Disease Information for Tuberculosis, intestinal (gut): Definition

The TB pathogen is Mycobacterium tuberculosis. Other mycobacterial species that simulate TB are M bovis, M avium, and M intracellulare.

Routes of GI infection include the following: (1) spread by means of the ingestion of infected sputum, in patients with active pulmonary TB and especially in patients with pulmonary cavitation and positive sputum smears; (2) spread through a hematogenous route from tuberculous focus in the lung to submucosal lymph nodes; and (3) local spread from surrounding organs involved by primary tuberculous infection (eg, renal TB causing fistulas into the duodenum or mediastinal TB lymphadenopathy involving the esophagus).

Clinical features of intestinal TB include abdominal pain, weight loss, anemia, and fever with night sweats. Patients may present with symptoms of obstruction, right iliac fossa pain, or a palpable mass in the right iliac fossa. Hemorrhage and perforation are recognized complications of intestinal TB, although free perforation is less frequent than in Crohn disease.

Malabsorption may be caused by obstruction that leads to bacterial overgrowth, a variant of stagnant loop syndrome. Involvement of the mesenteric lymphatic system, known as tabes mesenterica, may retard chylomicron removal because of lymphatic obstruction and result in malabsorption.

The ileum is more commonly involved than the jejunum. Ileocecal involvement is seen in 80-90% of patients with GI TB. This feature is attributed to the abundance of lymphoid tissue (Peyer patches) in the distal and terminal ileum.

Proximal small intestinal disease is seen more commonly with M avium-intracellulare (MAI) complex infection, predominantly infection involving the jejunum. Intestinal obstruction may be partial or complete with TB. Segmental involvement usually is in a stenotic form.

[eMedicine.com 2008 Online]

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