Table 1.

Diagnostic criteria for ulcerative colitis

A. Clinical manifestations: persistent or recurrent mucous-containing or bloody stools or a history of mucous-containing or bloody stools

B. (1) Endoscopic examination: (i) the mucosa is diffusely affected and coarse or finely granular, vascular translucency is absent, and lesions are fragile and easily hemorrhagic (hemorrhage on contact), with mucous and purulent secretions; (ii) multiple erosions, ulcers, or pseudopolyposis are present; and (iii) lesions are contiguous to the rectum (2) Intestinal radiography: (i) diffuse changes of the mucosal surface in the form of coarse or fine granules; (ii) multiple erosions and ulcers; or (iii) pseudopolyposis. Other findings include loss of the haustra (lead pipe appearance) and narrowing or shortening of the intestinal tract

C. Histopathology: during the active stage, diffuse inflammatory cell infiltration of the entire mucosal layer, crypt abscesses, and severe goblet cell depletion are observed. All of these findings are nonspecific and should be comprehensively evaluated. During remission, an abnormal glandular arrangement (meandering and branching) and atrophy remain. These changes are usually observed continuously from the rectum to the mouth

Examples of the confirmed diagnosis:  1. Cases that satisfy (1) or (2) of (B) or (C) in addition to (A)  2. Cases that satisfy (1) or (2) of (B) and (C) more than once during the course of disease  3. Cases with gross and histologic findings characteristic of disease observed during surgical resection or autopsy

Note 1: A confirmed case is defined as a case for which the following diseases should be excluded: infectious enteritis such as bacterial dysentery, Clostridioides difficile enteritis, amoebic colitis, Salmonella enteritis, Campylobacter enteritis, colonic tuberculosis, and Chlamydia enteritis, and other diseases, such as Crohn’s disease, radiation colitis, drug-induced colitis, lymphoid follicular hyperplasia, ischemic colitis, and intestinal Behçet’s disease

Note 2: If the diagnosis is not definite because of mild findings, then the diagnosis should be treated as uncertain

Note 3: When differentiating Crohn’s disease from ulcerative colitis proves difficult, follow-up should be performed. If a definitive diagnosis cannot be made based on the clinical picture, including endoscopic and biopsy findings, then the case should be classified as inflammatory bowel disease unclassified. If a definitive diagnosis cannot be made after a histopathological examination of the resected specimen, then the case should be classified as indeterminate colitis. During follow-up, more characteristic findings of either disease may emerge

Note 4: Familial Mediterranean fever may present with colorectal lesions, thus resembling ulcerative colitis, and may require differentiation based on the clinical course and other factors

Adapted from [1], with partial modification