Abdominal Tuberculosis in Children: Symptoms, Diagnosis & Treatment

What is ABDOMINAL TUBERCULOSIS in Children?

Infection by mycobacterium tuberculosis or related organisms involving GIT. (hepatobiliary and pancreatic parts, peritoneal lining, and abdominal lymph node involvement)

Etiopathogenesis and Spread

• The most common etiological agent is Mycobacterium tuberculosis.
• In rare cases, abdominal TB may also be caused by Mycobacterium bovis or by non-tubercular bacteria such as Mycobacterium avium and Mycobacterium intracellulae.
• Mode of spread: rarely primary; abdominal TB is found to be secondary.
  • Hematogenous spread (primary focus in lungs, which spreads through blood to the GIT)
  • Auto-ingestion of infected sputum in a patient with open or cavitary TB.
  • Direct contiguous spread.
  • Mediastinal lymph nodes, which can spread infection

Sites of Involvement in GIT

• Intestinal TB (65%); peritoneal TB (30%); glandular/nodal TB (5%).
• Most common site of abdominal TB is ILEOCECAL REGION

Why is the Ileocecal Region Most Commonly Affected?

• Because of increased physiological stasis
• Abundant Lymphoid tissue
• Increased rates of fluid and electrolyte absorption
• Minimal digestive activity

Aso read: Fetal Assessment: Key Evaluations & Prenatal Diagnosis 

Pathological Types of Intestinal TB

Ulcerative

• seen in 60% cases; most common type and is seen in children with SAM (severe acute malnutrition):
  • Shallow lesions seen mostly in the jejunum or colon are superficial and do not cross the muscularis mucosa. They can be single or multiple with normal areas in between. Shallow lesions are transversely placed along the long axis of the intestine.
  • Active form; characterized by bowel inflammation and wall fibrosis with regional lymph node involvement
  • Initial lesion: Infiltration of Mucosa and Peyer's patches, which then evolve as shallow ulcers
  • As disease progresses, shallow lesions coalesce and lead to complications such as bowel thickening, strictures (manifesting as Napkin-ring constriction or Hourglass constriction), pseudotumor mass lesions, fistulas, and nodular tubercles on the serosal surface.

Hyperplastic or Hypertrophic

• seen in 10% cases: in well-nourished children
  • No ulcers seen, but presence of stenosis, fibrosis and pseudotumor-like rigid mass formation
  • Thickening of bowel wall, scarring and fibrosis

Ulcero-Hyperplastic (Also Known as Ulcero-Hypertrophic) 

• Combination of ulcerative and hyperplastic lesions
  • Seen in 30% cases
  • Seen mainly in ileocecal region and colon
  • Sometimes may have a lump in RIF

What are the Types of Peritoneal Tuberculosis (TB)?

4 types of peritoneal TB:

1. Ascitic/Wet Type

• Most common type of peritoneal TB
• Presence of straw-colored ascites, which gradually increases in amount, causing anasarca
• Also associated with umbilical hernia due to increased intraabdominal pressure

2. Dry/Plastic/Fibrous Type

Presence of extensive adhesions and fibrosis, which will lead to the formation of pseudo-tumours or mass-like lesions.

3. Encysted/Loculated Type

• Considered to be a subtype of wet peritoneal TB
• Presence of localized ascitic fluid collection

4. Purulent Type

• It is very rare in children and is usually associated with TB salpingitis.
• Pus formation occurs

Also read: Alagille Syndrome – Clinical Features And Diagnosis 

Clinical Features of Abdominal Tuberculosis 

Varied presentation such as

• Constitutional features such as fever, anorexia, weight loss, generalized irritability, and poor gain of height.
• Lump in the abdomen is found anywhere in the abdomen but mostly in the RIF, or periumbilical region.
• SAIO- (subacute intestinal obstruction) colicky abdominal pain, vomiting, constipation
• Chronic diarrhea—non-bloody in nature
• Abdominal distention due to underlying ascites

What are the Causes of Abdominal Tuberculosis in Children?

Mass is due for the following reasons:

• Pseudotumor due to stricture formation
• Hyperplastic intestinal TB
• Nodular TB
• Loculated ascites
• Rolled up omentum
• Thickened bowel loops

Diagnosis of Abdominal Tuberculosis in Children 

Paustian's Criteria for Abdominal TB

(Any one out of the four points present confirms diagnosis of abdominal TB)

• Animal inoculation or culture of suspected enteric/mesenteric/intra-abdominal sample should grow tubercle bacillus
• Histology of lesion should demonstrate AFB
• Histology should demonstrate caseous necrosis with inflammation
• Gross intraop findings and biopsy of mesenteric lymph nodes should be consistent with TB.

Non-specific Findings Include

• Anemia
• Raised ESR (degree of elevation does not correlate with severity of disease)
• Hypoalbuminemia (serum albumin levels less than 2.5g/dl)
• TLC raised in 50%
• Mantoux test positive in 50%

Plain X-ray Abdomen (but also do CXR to Identify Area of Primary Focus)

• Presence of enteroliths—calcified material which is present in intestine
• Calcified lymph nodes or granulomas
• Dilated bowel with multiple air fluid levels

Barium Studies

• Barium meal follow-through is useful for small intestinal lesions
• Barium enema useful for large intestinal lesions or ileocecal lesions
  • Hyper segmented barium column known as Chicken Intestine
  • Nodular thickening of mucosal folds
  • Hourglass stenosis or Napkin ring constriction
  • Fleischner Sign/inverted umbrella sign: thickening and wide gaping of ileocecal valve with narrowed terminal ileum
  • String Sign of Kantor: persistent narrowing of colon due to stenosis
  • Conical cecum, which is shrunk and pulled out of the iliac fossa due to contraction and fibrosis of the mesocolon
  • Gooseneck deformity: loss of ileocecal angle and a dilated terminal ileum appearing suspended from a retracted, fibrosed cecum
  • Stierlin's sign: narrowing of terminal ileum with rapid emptying into a shortened, rigid cecum

Ascitic Fluid Examination

• Appearance: straw-colored fluid
• SAAG (serum ascitic albumin gradient) ≤ 1.1
• Increased protein content more than 3g%
• Cell count: 150–4000/mm3, 70% lymphocytes
• AFB positivity in only 3% cases
• Culture positive in 20% cases but takes 6-8 weeks
• ADA levels are high; cut off >33U/l
• IFN levels: high

IGRA/Quantiferon Assay

• IGRA-interferon gamma release assay
• Also called quantiferon-TB Gold test
• In vitro blood test used to detect cell-mediated immune response to T. b. Bacillus
• Highly sensitive and specific test but cannot distinguish between latent and active TB

Also read: Childhood Pneumonia- Causes, Symptoms, and Treatment 

ELISPOT

• Assay to detect T cells specific against M tuberculosis

NAAT

• Nucleic Acid Amplification Test
• Includes PCR for TB and gene expert MTB/RIF (real-time PCR test that also detects rifampicin resistance in MDR TB) but is expensive

USG Abdomen

• Ascites
• Club sandwich sign/inverted bread sign: Fluid between radially oriented bowel loops
• Pseudo-kidney sign: Involvement of ileo-cecal region, which is pulled up to a sub hepatic position
• Mesenteric, para-aortic, and paracaval LNs may be enlarged and calcified
• LNs will show mixed heterogeneous echotexture
• Small anechoic areas are highly suggestive of casseous necrosis

CT Abdomen

• Can detect bowel wall thickening, adherent loops, ulceration and nodularity
• Enlarged caseating LNs can be seen—hypodense centers with peripheral ring enhancement
• Calcification of LNs can be seen
• Retroperitoneal LN involvement as an isolated finding is very rare
• CT can also detect complications like perforation
• Mesenteric involvement can give a stellate (star-like) appearance

GIT Endoscopy

• Useful for upper GI lesions
• Enteroscopy or wireless capsule endoscopy—newer modalities used for small bowel TB
• Colonoscopy is useful for colonic or terminal ileal TB. Shows mucosal ulcers and nodules, and a biopsy can be taken from the edge of ulcers.
  • Biopsy shows caseous necrosis and granulomatous inflammation (composed of macrophages, epithelioid granulomas, Langerhans type giant cells)

USG/CT-guided FNAC of Abdominal Mass

• Liver biopsy can be done for suspected liver tubercles
• Laparoscopy in peritoneal TB: thickened peritoneum with or without tubercles and fibro-adhesive peritonitis
• Laparotomy done only in exceptional, diagnostic dilemma cases

Management of Abdominal TB

Mainstay is anti-tubercular therapy

INDEX-TB Guidelines-WHO/India

Recommendation: A 6-month ATT standard first-line regimen is recommended for abdominal TB.

Strength of recommendation: Strong

RNTCP-IAP 2019

2 months (HRZE)

4 months (HRE)

Surgery in Pediatric Abdominal TB

Indications Include:

• Bowel obstruction due to strictures
• Bowel perforation
• Massive haemorrhage

Surgical Options Include:

• Stricturoplasty with longitudinal incision and transverse sutures (surgical excision of stricture) is done in cases of single stricture or multiple strictures that are distantly placed. Done only if lumen of the gut decreased by 50%.
• Resection of the segment is used in cases of the presence of multiple strictures in a very small segment (5 to 10 cm). Can also be performed in case of Hyperplastic T.B localized lesion
• Resection of perforated segment and performing anastomosis of the remaining healthy gut segments

Also read: Staphylococcus Infections in Children: Signs and Treatment 

Points to Remember

• Abdominal Cocoon syndrome: fibrotic encapsulation of bowel, which sometimes leads to obstruction
  • Very common in adolescent females
  • Also seen in conditions such as SLE, Le Veen shunt for ascites, CAPD (continuous ambulatory peritoneal dialysis), use of adrenergic drugs such as practolol and use of povidone-iodine for abdominal washout

• Hyperplastic TB on palpation may produce doughy feel
• TB can cause secondary malabsorption
• least common site of Abdominal TB is Esophageal TB (0.2%); Stomach TB is also uncommon
  • Reasons for this include raised acidity in these two areas
  • Devoid of lymphoid tissue
  • Contents do not stay for long in these areas

Hope you found this blog helpful for your NEET SS Pediatrics Gastroenterology preparation. For more informative and interesting posts like these, keep reading PrepLadder’s blogs.