Small bowel tuberculosis is gastrointestinal involvement by Mycobacterium tuberculosis, with the ileocecal region affected in 60-75% of all abdominal TB cases. Infection may develop through ingestion (sputum, contaminated dairy products), hematogenous spread (from pulmonary TB), or contiguous extension (from peritoneal TB, tubal TB). The preferential ileocecal involvement is attributed to the abundant lymphoid tissue (Peyer's patches) in this region, which facilitates mucosal penetration of bacilli. The disease manifests in three morphological forms: ulcerative (60%), hypertrophic (10%), and ulcerohypertrophic (30%). Ulcers typically run transverse to the long axis of the bowel — a key distinguishing feature from the longitudinal ulcers of Crohn's disease. Caseous necrosis within granulomatous inflammation produces rim-enhancing low-attenuation centers in mesenteric lymph nodes. In advanced stages, cecal contraction and the cecal 'pull-up' sign (upward retraction of the cecum) are characteristic. Peritoneal involvement is also frequent, manifesting as wet (ascites), dry (fibrous adhesions), or fixed (omental cake) forms.
Age Range
15-55
Peak Age
35
Gender
Equal
Prevalence
Uncommon
M. tuberculosis bacilli traverse the M cells of Peyer's patches in the ileocecal region to reach submucosal lymphoid tissue. This region's abundant lymphoid tissue, physiological stasis (decelerating effect of the ileocecal valve), and high absorptive capacity predispose to infection establishment here. Following mucosal penetration, granulomatous inflammation begins; granulomas composed of epithelioid histiocytes, Langhans giant cells, and caseous necrosis develop. Caseous necrosis manifests on imaging as low-attenuation centers within lymph nodes — the surrounding active granulation tissue around this necrotic center produces rim enhancement. Ulcers develop transversely following the submucosal lymphatic drainage pattern within the bowel wall; this transverse ulcer pattern is critical for differentiation from the longitudinal ulcers of Crohn's disease. Chronic inflammation and fibrosis create bowel wall thickening, strictures, and cecal contraction — the contracted cecum is seen as upward retraction of the ileocecal valve (pull-up sign) on CT and barium studies. In peritoneal spread, exudative ascites and omental thickening develop; omental cake formation can mimic peritoneal carcinomatosis on imaging. During fibrotic healing, calcified granulomas and mesenteric lymph node calcification form.
Superior retraction of the ileocecal valve and terminal ileum due to fibrotic contraction of the cecum in chronic ileocecal TB. Narrowing of the angle between the contracted, shrunken cecum and the terminal ileum, with superior displacement of the cecum from its normal anatomical position, is pathognomonic. This finding reflects fibrosis and cecal wall contraction due to chronic granulomatous inflammation.
Concentric, symmetric wall thickening in the ileocecal region accompanied by cecal contraction. Terminal ileum and cecum wall are thickened to 4-8 mm. The contracted cecum has lost its normal haustral pattern, is shrunken, and the ileocecal valve is retracted superiorly (pull-up sign). The cecal lumen is narrowed, sometimes completely obliterated. This constellation of findings is pathognomonic for TB and distinctly different from the asymmetric wall thickening of Crohn's disease.
Report Sentence
Concentric wall thickening in the ileocecal region with cecal contraction and superior retraction of the ileocecal valve (pull-up sign) is consistent with small bowel tuberculosis.
Conglomerate lymphadenopathies in mesenteric and retroperitoneal regions showing low-attenuation necrotic centers with peripheral rim enhancement. Lymph nodes are frequently >10 mm in short axis and tend to coalesce. The necrotic center reflects caseous necrosis and measures 20-40 HU. Peripheral rim enhancement indicates active granulomatous inflammation. This pattern can also be seen in lymphoma and treated metastatic LAP, but its combination with ileocecal involvement strongly supports TB.
Report Sentence
Conglomerate rim-enhancing mesenteric lymphadenopathies with necrotic centers are identified; in conjunction with ileocecal involvement, mesenteric tuberculous lymphadenitis should be considered.
Peritoneal TB involvement manifests as high-density (15-30 HU) ascites, smooth diffuse peritoneal thickening, and omental thickening/cake formation. Ascites may be free or loculated. Peritoneal enhancement is homogeneous and smooth — in contrast to the nodular, irregular thickening of peritoneal carcinomatosis, TB produces smooth peritoneal thickening. Omental cake appears as infiltratively thickened omentum with homogeneous enhancement.
Report Sentence
High-density ascites, smooth peritoneal thickening, and omental infiltration are observed in the abdomen, consistent with peritoneal tuberculosis.
Calcification within mesenteric lymph nodes is seen in chronic/healed TB. Calcification pattern may be peripheral (eggshell) or diffuse homogeneous. Calcified lymph nodes are 1-3 cm in size and located in the ileocecal mesentery and peripancreatic/para-aortic regions. The presence of calcified nodes alongside active necrotic LAP indicates coexistence of old and new infection. Calcifications are easily detected on non-contrast CT (>100 HU).
Report Sentence
Calcified mesenteric lymph nodes are identified, consistent with prior/healed granulomatous disease (tuberculosis).
T2-weighted images show bowel wall edema and stratification in the ileocecal region. In active inflammation, submucosal edema causes the bowel wall to display a hyperintense layer — this is termed the 'target sign' or 'double halo sign.' The inner hyperintense ring corresponds to edematous submucosa, the outer hypointense ring to the muscularis propria. MRI provides better soft tissue contrast than CT, clearly delineating wall layers.
Report Sentence
Bowel wall edema and stratification (target sign) are observed on T2-weighted images in the ileocecal region, consistent with active inflammatory process.
Diffusion-weighted imaging (DWI) shows high signal (diffusion restriction) in areas of active TB inflammation. Restricted diffusion is particularly prominent in thickened bowel wall segments, necrotic lymph nodes, and peritoneal implants. Low values on ADC maps (<1.2 x 10-3 mm2/s) indicate active granulomatous inflammation. DWI is superior to CT in differentiating active disease from chronic fibrotic changes.
Report Sentence
Diffusion restriction is observed in thickened bowel wall segments and mesenteric lymph nodes, consistent with active granulomatous inflammation.
On delayed phase and CT enterography, TB-related strictures and proximal dilatation pattern can be observed. Strictures are typically short-segment, symmetric, and concentric — different from the long-segment asymmetric strictures of Crohn's disease. Single or multiple strictures in the terminal ileum with proximal dilatation may be seen. In the delayed phase, fibrotic stricture segments retain contrast and show late enhancement. The 'string sign' can be seen in the terminal ileum.
Report Sentence
Short-segment concentric stricture in the terminal ileum with proximal small bowel loop dilatation is observed, consistent with fibrotic stricture due to tuberculosis.
Ultrasonography shows bowel wall thickening in the ileocecal region and the 'pseudokidney sign.' The thickened bowel wall forms a kidney-like appearance with concentric stratification — hypoechoic outer ring (edematous/inflammatory wall) and hyperechoic center (lumen/mucosa). Mesenteric lymph nodes appear enlarged, hypoechoic, sometimes with necrotic centers. US is valuable as first-line modality in children and young patients.
Report Sentence
Concentric bowel wall thickening with pseudokidney sign in the ileocecal region is observed; in conjunction with clinical information, small bowel tuberculosis should be considered in the differential diagnosis.
Criteria
Most common form (60%). Mucosal ulcers run transverse to the long axis of the bowel. In advanced stages, ulcers encircle the entire circumference leading to annular strictures.
Distinct Features
On CT enterography: mucosal irregularity with wall thickening, short-segment involvement, symmetric concentric thickening. Transverse ulcers are distinguishing from longitudinal ulcers in Crohn's.
Criteria
Rarer form (10%). Forms an inflammatory mass in the ileocecal region. Granulomatous tissue and fibrosis massively thicken the bowel wall.
Distinct Features
On CT, mass-like prominent wall thickening at cecum and terminal ileum, enhancing granulomatous tissue. Can mimic cecal carcinoma — critical in differential diagnosis. Lumen narrows but usually does not cause complete obstruction.
Criteria
Combined form (30%). Both ulcerative and hypertrophic features coexist. Ulcers accompanied by wall thickening and inflammatory mass formation.
Distinct Features
Most complex imaging findings. Wall thickening, mucosal ulcers, strictures, inflammatory mass, and necrotic LAP may all be seen together. Peritoneal involvement frequently accompanies.
Criteria
Peritoneal involvement with prominent ascites. High-density ascites (exudative, protein >3 g/dL). Smooth peritoneal thickening and enhancement.
Distinct Features
Smooth (non-nodular) peritoneal thickening, high-density ascites, and coexistence of ileocecal bowel involvement are critical for differentiation from peritoneal carcinomatosis.
Distinguishing Feature
Crohn's shows longitudinal ulcers (cobblestone pattern), skip lesions, asymmetric wall thickening, creeping fat, fistula and sinus tract; TB shows transverse ulcers, concentric symmetric thickening, cecal contraction/pull-up, necrotic LAP, and peritoneal involvement. LAP in Crohn's is usually non-necrotic.
Distinguishing Feature
Lymphoma shows marked wall thickening (>2 cm), aneurysmal dilatation, homogeneous enhancement, obstruction is rare; TB shows thinner wall thickening, stricture and obstruction are common, necrotic LAP is dominant, cecal contraction is characteristic.
Distinguishing Feature
Adenocarcinoma shows focal, asymmetric, irregular mass, 'apple-core' sign, abrupt luminal narrowing; TB shows concentric symmetric thickening, gradual transition, necrotic LAP. Adenocarcinoma usually involves single segment, TB shows ileocecal predilection.
Distinguishing Feature
Carcinoid shows hypervascular small intramural nodule, desmoplastic mesenteric reaction; TB lacks hypervascular nodule, necrotic LAP is prominent, no desmoplastic reaction.
Distinguishing Feature
Metastasis shows multiple lesions in different segments, known primary malignancy; TB shows ileocecal predilection, necrotic LAP, smooth peritoneal thickening.
Urgency
urgentManagement
medicalBiopsy
NeededFollow-up
3-monthSmall bowel TB is treated with anti-tuberculous therapy (HRZE regimen: isoniazid, rifampicin, pyrazinamide, ethambutol — 2 months intensive + 4-7 months maintenance). Histopathological and/or microbiological confirmation is required before treatment. Complications include stricture, obstruction, perforation, and massive hemorrhage. Surgery is indicated in complicated cases. Treatment response is assessed by 3-month CT follow-up. Differentiation from Crohn's disease is critical — immunosuppressive therapy given with wrong diagnosis will exacerbate TB.
Intestinal tuberculosis responds to anti-tubercular therapy. Stricture and obstruction may require surgery. TB is more common in endemic areas and immunosuppressed patients.