Confocal laser endomicroscopy detects colonic inflammation in patients with irritable bowel syndrome: a prospective study

Background and aims Irritable bowel syndrome (IBS) is considered to be a functional disease, but recent data indicate measurable organic alterations. We aimed to determine the presence of colorectal mucosa microinflammation in vivo via probe-confocal laser endomicroscopy (pCLE) and histological evaluation in IBS patients. Methods This was a prospective, controlled, nonrandomized single-blind diagnostic trial performed in a tertiary institution. pCLE images and targeted biopsy of each colon segment obtained during colonoscopies of IBS patients and controls were analyzed for inflammatory changes. Biopsies were classified using the Geboes scale, and the odds ratio and overall diagnostic accuracy were calculated. Results During the 15-month study period, 37 patients were allocated to each group. The mean age was 53.1 ± 14.3 years; 64.9 % were female. Signs of colonic mucosa inflammation were evident on 65.8 % of pCLE images from IBS patients compared to 23.4 % of images from controls (OR 6.28; 4.14–9.52; P < 0.001). In total, 20/37 patients had microinflammation via pCLE in ≥ 3 colon segments in the IBS group, compared to 1/37 in the control group. A Geboes score > 0 was attributed to 60.8 % of biopsies from patients in the IBS group compared to 27.5 % of biopsies from the control group. The sensitivity, specificity, positive and negative predictive values, observed and interrater agreement of pCLE-detected inflammatory changes in IBS using histology as gold standard were 76 %, 91 %, 76 %, 91 %, 86.5 %, and 66.8 %, respectively. Conclusions Patients with IBS have a six-fold higher prevalence of colorectal mucosa microinflammation than healthy controls. pCLE might be a reliable method to detect colorectal mucosa microinflammation in IBS patients.