Tuberculosis (TB)

Over 95% of cases and deaths are in middle- and lower income countries

Aetiology

  • Most children infected with M. tuberculosis do not develop TB - development of TB depends on the competence of the immune system to resist multiplication of the infection

Risk factors

  • HIV - over 50% of TB cases in Sub-Saharan Africa are co-infected with HIV
  • Malnutrition
  • Household contact

Clinical presentation

  • Chronic cough or fever >2 weeks
  • Night sweats
  • Weight loss
  • Lymphadenopathy

Investigations

  • Chest x-ray
    • Shadows, lesions, consolidation
    • Ghon focus in periphery of mid zone of lung - primary site of infection
    • Bilateral hilar lymphadenopathy
    • ‘Miliary shadowing’ = miliary TB
  • Mantoux - tuberculin skin test
  • Ziehl-Neelson stain - tests for acid-fast bacilli (low yield in children)
  • Interferon-Gamma Release Assays (not used under 5)

Management

  • Active TB - Rifampicin, Isoniazid, Pyrazinamide and Ethambutol for 4 months, then Rifampicin and Isoniazid for a further 2 months
  • Latent TB - Rifampicin and Isoniazid for 3 months OR Isoniazid for 6 months
  • Longer if TB meningitis, spinal or osteo-articular disease
  • 'Directly observed therapy' to improve compliance