Indeterminate colitis.

The term indeterminate colitis has been used to describe cases of inflammatory bowel disease that cannot be classified as ulcerative colitis or Crohn's disease. However, this term has suffered varying definitions, which in addition to numerous difficulties in diagnosing inflammatory bowel disease has led to much confusion. The term indeterminate colitis should only be used in cases where a colectomy has been performed and the overlapping features of Crohn's disease and ulcerative colitis do not allow a definitive diagnosis. Over time the majority of patients remain with a diagnosis of indeterminate colitis, or show symptoms similar to ulcerative colitis. Ileal pouch-anal anastomosis surgery can be performed in such patients, with outcomes of pouch failure and functional outcome that are similar to those in patients with ulcerative colitis but with increased risk of postoperative pouch complications. This review addresses the definition of indeterminate colitis, its pathology, natural history, and outcomes of restorative proctocolectomy.