Diagnostic approach to small bowel involvement in inflammatory bowel disease: View of the endoscopist

Recent advances in endoscopic small bowel (SB) techniques have revolutionalized the diagnostic approach of patients with suspected or known inflammatory bowel disease (IBD). Wireless capsule endoscopy (WCE) has become an important diagnostic tool for the evaluation of suspected CD of the SB or in patients with known IBD to rule out SB involvement. The greatest utility of WCE has been observed in cases of suspected CD, where the initial evaluation with traditional radiographic and endoscopic studies has failed to establish the diagnosis. WCE can detect early SB lesions that can be overlooked by traditional radiological studies. The sensitivity of diagnosing SB CD by WCE is superior to other endoscopic or radiological methods such as push enteroscopy, computed tomography or magnetic resonance enteroclysis. The utility of WCE in patients with known CD, IBD unclassified (IBDU) and a select group of patients with ulcerative colitis (UC) can better define the diagnosis and extent of the disease and may lead to reclassification of IBD from UC/IBDU to definitive CD. In addition, previously diagnosed patients with CD may be found to have more significant disease burden in the SB. This information may facilitate more targeted and effective therapies and potentially lead to better patient outcomes. A disadvantage of WCE is its low specificity and the risk of being retained in a strictured area of the SB. Balloon-assisted enteroscopy has essentially replaced push enteroscopy, and has been used to treat CD strictures, obtain biopsies from areas of SB involvement and even retrieving a retained capsule.