Introduction:

Colonoscopy is part of the diagnostic arsenal in patients with chronic non-inflammatory diarrhea; however the colon mucosa may be normal. The diagnostic yield of colonoscopy is 7-31%, but it can provide a definitive diagnosis.

Aim:

To evaluate the usefulness of endoscopic biopsies in patients with chronic non-inflammatory diarrhea and normal colonoscopy.

Material and Methods:

Retrolective, transversal, descriptive study in a period of 5 years. Men and women between 18-90 years with non-inflammatory chronic diarrhea> 4 weeks were included, with normal initial laboratory tests (hemoglobin, C-reactive protein, thyroid-stimulating hormone, albumin), and normal colonoscopy.

Statistical Analysis:

Qualitative variables are presented in percentages and frequencies. Qualitative variables Chi2 or Fisher's exact test was used. P value less than 0.05 was considered significant.

Results:

349 patients were reviewed, 141/349 met inclusion criteria. The endoscopic biopsies in normal colonoscopy had a utility for a specific histological diagnosis in 25/141 (17.7%): eosinophilic colitis 11/141 (7.8%), lymphocytic colitis 9/141 (6.4%), ulcerative colitis 3/141 (2.1%), Crohn's disease 1/141 (0.7%), melanosis coli 1/141 (0.7%). The evolution of diarrhea < 6 months is more likely than a specific diagnosis compared > 6 months 20/51 (39.2%) vs 5/90 (5.5%) OR 10.9 (95% IC: 3.78-31.74). Eosinophilic colitis is more likely in the right colon compared to the left colon 9/11 (81%) vs 6/11 (54%) p = 0.001, and lymphocytic colitis 8/9 (88%) vs 5/9 (55%) p = 0.001.

Conclusions:

The usefulness of the biopsies in patients with chronic non-inflammatory diarrhea and normal macroscopic colon was 17.7%, these patients could benefit from a definitive treatment. Specific diagnoses were observed more frequently in patients with an evolution < 6 months and right colon biopsies.