Role of Colonoscopy in Differentiating Intestinal Tuberculosis from Crohn’s Disease

Background: The interface between tuberculosis (TB) and Crohn’s disease (CD) is relevant as TB complicates both the diagnosis and management of CD. Aim: This study aimed to identify the distinctive characteristics of ileocaecal and colonic TB (C‑TB) and colonic CD (C‑CD) at colonoscopy and to correlate the colonoscopy findings with histology. Materials and Methods: This prospective study included consecutive patients presenting with classical symptoms of TB or CD. The colonoscopic findings were compared with histology, which was taken as gold standard. Appropriate statistical tests were applied. Results: Fifty‑eight individuals fulfilled the inclusion criteria. Nine and 16 patients with C‑TB and C‑CD, respectively, had histological confirmation of respective diagnosis. In 33 specimens, the histological diagnosis was inconclusive. The sensitivity of colonoscopy for diagnosing C‑TB was high at 88.9% (95% confidence interval [CI]: 51.8–99.7). It was 50% (95% CI: 24.7–75.4) for CD. The reverse was true for CD whose specificity was high at 71.4% (95% CI: 55.3–84.3) and low for TB at 46.9% (95% CI: 32.5–61.7). All the patients diagnosed as confirmed CD or TB responded well to respective treatment. Six of the thirty patients with failed response to anti‑TB treatment required surgery or change in treatment after 2 months. Conclusion: Colonoscopic findings of isolated ileal involvement, aphthous ulcer, cobble stoning, long‑segment strictures, skip lesions and perianal involvement favored a diagnosis of CD. Correlation of colonoscopy with histology is poor for both CD and TB. The accuracy, sensitivity and specificity of colonoscopy were better and superior for the diagnosis of CD, than in the diagnosis of TB.