Tuberculosis (TB) is still a prevalent disease in Korea, although its incidence has been gradually decreasing [12, 13]. Intestinal involvement of TB, that is ITB, shares clinical features with CD, such as abdominal pain, diarrhea, weight loss, and fever. It is often challenging to differentiate between CD and ITB during colonoscopic evaluations. A Korean study proposed a simple colonoscopic scoring system for differentiation between CD and ITB [14]. In that study, anorectal lesions, longitudinal ulcers, aphthous ulcers, and a cobblestone appearance were more commonly observed in CD (Fig. 24.3), whereas the involvement of fewer than four segments, a patulous ileocecal valve, transverse ulcers, and scars or pseudopolyps suggested ITB rather than CD (Fig. 24.4) [14]. A score of +1 was assigned to the four parameters that were suggesting CD, and −1 to the other four parameters, which were indicative of ITB [14]. The colonoscopic diagnosis was considered to be CD when the sum of the scores for the above eight parameters was greater than zero, and the diagnosis to be ITB when that sum was less than zero; the diagnosis was regarded as indeterminate when the sum was zero [14]. Using the above scoring system, 87.5% of patients (77/88) were able to be correctly diagnosed with either CD or ITB [14]. Meanwhile, through a culture assay using both solid and liquid media for colonoscopic biopsy tissue, the sensitivity of a culture for Mycobacterium tuberculosis in diagnosing ITB could be increased up to 44.1%, suggesting the importance of culture assay for suspected ITB cases [15].

During a screening colonoscopy, aphthous or small ulcerations confined to the terminal ileum unaccompanied by coincidental ulcerations in the ileocecal valve or colon (isolated terminal ileal ulcers [ITIUs]) may be observed sometimes [16]. However, their natural course and prognosis have remained unclear. In a recent Korean study, 93 cases with ITIUs without colorectal symptoms, a history of nonsteroidal anti-inflammatory drug consumption, a history of colorectal surgery, or oral or genital ulcerations were followed for a mean duration of 30 months [16]. Of the 93 patients, ITIUs resolved without any treatment in 60 patients (64.5%) and continued in 30 patients (32.3%) without any progression [16]. Of the remaining three patients, two patients (2.2%) were diagnosed with ITB and one patient (1.1%) was diagnosed with CD [16]. These results suggest a favorable prognosis of ITIU, but larger-scaled, long-term follow-up studies in other ethnic groups are needed for a more proper characterization of ITIUs.

In areas with distinctive epidemiologic characteristics of chronic inflammatory disorders of the gastrointestinal tract, such as Korea, endoscopy may play a unique role. Recent Korean studies suggest the essential role of colonoscopy in the correct differential diagnosis of IBD as well as in predicting the clinical course of IBD. By acquiring knowledge of the endoscopic features of various inflammatory disorders and by applying this knowledge appropriately depending on the clinical situation, the quality of IBD care can be improved.