Indeterminate colitis - definition, diagnosis, characteristics and management

Abstract

The distinction between ulcerative colitis (UC) and Crohn's disease (CD) affecting the colon is of paramount importance in inflammatory bowel disease (IBD) patients. However, this differentiation cannot always be definitively made, and these cases are usually characterized as cases of "indeterminate colitis". The Working Party of the World Congress of Gastroenterology in Montreal recommended the term IBD-type unclassified (IBDU) for IBD cases when characteristic features of UC and CD are absent, and the term indeterminate colitis (IC) only when colectomy is performed and a definitive diagnosis cannot be reached. Most cases of IC eventually evolve into definite CD or UC, but a percentage of patients remain with a diagnosis of IC for many years without ever showing typical features of either disease, suggesting that IC might represent a separate subgroup of IBD. There are no widely accepted histological criteria or findings for the diagnosis of IC; therefore it remains a diagnosis of exclusion. The use of ancillary tests, like serological markers and wireless capsule endoscopy, as an aid in the diagnosis of IC is still under investigation. Medical treatment of IC is similar to UC and CD. Ileal pouch-anal anastomosis surgery can be performed in IC patients with rates of pouch failure and functional outcome similar to UC patients, but with an increased risk of postoperative complications.