Background: Clinical phenotypes in inflammatory bowel disease (IBD) patients include ulcerative colitis (UC) and Crohn's disease (CD). Moreover, genetic aetiology studies suggest a continuum of phenotypes from exclusively ileal to left-sided colonic disease.
Patients and methods: A nationwide registry (BioColitis Registry) prospectively recorded ∼900 UC-patients in Germany and in the CapColitis substudy, small bowel capsule endoscopy (SBCE) was consecutively offered at participating centres. The primary objective was to investigate the presence of small bowel lesions. In total, 127 UC-patients were included.
Results: SBCE was evaluable in 125 of 127 UC-patients. Small bowel lesions were found in 16/125 (13%) patients, of which nine were classified as clinically significant [backwash ileitis (n=4) or lesions suggestive of CD (n=5)], and seven were not significant [biopsy-induced lesions (n=3) or single small bowel lesions (n=4)]. The SBCE results prompted diagnostic workups in all patients with clinically relevant lesions, and all patients with lesions suggestive for CD (4%) were re-classified as CD by the treating physicians.
Conclusion: Systematic examination of 125 consecutive UC-patients failed to confirm a clinically important phenotype overlap with CD, as suggested by genetic aetiology studies. In five patients (4%) with small bowel lesions, the diagnosis was changed to CD.