Clinical indications of the use of antineutrophil cytoplasmic antibodies and anti-Saccharomyces cerevisiae antibodies in the evaluation of inflammatory bowel disease at an Academic Medical Center

Nonbloody Diarrhea but Not Significant Weight Loss at Diagnosis Is Associated with the Development of Denovo Crohn's Disease After Ileal Pouch-anal Anastomosis for Ulcerative Colitis

BACKGROUND

Denovo Crohn's disease (CD) develops in 5% to 10% of patients after ileal pouch-anal anastomosis (IPAA) for ulcerative colitis (UC) leading to increased morbidity and rates of pouch failure. Initial nonbloody diarrhea and weight loss at diagnosis are independent risk factors for a change in diagnosis from UC to CD in nonsurgical patients. We investigated whether these features were risk factors for denovo CD in a longitudinal cohort of patients with UC undergoing IPAA.

METHODS

Prospective profiles of patients with UC undergoing IPAA followed over a 22-year period by 1 surgeon were analyzed. Denovo CD was diagnosed when mucosal inflammation (5 or more ulcers) involved the small bowel mucosa proximal to the ileal pouch any time after surgery and/or when a pouch fistula or other perianal complication developed more than 3 months after ileostomy closure. Patients with inflammatory bowel disease unclassified, acute pouchitis, chronic pouchitis, and those lost to follow-up were excluded from analysis. Cox regression analysis was performed for statistical significance.

RESULTS

Of the 199 study patients included in the analysis, denovo CD developed in 42 patients (21%). Patients who developed denovo CD had an increased incidence of nonbloody diarrhea (n = 12; 29%) compared with patients who had no evidence of pouch inflammation (n = 25; 16%) (P = 0.03). In contrast, the incidence of weight loss was not significantly increased in patients with denovo CD (n = 7; 17%) compared with patients who never had pouch inflammation (n = 16; 10%) (P = 0.12).

CONCLUSIONS

Initial nonbloody diarrhea is associated with denovo CD after IPAA. This association warrants close consideration before surgery.

Gastro 2013 APDW/WCOG Shanghai working party report: chronic diarrhea: definition, classification, diagnosis

Diarrhea is best defined as passage of loose stools often with more frequent bowel movements. For clinical purposes, the Bristol Stool Form Scale works well to distinguish stool form and to identify loose stools. Laboratory testing of stool consistency has lagged behind. Acute diarrhea is likely to be due to infection and to be self-limited. As diarrhea becomes chronic, it is less likely to be due to infection; duration of 1 month seems to work well as a cut-off for chronic diarrhea, but detailed scientific knowledge is missing about the utility of this definition. In addition to duration of diarrhea, classifications by presenting scenario, by pathophysiology, and by stool characteristics (e.g. watery, fatty, or inflammatory) may help the canny clinician refine the differential diagnosis of chronic diarrhea. In this regard, a careful history remains the essential part of the evaluation of a patient with diarrhea. Imaging the intestine with endoscopy and radiographic techniques is useful, and biopsy of the small intestine and colon for histological assessment provides key diagnostic information. Endomicroscopy and molecular pathology are only now being explored for the diagnosis of chronic diarrhea. Interest in the microbiome of the gut is increasing; aside from a handful of well-described infections because of pathogens, little is known about alterations in the microbiome in chronic diarrhea. Serological tests have well-defined roles in the diagnosis of celiac disease but have less clearly defined application in autoimmune enteropathies and inflammatory bowel disease. Measurement of peptide hormones is of value in the diagnosis and management of endocrine tumors causing diarrhea, but these are so rare that these tests are of little value in screening because there will be many more false-positives than true-positive results. Chemical analysis of stools is of use in classifying chronic diarrhea and may limit the differential diagnosis that must be considered, but interpretation of the results is still evolving. Breath tests for assessment of carbohydrate malabsorption, small bowel bacterial overgrowth, and intestinal transit are fraught with technical limitations that decrease sensitivity and specificity. Likewise, tests of bile acid malabsorption have had limited utility beyond empirical trials of bile acid sequestrants.

The promise and pitfalls of serologic testing in inflammatory bowel disease

The role of IBD serologies is still evolving. However, as that evolution progresses, it will continue to provide important insights into the etiology of IBD and help define individualized treatment strategies for patients. The presence of multiple IBD antimicrobial antibodies and increased reactivity form a useful heuristic model to understand the evolution of CD. The role of ANCAs and autoantibodies in pathogenesis of UC is an area that requires further investigation. Although IBD serologies exhibit considerable diagnostic accuracy, it is unclear whether they will supplant simpler and more direct evaluations in making an initial diagnosis of UC or Crohn (Table 3). The utility of panels of IBD serologies to stratify and predict the course of CD has been an arena of fertile investigation. Developing individual treatment strategies based on the probability of developing complicated aggressive disease would be a significant advance in medical management of CD. However, if major clinical decisions are to be made based on these serologies, we will need more prospective critical studies from the time of diagnosis to define their clinical applicability and to demonstrate a true difference in outcomes.

Clinical significance of inflammatory markers

Inflammatory markers play a key role in the evaluation of patients with gastrointestinal symptoms. For patients presenting with nonspecific symptoms of abdominal pain and diarrhea, distinguishing inflammatory bowel disease from other disorders can be difficult, and invasive diagnostic procedures may be required. Inflammatory markers can be useful to differentiate patients who may require further workup from those who do not. Several serum, fecal, and other markers are reviewed for their use in clinical practice. Although no single ideal marker exists, a few show promise in diagnosing inflammatory disease, monitoring disease activity, and predicting relapse.

Laboratory values for children with newly diagnosed inflammatory bowel disease

OBJECTIVE

The goal was to determine how often common laboratory tests yield normal results at the time of diagnosis for children with inflammatory bowel disease.

METHODS

Data were obtained from a registry of children with newly diagnosed inflammatory bowel disease who were enrolled prospectively in 18 US/Canadian centers. Laboratory values investigated included hemoglobin level, platelet count, albumin level, and erythrocyte sedimentation rate. Disease severity was categorized by physician global assessment.

RESULTS

A total of 526 children (mean age: 11.6 years; 58% male; 392 with Crohn disease and 134 with ulcerative colitis) were studied. All 4 values were normal for 21% of patients with mild Crohn disease and 54% with mild ulcerative colitis. In contrast, only 3.8% of children with moderate/severe Crohn disease and 4.3% with moderate/severe ulcerative colitis had normal results for all 4 tests. The erythrocyte sedimentation rate was least likely to be normal; overall, 26% of patients with inflammatory bowel disease had a normal erythrocyte sedimentation rate, including 18% with moderate/severe disease. Hemoglobin levels were normal for 32%, platelet counts for 50%, and albumin levels for 60%. There was no clear association between Crohn disease location and either severity or number of normal laboratory values. In contrast, there were direct correlations between ulcerative colitis disease severity and both the extent of bowel inflammation and the number of abnormal laboratory tests.

CONCLUSION

The presence of normal screening laboratory studies should not dissuade clinicians from considering a diagnosis of inflammatory bowel disease.