Microscopic colitis in patients with diarrhea predominant irritable bowel syndrome

Background and aim Functional bowel disorders, such as irritable bowel syndrome accompanied by diarrhea (IBS-D), present symptoms similar to microscopic colitis (MC), which include recurrent watery diarrhea and abdominal discomfort. This study aimed to find whether IBS-D patients have MC. Patients and methods The study involved 100 IBS-D patients based on Rome IV criteria. Participants underwent medical history assessment, clinical examination, and colonoscopy with biopsy and histological examination. Results The mean duration of diarrhea whether continuous or intermittent is 10.34±2.26. Histological examination of biopsy in patients with normal colonoscopy revealed that MC is present in 10% of the patients, and lymphoid hyperplasia and eosinophilic colitis constitute 4% of the patients for each one. Normal histological findings were found in 50% of IBS-D patients. MC patients were older and most of them were females when compared with the other IBS-D patients. Conclusion MC is a relatively common condition, particularly in older adults, and can be easily mistaken for IBS-D. Accurate diagnosis requires histopathological examination of colonoscopic biopsies from normal-appearing mucosa.