The physiology of ileo-anal pouch function

Functional Disorders of the Ileal-Anal Pouch: A Systematic Review

BACKGROUND

The IPAA is a boon to patients needing proctocolectomy but maintains per anal function through anatomic and physiologic compromises. The state of pouch function is hard to define because pouch anatomy is not normal and pouch physiology is a distortion of normal defecation. Patients with pouches develop multiple symptoms: some are expected, some are disease related, and some are the result of surgical complications. It is important to understand the cause of pouch-related symptoms so that appropriate management is offered.

OBJECTIVES

The study aimed to review pouch symptoms and discuss their likely cause, review the literature on pouch function and dysfunction, and provide clarity to clear the confusion.

DATA SOURCES

PubMed and Cochrane databases were searched using the terms "ileoanal pouch function" and "ileoanal pouch dysfunction."

STUDY SELECTION

From 1983 to 2023, 553 articles related to "ileoanal pouch function" and 178 related to "ileoanal pouch dysfunction" were reviewed. Nine studies appeared under both headings. Case studies, duplicate publications, and articles concerning pouch diseases were excluded.

MAIN OUTCOME MEASURES

Definitions of pouch function and dysfunction, methods of describing and scoring symptoms, and understanding of expected changes in pouch function given the nature of the surgery.

RESULTS

Twenty-seven studies were reviewed from the ileoanal pouch dysfunction search and 38 from ileoanal pouch function. Three studies tried to define normal pouch function, 10 attempted to measure pouch function, and 4 aimed to score pouch function. Only 3 studies addressed pouch physiology.

LIMITATIONS

A full discussion of pouch dysfunction is limited by the lack of studies focussing on the anatomic and physiologic consequences of turning the terminal ileum into an organ of storage.

CONCLUSIONS

Most studies of pouch function and dysfunction do not consider expected changes in the physiology of defecation that follow restorative proctocolectomy. Thus, most studies of pouch function produce conclusions that lack an important dimension. See video from symposium.

Etiopathogenesis of Nephrolithiasis in Ulcerative Colitis Patients with the Ileal Pouch Anal Anastomosis

BACKGROUND

Our previous study showed that nephrolithiasis is a common complication in ulcerative colitis patients after ileal pouch anal anastomosis (IPAA). However, the pathogenesis of nephrolithiasis in IPAA patients has not been studied. The aim of this study was to compare urine and serum metabolic compositions in IPAA patients with nephrolithiasis and controls with IPAA and no nephrolithiasis.

METHODS

Using cross-sectional study design, serum and 24-hour urine metabolic compositions were compared between IPAA patients with nephrolithiasis (the study group) and those without (the control group). Urinary supersaturation of calcium oxalate, calcium phosphate, and uric acid was calculated.

RESULTS

A total of 40 patients were enrolled in the study. There were no significant differences in serum electrolytes, vitamin D, parathyroid hormone, and kidney function tests between the study (n = 20) and control groups (n = 20). Patients in the study group were found to have a significantly higher 24-hour urine supersaturation of calcium oxalate (8.8 versus 5.0, P = 0.037) and calcium phosphate (0.61 versus 0.27, P = 0.028) as compared with controls. Nineteen (95%) patients in the study group were symptomatic due to nephrolithiasis with several requiring procedural intervention for treatment, including ureteroscopy in 3 (15%) patients, lithotripsy in 5 (25%) patients, and percutaneous surgery in 1 (5%) patient.

CONCLUSIONS

Ulcerative colitis-IPAA patients are at risk for the development of calcium oxalate and calcium phosphate stones. Nephrolithiasis is symptomatic in a majority of the patients and frequently requires procedural intervention for treatment.

The efficacy and tolerability of AST-120 (spherical carbon adsorbent) in active pouchitis

OBJECTIVES

Although a majority of patients with pouchitis respond favorably to antibiotic therapy, many relapse frequently, and nonabsorbable and non-antibiotic-based agents are desirable for reducing bacterial resistance and the systemic adverse effects associated with long-term antibiotic exposure. AST-120 (a spherical carbon adsorbent) comprises highly adsorptive, porous carbon microspheres with the ability to adsorb small-molecular-weight toxins, inflammatory mediators,and harmful bile acids. The aim of this pilot trial was to evaluate the efficacy and tolerability of AST-120 in the treatment of active pouchitis.

METHODS

Eligible patients were recruited from two subspecialty pouchitis clinics. Inclusion criteria were(i) ileal pouch-anal anastomosis performed for ulcerative colitis; (ii) active pouchitis with Pouchitis Disease Activity Index (PDAI) scores > or =7; and (iii) discontinuation of antibiotic therapy for at least 2 weeks. Exclusion criteria included Crohn's disease of the pouch, isolated cuffitis, pouch strictures, abscess, and sinuses. All eligible patients received AST-120 in 2-g sachets (oral) open label, thrice a day for 4 weeks. The primary efficacy end point was remission as defined by a PDAI score of < 7 points; the main secondary end point was clinical response, defined by a reduction of the PDAI score of > or =3 points.

RESULTS

Nineteen of 20 patients completed the trial. Eleven patients (55.0 % ) had a clinical response to the therapy and 10 patients (50.0 % ) entered remission. Median reduction in the PDAI symptom, endoscopy, and histology subscores, and PDAI total scores after 4 weeks were -2( P = 0.002), -2 ( P = 0.003), 0 ( P = 0.32), and -4 ( P = 0.001) points, respectively. The agent was well tolerated; one patient experienced transient mild elevation of alkaline phosphatase of uncertain significance and one patient experienced an upper respiratory infection after taking one dose of AST-120 and was excluded from the fi nal analysis for the calculation of pre- and post-trial PDAI scores.

CONCLUSIONS

AST-120 seems to be effective and well tolerated in treating patients with active pouchitis.A randomized, placebo-controlled trial is warranted for assessing the long-term efficacy and safety of AST-120 in the disease.

A proposed classification of ileal pouch disorders and associated complications after restorative proctocolectomy

Both medical and surgical therapies for ulcerative colitis have inherent advantages and disadvantages that must be balanced for patients with moderate to severe disease. Restorative proctocolectomy with ileal pouch-anal anastomosis has become the surgical treatment of choice for the majority of patients with ulcerative colitis who require proctocolectomy. However, adverse sequelae of mechanical, inflammatory, functional, neoplastic, and metabolic conditions related to the pouch can occur postoperatively. Recognition and familiarization of the disease conditions related to the ileal pouch can be challenging for practicing gastroenterologists. Accurate diagnosis and classification of the disease conditions are imperative for proper management and prognosis.

Serum biochemical evaluation of patients with functional pouches ten to 20 years after restorative proctocolectomy

BACKGROUND

Restorative proctocolectomy with an ileal pouch-anal anastomosis is a surgical treatment of choice for ulcerative colitis and familial adenomatous polyposis (FAP). Pouchitis is a significant enigmatic morbidity. In the long-term, these patients, we anticipated, would experience biochemical profiling alterations after years of retaining functionally acceptable pouches. This pilot study was aimed at assessing results of essential biochemical variables more than 10 years after surgery.

METHODS

The investigation was carried out in 91 patients; 39 were women. Eight-eight had ulcerative colitis, while three had FAPs. The hand-sewn ileal reservoirs after mucoso-proctocolectomy were 66 S and 25 J. The analyses were compared short-term vs long-term. Patients were investigated and were their own control.

RESULTS

Long-term, incidence of acute and chronic pouchitis was 2 and 13%. Eleven and 4% of patients had hypomagnesaemia and hypocalcaemia. Mean levels were significantly enhanced (p<0.01 and p<0.0002). Hypomagnesaemia corresponded to episodes of pouchitis and was corrected with oral magnesium and antibiotics. Hypoferric anaemia was diagnosed in 7% and treated with oral iron tablets. Chronic pouchitis and recurrent pouch mucosa bleeding were the cause. Hypohemoglobinemia and hypocyanocobalaminemia were noted in 5% and 5%, respectively. Erythrocyte sedimentation rate and white blood cells were supra-normal in 13 and 10%, which corresponded with pouchitis. A significant (p<0.03) steady rise of mean serum immunoglobulin G without correlation to pouchitis was noted.

CONCLUSION

Long-term functional results did not deteriorate. Pouchitis was a significant enigmatic morbidity. Severe or chronic pouchitis complicated hypoferric and vitamin B(12) anemia and hypomagnesaemia.

Pouchitis: a spectrum of diseases

Restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) is the surgical treatment of choice for ulcerative colitis and familial adenomatous polyposis patients who require surgery. Pouchitis is the most common long-term complication after IPAA. Patients with pouchitis represent a heterogeneous group in terms of pathogenesis, clinical presentation, disease course, and prognosis, suggesting a wide range of disease mechanisms. Before the diagnosis of pouchitis is made, other inflammatory and non-inflammatory disease conditions, such as Crohn's disease, cuffitis, and irritable pouch syndrome, should be ruled out. Pouch endoscopy is the most important tool for diagnosis and differential diagnosis. Accurate diagnosis and classification are essential for appropriate management. Although the majority of patients with pouchitis respond to antibiotic therapy, a subset of these patients cannot achieve remission by means of antibiotics and thus require anti-inflammatory or immunosuppressive treatment.