EXCELLENT LONG-TERM NEGATIVE PREDICTIVE VALUE OF CAPSULE ENDOSCOPY IN SUSPECTED ISOLATED SMALL BOWEL CROHN’S DISEASE

Abstract

There is no unique diagnostic test for Crohn's disease (CD), and the diagnosis of isolated small bowel Crohn’s disease (SBCD) is even more challenging, due to non-pathognomonic clinical picture and low availability of accurate exploration methods.  Small bowel capsule endoscopy (SBCE) revolutionized the approach of middle gastrointestinal tract, becoming the first investigation tool when small bowel pathology is suspected. The aim of our study was to assess the value and safety of SBCE in diagnosing isolated SBCD. Materials and methods: We retrospectively studied the patients undergoing SBCE for suspected isolated SBCD, in a six-year period, including in our analysis only the patients with a minimum of 18-month follow-up period. We assessed the global diagnostic yield (DY) of SBCE, as well as its yearly variation in time over the six-year period, and the complication rate. Subsequently, analyzing follow-up data, positive and negative predictive values were assessed. Results: 78 patients were investigated by SBCE for suspected isolated SBCD, mostly men (60.3%), with age ranging from 20 to 69 years old. SBCE showed lesions compatible with the diagnosis of SBCD in 49 patients, corresponding to a specific diagnostic yield of 62.8%, while for the remaining 29 patients (37.2%), no suggestive lesions were found. Following additional investigations, three of the 49 patients initially thought as having isolated SBCD were reclassified as intestinal lymphoma, eosinophilic gastroenteritis and intestinal tuberculosis, respectively, corresponding to a positive predictive value of 93.8%. During follow-up, none of the 29 patients with negative SBCE was diagnosed with CD, corresponding to a negative predictive value of 100%. We found a progressively increase of the diagnostic yield over time (from 42.6% in the first year to 70.2% in the last year of the analyzed period), corresponding the most probably to the refinement of the indication. Conclusions: SBCE has good DY and a high positive predictive value for isolated SBCD. However, it remains a purely visual technique with no capability of taking biopsies, so final diagnosis needs confirmation by additional investigations. Nevertheless, SBCE has a 100% long-term negative predictive value, being an excellent tool for ruling out isolated SBCD.