Background: Along with the increased incidence of pulmonary tuberculosis in parallel with the increase in population in various parts of the world, in recent years, the incidence of abdominal tuberculosis has also increased. The pathogenetic events in intestinal tuberculosis, which culminate in ulcer formation, perforation, and stricture, still have to be identified.
Aim: To correlate the gross and microscopic features in intestinal tuberculosis, in particular tuberculous perforation with changes in mesenteric vasculature.
Patients and methods: A one-year prospective study of excised/resected tissues from patients with abdominal tuberculosis requiring surgical intervention was conducted. Tissues from fifty-six patients were included in the study-of which 36 were resected intestinal segments and 20 were intestinal and lymph node biopsies. Hematoxylin and Eosin and Ziehl-Neelsen stains were used for histopathological examination.
Results: Tuberculous enteritis was found to be present in 49 of the 56 patients (87.5%) (ileum being the site most commonly affected), while nodal involvement was seen in 39 (69.6%) patients. Perforations were present in 39 out of 49 (79.6%) intestinal tissues; most being solitary and ileum was the commonest site. Typical epithelioid cell granulomas were seen in the intestine and lymph nodes, with caseation being more prevalent in the latter. The mesenteric vasculature was frequently involved by granulomatous inflammation, with intravascular organizing thrombus being present in 30% of the resected specimens with perforation. Acid fast bacilli were demonstrated in the tissue sections of 37.5% of the patients. AFB positivity was higher in caseating granulomas.
Conclusion: Involvement of mesenteric vasculature by granulomatous inflammation was commonly associated with the ulcerative type with perforation, suggesting that ischemia caused by vascular thrombosis is responsible for tissue breakdown. This implies that vasculitis plays an important role in the natural history of abdominal tuberculosis.
Keywords: Abdominal tuberculosis; acid fast bacilli; intestinal perforation; mesenteric vasculopathy.