Abdominal Tuberculosis in a 7-Year-Old Male

Introduction: Abdominal tuberculosis (TB) is a rare but significant extrapulmonary manifestation of TB in children. Diagnosis is often challenging due to its nonspecific clinical presentation. This case report discusses a 7-year-old male presenting with ascites and a positive Mantoux test but with normal liver and kidney function tests and normal ascitic fluid analysis.

Case Presentation: A 7-year-old male child presented with progressive abdominal distension for 2 months. There was no history of fever, weight loss, night sweats, or chronic cough. There was no significant past medical history or family history of tuberculosis.

Examination Findings:

• General examination: The child was afebrile, well-nourished, and hemodynamically stable.
• Abdominal examination: Mildly distended abdomen with shifting dullness suggestive of free fluid. No organomegaly or palpable mass.
• Systemic examination: No respiratory distress or lymphadenopathy.

Investigations:

• Mantoux test: Positive (15 mm induration after 72 hours)
• Complete blood count: Mild anemia (Hb: 10 g/dL), normal total leukocyte and platelet count
• Liver function tests (LFTs): Normal
• Kidney function tests (KFTs): Normal
• Ascitic fluid analysis:
  • Appearance: Clear, no turbidity
  • Protein: 2.5 g/dL (exudative)
  • Serum-ascitic albumin gradient (SAAG): <1.1 g/dL (suggestive of tuberculous peritonitis)
  • White blood cell count: 200 cells/mm³ (lymphocyte predominant)
  • Acid-fast bacilli (AFB) stain: Negative
  • GeneXpert for TB: Negative
  • ADA (Adenosine Deaminase): 45 U/L (elevated, suggestive of TB)
• Abdominal ultrasound: Mild free fluid, no significant lymphadenopathy or bowel thickening
• Chest X-ray: Unremarkable, no signs of pulmonary TB
• CT Abdomen (if done): May show thickened peritoneum, lymphadenopathy, or bowel involvement suggestive of TB

Diagnosis: Based on clinical presentation, positive Mantoux test, exudative ascitic fluid with lymphocytic predominance, and elevated ADA, a diagnosis of abdominal tuberculosis (likely tuberculous peritonitis) was made.

Management:

1. Antitubercular Therapy (ATT):
   • Intensive phase (2 months): Isoniazid, Rifampicin, Pyrazinamide, Ethambutol
   • Continuation phase (4–7 months): Isoniazid, Rifampicin
2. Nutritional support: High-protein diet, vitamin supplements
3. Symptomatic management: Diuretics if required for symptomatic relief of ascites
4. Follow-up: Clinical and radiological monitoring for response to therapy

Discussion: Abdominal TB can manifest as tuberculous peritonitis, intestinal TB, or lymphadenopathy. It often presents with nonspecific symptoms, making early diagnosis difficult. The Mantoux test, ADA levels, and ascitic fluid characteristics are helpful diagnostic tools. GeneXpert has low sensitivity for peritoneal TB but is useful in other forms of extrapulmonary TB. Early initiation of ATT is crucial to prevent complications.

Conclusion: This case highlights the importance of considering TB in children with unexplained ascites, even when ascitic fluid analysis appears normal. A high index of suspicion, supportive investigations, and empirical ATT can be lifesaving in resource-limited settings.

References:

1. Sharma SK, Ryan H, Khaparde SD, et al. Index-TB Guidelines: Guidelines on extrapulmonary tuberculosis for India. Indian J Med Res. 2017;145(4):448-463.
2. World Health Organization (WHO). Tuberculosis management guidelines 2022.
3. Kashyap RS, Nayak AR, Sahu M, et al. Diagnostic value of adenosine deaminase in peritoneal tuberculosis. Clin Chem Lab Med. 2018;56(2):221-226.