Abdominal Tuberculosis in Pediatric Age: Case Discussion & Key Points
Model Case Presentation
Patient Demographics
Name: Master Rajan, Age: 11 years, Gender: Male, Informant: Mother (Reliable), Socioeconomic status: Lower middle class, overcrowded household
Chief Complaints
- Intermittent colicky abdominal pain – 4 months
- Low-grade fever with evening rise – 3 months
- Progressive weight loss – 3 months
- Abdominal distension – 6 weeks
History Summary
An 11-year-old boy presents with a 4-month history of intermittent, colicky, periumbilical pain, worse after meals. Associated with low-grade fever (37.8–38.2°C), more prominent in the evenings, along with night sweats and anorexia. Progressive weight loss of approximately 4 kg over 3 months. Gradually increasing abdominal distension over 6 weeks. 2 episodes of loose stools alternating with constipation. No hematemesis, melena, or jaundice.
History of contact with a sputum-positive pulmonary TB uncle living in the same household for the past year. BCG scar present. Not on any regular medications. No history of previous TB treatment.
Born at term, NVD, immunized as per schedule. No family history of malignancy.
Examination Summary
| Parameter | Finding | Significance |
|---|---|---|
| Weight | 24 kg (expected ~35 kg) | Severe underweight / Failure to thrive |
| Temperature | 38.1°C (evening) | Low-grade fever, evening rise |
| HR | 92/min | Normal |
| RR | 18/min | Normal |
| Pallor | Mild | Chronic disease anaemia |
| BCG scar | Present | Vaccinated — does not exclude TB |
| Cyanosis / Clubbing / Jaundice | Absent | — |
| Lymph nodes | Right inguinal 1.5 cm, firm, non-tender, discrete | Lymphadenopathy |
Abdomen: Distended. Flanks full. Shifting dullness positive (ascites). Doughy feel of abdomen on palpation. A firm, irregular mass palpable in the right iliac fossa (RIF) — approximately 5×4 cm, non-tender, moves with respiration. Liver: 2 cm below right costal margin (hepatomegaly). Spleen: not palpable. Bowel sounds: sluggish.
Chest: Normal breath sounds bilaterally. No added sounds.
✅ Complete Diagnosis
Abdominal Tuberculosis — Intestinal (Ileocecal) + Peritoneal Type, presenting as a Right Iliac Fossa mass with ascites and constitutional symptoms (fever, weight loss, anorexia), with a history of close contact with a known sputum-positive case of pulmonary tuberculosis.
📝 History — Exam Q&A
Abdominal tuberculosis (ATB) is infection by Mycobacterium tuberculosis (or rarely M. bovis) involving the gastrointestinal tract, peritoneum, mesenteric lymph nodes, or solid abdominal organs (liver, spleen, pancreas).
Three main types:
- Intestinal TB (~65%) — most common; ileocecal region most frequently affected
- Peritoneal TB (~30%) — presents with ascites, thickened peritoneum
- Glandular/Nodal TB (~5%) — mesenteric lymphadenopathy predominant
Multiple sites are involved simultaneously in ~54% of cases.
- Accounts for 0.3–4% of all pediatric TB cases
- Sixth most common site of extrapulmonary TB
- Most common age group: 9–14 years
- Median diagnostic delay: 4–6 months due to nonspecific symptoms
- More common in developing countries; India bears the highest global TB burden (~25% of global cases)
- Up to 25% of abdominal TB children have concurrent pulmonary TB (sometimes asymptomatic)
| Route | Mechanism |
|---|---|
| Hematogenous spread | Most common — primary pulmonary focus seeds the GI tract via bloodstream |
| Auto-ingestion of sputum | In open/cavitary pulmonary TB, swallowed infected sputum seeds the intestinal mucosa |
| Direct contiguous spread | From adjacent infected organs (e.g., spine, psoas abscess) |
| Lymphatic spread | From mediastinal lymph nodes via thoracic duct |
| Ingestion of infected milk | M. bovis from unpasteurized milk → primary intestinal TB (less common in vaccinated populations) |
💡 Key Point
In children, abdominal TB is almost always secondary to a primary pulmonary focus (primary abdominal TB is rare). Always look for pulmonary involvement with a CXR.
Multiple factors make the ileocecal region particularly susceptible:
- Abundant lymphoid tissue (Peyer's patches) in terminal ileum — mycobacteria are phagocytosed here
- Slow intestinal transit at the ileocecal junction — prolonged contact of bacilli with mucosa
- High physiological absorption rate — allows deeper tissue invasion
- Relative stasis at the cecum promotes bacterial proliferation
The classic triad is present in ~54% of cases:
- Abdominal pain — intermittent, colicky, periumbilical or RIF, worse after meals (most common symptom)
- Fever — low-grade, with evening rise, associated night sweats
- Weight loss / failure to thrive — anorexia, progressive weight loss
Other symptoms: Altered bowel habits (diarrhea/constipation or alternating), abdominal distension, nausea/vomiting (especially in obstruction), hematemesis or melena (rare).
- Contact history: Close contact (household) with a known/suspected TB case — smear-positive contact is highly significant
- BCG vaccination: Vaccination status — does NOT rule out TB
- Previous TB or ATT: Previous TB disease or anti-TB treatment — raises risk of drug resistance
- Socioeconomic status: Overcrowding, malnutrition — high-risk environment
- HIV status: Must be screened in all children with suspected TB
- Immunocompromised state: Steroid use, malignancy, malnutrition
- Diet: Consumption of unpasteurized milk (M. bovis)
- Pulmonary symptoms: Cough >2 weeks, hemoptysis (concurrent pulmonary TB)
| Type | Features | Clinical Presentation |
|---|---|---|
| Ulcerative | Transverse mucosal ulcers (perpendicular to long axis); superficial; most common in jejunum/colon | Diarrhea, malabsorption, bleeding |
| Hypertrophic / Hyperplastic | Fibrosis, thickening, narrowing; pseudo-tumour-like mass at ileocecal junction | RIF mass, subacute intestinal obstruction; doughy feel on palpation |
| Ulcero-hypertrophic | Mixed — both ulceration and fibrosis | Mixed features — most common overall type |
💡 Mnemonic
U-H-UH = Ulcerative, Hypertrophic, Ulcero-Hypertrophic (most common)
| Type | Description |
|---|---|
| Wet type (exudative) | Most common. Free or loculated ascites — straw-coloured exudative fluid |
| Dry type (fibrous) | Dense adhesions, fibrous peritoneal bands — can cause intestinal obstruction; Abdominal cocoon |
| Fibro-adhesive (mixed) | Combination of both — thickened omentum ("omental cake"), matted bowel loops |
🩺 Examination — Exam Q&A
- Anthropometry: Underweight, wasted, stunted — chronic disease
- Pallor: Mild to moderate (anaemia of chronic disease)
- Lymphadenopathy: Peripheral — firm, discrete, non-tender lymph nodes (inguinal, axillary, cervical)
- Fever: Low-grade, evening rise (~38°C)
- BCG scar: Usually present — does not rule out TB
- No clubbing, cyanosis, or jaundice in uncomplicated cases
Inspection: Abdominal distension (ascites, mass), prominent flanks, dilated veins (if hepatic involvement), visible peristalsis (in obstruction).
Palpation:
- RIF mass — firm, irregular, non-tender, may have well-defined edges (ileocecal TB)
- Doughy feel (putty abdomen) — the abdomen feels soft, with a "kneading dough"-like consistency due to thickened, inflamed omentum and bowel loops matted together — classic sign of peritoneal TB
- Hepatomegaly (granulomatous involvement or portal hypertension)
- Splenomegaly (less common)
Percussion: Shifting dullness or fluid thrill (ascites). Dullness in RIF (mass).
Auscultation: Sluggish or absent bowel sounds (in obstruction/peritonitis); tinkling sounds may be present.
Tuberculous ascites is typically an exudate:
- Appearance: Straw-coloured (yellow), slightly turbid
- Protein: >2.5 g/dL (exudate)
- SAAG (Serum-Ascites Albumin Gradient): <1.1 g/dL — low SAAG indicates an exudate
- Cell count: 500–2000 cells/mm³ with lymphocytic predominance (>70% lymphocytes)
- ADA (Adenosine Deaminase): Elevated (>30–40 U/L) — highly sensitive and specific
A RIF mass in a child should always raise suspicion for ileocecal tuberculosis. The hypertrophic/hyperplastic form causes a firm, non-tender mass due to thickened bowel wall, matted lymph nodes, and fibrotic omentum.
Differential diagnosis of RIF mass in a child:
- Ileocecal tuberculosis (most common in endemic areas)
- Appendicular mass / appendicular abscess
- Crohn's disease (Ileocecal Crohn's — important differential)
- Lymphoma (NHL)
- Mesenteric adenitis
- Ameboma
- Carcinoid tumor (rare in children)
Fibrotic healing of intestinal TB causes strictures (especially at the ileocecal junction), leading to partial/intermittent obstruction:
- Colicky, periumbilical pain — episodic, worse after meals
- Vomiting
- Constipation alternating with diarrhea
- Borborygmi (loud bowel sounds)
- Distension proximal to the stricture
- On examination: visible peristalsis, tinkling bowel sounds, tender distended abdomen
⚠️ Surgical Emergency
Complete obstruction, perforation, or peritonitis from abdominal TB requires emergency surgical intervention. Perforation in TB is typically silent due to the anti-inflammatory state.
Abdominal cocoon (sclerosing encapsulating peritonitis) is a rare but severe complication where the small bowel is encased in a thick fibrous membrane, forming a cocoon-like structure due to dense fibro-adhesive peritoneal TB.
Clinical features: Recurrent episodes of subacute intestinal obstruction, a mobile, central, soft abdominal mass that is well-defined. CT shows a cauliflower-like or cocoon appearance — bowel loops wrapped in a thick membrane.
💡 Key Fact
Abdominal cocoon in India is most commonly caused by peritoneal TB. In Western countries it is associated with continuous ambulatory peritoneal dialysis (CAPD) and practolol use.
- Intestinal obstruction — stricture at ileocecal junction (most common)
- Perforation — can be silent; leads to peritonitis
- Malabsorption — severe wasting, hypoproteinemia, edema
- Fistula formation — enterocutaneous, enterovesical, enteroenteric
- Hemorrhage — GI bleeding from ulcers
- Hepatic involvement — hepatomegaly, granulomata, rarely portal hypertension
- Miliary dissemination — if untreated
- Abscess — psoas abscess, intraabdominal abscess
🔬 Investigations — Exam Q&A
| Investigation | Expected Finding | Significance |
|---|---|---|
| CBC | Normocytic normochromic anaemia; lymphocytosis; elevated WBC (TB lymphocytosis) | Chronic disease, immune activation |
| ESR | Markedly elevated (>60–80 mm/hr) | Non-specific marker of inflammation; useful for monitoring response |
| CRP | Elevated | Acute phase reactant |
| Serum albumin | Low (<3.5 g/dL) | Chronic malnutrition, protein-losing enteropathy |
| LFT | May show elevated ALP, transaminases (hepatic involvement) | Hepatic granulomas |
| Serum calcium | Rarely elevated (hypercalcemia) | Granuloma-mediated 1,25-OH Vitamin D production |
The Mantoux test (Tuberculin Skin Test/TST) involves intradermal injection of 5 TU (tuberculin units) of PPD on the volar aspect of the forearm, read at 48–72 hours as induration (not redness).
| Induration | Interpretation |
|---|---|
| ≥10 mm | Positive in immunocompetent children (standard) |
| ≥5 mm | Positive in HIV-positive, severely malnourished, or close contacts of confirmed TB |
| ≥15 mm | Positive in children with no risk factors (some guidelines use this cutoff) |
⚠️ Limitations
Mantoux is positive in only 46–68% of children with abdominal TB. It can be falsely negative in: severe malnutrition, immunosuppression, disseminated/miliary TB, early TB infection, and recent viral illness. A negative Mantoux does NOT rule out abdominal TB.
IGRAs (e.g., QuantiFERON-TB Gold, T-SPOT.TB) are in-vitro blood tests that detect T-cell-mediated immune response (interferon-gamma release) to M. tuberculosis-specific antigens (ESAT-6 and CFP-10).
| Feature | Mantoux (TST) | IGRA |
|---|---|---|
| Affected by BCG | Yes (false positive) | No (more specific) |
| Requires 2 visits | Yes | No (single blood draw) |
| Sensitivity in children <5 yr | Better | Less reliable |
| Cost | Low | High |
| Cannot distinguish latent from active TB | Correct | Correct |
Both tests indicate TB infection, not active disease. Used together they improve diagnostic yield. WHO recommends either test based on availability and resource setting.
1. Ultrasound Abdomen (first-line imaging):
- Ascites (free or loculated)
- Mesenteric and para-aortic lymphadenopathy — lymph nodes with central necrosis (target sign) or calcification
- Thickened bowel wall (ileocecal region)
- Hepatosplenomegaly, hepatic granulomas
- Matted bowel loops / omental thickening
2. Contrast-Enhanced CT Abdomen (most informative):
- Ileocecal wall thickening with asymmetric pattern (unlike symmetric in Crohn's)
- Necrotic lymph nodes with peripheral rim enhancement (central necrosis — characteristic of TB)
- Conical cecum, retraction of cecum out of iliac fossa
- Peritoneal nodules, omental thickening ("omental cake")
- Ascites — often loculated in TB peritonitis
- Calcification in lymph nodes (healed TB)
3. Chest X-Ray (mandatory in all cases):
- May show primary complex, hilar lymphadenopathy, pleural effusion, or infiltrates
- Up to 25% of abdominal TB cases have pulmonary involvement (may be asymptomatic)
4. Barium studies (less commonly used now):
- Stierlin's sign — rapid emptying of the terminal ileum into a shortened, rigid cecum
- String sign of Kantor — persistent, thread-like narrowing of terminal ileum
- Fleischner's sign (Inverted umbrella sign) — wide, gaping ileocecal valve with narrowed terminal ileum
- Conical cecum — cecum shrunken and pulled out of iliac fossa
- Gooseneck deformity — dilated terminal ileum suspended from a fibrosed, retracted cecum
ADA is an enzyme involved in purine metabolism, markedly elevated in conditions requiring intense T-lymphocyte proliferation (as in TB). It can be measured in ascitic fluid, pleural fluid, and CSF.
| Parameter | Value |
|---|---|
| Cut-off in ascitic fluid | >30–40 U/L (most studies use >30 U/L) |
| Sensitivity | ~100% |
| Specificity | ~96% |
Advantages: Simple, inexpensive, rapid, highly sensitive/specific for tuberculous peritonitis.
False positives: Lymphoma, malignant ascites, spontaneous bacterial peritonitis — must be interpreted in clinical context.
False negatives: Can occur in HIV-positive patients with low CD4 count (impaired T-cell response).
Xpert MTB/RIF is a real-time PCR assay that simultaneously detects M. tuberculosis DNA and rifampicin resistance within 2 hours.
- Can be performed on: ascitic fluid, tissue biopsy (colonoscopic/laparoscopic/lymph node), gastric aspirate, or peritoneal fluid
- WHO-recommended as a rapid diagnostic tool for extrapulmonary TB
- Sensitivity on ascitic fluid: ~40–50% (lower than for pulmonary TB due to paucibacillary nature)
- Sensitivity on tissue biopsy (colonoscopic): ~42%
- Specificity: ~98%
- Detects rifampicin resistance — crucial for MDR-TB identification
💡 Key Point
Abdominal TB is a paucibacillary disease — microbiological confirmation is difficult. A negative Xpert does NOT exclude the diagnosis. Clinical, radiological, and biochemical (ADA) evidence together guide diagnosis.
Colonoscopy with biopsy:
- Best for suspected ileocecal/colonic TB
- Findings: Transverse ulcers, nodularity, strictures, deformed ileocecal valve, patulous (widely open or gaping) valve
- Biopsy from ulcer edge: Caseous granuloma with Langerhans giant cells and epithelioid cells — pathognomonic of TB
- AFB stain and culture from biopsy can be done
Laparoscopy (peritoneal TB):
- Thickened peritoneum with whitish nodules/tubercles on peritoneal and omental surfaces
- Fibro-adhesive peritonitis
- Biopsy of peritoneal nodules — most sensitive for diagnosis
- Sensitivity of laparoscopy: ~92%
Laparotomy: Reserved for diagnostic dilemma or surgical complications (obstruction, perforation). Gross intraoperative findings + mesenteric lymph node biopsy can confirm diagnosis.
TB histopathology: Caseating granuloma — central caseous necrosis surrounded by epithelioid macrophages, Langerhans giant cells, and lymphocytes.
| Feature | Intestinal TB | Crohn's Disease |
|---|---|---|
| Granuloma type | Caseating (necrotic centre) | Non-caseating |
| Granuloma size | Large, confluent | Small, discrete |
| Ulcer orientation | Transverse (circumferential) | Longitudinal (aphthous/cobblestone) |
| Submucosal fibrosis | Prominent | Transmural inflammation |
| AFB stain | May be positive | Negative |
| Fissuring ulcers/skip lesions | Less common | Characteristic |
Confirmed (definitive) ATB: Bacteriological confirmation — growth of M. tuberculosis on culture, positive AFB smear, or positive molecular test (Xpert/PCR) from abdominal specimen (ascites, tissue biopsy, lymph node).
Probable ATB (clinical diagnosis): Combination of:
- Classic symptoms (fever, abdominal pain, weight loss) + contact history
- Positive Mantoux/IGRA
- Suggestive imaging (lymphadenopathy with central necrosis, ileocecal thickening, ascites)
- Elevated ascitic ADA (>30 U/L) with lymphocytic exudate
- Suggestive histology (caseating granuloma — even without bacteriological confirmation)
- Concurrent/previous TB at another site
- Response to empirical ATT (therapeutic trial)
💡 Therapeutic Trial
In resource-limited settings with high clinical suspicion but unconfirmed bacteriology, a therapeutic trial of ATT with clinical and radiological monitoring is an accepted diagnostic approach. Response (fever resolution, weight gain, reduction in ascites/mass) within 4–8 weeks supports the diagnosis.
💊 Management — Exam Q&A
Abdominal TB is treated as extrapulmonary TB with standard first-line ATT:
| Phase | Duration | Drugs | Abbreviation |
|---|---|---|---|
| Intensive phase | 2 months | Isoniazid (H) + Rifampicin (R) + Pyrazinamide (Z) + Ethambutol (E) | 2HRZE |
| Continuation phase | 4 months | Isoniazid (H) + Rifampicin (R) | 4HR |
Total duration: 6 months — A Cochrane review (2016) confirmed that 6-month therapy is as effective as 9-month therapy for abdominal TB.
💡 WHO 2022 Update
WHO recommends 6-month standard regimen (2HRZE/4HR) for all drug-sensitive extrapulmonary TB in children, including abdominal TB. Ethambutol is included in the intensive phase unless there is documented sensitivity or CNS/disseminated disease (where Ethambutol may be extended).
| Drug | Dose (mg/kg/day) | Route | Key Side Effects |
|---|---|---|---|
| Isoniazid (H) | 10 mg/kg/day (range 7–15); max 300 mg | Oral | Hepatotoxicity, peripheral neuropathy (add pyridoxine/B6) |
| Rifampicin (R) | 15 mg/kg/day (range 10–20); max 600 mg | Oral | Hepatotoxicity, orange discolouration of body fluids, drug interactions |
| Pyrazinamide (Z) | 35 mg/kg/day (range 30–40); max 2000 mg | Oral | Hepatotoxicity, hyperuricemia, arthralgia |
| Ethambutol (E) | 20 mg/kg/day (range 15–25); max 1200 mg | Oral | Optic neuritis (colour vision, visual acuity) — monitor in children |
Pyridoxine (Vitamin B6): 5–10 mg/day added to Isoniazid to prevent peripheral neuropathy.
Steroids are not routinely recommended for all abdominal TB. They may be used as an adjunct in specific situations:
- Peritoneal TB with severe ascites — Prednisolone 1–2 mg/kg/day tapered over 6–8 weeks; reduces inflammatory exudate, prevents adhesions and stricture formation
- Intestinal obstruction secondary to active inflammation (not fibrotic stricture) — may reduce edema and temporarily relieve obstruction
- Hypercalcemia due to TB granulomas (rare)
Contraindicated in: Active bleeding, perforation, uncontrolled infection. Not used for fibrotic strictures (surgical treatment required).
Indications for surgery:
- Intestinal obstruction not responding to medical management (ATT ± steroids)
- Perforation → peritonitis (emergency)
- Massive GI hemorrhage
- Fistula formation (enterocutaneous, enteroenteric)
- Abdominal abscess / cold abscess not responding to treatment
- Diagnostic laparotomy (rarely, when diagnosis uncertain despite all investigations)
Surgical procedures:
- Right hemicolectomy — for ileocecal TB mass or obstruction
- Stricturoplasty — preferred for multiple or widely spaced strictures (preserves bowel length); longitudinal incision closed transversely
- Resection and anastomosis — for single short stricture or perforation
- Drainage of abscess — psoas/peritoneal abscess
⚠️ Important
Surgery alone is not curative — ATT must be continued before and after surgery. Operate on ATT; do not wait for surgical recovery before starting ATT.
Response is assessed clinically, biochemically, and radiologically:
- Clinical response (within 4–8 weeks): Resolution of fever, improvement in appetite, weight gain — most reliable early indicators
- ESR/CRP: Should fall with treatment
- Anthropometry: Serial weight gain monitoring
- Imaging (USG/CT abdomen): Reduction in ascites, decrease in lymph node size, resolution of bowel wall thickening — usually assessed at 2–3 months
- Liver function tests: Monitor at baseline and during treatment for hepatotoxicity
Lack of response after 4–8 weeks: Consider drug resistance (send Xpert MTB/RIF), drug malabsorption, poor compliance, or an alternative diagnosis (Crohn's, lymphoma).
MDR-TB (Multidrug-resistant TB): Resistance to at least Isoniazid and Rifampicin — the two most powerful first-line drugs.
- Observed in approximately 12.5–13% of abdominal TB cases in some studies
- Suspect MDR if: contact with known MDR-TB case, prior ATT failure or relapse, non-response after 2 months of standard ATT
- Diagnosis: Xpert MTB/RIF detects rifampicin resistance (surrogate for MDR); LPA (Line Probe Assay) for isoniazid resistance; culture + DST for confirmation
- Treatment: Longer individualized regimens (18–20 months) with Group A, B, C drugs (Bedaquiline, Linezolid, Levofloxacin preferred)
- High-calorie, high-protein diet — 120–150% of recommended daily allowance for age
- Correct micronutrient deficiencies — Vitamin D, Vitamin A, zinc, iron
- Pyridoxine (Vitamin B6) — supplement with isoniazid to prevent neuropathy
- In malabsorption: elemental or semi-elemental feeds; small, frequent meals
- Nutritional rehabilitation is as important as ATT — malnutrition impairs immune response and drug metabolism
| Feature | Intestinal TB | Crohn's Disease |
|---|---|---|
| Epidemiology | Endemic areas (India, Asia, Africa); any age | Westernized countries; bimodal (15–25 yr, 55–70 yr) |
| TB contact / Mantoux | Often positive | Negative |
| Perianal disease | Rare | Common (fistula, abscess, skin tags) |
| Extraintestinal features | Pulmonary TB, lymphadenopathy | Uveitis, pyoderma, arthritis, oral ulcers |
| Ulcer pattern (colonoscopy) | Transverse ulcers, nodularity, patulous ileocecal valve | Longitudinal/aphthous ulcers, cobblestoning, strictures |
| Histology | Caseating granuloma (large, confluent) | Non-caseating granuloma (small, discrete) |
| CT lymph nodes | Central necrosis (rimenhancement) | Homogeneous enhancement, no necrosis |
| Response to ATT | Improves in 4–8 weeks | No improvement |
💡 Clinical Pearl
In endemic areas, when differentiation is impossible, a therapeutic trial of ATT for 2 months is recommended before labelling a patient as Crohn's disease. Failure to respond should prompt reconsideration of Crohn's and immunomodulatory therapy.
🔭 Recent Advances — Exam Q&A
Xpert MTB/RIF Ultra is the next-generation cartridge for the GeneXpert platform with enhanced sensitivity compared to the original assay, especially in paucibacillary disease (like extrapulmonary TB and pediatric TB).
- Contains two additional targets (IS6110 and IS1081 repetitive elements) — increases detection sensitivity to as low as 16 CFU/mL (vs. 131 CFU/mL for original Xpert)
- Sensitivity for EPTB is ~5–10% higher than original Xpert
- WHO recommends Xpert Ultra as preferred test over original Xpert for pediatric TB and extrapulmonary samples
- Limitation: Higher rate of "trace" results (low bacterial load detected but uncertain significance); slightly lower specificity
- Ascitic fluid Interferon-Gamma (IFN-γ): Elevated in tuberculous peritonitis; combined with ADA improves diagnostic accuracy; sensitivity ~93%, specificity ~98%
- Ascitic fluid IFN-γ Release Assay: T-SPOT adapted for ascitic fluid — experimental
- Lipoarabinomannan (LAM) antigen: Urine LAM antigen test (Alere Determine TB LAM Ag) — useful in HIV-positive patients; not yet validated for abdominal TB specifically
- Transcriptomic/host gene expression signatures: Blood RNA signatures (e.g., RISK6 signature) — can distinguish active TB from other diseases; under investigation
- Metabolomics and proteomics: Exploring metabolite profiles in ascitic fluid for TB diagnosis — research stage
The SHINE trial (2022) was a landmark study showing that a 4-month regimen (2HRZE/2HR) is as effective as 6 months for non-severe drug-sensitive TB in children (smear-negative, non-cavitary disease confined to one lobe — with HIV-negative status).
- Non-severe pulmonary TB and peripheral lymph node TB qualify for 4-month regimen
- Abdominal TB is generally still treated with standard 6-month regimen as it falls under extrapulmonary TB
- WHO 2022 guidelines allow 4-month regimen for specifically defined non-severe TB in children — not for abdominal/peritoneal/severe EPTB
BPaL/BPaLC regimens (Bedaquiline, Pretomanid, Linezolid ± Clofazimine) — 6-month regimens for MDR/XDR-TB — increasingly used in children following WHO 2022 recommendations.
- Capsule endoscopy: Useful for evaluating the entire small bowel when conventional colonoscopy cannot reach the lesion; can detect mucosal ulcers and nodules in the jejunum and ileum; risk of capsule retention if strictures are present
- Balloon-assisted enteroscopy (BAE): Double-balloon or single-balloon enteroscopy allows visualisation and biopsy of deep small bowel lesions; useful when capsule endoscopy finds abnormalities and tissue diagnosis is needed
- Both techniques are increasingly used in abdominal TB when ileocolonoscopy is inconclusive and the disease is in the mid-small bowel
National Tuberculosis Elimination Programme (NTEP) — formerly RNTCP (Revised National TB Control Programme) — is India's national program for TB control, aiming to eliminate TB by 2025.
- Nikshay Poshan Yojana (NPY): Financial incentive scheme — ₹500/month provided directly to TB patients (DBT) for nutritional support during the entire treatment duration
- Nikshay portal: Online case notification system — all TB cases must be notified within 24 hours
- Free diagnosis and treatment: All diagnostic tests (Xpert MTB/RIF, culture, DST) and ATT drugs are provided free of cost under NTEP
- Universal Drug Susceptibility Testing (UDST): All confirmed TB patients tested for drug resistance upfront
- TB-Free India Campaign / TB Mukt Bharat: National mission to end TB by 2025 (5 years ahead of UN 2030 SDG target)
⚡ Key Points — Quick Revision
One-Liners for Exam
- Most common site: Ileocecal region (abundant Peyer's patches, slow transit)
- Most common age group: 9–14 years
- Classic triad: Abdominal pain + Fever (evening rise) + Weight loss — present in 54%
- Route of spread: Hematogenous from primary pulmonary focus (most common in children)
- Types: Intestinal (65%) > Peritoneal (30%) > Glandular/Nodal (5%)
- Pathological forms (intestinal): Ulcerative, Hypertrophic, Ulcero-hypertrophic (most common)
- Doughy feel of abdomen: Classic sign of peritoneal TB — thickened, matted omentum and bowel
- Ascites in peritoneal TB: Exudate; low SAAG (<1.1 g/dL); lymphocytic predominance; elevated ADA
- ADA in ascitic fluid: >30 U/L — sensitivity ~100%, specificity ~96% for TB peritonitis
- Mantoux positive in only: ~46–68% of abdominal TB — a negative Mantoux does NOT rule out ATB
- Gold standard imaging: CT abdomen — central necrosis in lymph nodes, ileocecal thickening
- Gold standard diagnosis: Bacteriological confirmation (culture/Xpert from tissue/fluid)
- Histopathology: Caseating granuloma with Langerhans giant cells + epithelioid macrophages
- Xpert MTB/RIF on ascitic fluid: Sensitivity only ~40–50% (paucibacillary disease)
- Key barium signs: Stierlin's sign, String sign of Kantor, Fleischner's (inverted umbrella) sign, Conical cecum, Gooseneck deformity
- Standard ATT: 2HRZE + 4HR (6 months total) — 6 months = as effective as 9 months (Cochrane 2016)
- Surgery for: Obstruction not responding to ATT, perforation, fistula, abscess, hemorrhage
- Stricturoplasty: Preferred surgical procedure for multiple/widely spaced strictures (bowel-preserving)
- TB vs Crohn's: Caseating granuloma, transverse ulcers, positive Mantoux, central necrosis on CT = TB; non-caseating granuloma, perianal disease, extraintestinal features = Crohn's
- Therapeutic trial: Clinical + imaging response within 4–8 weeks of ATT supports diagnosis
- MDR-TB in ATB: ~12.5% — always send Xpert MTB/RIF to detect rifampicin resistance
- Abdominal cocoon: Encasement of small bowel in fibrous membrane — complication of peritoneal TB
- Steroid use: For peritoneal TB with severe ascites or inflammatory obstruction — reduces adhesions
- National programme: NTEP (India); Nikshay Poshan Yojana — ₹500/month nutritional support
🚨 Exam Traps to Avoid
- BCG vaccination does NOT exclude TB — do not dismiss TB because BCG scar is present
- A negative Mantoux does NOT rule out abdominal TB — Mantoux is positive in only ~50–68% of cases
- Softer murmur does not apply here (that's VSD) — in ATB, a larger mass / more ascites = more severe disease
- Xpert sensitivity on ascitic fluid is low (~40–50%) — a negative Xpert does not exclude TB peritonitis
- ATT must be continued even after surgery — surgery is not curative alone
- Abdominal TB is secondary TB in children — always do a CXR to look for pulmonary involvement