Intermittent Inflammatory Bowel Disease and Microscopic Colitis: Variant or Epiphenomenon?

Background: Idiopathic inflammatory bowel disease and microscopic colitis are distinct entities; however, some clinical features overlap. Aims: To identify if these alternative diagnoses may direct clinical therapy more effectively. Methods: We describe seven patients who had intermittent phases of either inflammatory bowel disease or microscopic colitis in at least two separate occasions with matching clinical and endoscopic pictures. Results: Diarrhea was the presenting symptom in all cases. In two of seven cases, the initial diagnosis was microscopic colitis, and in five cases it was inflammatory bowel disease. Addition of medication specific to diagnosis had resulted in improvement in six out of seven cases. Among the seven patients we reported, three had used nonsteroidal antiinflammatory drugs, a well-known trigger, before the onset of microscopic colitis. Conclusions: Inflammatory bowel disease and microscopic colitis are distinct clinicopathologic entities that may coexist in the same patient. Triggering factors for microscopic colitis in the general population can also be the culprit in inflammatory bowel disease patients. Microscopic colitis may present as an epiphenomenon which is superimposed on predisposing inflammatory bowel disease patients. A thorough synthesis of all clinical, medication, endoscopic, radiology, and pathological data is crucial in these patients.