Diagnostic techniques for IBD: the ECCO-ESGAR Guidelines

The ECCO and the ESGAR have developed new comprehensive and user-friendly guidelines for IBD. The key areas are initial diagnosis and monitoring of therapy, complications, endoscopic and clinical scoring, and general principles as well as technical aspects of IBD.

Upper gastrointestinal endoscopy is (still) recommended for Crohn’s disease (CD) patients with upper gastrointestinal symptoms, but it is no longer recommended for asymptomatic, newly diagnosed patients. They should undergo small bowel assessment, with the preferred method depending on local availability and expertise. Capsule endoscopy has good sensitivity for early mucosal inflammation, but can only detect mucosal changes. Magnetic resonance imaging (MRI) and intestinal ultrasound (IUS) can describe the transmural inflammation and detect complications such as fistulas. MRI can also detect deep ulcerations, and thickened small bowel walls. IUS can be performed by the treating gastroenterologist, no preparation is needed, and it is inexpensive. When monitoring the therapeutic success in CD, clinical and biochemical responses to CD treatment should be determined within 12 weeks following initiation of therapy. Endoscopic or transmural response to therapy should be evaluated within six months following initiation of therapy. In clinically responsive ulcerative colitis (UC) patients, mucosal healing should be determined endoscopically or by using faecal calprotectin (FCP) levels approximately three to six months after medical therapy.

For clinically asymptomatic IBD patients, monitoring is aimed at early recognition of a disease flare. The interval of monitoring should be between three and six months depending on the duration of remission and current therapy. Relapse can be detected with FCP before clinical symptoms occur.

Colonoscopy is the technique of choice to assess disease activity in symptomatic CD or UC patients. Complementary cross-sectional imaging can be used to assess phenotype as an alternative. Sigmoidoscopy should be considered in UC if symptoms suggest an acute severe flare. Symptomatic small bowel disease can be investigated with MR enterography, IUS, or small bowel capsule endoscopy.

The reference standard in diagnosing post-operative recurrence after ileocolonic resection is ileocolonoscopy, while endoscopy is recommended within the first 6 to 12 months post-surgery. Non-invasive alternatives to detect post-operative recurrence – especially in small bowel resection – are FCP, IUS, MR enterography and small bowel endoscopy. For the detection of strictures in the case of complications, cross-sectional imaging should be used. Due to radiation associated with computed tomography (CT), the preferred methods are MRI and IUS. Cross-sectional imaging is also recommended for the detection of abscesses and fistulae. Perianal CD should be reassessed by clinical and endoscopic examination of the rectum and MRI. Ultrasonography in the absence of anal stenosis or transperineal ultrasonography can be used instead of MRI. CT is the recommended technique for investigating acute post-operative complications in IBD patients.

A number of clinical scoring systems exist for CD and UC. The guidelines point out that endoscopic scores in UC should be used for standardisation of care. The Mayo subscore is accepted and extensively used, and the UC Endoscopic Index of Severity is formally validated. The Pouchitis Disease Activity index provides a standard definition of pouchitis. In CD, the CD Endoscopic Index of Severity (CDEIS) and the Simple Endoscopic Score (SES-CD) are validated and reproducible scoring systems measuring luminal endoscopic activity. There is no validated definition and score of mucosal healing in CD, however. The severity of post-surgical CD recurrence in the neo-terminal ileum should be stratified using the Rutgeert’s score.

These newly developed guidelines have been submitted for publication and are expected to be available online by spring 2018 [1].