Endoscopic skipping of the terminal ileum in pediatric Crohn disease

OBJECTIVE. Pediatric small-bowel (SB) Crohn disease (CD) may be missed if the terminal ileum (TI) appears normal at endoscopy and SB imaging is not performed. We sought to estimate the prevalence and clinical characteristics of pediatric patients with CD and endoscopic skipping of the TI-that is, pediatric patients with active SB or upper gut inflammation and an endoscopically normal TI. MATERIALS AND METHODS. This retrospective study included pediatric patients with CD who underwent both CT enterography (CTE) or MR enterography (MRE) and ileo-colonoscopy within a 30-day period between July 2004 and April 2014. The physician global assessment was used as the reference standard for SB CD activity. Radiologists reviewed the CTE and MRE studies for inflammatory parameters; severity, length, and multifocality of SB inflammation; and the presence of penetrating complications. RESULTS. Of 170 patients who underwent ileal intubation, the TI was macroscopically normal or showed nonspecific inflammation in 73 patients (43%). Nearly half (36/73, 49%) of the patients with normal or nonspecific findings at ileocolonoscopy had radiologically active disease with a median length of SB involvement of 20 cm (range, 1 to > 100 cm). Seventeen (47%) of these patients had multifocal SB involvement and five (14%) had penetrating complications. Overall, endoscopic TI skipping was present in 43 (59%) patients with normal or non-specific ileocolonoscopic findings: 20 with histologic inflammation (17 with positive imaging findings), 14 with inflammation at imaging only, and nine with proximal disease (upper gut, jejunum, or proximal ileum). There were no significant differences in the clinical parameters of the patients with and those without endoscopic TI skipping. CONCLUSION. Ileocolonoscopy may miss SB CD in pediatric patients that is due to isolated histologic, intramural, or proximal inflammation. Enterography is complementary to ileocolonoscopy in the evaluation of pediatric CD.