Abstract:

Objective To investigate the evaluation standard and proper time point of anti-tuberculosis trial treatment for differential diagnosis between Crohn's disease (CD) and intestinal tuberculosis (ITB) in children. Methods Patients who were suspected CD or ITB by clinical symptoms and pathological examination, and confirmed with tuberculosis infection or positive acid-fast bacilli stain were retrospectively reviewed. Patients who had a history of anti-tuberculosis or immunosuppressant treatment and were diagnosed with congenital immunodeficiency disease combined with tuberculosis infection were excluded. Patients with caseous necrosis, positive acid-fast bacilli stain, extra-intestinal active tuberculosis, positive PPD test, positive bacterial smear test were administrated with anti-tuberculosis trial treatment. Pediatric Crohn's Disease Activity Index (PCDAI) and endoscopic evaluation were analyzed at 3, 6 and 12 months. ITB was confirmed by Paustian's criteria with Logan's modification and CD by pathological examination. Trial of anti-tuberculosis treatment were with 2-3 months of HRZE and 7-10 months OF HR. Results A total of 26 patients suspected CD or ITB were enrolled in this study. All cases were done PCDAI and endoscopic evaluation, 17 of them were diagnosed with ITB, 9 were with CD. No significant differences were found in clinical characteristics, laboratory index, endoscopy, small bowel MRE test, pathological examination, duration of anti-tuberculosis treatment and anti-tuberculosis drugs. In ITB group, the decrease of PCDAI ≥12.5 or the PCDAI≤10 between 3 months and baseline, between 6 months and baseline, between 12 months and baseline occurred in 6, 14 and 16 cases, respectively; whereas in CD group, the data were 1, 2 and 1 case, respectively. Mucosal healing and improvement rates of lesions at 6 months of treatment in ITB and CD group were 76.5% and 22.2%, respectively; the rate at 12 months was 94.1% and 11.1%, respectively (Fisher's exact test, P=0.000). To use success of anti-tuberculosis trial treatment as a golden standard, the positive predictive values of PCDAI at 3 and 6 months were 85.7% and 86.7%, respectively. The positive predictive value of endoscopic evaluation at 6 months was 86.7%. The specificity of PCDAI plus endoscopic evaluation was 88.9%, the positive predictive value was 92.9% which was 1.2% lower than that value at 12 months (94.1%). Conclusion With lack of special markers for differential diagnosis between CD and ITB, some cases still need to receive anti-tuberculosis trial treatment. In the course of anti-tuberculosis treatment, the improvement of clinical symptoms goes quickly compared with endoscopic evaluation. PCDAI plus endoscopic evaluation at 6 months of anti-tuberculosis trial treatment can be used as the best tool and time point for differentiating between ITB and CD in children.