Prevalence of Microscopic Colitis in Patients with Chronic Diarrhea in Egypt: A Single-center Study

BACKGROUND/AIM: Microscopic colitis (MC) is diagnosed when a patient with chronic watery non-bloody diarrhea (CWND) has an endoscopically normal colon, but colonic biopsies show unique inflammatory changes characteristic of lymphocytic or collagenous colitis. MC is a disorder of unknown etiology. Studies comparing the prevalence of the disease in developing countries as compared to developed countries may shed more light on the possibility of a post-infectious etiology. Most data on the incidence and prevalence of MC are from developed countries where it accounts for 4-13% of cases of CWND. There are only a few reports from developing countries. Two studies from Peru and Tunis, with high prevalence of infectious gastroenteritis, revealed MC in 40% and 29.3% of cases of CWND, respectively. The aim of this study was to investigate the prevalence of MC in patients presenting with CWND in Egypt. MATERIALS AND METHODS: A total of 44 patients with CWND of unexplained etiology who had undergone full colonoscopy with no macroscopic abnormalities between January 2000 and January 2010 were assessed retrospectively. RESULTS: The histological appearance of MC was identified in 22 (50%) patients. Twelve (55%) patients were male and 10 (45%) female. Mean age was 40 years (range: 20-65 years). Twenty (91%) of MC cases had lymphocytic colitis and 2 (9%) had collagenous colitis. CONCLUSIONS: The prevalence of MC in Egyptian patients with CWND is high when compared to that in developed countries. MC mainly affects young and middle-aged patients and it is more commonly of the lymphocytic type.