Tissue polymerase chain reaction in diagnosis of intestinal tuberculosis and Crohn's disease

1) To evaluate the utility of PCR in differentiating intestinal tuberculosis from Crohn's disease. 2) To compare histological features of tuberculosis and Crohn's disease. A total of 60 cases of diagnosed intestinal tuberculosis and 20 Crohn's disease were included in the study. Clinical data, radiological and endoscopic findings and response to treatment were taken into consideration. Endoscopic biopsies from affected areas were subjected to histopathological examination and polymerase chain reaction (PCR) assay. Acid fast staining on tissue and culture was done whenever possible. Clinical symptoms, radiological and endoscopic findings were almost similar between intestinal tuberculosis and Crohn's disease. PCR was positive in 21.6% cases of intestinal tuberculosis and 5% Crohn's disease. Nine out of 42 cases (21.4%) without granuloma were also positive by PCR. There was no statistical difference for PCR positivity between patients with intestinal tuberculosis with or without granuloma on histology and also between caseating and non-caseating granuloma. PCR assay showed high specificity (95%) for the diagnosis of intestinal tuberculosis hence may be valuable method to differentiate intestinal tuberculosis from Crohn's disease.