Differentiation of Intestinal Tuberculosis from Crohn's Disease: Role of Colonoscopy.

INTRODUCTION : The tuberculosis epidemic is expanding and currently a third of the world's population is infected, the majority residing in the developing world. The epidemiology of IBD is also changing, though far less dramatically, with more cases from low and middle income countries being reported. There exists a multifaceted relationship between intestinal tuberculosis (ITB) and Crohn's disease (CD), as they share common pathogenic and clinical characteristics and were thought to be one in the same disease. The interface between these two diseases is particularly relevant in the developing world where tuberculosis complicates both the diagnosis and management of CD. Eighty per cent of all new cases in 2004 occurred in Africa, South-East Asia and Western Pacific regions and several studies have shown an increasing incidence of extrapulmonary TB. Recently drug resistant tuberculosis has been reported from 17 countries including the USA. Mortality in this untreatable form of TB is almost 100%. In patients with active pulmonary tuberculosis concurrent ITB can occur in up to 46% of patients if the gastrointestinal tract is examined. Autopsy studies have also shown that ITB often goes clinically undetected. Once considered rare in the developing world, the epidemiology of IBD is changing and the incidence of both CD and ulcerative colitis (UC) is increasing in the Asian Pacific region, India, Eastern Europe and South Africa. This is heralded by an increase in the incidence of UC followed by CD 15-20 years later. Making a diagnosis of Inflammatory Bowel Disease (IBD) in developed countries is facilitated by a limited differential diagnosis and unrestricted access to endoscopy and abdominal imaging. Moreover, a range of therapeutic options, including costly biological therapies are available, well-developed healthcare infrastructure is in place and patients have ready access to information about their disease. In contrast IBD in the developing world is overshadowed by enteric infections and awareness of the condition, by both patient and clinician, is often limited. In resource poor environments access to technology, such as endoscopy, is reduced making the diagnosis of IBD difficult. In those patients with an established diagnosis of IBD treatment is complicated by a high burden of infectious diseases, poorly developed healthcare infrastructure and barriers to accessing information. Furthermore, funding for IBD research in these environments is limited by competing healthcare needs. AIMS OF THE STUDY : To identify the distinctive characteristics of ileocecal and colonic tuberculosis (TB) and Crohn’s disease (CD) at colonoscopy and to correlate the colonoscopic findings with histology. CONCLUSIONS : Study population consisted of 58 cases. • Mean age was 30 + 12.44 yrs (range: 18 – 48yrs) with M: F ratio of 1.3:1, • Patients with a clinical suspicion of TB were from lower socio-economic strata, whereas those with CD were from affluent society. • Colonoscopic diagnosis of intestinal tuberculosis was in 55.1%, Crohn’s disease in 18.9%, and indeterminate disease in 25.9% of cases. • Colonoscopic findings of isolated ileal involvement, aphthous ulcer, cobble stoning, long segment strictures, and perianal involvement favored a diagnosis of Crohn’s disease rather than intestinal TB (P