Isolated nonspecific terminal ileitis: prevalence, clinical evolution and correlation with metachronous diagnosis of Crohn's disease: a retrospective study and review of the literature.

Background: The existing literature does not provide adequate guidance on the diagnosis and management of patients with nonspecific terminal ileitis, while data regarding the percentage of patients who ultimately develop Crohn's disease (CD) are scarce. We evaluated the prevalence and natural course of nonspecific terminal ileitis in patients who underwent colonoscopy during a 11-year period. Methods: All patients with endoscopic findings of terminal ileitis and nonspecific histological findings were included. Exclusion criteria were a clinical history of CD or any other disease that can cause terminal ileitis, or a recent history of using drugs implicated in lesions of the terminal ileum. Results: From 5353 colonoscopies, 92 patients with nonspecific terminal ileitis were identified (prevalence: 1.7%). Among these patients, 56 (61%) had available follow up for ≥6 months after the initial endoscopy. Main indications for endoscopy were chronic diarrhea (37.5%), screening endoscopy (23%), and abdominal pain (20%). Sixteen (29%) patients received medical treatment, while recession of symptoms was recorded in 19 of 43 symptomatic patients (44.1%). Twenty-three (41%) of the 56 patients underwent a second endoscopy and 15 (65.2%) cases had persistent endoscopic findings. Eleven (19.6%) of the 56 patients were eventually diagnosed with CD. The probability of CD diagnosis was significantly higher in patients with persistent symptoms (P=0.002) and endoscopic findings at follow up (P=0.038). Conclusions: Nonspecific terminal ileitis generally has a benign clinical course. However, patients with persistent symptoms and endoscopic lesions are at increased risk for subsequent development of CD.