Primary intestinal tuberculosis without pulmonary disease often results in hypertrophic mucosal changes. Patients with acute miliary tuberculosis may also have gastrointestinal involvement.173 Patients with primary intestinal tuberculosis may present with abdominal pain, fever, and a tender, fixed, palpable mass in the ileocecal area. Primary hypertrophic intestinal tuberculosis continues to occur in the Middle East174 and in India.175 Intestinal involvement secondary to pulmonary tuberculosis may result from swallowing infected sputum or from biliary excretion of the organism from an infected liver. The frequency of secondary intestinal tuberculosis increases with far-advanced pulmonary disease. Hippocrates stated that “diarrhea attacking a person with phthisis is a mortal symptom.”

Tuberculosis may involve any part of the gastrointestinal tract, but most ulcerative and hypertrophic types occur in the ileocecal region, where there is a predominance of submucosal lymphatic tissue. The most common features are fever and abdominal pain that is often relieved by defecation or vomiting. Weight loss is more common in secondary intestinal tuberculosis. Only one third of the patients with gastrointestinal tuberculosis have diarrhea. Diarrhea may be related to exacerbations of abdominal pain and occasionally occurs with extensive involvement of the small intestine, which may cause steat­orrhea and a malabsorption syndrome. Although ulceration and mucous diarrhea are relatively common with secondary intestinal tuberculosis, hemorrhage and the presence of gross blood in the stool are distinctly uncommon, perhaps because of the associated obliterative endarteritis.

The diagnosis of gastrointestinal tuberculosis may be very difficult radiologically and even histologically. It must be distinguished from regional enteritis, sarcoidosis, actinomycosis, ameboma, carcinoma, and periappendiceal abscess. In contrast to Crohn’s disease, gastrointestinal tuberculosis rarely causes anal lesions, fistulas, or perforation. It is often associated with miliary nodules on the serosa, it rarely causes strictures longer than 3 cm, and it may cause circumferential transverse ulcers. Tuberculosis may also cause fibrosis of the muscularis mucosa, pyloric metaplasia, and epithelial regeneration.There may be minimal or no radiologic changes in the bowel mucosa. Small mucosal ulcerations may result in tiny calcified nodules in the mucosa in association with calcified mesenteric lymph nodes analogous to those seen in the pulmonary Ghon complex. The ileocecal region often reveals radiologic evidence of irritability and hypermotility, with hypersegmentation of the mucosal folds or poor filling of the ileocecal region detected by barium enema. On occasion, frank ulcerations can be noted on contrast studies, and, late in the course, there is scarring. The diagnosis requires a careful examination of involved tissue for acid-fast bacilli by using special stain and culture. Caseous necrosis is more frequently found in the mesenteric nodes than in intestinal tissue itself. Complications of intestinal tuberculosis include perforation, peritonitis, and obstruction from hypertrophy, scarring, or tuberculoma.