The Pediatric Pouch in Inflammatory Bowel Disease

A Primer for the Gastroenterologist

Ghassan T Wahbeh; David L Suskind; Scott D Lee; John T Waldhausen; Karen F Murray

Disclosures

Expert Rev Gastroenterol Hepatol. 2013;7(3):215-223. 

In This Article

Ileal Pouch–Anal Anastomosis

The IPAA procedure has been performed for over 40 years.[13] Its original goal was to create a reservoir of two connected open ileal segments. At the time of colectomy, in a two-step approach, most surgeons opt to fashion a pouch with pouch–anal anastomosis along with a diversion ileostomy, followed by an ileum–pouch anastomosis a few months later. A pouchogram is done before the ileostomy reversal to screen for any leaks. At the time of ileostomy closure, the pouch–anal anastomosis is evaluated for any evidence of stricture. Significant strictures may be due to ischemia or leakage at the anastomotic site. They may occur early, but typically do not present until 6–9 months following the operation. When present, they may be dealt with by using one of several different surgical techniques, such as simple dilation, a Y–V stricturoplasty or diamond advancement flap. If the stricture is encountered prior to ileostomy closure, the closure may be delayed while the anoplasty heals. For malnourished or steroid-dependent children, or patients who receive infliximab within 8 weeks,[14] the following three-step approach is usually considered: colectomy–ileostomy, pouch creation with anal anastomosis and ileostomy closure and ileum–pouch anastomosis. The first step leaves an ileostomy and a rectal residual (Hartman's) pouch. Within the residual pouch, the diseased mucosa may continue to be the source of blood and mucous despite the diversion ileostomy. Most surgeons proceed to the second step within a few months after the first. Overall, one-step procedures without a temporary 'protective' ileostomy pose higher risks of anastomotic leaks and pelvic sepsis.[15] In select pediatric patients, a one-step procedure may be safely completed, reducing the number of operations, operative time and incidence of anastomotic strictures.[16,17] Laparoscopic and laparoscopic-assisted surgery may also be completed successfully.[18–20] It is important to keep in mind that the connection of the ileal pouch to the anal canal is not technically feasible without some residual rectal 'cuff'; a small segment of the rectum (at least 0.5 cm), which must be maintained to preserve nervous enervation and sphincter continence (Figure 1). Less of this cuff is left behind with a handsewn anastomosis, while at least 1–2 cm of cuff is left behind after a double-stapled technique. While complications of the handsewn technique are higher in regard to anal sphincter function, the double-stapled technique is more prone to the development of symptomatic inflammation (known as cuffitis; Figure 2) or dysplasia and neoplasia. Because laparoscopic techniques may be challenging in adequately dividing the rectum near the dentate line because of the instrumentation available, an even longer rectal cuff may be left behind.[21,22] The residual rectal mucosa warrants future endoscopic monitoring of the pouch. Surgical outcomes are also related to the surgeon's experience, the number of pouches done and the technique (handsewn vs stapled pouch–anal anastomosis).[23] Our own technique removes 5 cm of rectal mucosa while the patient is in a prone jack-knife position. This allows excellent visualization of the rectum. The patient is then repositioned into lithotomy and the colectomy and partial proctectomy are completed laparoscopically with the J-pouch reconstruction done via a small pfannenstiel incision.

Figure 2.

Cuff inflammation.

Children with IPAA (mean age: 12 years), who were followed for a mean of 3.7 years after surgery, were noted to have a similar quality of life, physical function and self-esteem compared with healthy children.[24] In another study, 26 out of 27 children with median age of 15 years described their health after IPAA as completely or fairly good.[25] The parents of younger children who received a pouch at a median age of 6.8 years, and were followed for a mean of 9 years, reported excellent outcomes.[26]

After the Colectomy, Before the Pouch: Deciding Whether to Continue on or Not

Naturally, before IPAA surgery is determined to be the desired course of action, realistic expectations, potential complications and risk to the patient must be considered. Of all complications, the patient's (and providers') perhaps most-feared complication is pouch failure and the need to revert to a permanent ileostomy, with or without pouch removal. Pouch failure occurs in 5–7% of adult patients within 10 years of its construction.[27,28] Predictors include early pelvic sepsis and need for transanal drainage.[29] Crohn's disease, highly associated with pouch complications, including failure,[30] can manifest with inflammation of the pouch, the afferent small bowel limb and other small bowel locations or fistula formation. Patients with known Crohn's disease are not commonly offered IPAA, although select patients with Crohn's colitis, no extensive small bowel disease and no perianal disease can be considered.[31] For some patients with severe or intractable colitis, clarifying whether they have UC or Crohn's disease can be challenging.[32] When the type of IBD is not clear in adults, known as IBD Unclassified (IBDU), the outcomes do not appear to be different after IPAA than those in UC.[33] A change of diagnosis from IBDU or UC to Crohn's disease can occur after colectomy, based on a gross and microscopic exam of the resected colon and ileum. Should this change in diagnosis mean no IPAA? A prospective study of 153 adults with UC or IBDU did not show that any single or combination UC-atypical histologic findings after colectomy (including giant cells, transmural inflammation and patchy disease) predicted pouch complications or Crohn's disease of the pouch.[34] On the other hand, a family history of Crohn's disease and anti-Saccharomyces cerevisiae IgA antibodies are independently associated with a post-IPAA diagnosis of Crohn's disease in adults with UC or IBDU.[35] Coukos et al. explored whether serology tests obtained after ileostomy closure and ileal anastomosis to IPAA are associated with pouch complications and Crohn's of the pouch in 142 adults, with a median follow-up of 86 months.[36] Complications occurred in 31% of all patients. Positive anti-S. cerevisiae IgG or anti-CBir1 markers were associated with a higher risk for developing any post-IPAA complication, particularly fistulae and Crohn's of the pouch. Since such risk factors raise the risk of pouch complications, they should be discussed with patients before proceeding. Further study is needed to define the ideal time for assessing serologic markers and their utility in decision making preoperatively.

Postoperative Complications

More than 50% of all patients develop at least one complication after pouch surgery, the most common of which is pouchitis.[37–39] Approximately one out of ten children develop a stricture, leak or fistula. Certainly, multiple preoperative risk factors, including malnutrition, opportunistic infections and exposure to steroid, tacrolimus, cyclosporin and anti-TNF-α agents, exist for an ill patient with UC. Prolonged preoperative steroid therapy may relate to poor postoperative catch-up growth.[40] Infliximab increases post-IPAA complications in children, including infections and small bowel obstruction.[14] Calcineurin inhibitor use does not seem to increase early postoperative complications.[41] Ileus can be prolonged in patients with a protracted preoperative course or prolonged narcotic use.

Anastomotic leaks can appear at multiple sites (Figure 3): peristomal, Hartman's pouch, proximal ileal pouch end, IPAA or ileo–ileal anastomosis site after ileostomy take-down. Leakage may result in abscess formation and lead to fistula development. Small bowel obstruction can similarly appear at any of the anastomotic sites or ileostomy. Portal vein thrombosis is a rare complication that has been reported in children after colectomy and IPAA.[42] Patients presenting with abdominal pain, fever and leukocytosis should be considered for this diagnosis, which may also be the presentation of a surgical leak or pouchitis. Adhesions can predispose patients to such complications as internal herniation and bowel strangulation.[14,40,41] Fistulas can develop and extend from the pouch to nearby structures. The presence of a fistula heralds pouch failure in 29% of adult patients.[43] While earlier-appearing fistulae may be related to the surgery itself, those appearing from 6 months to a year later may be caused by Crohn's of the pouch.

Figure 3.

Pouch leaks. Pouch leaks at the tip of 'J' (A2), pouch body (A3) and pouch–anal anastomosis, leading to pelvic sepsis (A4), pouch–vaginal fistula (A5) and pre-sacral fluid collection (A1). Endoscopic view of a leak at the tip of 'J' (B).Reproduced with permission from [66].

In a small pediatric case series, a manometry study of the neorecto-anal function revealed similar maximum neorectal tolerated threshold volume and preserved neorectoanal inhibitory reflex between children with IPAA with or without incontinence compared with healthy controls.[44] However, patients with IPAA and incontinence showed significantly lower maximum anal sphincter pressure at rest and during voluntary contraction, in addition to higher sensory threshold. Both findings suggest sphincter and sensory dysfunction as the causes of incontinence.

In adult patients who receive an IPAA, there is evidence of increased infertility of up to 48 versus 15% for medically treated UC patients;[45] it is unclear how this risk is modified in children; further study is needed. Adenocarcinoma within the IPAA has been reported in adults with FAP and UC.[46] Presence of precolectomy neoplasia, which is quite uncommon in children with UC due to short duration of disease before surgery, is a risk factor for pouch neoplastic changes.[47] A pediatric retrospective review by Sarigol et al. found similar histologic findings in pediatric and adult pouches, with no dysplasia 5 years on from pouch creation in their pediatric patients.[48] The authors suggest screening pouchoscopy 5 years after pouch surgery, or 7 years from UC diagnosis, followed by more frequent pouchoscopy, should severe inflammation be present. Biopsies from the residual cuff area should be carefully obtained.

Pouchitis

Pouchitis is the most common complication of IPAA. Chronic pouchitis and Crohn's of the pouch are the two most common causes of pouch failure and removal. The term 'pouchitis' denotes symptoms resulting from pouch inflammation that can be demonstrated endoscopically and histologically. A pouch disease activity index, based on symptoms, endoscopic and histologic criteria, is commonly used to assess pouchitis.[49] Pouchitis symptoms can be quite debilitating, including daytime or nocturnal diarrhea, urgency, tenesmus, incontinence, pain and bleeding. When these symptoms are present without inflammation, a diagnosis of irritable pouch syndrome is suspected.[50] On endoscopic exam (known as a pouchoscopy), pouchitis appearance is nonspecific and spans findings from edema to ulceration (Figure 4). Microscopically, the hallmark of pouchitis is the presence of polymorphonuclear cells, crypt abscesses and ulceration. Calprotectin has been shown to correlate with pouch inflammation in children.[51] The pediatric literature on pouchitis is quite meager and, therefore, much of what we know is from adult data or anecdotal experience. What is unique about pouchitis is that it does not occur commonly in patients who receive a pouch for familial polyposis.[11,52] This supports the idea that pouchitis is the end point of pouch flora interaction with the intestinal cells in a predisposed patient. Generally, pouchitis occurs within 6 months after ileostomy take-down, although it can also occur prior to the ostomy being closed. Risk factors for pouchitis include NOD2/CARD15 mutations, extensive UC, backwash ileitis, positive perinuclear antineutrophil cytoplasmic antibodies, primary sclerosing cholangitis, preoperative corticosteroid or calcineurin inhibitor exposure, preoperative thrombocytosis and use of NSAIDs.[41,50] Preoperative infliximab does not seem to increase the likelihood of chronic pouchitis.[14] There are different types of pouchitis: acute versus chronic (>4 weeks); infrequent (one to two acute episodes) versus relapsing (≥three acute episodes) versus continuous; and treatment-responsive versus treatment-refractory.[53]

Figure 4.

Pouchitis.

The bacterial flora within the ileal pouch may differ between patients with UC versus FAP.[54] A role for pouch flora in pouchitis is also suggested by the successful use of antibiotics as the first-line of therapy. Limited placebo-controlled trials using antibiotics for pouchitis have been conducted in adults; none, however, have been completed in children. Generally, treating pouchitis in children follows the practice for adults. Both metronidazole and ciprofloxacin have been shown to be effective for pouchitis.[50,55,56] Liquid metronidazole has poor palatability, which presents a challenge for its use with children. Although liquid ciprofloxacin is available, the warning for Achilles tendonitis and tendon rupture raises concerns about its use, especially with concomitant steroids. For patients who do not respond to monotherapy with metronidazole or ciprofloxacin, an alternative regimen combining antibiotics, topical antibiotics (enema form) and a sequential antibiotic regimen has been used.[8] The probiotic VSL#3 seems to be more effective compared with placebo for maintaining remission of chronic pouchitis in adults who achieved remission with antibiotics. However, it is unclear whether VSL#3 is useful in preventing pouchitis.[57] Fewer than one out of three patients with chronic pouchitis have an identifiable cause ( Box 1 ).

A unique pouchitis entity has been described comprising of: antibiotic-resistant pouchitis, positive autoimmune markers, association with immune-mediated disease and increased apoptotic cells on pouch histology.[58] When antibiotics are not helpful, anti-inflammatory agents can be used. In adults, mesalamines and steroids, both in topical and oral forms, have been used as second-line options for treating pouchitis.[8] Immunosuppressive and biological therapies have also been used (see Crohn's of the pouch). Chronic treatment-unresponsive pouchitis can severely compromise quality of life and remains one of the most common indications for pouch excision.

Crohn's After Pouch Creation

Between six and 13% of children with UC will have a diagnosis change to Crohn's disease after colectomy.[38,59] A Crohn's disease diagnosis can occur at the following different stages: when patients with known Crohn's disease undergo the surgery for severe Crohn's colitis; after colectomy, based on surgical specimen exam; and after pouch surgery (known as de novo Crohn's).

Crohn's disease can appear within the pouch (CDP) and/or in any part of the gastrointestinal tract or perianal area. CDP was seen in 13–15% of children.[59,60] A comprehensive clinical review on CDP has been authored by Shen.[61] Crohn's disease behavior can be inflammatory, causing ulcerations within the pouch or proximal small bowel (Figure 5). This should not be confused with NSAID-induced ulcers or backwash ileitis.[27,62] Interestingly, ongoing primary sclerosing cholangitis is associated with prepouch significant ileitis.[63] CDP induces symptoms that are similar to chronic pouchitis. Fistulizing Crohn's disease can extend into the perianal area and nearby structures, including the vagina. This can be confused with surgery-related fistulae that may appear within a few months of surgery. Fibrostenosing CDP can compromise the pouch structure itself and evacuation dynamics. It is important to distinguish fibrostenosing CDP from a surgery-associated stricture, although in reality this may be difficult. De novo Crohn's of the pouch, which can occur weeks to years after surgery, carries a poorer prognosis, with higher pouch failure compared with early-appearing CDP.[62] CDP should be suspected if a patient develops de novo fistula more than 6–12 months after ileostomy take-down in the absence of postoperative leak, abscess and sepsis. The presence of histologic evidence of granulomas or pyloric gland metaplasia would also suggest a diagnosis of Crohn's disease. However, caution is suggested against obtaining tissue samples from the pouch suture line, since these may show foreign-body granulomas. Although immune modulators and anti-TNF agents have been used for CDP, the risk of needing surgery for pouch failure is high.[64,65]

Figure 5.

Crohn's of the pouch.

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