Differentiation of Isolated Small Bowel Crohn's Disease from Other Small Bowel Ulcerative Diseases: Clinical Features and Double-Balloon Enteroscopy Characteristics

BACKGROUND: The diagnosis of isolated small bowel Crohn's disease (ISBCD) has always been challenging. AIMS: This study is aimed at comparing the clinical features and double-balloon enteroscopy (DBE) characteristics of ISBCD with those of other small bowel ulcerative diseases (OSBUD). METHODS: Patients with coexisting colonic and/or ileal valve lesions (n = 45) or whose final diagnosis was not determined (n = 29) were excluded. One hundred thirty-nine patients with ISBCD and 62 patients with OSBUD found by DBE were retrospectively analyzed. RESULTS: The age of ISBCD onset was lower than that of OSBUD (OR 0.957, 95% CI 0.938-0.977, p < 0.001). Abdominal pain was more common in ISBCD (OR 4.986, 95% CI 2.539-9.792, p < 0.001). Elevated fibrinogen levels (OR 1.431, 95% CI 1.022-2.003, p = 0.037) and lower levels of D-dimer (OR 0.999, 95% CI 0.999-1.000, p = 0.017) were also more supportive of the diagnosis of ISBCD. Nonsteroidal anti-inflammatory drugs (NSAIDs) used for more than two weeks decreased the probability of a diagnosis of ISBCD (OR 0.173, 95% CI 0.043-0.695, p = 0.013). Abdominal computed tomography revealed a higher proportion of skip lesions in ISBCD than in OSBUD (OR 9.728, 95% CI 3.676-25.742, p < 0.001). The ulcers of ISBCD were more distributed in the ileum (111 (79.9%) vs. 29 (46.8%), p < 0.001), and their main morphology differed in different intestinal segments. Longitudinal ulcers (OR 14.293, 95% CI 4.920-41.518, p < 0.001) and large ulcer (OR 0.128, 95% CI 0.044-0.374, p < 0.001) contributed to the differentiation of ISBCD from OSBUD. We constructed a diagnostic model, ISBCD index (AUROC = 0.877, 95% CI: 0.830-0.925), using multifactorial binary logistic regression to help distinguish between these two groups of diseases. CONCLUSION: Clinical features, laboratory tests, abdominal computed tomography, DBE characteristics, and pathology help to distinguish ISBCD from OSBUD.