Guidelines of the French Society for Digestive Endoscopy (SFED). Role of endoscopy in microscopic colitis

Microscopic colitis in patients with chronic diarrhea and normal colonoscopic findings in Southern China

BACKGROUND AND OBJECTIVES

Microscopic colitis includes lymphocytic colitis and collagenous colitis. The entity is considered as an important cause for unknown chronic diarrhea, but rarely reported in China before. This study aimed to determine the prevalence of microscopic colitis in patients with chronic diarrhea and normal colonoscopy findings in Southern China, and to reveal the clinical feature of microscopic colitis in these patients.

METHODS

Patients with chronic diarrhea and normal colonoscopic findings were enrolled from three hospitals in Southern China from January, 2009 to June, 2010. Multiple colorectal biopsies were obtained in these patients and histological examination was underwent with hematoxyin and eosin stain, Masson's trichrome stain and immunohistochemistry for tenascin to screen lymphocytic colitis and collagenous colitis. The clinical symptom and risk factor of microscopic colitis were assessed by comparing with controls. The diagnostic overlap between microscopic colitis and irritable bowel syndrome or functional diarrhea was also analyzed.

RESULTS

Randomly mucosal biopsies were performed in 613 patients with chronic diarrhea and normal or near normal colonoscopic finding. Fifty-nine cases of lymphocytic colitis and 28 cases of collagenous colitis were found by histological examination. The rates of rheumatoid arthritis in lymphocytic colitis group (15.4 %) and collagenous colitis group (14.3 %) were significant higher than in control group (2.2 %). Rheumatoid arthritis was confirmed as the risk factor of microscopic colitis by logistic regression analysis. There was no difference on the symptoms among the controls, patients with lymphocytic colitis, and patients with collagenous colitis. There were 13.8 % (12/87) of patients with microscopic colitis fulfilled Rome III criteria of irritable bowel syndrome and 42.5 % (37/87) fulfilled the criteria of functional diarrhea.

CONCLUSIONS

Microscopic colitis is not an uncommon disorder in Chinese population. Rheumatoid arthritis is the risk factor of microscopic colitis. Microscopic colitis has a symptomatic overlap with irritable bowel syndrome and functional diarrhea. It is reasonable to obtain multiple biopsies in patients with chronic diarrhea when the mucosa grossly normal at colonoscopy.

Biopsy interpretation of colonic biopsies when inflammatory bowel disease is excluded

The interpretation of colonic biopsies related to inflammatory conditions can be challenging because the colorectal mucosa has a limited repertoire of morphologic responses to various injurious agents. Only few processes have specific diagnostic features, and many of the various histological patterns reflect severity and duration of the disease. Importantly the correlation with endoscopic and clinical information is often cardinal to arrive at a specific diagnosis in many cases.

Current application of confocal endomicroscopy in gastrointestinal disorders

Confocal endomicroscopy (CEM) is a recent advancement in imaging technology that incorporates a confocal laser microscope into the tip of a flexible endoscope. The 1000-fold magnification and high resolution allows for real time in vivo histology or "virtual biopsies" of the gastrointestinal tract mucosa. CEM has the capability to instantaneously diagnose intra-epithelial neoplasia during endoscopy, alone or in combination with a "red-flag" technique, such as chromoendoscopy. Therefore, there is clinical utility in the surveillance or diagnosis of Barrett's esophagus, gastric intestinal metaplasia and cancer, longstanding ulcerative colitis, and colonic neoplasia. Furthermore, CEM also appears to be useful in the evaluation of coeliac disease, microscopic colitis, and in diagnosing Helicobacter pylori chronic gastritis. This review examines the current available data on the utility of this new technology in clinical gastroenterology and its potential impact in the future.