Tuberculosis of GITDr Parvathy S Nair

Introduction

• TB can involve any part of GIT from mouth to anus, peritoneum & pancreatobiliary system.

• TB of GIT- 6th most frequent extrapulmonary site.

• Mycobacterium tuberculosis is the pathogen in most cases.

• Mycobacterium bovis in some parts of the world

• Mycobacterium avium intracellulare has become a major pathogen in HIV patients.

Etiopathogenesis

• Mechanisms by which M. tuberculosis reach the GIT:

– Hematogenous spread from primary lung focus

– Ingestion of bacilli in sputum from active pulmonary focus.

– Direct spread from adjacent organs.

– Via lymph channels from infected LN

PATHOGENESIS

Bacilli in the depth of mucosal glands

Inflammatory Reaction

Phagocytes carry bacilli to Peyer’s Patches

Formation of tubercle and necrosis

Endarteritis,edema and sloughing

Ulcer formation

Accumulation of collagen-Thickening and stenosis

Inflammation spreads from submucosa to serosa

Bacilli via lymphatics – Lympahtic obstruction and Regional Lymphadenitis

Pathology

• (A) Ulcerative form: Ulcers wit their long axis perpendicular to the axis of the intestines; with pseudopolyps

• (B) Hypertrophic form: Thickeningof bowel wall

• (C) Mixed type

Distribution of tuberculous lesions

Ileum > caecum > ascending colon > jejunum

>appendix > sigmoid > rectum > duodenum

> stomach > oesophagus

• More than one site may be involved

Illeoceacal TB (80-90%)PLAIN XRAY• Enteroliths with features of obstruction• Small or large lamellated stones

BARIUM ENEMA• Irregular thickened nodular folds in the

terminal illeum• ‘Stierlin sign’: on Ba enema -rapid emptying of

narrowed terminal illeum into the cecum which is shortened and rigid

• Thickened illeoceacal valve

• ‘Fleischner sign’: Inverted umbrella defect:- wide gaping patulous IC valve associated with narrowing of the immediately adjacent terminal illeum

• Deep fissures and large shallow linear/stellate ulcers with elevated margins

• Sinus tracts and fistulas• Symmetric annular ‘napkin ring ‘ stenosis

Enema shows wide gaping of ileocecal valve with thickening of valve

Contrast barium enema image demonstrates marked narrowing of the caecum, ascending colon and terminal ileum. Dilatation of the small intestine proximal to the narrowed segment of ileum is also seen.

CT• Circumferential wall thickening of cecum and

terminal ileum• Asymmetric thickening of ileoceacal valve and

medial wall of ceacum• Localized mesenteric lymphadenopathy with

areas of central low attenuation

USG

• Thickening of IC valve and adjacent medial wall of cecum- asymmetrically thickened.

• Crohn’s – Eccentric thickening in mesenteric border.

• Carcinoma- Variegated appearance.

• Pseudokidney mass.

• Advanced cases – Complex mass - wall thickening, adherent loops, regional nodes, mesenteric thickening.

Colonic TB (9%)

• Segmental colonic involvement-rt sided• Imaging:–Rigid,contracted cone shaped ceacum– Spiculations with wall thickening–Diffuse ulcerative colitis and pseudopolyps– Short hour glass strictures–Ulcer- Circumferential in TB, along the

mesenteric border in Crohn’s.

Gastroduodenal TB (1%)

• Simultaneous involvement of antrum,pylorus and duodenum

• Imaging:-– Stenotic pylorus with GOO– Narrowed antrum –linitis plastica appaearance– Antral sinus tracts/fistula– Multiple, large and deep ulcerations on the lesser

curvature – Thickened duodenal folds wit irregular contour

TB of esophagus(0.2%)

• More assc with HIV• Deep ulceration-mid esophageal• Strictures• Intramural dissection/fistula formation

Peritoneal tuberculosis occurs in 3 forms.

• Wet type – 90 %. - Ascitis, free or encysted fluid

High density 25-45HU.- Cellular / fibrin content.

• Fibrotic fixed type – Mescentric and omental thickening, matted lymph nodes with occasional fluid.

• Dry or plastic type – Caseous nodules, fibrotic peritoneal reflections.

Imaging• Omental cake.

- Irregular thickened outer contour- Malignancy. -Thin omental line, fibrous wall –TB - Extra peritoneal spread-TB

• Mesentery- Stellate sign- Mesentric contraction results in fixed loops of bowel and mesentery standing out as spokes from the root.

• Club sandwich sign – localised ascites in between the radially oriented bowel loops.

Omental cake and ascites

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