Importance of biopsies and histological evaluation in patients with chronic diarrhea and normal colonoscopies

BACKGROUND: In patients with chronic diarrhea, colonoscopy may identify inflammatory causes or some occult disease, and also can show a normal mucosa. Serial biopsies of intestinal mucosa can be useful for a differential diagnosis, and to modify the treatment. AIM: To evaluate whether the biopsies performed in patients with chronic diarrhea and a normal colonoscopy contribute to the differential diagnosis and alter the therapeutic approach. METHODS: A descriptive, retrospective and cross-sectional study using a computerized database was done. Patients with chronic diarrhea and a normal colonoscopy underwent serial biopsies of the terminal ileum, ascending colon and rectum. RESULTS: From 398 records, 214 were excluded. Of the 184 patients enrolled, 91 showed histological changes: 40% nonspecific inflammation; 5.18% lymphocytic inflammation, 10.37% eosinophilic inflammation; 39.26% lymphoid hyperplasia; 2.22% collagenous colitis; 2.22% melanosis; and 0.74% pseudomelanose. The sites with the largest number of changes were the terminal ileum and right colon. CONCLUSIONS: Serial biopsies in patients with chronic diarrhea and normal colonoscopy identified changes in almost 50% of cases and 22% of these cases may had modified the treatment after identification of collagenous, lymphocytic and eosinophilic colitis.