Frequency and Distribution of Microscopic Findings in Patients with Chronic Non-Bloody Diarrhea and Normal Colonoscopy

Background: chronic diarrhea is a common problem in patientswith symptoms related to gastro-intestinal tract. some ofthese patients present with chronic non-bloody, watery diarrheaand no specific clinical, laboratory, or endoscopic findings.the aim of the present study was to investigate the valueof histological findings in patients with chronic diarrhea whohave normal or non-specific endoscopic findings.we also determined the frequency and distribution of histologicalchanges related to different anatomical sites in the colon.methods: this study was performed in kerman city on 90patients with chronic watery diarrhea whose diseases had notbeen exactly diagnosed after extensive clinical, laboratory,and endoscopic studies.laboratory tests including complete blood count, erythrocytesedimentation rate, c-reactive protein, stool examination,thyroid and liver function tests, and serologic study for celiacdisease were all normal in this group of patients. colonoscopywas performed and mucosal biopsies were taken from rectosigmoid,descending, and transverse colon.results: the histologic findings were as follows: 39 (43.3%)patients showed normal histology, 25 (27.8%) patients showedmicroscopic colitis, not otherwise specified form. ten (11.1%)patients had classic lymphocytic colitis, and 15 (16.7%) patientshad paucicellular lymphocytic colitis. one (1.1%) patient showedfocal active colitis. none of them had collagenous colitis.conclusion: diagnostic histological findings were seen in28.9% of biopsy samples in patients with chronic diarrhea andnormal or near normal endoscopic findings.we recommend multiple punch biopsy sampling in suchpatients from different sites of the colon to avoid missingsome cases of microscopic colitis.iran j med sci 2008; 33(2): 101-105.