Define Childhood Tuberculosis. Describe its pathogenesis, types, clinical features and treatment.

Definition

• Tuberculosis (TB) is a chronic granulomatous infectious disease caused by Mycobacterium tuberculosis.
• Children usually develop primary, paucibacillary disease acquired from an infectious adult (the index case) with sputum-positive pulmonary TB.

Pathogenesis

• Inhaled bacilli form a subpleural Ghon focus; with the draining lymphangitis and regional (hilar) lymph node this is the primary (Ghon) complex.
• Most primary infections are contained (latent TB); progression gives primary disease, and reactivation later gives post-primary TB.
• Haematogenous spread → miliary TB and TB meningitis (especially in young/immunocompromised children).

Types

• Pulmonary TB — commonest (hilar lymphadenopathy, consolidation, effusion).
• Extrapulmonary — lymph node (commonest EP), TB meningitis, miliary, abdominal, spinal (Pott's), pleural, osteoarticular.

Clinical Features

• Persistent fever and/or cough > 2 weeks, weight loss / failure to thrive / no weight gain, and fatigue.
• A history of contact with an adult TB case is a very important clue.
• Site-specific — matted cervical lymphadenopathy, meningitis, gibbus (spinal), abdominal distension/ascites.

Diagnostic Approach

• History of contact + suggestive symptoms.
• Tuberculin skin test (Mantoux) — ≥ 10 mm positive (≥ 5 mm if HIV/severely malnourished).
• Chest X-ray — hilar/mediastinal lymphadenopathy, consolidation, miliary mottling.
• Microbiology — sputum or gastric aspirate for AFB; CBNAAT/GeneXpert (rapid; also detects rifampicin resistance); culture (gold standard).
• IGRA where available; site-specific samples (CSF, lymph-node FNAC, pleural fluid).

Management — Att (daily Regimen, Weight-band Dosing)

• Intensive phase — 2 months of HRZE (isoniazid, rifampicin, pyrazinamide, ethambutol).
• Continuation phase — 4 months of HRE (total 6 months for drug-sensitive TB).
• TB meningitis / miliary / osteoarticular — prolonged therapy (about 12 months) and corticosteroids for TBM.
• Directly observed treatment, nutritional support, and monitoring for adherence, response and drug toxicity.

Latent TB VS Active TB Disease

Monitoring on Treatment

• Clinical response — resolution of fever, weight gain, improved appetite (usually within weeks).
• Watch for drug toxicity — hepatotoxicity (H, R, Z), optic neuritis (ethambutol), and ensure adherence.
• Follow-up radiology/microbiology as indicated; document treatment outcome.

TB & HIV

HIV co-infection increases the risk of active TB, extrapulmonary and disseminated disease, and atypical presentations; all children with TB should be offered HIV testing, and ART is combined with ATT (with attention to drug interactions).

BCG Vaccine

• Live attenuated vaccine given at birth; protects mainly against severe childhood forms (miliary TB and TB meningitis).
• Does not reliably prevent primary pulmonary infection; a normal scar indicates prior vaccination.

Prevention

• BCG vaccination at birth (protects against severe forms — miliary TB and TBM).
• Contact screening and chemoprophylaxis (INH) for under-5 and HIV-positive contacts.
• Prompt treatment of infectious adults; infection control; addressing malnutrition.