Prevalence of microscopic colitis in patients with chronic diarrhea in Egypt: a single-center study

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.

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.

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.

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.