Clinical outcome of patients examined by capsule endoscopy for suspected small bowel Crohn's disease

Capsule endoscopy has a greater diagnostic yield than radiology for detecting subtle inflammatory changes of the small bowel mucosa, but the clinical significance of these abnormalities is still uncertain because of the lack of long-term follow-ups.

To verify the accuracy of capsule endoscopy in a cohort of patients with suspected Crohn's disease of the small bowel, taking as 'gold standard' the final diagnosis made after a long follow-up. From April 2002 to March 2005, we enrolled and examined by capsule endoscopy 27 consecutive patients with abdominal pain and diarrhea lasting more than 3 months and at least one of the following: anaemia, weight loss, fever, extra-intestinal manifestation(s) of inflammatory bowel disease. All patients already had an unremarkable pan-endoscopy, serology for celiac disease and intestinal radiology inconclusive for small bowel abnormality. On the basis of capsule endoscopy findings, patients were distributed in three groups; Group A had severe stricturing lesions requiring surgery; Group B, moderate inflammatory lesions further investigated invasively; Group C, minimal inflammatory changes or normal findings, clinically observed every 3 months (median 21 months, range 15-29).

Small bowel inflammatory lesions were found in 16 of the 27 patients (diagnostic yield 59%). Three had surgery (Group A) and Crohn's disease was confirmed in two; the remainder had ileal adenocarcinoma in a pathological context of chronic inflammation. Crohn's disease was histologically confirmed in four of the five patients in Group B. Group C comprised 19 patients; Crohn's disease was confirmed in seven out of eight with positive capsule endoscopy, while only one of the patients with normal findings later developed overt ileal Crohn's disease. Sensitivity, specificity, positive and negative likelihood ratio were, respectively, 93%, 84%, 5.8 and 0.08. Assuming a 50% pre-test probability of disease, capsule endoscopy gave a post-test probability of 85%.

In our selected cohort, capsule endoscopy was highly sensitive in detecting small bowel inflammatory changes, enhancing by nearly 35% the pre-test probability of structural small bowel disease. Focal erythema and luminal debris may limit the specificity of capsule endoscopy.