Microscopic Colitis in a Tertiary Care Hospital in Nigeria: Rare or Under-reported?

A bstract Background: Chronic diarrhea is a cause of significant morbidity among Nigerians. Microscopic colitis (MC) is characterized by chronic watery diarrhea with no macroscopic abnormality observed on endoscopy. There is limited data on MC in Nigeria, and hence the need for this study. Objectives: The objective was to determine the pattern of chronic watery diarrhea among patients who underwent colonoscopy for this indication. Materials and Methods: This was a 5-year retrospective study of patients who underwent colonoscopy at Nigerian healthcare facility from January 2018 to December 2022. The pattern of chronic watery diarrhea was assessed, and patients who had it with a normal-looking mucosa on colonoscopy were further isolated from the colonoscopy register and studied. Results: A total of 789 colonoscopies were carried out within the study period. The prevalence of chronic watery diarrhea was 4.4% (n = 35). The most common indication for colonoscopy was lower gastrointestinal bleeding, (35.4%), while anemia was among the least common indication (1.8%). The commonest endoscopic finding in the 35 patients with chronic watery diarrhea was ‘a healthy-looking mucosa’, diagnostic of MC (18/35, 54.4%). Conclusion: MC is an under-recognized cause of chronic watery diarrhea in Nigeria.