Differentiating Crohn's disease from intestinal tuberculosis at presentation in patients with tissue granulomas.

Background: Overlapping clinical, endoscopic, radiographic and histological features, coupled with poor microbiological yield, make differentiating Crohn's disease (CD) from intestinal tuberculosis (ITB) challenging. Granulomas are present in both diseases; in CD they predict the need for immunosuppressive therapy that requires ITB to be excluded before initiation.
Objectives: To compare granuloma-positive CD and ITB, to identify factors that may aid in diagnosis.
Methods: This was a retrospective cohort study evaluating granuloma-positive CD and ITB identified from a pathology database.
Results: Sixty-eight ITB and 48 CD cases were identified. Patients with ITB were more likely to be male, and to have HIV infection, isolated colitis, night sweats and tachycardia. ITB was also associated with lower serum albumin and haemoglobin and higher C-reactive protein levels, a chest radiograph showing active tuberculosis, and lymph nodes >1 cm on imaging. Extraintestinal manifestations (EIMs) were predictive of CD. There were no significant differences in smoking status, symptom duration or perianal disease. On multivariate analysis, HIV positivity (odds ratio (OR) 29.72, 95% confidence interval (CI) 2.15 - 410.96; p=0.01), isolated colitis (OR 6.17, 95% CI 1.17 - 32.52; p=0.03) and the absence of EIMs (OR 0.10, 95% CI 0.01 - 0.65; p=0.02) remained significant risk factors for ITB.
Conclusion: This is the first study to identify clinical and biochemical factors to aid in differentiating granuloma-positive ITB from CD. EIMs support a diagnosis of CD, while isolated colitis and HIV are predictors of ITB.