Microscopic colitis in children with chronic diarrhea.

Objective: The aim of the present study was to study microscopic colitis (MC) in children with special reference to its role in chronic diarrhea and changes in mucosal biopsies.

Methods: A total of 100 consecutive children ages 3 to 12 years, with nonbloody diarrhea (passage of ≥3 loose stools per day) of >12 weeks' duration were screened and 26 were enrolled in the study in which no specific etiology could be found and colonoscopy did not reveal any mucosal abnormality. Colonic biopsies were evaluated for the presence of lymphocytic colitis or collagenous colitis and those with the characteristic changes were defined to have MC (group A). Colonic biopsies from patients with MC were compared with biopsies from patients with chronic diarrhea but no evidence of MC (group B). One hundred children ages 3 to 12 years with bleeding per rectum were screened and colonic biopsies from 45 patients (group C) who had colonic mucosal changes but no vascular or polyp lesion were compared with patients with MC.

Results: Of the 26 patients with chronic diarrhea, MC was found in 5 (3 lymphocytic colitis and 2 collagenous colitis). Significantly higher polymorphonuclear infiltration was seen in group A as compared with group B (13.8 [5.4-20.6] vs 7.2 [0-19.6]; P = 0.03) or group C (13.8 [5.4-20.6] vs 4 [0-13.4]; P = 0.007). Intraepithelial lymphocytes (12 [4-32] vs 4 [0-24]; P = 0.008) and basement membrane thickening (3.5 [2.9-10.6] vs 2.5 [1.6-5.86]; P = 0.008) were also significantly higher in group A as compared with group C.

Conclusions: MC was found to be present in children with nonbloody chronic diarrhea in children. Further multicentric studies may provide adequate data on its prevalence.