Diagnosis and management of microscopic colitis

Microscopic colitis,comprising collagenous and lymphocytic colitis,is characterized clinically by chronic watery diarrhea,and a macroscopically normal colonic mucosa where diagnostic histopathological features are seen on microscopic examination.The annual incidence of each disorder is 4-6/100000 inhabitants,with a peak incidence in 60-70-year-old individuals and a noticeable female predominance for collagenous colitis.The etiology is unknown.Chronic diarrhea,abdominal pain,weight loss,fatigue and fecal incontinence are common symptoms,which impair the health-related quality of life of the patient.There is an association with other autoimmune disorders such as celiac disease,diabetes mellitus,thyroid disorders and arthritis.Budesonide is the best-documented shortterm treatment,but the optimal long-term strategy needs further study.The long-term prognosis is good and the risk of complications including colonic cancer is low.