis, or on antibiotic therapy, and in patients with FAP. This particular group of bacteria was sensitive to antibiotic treatment. Gosselink and colleagues analyzed bacteria content at the episode of pouchitis before and during treatment with ciprofloxacin or metronidazole, and during pouchitis-free periods, and found that, in the absence of inflammation, the pouch microbiota was characterized by the presence of Lactobacilli and large numbers of anaerobes. During pouchitis episodes, there was a decreased number of anaerobes, an increased number of aerobic bacteria, lower numbers of Lactobacilli , and higher numbers of Clostridium perfringens . In addition, hemolytic strains of Escherichia coli were observed. Administration of metronidazole was shown to eradicate anaerobic microbiota including C perfringens , whereas treatment with ciprofloxacin inhibited the growth of C perfringens and that of coliforms, including hemolytic strains of E coli .

Advances in molecular microbiology with 16S ribosomal RNA techniques have provided a cornerstone of microbial taxonomy and made the assay of bacterial composition in the gut community possible. In a case study, mucosa-associated bacteria of the pouch were assayed using tissue biopsy samples at the time of colectomy, pouch construction, ileostomy closure, and postoperative routine pouch examination at 1, 3, and 12 months after ileostomy closure. The pouch microbiota were similar to the normal colon microbiota except for the presence of clones with sequences resembling those of the C perfringens group and Turicibacter . The bacterial composition differed between the 2 patients studied and the microbiota changed with time, suggesting that the composition is not stable during the first year of ileostomy closure. Komanduri and colleagues studied pouch biopsy specimens from 5 patients with active pouchitis and 15 patients with normal pouches, using a fingerprinting technique. The study showed mucosa-associated microbiota patterns unique to each individual. Moreover, specific bacterial amplicons were unique to active pouchitis mucosa: clostridial cluster XIVa, Enterobacteriaceae, and Streptococci were associated with control pouches. The persistence of Fusobacter and enteric species associated with the disease state was also shown.

Alterations in innate and adaptive mucosal immunity in the pouch and pouchitis have been reported. An increased bacterial permeability was associated with duration of having a pouch with mucosal adaptive changes in an ex vivo study. UC patients with backwash ileitis were shown to have impaired barrier function in the future course of the IPAA. Toll-like receptors (TLR) serve an important immune and nonimmune function in human intestinal epithelial cells (IEC) by binding microbial signature molecules and triggering innate and adaptive immune responses on stimulation. TLRs comprise a defense line against invading pathogens challenging the IEC layer. TLRs can trigger the secretion of antibacterial peptides, and also link innate and adaptive immune responses of the intestinal mucosa by attracting immune cells from the lamina propria. An aberrant TLR expression pattern has been found in IBD. An immunohistochemical study showed that TLR2 expression is up-regulated in pouchitis and TLR4 expression is increased in the normal pouch and in pouchitis compared with the normal ileum. Alterations in mRNA levels of TLR3 and TLR5 were present. TLR3 expression was decreased significantly, whereas TLR5 expression was increased significantly in normal pouch mucosa compared with normal ileal mucosa. A combined carriership of the TLR9-1237C and CD14-260T allele seemed to be associated with development of chronic pouchitis.

Antimicrobial peptides produced from Paneth cells and other gut epithelial cells are an important component of innate immunity in the intestinal tract. Paneth cells synthesize and secrete several antimicrobial peptides, including lysozyme, secretory phospholipase 2, and human α-defensins 5 and 6 (HD5 and HD6). The copy number of HD5 mRNA was significantly decreased in the inflamed or noninflamed pouch compared with the normal terminal ileum. Tissue mRNA copies of HD5 produced by Paneth cells and β (hBD-1, 2, 3)-defensins produced by gut epithelial cells were increased in UC and FAP pouches immediately after surgery, compared with ileum of controls. Initially, α- and β-defensin mRNAs were higher in UC pouches than in FAP pouches. However, the defensin expression declined in UC and FAP pouch groups and increased again slightly in pouchitis in patients with UC. FAP pouches without pouchitis had strong expression of hBD-1, whereas all other defensins remained at low levels.

As in IBD, adaptive immune mechanisms for pouchitis have been extensively studied. For example, proliferation of immature plasma cells was increased in pouchitis. Proinflammatory cytokines, such as tumor necrosing factor-α, are released mostly in the inflamed mucosa by macrophages and monocytes, leading to tissue injury, and are considered to be involved as a secondary pathophysiologic mechanism in pouchitis. The production of inflammatory mediators is increased including proinflammatory cytokines, cell adhesion molecules, platelet-activating factor, lipoxygenase products of arachidonic acids, vascular endothelial growth factor, proinflammatory neuropeptides, and other mediators. In general, UC pouches expressed higher levels of inflammatory cytokines than FAP pouches. Abnormalities in immunoregulatory cytokines such as IL-2, interferon-γ, IL-4, and IL-10 are also observed in pouchitis. Imbalance between proinflammatory and immunoregulatory cytokines has been described in patients with pouchitis. However, it is likely that those abnormalities in mucosal adaptive immunity reflect activation of nonspecific inflammatory cascade.

The natural history of pouchitis may mimic that of UC, starting from an acute disease process of bacterial etiology to chronic disease of persistent inflammation. There are similarities in clinical presentations and immunologic abnormalities between chronic pouchitis and UC. The presence of fecal stasis in the pouch, exposure to fecal contents, and an increased microbial load of the pouch epithelia may result in inflammatory changes leading to morphologic alterations in the ileal pouch mucosa mimicking the colon epithelia in UC, namely colonic metaplasia. Colonic metaplasia, characterized by villous blunting, crypt cell hyperplasia, and colon epithelium-specific antigens such as human tropomyosin 5, may be associated with UC-like clinical presentations. Colonic metaplasia seems to be associated with dysbiosis, particularly the presence of sulfate-reducing bacteria. It has been reported that mucosal butyrate oxidation in pouchitis is similar to the findings in UC. An alteration in mucin glycoproteins occurs in pouchitis similar to that seen in UC. It is possible that the altered glycoproteins are more susceptible to enzymatic degradation by bacteria, making the mucus barrier less effective.

Etiology and pathogenesis of pouchitis

Pouchitis occurs almost exclusively in patients with underlying UC, not in patients with FAP who undergo the same surgical procedure. It is generally believed that pouchitis results from alternations in luminal microflora (ie, dysbiosis), leading to abnormal mucosal immune response in genetically susceptible hosts. Attempts have been made to identify true pathogenic microbes. In a subset of patients with pouchitis, pathogenic factors may be identified. A recent study showed that 18% of patients seen in a specialty pouchitis clinic tested positive for Clostridium difficile toxins A or B. Cytomegalovirus (CMV) and fungi (such as Candida albicans ) have also been implicated in pouchitis, particularly in patients with chronic antibiotic-refractory pouchitis.

Although microbiological investigation of the bacterial communities in the gut failed to demonstrate consistently the existence of pathogens in pouchitis, a large body of evidence suggests that alteration in the bacteria community, ie, dysbiosis, of the human gut likely plays a key role in the initiation and development of pouchitis. In a culture-based study of fecal specimens in patients with UC pouches or FAP pouches, viable sulfate-reducing bacteria were exclusively detected in pouches of UC patients, but not in patients with FAP. Sulfate-reducing bacteria were detected in higher numbers in active pouchitis than in those without a history of pouchitis, past episode(s) of pouchitis, or on antibiotic therapy, and in patients with FAP. This particular group of bacteria was sensitive to antibiotic treatment. Gosselink and colleagues analyzed bacteria content at the episode of pouchitis before and during treatment with ciprofloxacin or metronidazole, and during pouchitis-free periods, and found that, in the absence of inflammation, the pouch microbiota was characterized by the presence of Lactobacilli and large numbers of anaerobes. During pouchitis episodes, there was a decreased number of anaerobes, an increased number of aerobic bacteria, lower numbers of Lactobacilli , and higher numbers of Clostridium perfringens . In addition, hemolytic strains of Escherichia coli were observed. Administration of metronidazole was shown to eradicate anaerobic microbiota including C perfringens , whereas treatment with ciprofloxacin inhibited the growth of C perfringens and that of coliforms, including hemolytic strains of E coli .

Advances in molecular microbiology with 16S ribosomal RNA techniques have provided a cornerstone of microbial taxonomy and made the assay of bacterial composition in the gut community possible. In a case study, mucosa-associated bacteria of the pouch were assayed using tissue biopsy samples at the time of colectomy, pouch construction, ileostomy closure, and postoperative routine pouch examination at 1, 3, and 12 months after ileostomy closure. The pouch microbiota were similar to the normal colon microbiota except for the presence of clones with sequences resembling those of the C perfringens group and Turicibacter . The bacterial composition differed between the 2 patients studied and the microbiota changed with time, suggesting that the composition is not stable during the first year of ileostomy closure. Komanduri and colleagues studied pouch biopsy specimens from 5 patients with active pouchitis and 15 patients with normal pouches, using a fingerprinting technique. The study showed mucosa-associated microbiota patterns unique to each individual. Moreover, specific bacterial amplicons were unique to active pouchitis mucosa: clostridial cluster XIVa, Enterobacteriaceae, and Streptococci were associated with control pouches. The persistence of Fusobacter and enteric species associated with the disease state was also shown.

Alterations in innate and adaptive mucosal immunity in the pouch and pouchitis have been reported. An increased bacterial permeability was associated with duration of having a pouch with mucosal adaptive changes in an ex vivo study. UC patients with backwash ileitis were shown to have impaired barrier function in the future course of the IPAA. Toll-like receptors (TLR) serve an important immune and nonimmune function in human intestinal epithelial cells (IEC) by binding microbial signature molecules and triggering innate and adaptive immune responses on stimulation. TLRs comprise a defense line against invading pathogens challenging the IEC layer. TLRs can trigger the secretion of antibacterial peptides, and also link innate and adaptive immune responses of the intestinal mucosa by attracting immune cells from the lamina propria. An aberrant TLR expression pattern has been found in IBD. An immunohistochemical study showed that TLR2 expression is up-regulated in pouchitis and TLR4 expression is increased in the normal pouch and in pouchitis compared with the normal ileum. Alterations in mRNA levels of TLR3 and TLR5 were present. TLR3 expression was decreased significantly, whereas TLR5 expression was increased significantly in normal pouch mucosa compared with normal ileal mucosa. A combined carriership of the TLR9-1237C and CD14-260T allele seemed to be associated with development of chronic pouchitis.

Antimicrobial peptides produced from Paneth cells and other gut epithelial cells are an important component of innate immunity in the intestinal tract. Paneth cells synthesize and secrete several antimicrobial peptides, including lysozyme, secretory phospholipase 2, and human α-defensins 5 and 6 (HD5 and HD6). The copy number of HD5 mRNA was significantly decreased in the inflamed or noninflamed pouch compared with the normal terminal ileum. Tissue mRNA copies of HD5 produced by Paneth cells and β (hBD-1, 2, 3)-defensins produced by gut epithelial cells were increased in UC and FAP pouches immediately after surgery, compared with ileum of controls. Initially, α- and β-defensin mRNAs were higher in UC pouches than in FAP pouches. However, the defensin expression declined in UC and FAP pouch groups and increased again slightly in pouchitis in patients with UC. FAP pouches without pouchitis had strong expression of hBD-1, whereas all other defensins remained at low levels.

As in IBD, adaptive immune mechanisms for pouchitis have been extensively studied. For example, proliferation of immature plasma cells was increased in pouchitis. Proinflammatory cytokines, such as tumor necrosing factor-α, are released mostly in the inflamed mucosa by macrophages and monocytes, leading to tissue injury, and are considered to be involved as a secondary pathophysiologic mechanism in pouchitis. The production of inflammatory mediators is increased including proinflammatory cytokines, cell adhesion molecules, platelet-activating factor, lipoxygenase products of arachidonic acids, vascular endothelial growth factor, proinflammatory neuropeptides, and other mediators. In general, UC pouches expressed higher levels of inflammatory cytokines than FAP pouches. Abnormalities in immunoregulatory cytokines such as IL-2, interferon-γ, IL-4, and IL-10 are also observed in pouchitis. Imbalance between proinflammatory and immunoregulatory cytokines has been described in patients with pouchitis. However, it is likely that those abnormalities in mucosal adaptive immunity reflect activation of nonspecific inflammatory cascade.

The natural history of pouchitis may mimic that of UC, starting from an acute disease process of bacterial etiology to chronic disease of persistent inflammation. There are similarities in clinical presentations and immunologic abnormalities between chronic pouchitis and UC. The presence of fecal stasis in the pouch, exposure to fecal contents, and an increased microbial load of the pouch epithelia may result in inflammatory changes leading to morphologic alterations in the ileal pouch mucosa mimicking the colon epithelia in UC, namely colonic metaplasia. Colonic metaplasia, characterized by villous blunting, crypt cell hyperplasia, and colon epithelium-specific antigens such as human tropomyosin 5, may be associated with UC-like clinical presentations. Colonic metaplasia seems to be associated with dysbiosis, particularly the presence of sulfate-reducing bacteria. It has been reported that mucosal butyrate oxidation in pouchitis is similar to the findings in UC. An alteration in mucin glycoproteins occurs in pouchitis similar to that seen in UC. It is possible that the altered glycoproteins are more susceptible to enzymatic degradation by bacteria, making the mucus barrier less effective.

Risk factors for pouchitis

Factors associated with pouchitis have been studied extensively as part of the investigation of the etiology and pathogenesis of pouchitis. In addition, the identification of risk factors may have a direct impact on disease prevention and prognostication. Immunogenetic studies showed that genetic polymorphisms, such as those of the IL-1 receptor antagonist and NOD2/CARD15, may increase the risk for pouchitis. Other reported risk factors include extensive UC, the presence of backwash ileitis, precolectomy thrombocytosis, the presence of concurrent primary sclerosing cholangitis (PSC) or arthralgia/arthropathy, seropositive perinuclear antineutrophil cytoplasmic antibodies (pANCA) or anti-CBir1 flagellin, being a nonsmoker, and the use of nonsteroidal anti-inflammatory drugs (NSAID). Acute antibiotic-responsive pouchitis and chronic antibiotic-refractory pouchitis may represent different disease processes associated with different etiopathogenetic pathways. As such, acute and chronic pouchitis may be associated with different risk factors. In a recent study of 238 patients with different phenotypes of pouchitis, antibiotic-responsive pouchitis developed in 37 pANCA-positive patients (22%) versus 6 pANCA-negative patients (9%), and in 12 anti-CBir1–positive patients (26%) versus 31 anti-CBir1–negative patients (16%) during a median of 47 months of follow-up. In one report, patients with backwash ileitis or PSC were associated with chronic pouchitis, but not with acute pouchitis. Smoking was associated with acute pouchitis, whereas extraintestinal manifestations, preoperative thrombocytosis, a long duration of IPAA, and postoperative surgery-related complications were reported to be associated with chronic pouchitis. Smoking seems to be protective against the development of chronic pouchitis. These findings suggest that chronic pouchitis and UC may share similar pathogenetic pathways, as smoking has also been shown to be protective against progression of UC. Patients with chronic antibiotic-refractory pouchitis, not acute pouchitis, were associated with concurrent autoimmune disorders.

Concurrent PSC is associated with an increased risk for backwash ileitis in patient with UC. Furthermore, the prevalence of PSC among patients with UC needing proctocolectomy was higher than in patients with UC in general. Although PSC seems to be a risk factor for pouchitis, particularly chronic pouchitis, orthotopic liver transplantation together with post-transplant use of immunosuppressive agents seems not to have a detrimental impact on the disease course of pouchitis.

There have been discrepancies in the literature in reported risk factors associated with pouchitis. With regard to inconsistency in the reported risk factors, there were intrainstitutional and interinstitutional variations. These variations could largely be due to the difference in study design, sample size, diagnostic criteria used for pouchitis, referral pattern, and statistical methods.

Diagnosis of pouchitis

Diagnosis of pouchitis is not always straightforward, because there are no specific symptoms and signs. Patients with pouchitis have a wide range of clinical presentations, ranging from increased stool frequency, urgency, incontinence, night-time seepage, to abdominal perianal discomfort. These symptoms, however, can be present in other inflammatory and noninflammatory disorders of the pouch, such as cuffitis, CD of the pouch, and irritable pouch syndrome. Therefore, the diagnosis of pouchitis should not be solely dependent on symptom assessment. In addition, severity of symptoms does not necessarily correlate with the degree of endoscopic or histologic inflammation of the pouch. To complicate the matter even more, the diagnosis of pouch disorders can resemble hitting a moving target, as the disease process may not be static. For example, a patient may have typical pouchitis at 1 point, and may present CD of the pouch several months later. Therefore, a combined assessment of symptoms, endoscopic, and histologic features is advocated for the diagnosis and differential diagnosis of pouchitis. Pouch endoscopy provides the most valuable information on the severity and extent of mucosal inflammation, backwash ileitis, CD of the pouch or cuffitis, and the presence of other abnormalities such as polyps, strictures, sinuses, and fistula openings ( Fig. 1 ). Although histology has a limited role in grading the degree of pouch inflammation, it can provide valuable information on some special features, such as granulomas, viral inclusion bodies (for CMV infection), pyloric gland metaplasia (a sign of chronic mucosal inflammation), and dysplasia. A diagnostic and treatment algorithm is proposed ( Fig. 2 ).

Endoscopy of inflammatory disorders of the pouch. ( A ) Pouchitis, inflammation of the pouch body; ( B ) cuffitis, inflammation of the cuff; ( C ) Crohn disease of the pouch, ulcers at the neoterminal ileum.

Diagnostic and treatment algorithm of pouchitis.

Laboratory testing is often necessary as a part of the evaluation of patients with pouch disorders, particular patients with chronic pouchitis. In patients with persistent symptoms of pouchitis, celiac serology, salicylate screening, and microbiological assays for C difficile and CMV may be performed. As most patients undergo repeated or chronic antibiotic exposure, C difficile infection has been a growing problem. Fecal assays of lactoferrin and calproprotectin have been evaluated for the diagnosis and differential diagnosis of pouchitis. Quantitative and qualitative assays of lactoferrin have been used to distinguish pouchitis from normal pouches or irritable pouch syndrome. Fecal lactoferrin may be used as an inexpensive screening test for pouchitis. Fecal calprotectin assay had a sensitivity of 90% and a specificity of 76.5% for the diagnosis of pouchitis in a recent study. However, the diagnostic accuracy of these studies was assessed based on the comparison of patients with pouchitis and patients with healthy pouches, whereas other inflammatory conditions such as cuffitis and CD of the pouch were not included in the prior studies. Other laboratory tests, such as assays of fecal dimeric M2-pyruvate kinase and tissue proinflammatory cytokine gene scripts, may also be useful in distinguishing pouchitis from noninflammatory conditions of the pouch. However, laboratory tests should not replace pouch endoscopy as the first-line evaluation for the diagnosis and differential diagnosis of pouchitis.

Differential diagnosis of pouchitis

There are overlaps in clinical presentations between a variety of inflammatory and noninflammatory disorders of ileal pouches (see Fig. 1 ). Cuffitis is considered a variant form of UC in the rectal cuff, particularly in patients with IPAA without mucosectomy. Patients with cuffitis often present with bloody bowel movements, which seldom occur in conventional pouchitis. When IPAA is constructed, there are 2 techniques to be used for the pouch-anal anastomosis, hand-sewn versus staple techniques: the hand-sewn IPAA with mucosectomy of the anal transition zone (ATZ) mucosa (or rectal cuff mucosa) or a stapled IPAA at the level of the anorectal ring without mucosectomy of the ATZ. To remove the rectal mucosa as completely as possible, a mucosectomy with hand-sewn anastomosis is necessary. This technique normally takes longer and has a high risk for postoperative functional problems related to seepage and incontinence due to anal canal manipulation. In contrast, the stapled anastomosis is easy to perform and is less likely to result in functional and septic complications. The preservation of ATZ is meant to optimize anal canal sensation, eliminate sphincter stretching, and preserve normal postoperative resting and squeeze pressures. However, to allow transanal insertion of the stapler head, it is usually necessary to leave a 1- to 2-cm strip of rectal cuff/ATZ mucosa that is at risk for developing symptomatic inflammation (cuffitis) or even dysplasia.

Another common inflammatory disorder of the pouch is CD. It has been speculated that IPAA surgery with change of bowel anatomy, anastomoses, and fecal stasis creates a “CD-friendly” environment. CD of the pouch can occur after IPAA intentionally performed in a selected group of patients with Crohn colitis with no small intestinal or perianal diseases ; CD is also inadvertently found in proctocolectomy specimens of patients with a preoperative diagnosis of UC or indeterminate colitis. De novo CD of the pouch, by far the most common form of CD, may develop weeks to years after IPAA for UC or indeterminate colitis. Clinical phenotypes of CD of the pouch can be inflammatory, fibrostenotic, or fistulizing. There are symptoms and signs that would suggest a diagnosis of CD, particularly fibrostenotic and fistulizing CD. It is critical to differentiate NSAID-induced ileitis/pouchitis from CD ileitis, backwash ileitis from diffuse pouchitis. Making a diagnosis of CD of the pouch often needs a combined assessment of symptoms, endoscopy, histology, radiography, and sometimes examination under anesthesia.

Irritable pouch syndrome is a functional disorder in patients with IPAA. The disease entity has a significant negative impact on health-related quality of life. There are great overlaps in clinical presentation between irritable pouch syndrome and pouchitis. Contributing factors for the pathophysiology of irritable pouch syndrome include visceral hypersensitivity, enterochromaffin cell hyperplasia, and proximal small bowel bacterial overgrowth. Currently, irritable pouch syndrome is a diagnosis of exclusion. Pouch endoscopy is the diagnostic modality of choice for to distinguish between pouchitis and irritable pouch syndrome.

Patients with surgical complications (such as pouch sinus and pouch ischemia) can present symptoms resembling those of pouchitis. Again, pouch endoscopy is considered the first-line diagnostic modality.

Classification of pouchitis

The natural history of pouchitis is poorly defined. Patients with initial episodes of pouchitis almost uniformly respond to antibiotic therapy. However, relapse of pouchitis is common. Among patients with acute pouchitis, 39% had a single acute episode that responded to antibiotic therapy; the remaining 61% developed at least 1 recurrence. Approximately 5% to 19% of patients with acute pouchitis develop refractory or rapidly relapsing forms of the disease. Pouchitis likely represents a disease spectrum from an acute, antibiotic-responsive type to a chronic, antibiotic-refractory entity. Based on the cause, disease duration, and activity, and response to medical therapy, pouchitis can be categorized into: (1) idiopathic versus secondary, with causes such as NSAID use and C difficile or CMV infection; (3) acute versus chronic, with a cut-off time of 4 weeks of persistent symptoms; (4) infrequent episodes versus relapsing versus continuous; and (5) responsive versus refractory to antibiotic therapy.

Classification based on the response to antibiotic therapy is useful in clinical practice. Analogous to the classification of UC according to the response to or dependency on corticosteroids, pouchitis can be classified into antibiotic-responsive, antibiotic-dependent, and antibiotic-refractory pouchitis ( Table 1 ). Pouchitis can be diffuse or patchy. Based on the distribution of inflammation, pouchitis can be categorized into diffuse pouchitis, pouchitis with backwash ileitis, pouchitis with concurrent cuffitis, and segmental pouchitis. It is now clear that pouchitis can be seen as a heterogeneous group, with different clinical phenotypes, that may be associated with different risk factors, pathogenetic pathways, natural courses, and outcomes.

Table 1

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related posts:

Treatment of Fistulizing Inflammatory Bowel Disease Pediatric Inflammatory Bowel Disease: Highlighting Pediatric Differences in IBD Pregnancy and Inflammatory Bowel Disease Safety Profile of IBD: Lymphoma Risks Safety Profile of IBD Therapeutics: Infectious Risks Clostridium Difficileand Inflammatory Bowel Disease

Stay updated, free articles. Join our Telegram channel

Join