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• 30% of the world population (2 billion) are infected with tuberculosis
• 2.3 million deaths from tuberculosis per year
• 8.4 million cases of tuberculosis illness per year
• 1.3 million cases and 450,000 deaths from tuberculosis occur in children each year
• Tuberculosis in children is increasing by 6% annually
• WHO estimates 159 & 370/100,000 new smear positive pulmonary TB & all other forms of TB respectively
• 40% of adult tuberculosis cases are HIV positive
• Tuberculosis


  A neglected disease, "Orphan disease"
• Tuberculosis accounts for 20% or more of the TB case-load in many countries with high TB incidence
• Mycobacterium species


  • M.tuberculosis
  • M.bovis
  • M.africanum
  • M.microti
  • M.canetti
• Mycobacterium tuberculosis


  • Non–spore-forming, non-motile, pleomorphic, weakly gram-positive curved rods 2-4µm long which are obligate aerobes
  • Acid-fast
  • Form stable mycolate complexes with arylmethane dyes
  • Resist discoloration with ethanol and hydrochloric or other acids
  • Grow slowly, with a generation time of 12-24 hr
• Isolation of mycobacterium from clinical specimens

  1. On solid synthetic media - takes 3-6 weeks

  2. In selective liquid medium using radiolabeled nutrients - 1-3 weeks
• Exposure

  A child has had significant contact with an adult or adolescent with infectious tuberculosis but lacks proof of infection
• Infection


  The individual has inhaled droplet nuclei containing M. tuberculosis, which survive intracellularly within the lung and associated lymphoid tissue
• Disease


  Signs, symptoms or radiographic manifestations of tuberculosis become apparent
• An immunocompetent adult with untreated tuberculosis infection has approximately a 5-10% lifetime risk of developing disease
• An infected child under 1 year of age has a 40% chance of developing disease within 9 months
• Modes of tuberculosis transmission

  • Inhalation of airborne mucus droplet nuclei
  • Ingestion of milk (M. bovis)
  • Skin (direct contact)
  • Transplacental
• Factors affecting tuberculosis transmission

  • Environmental factors: Crowding, poverty, UV light, genetics, close contact, dark & humid area, indoors, large # of bacilli in sputum
  • Patient factors: Positive acid-fast smear of sputum, extensive upper lobe infiltrate or cavity, copious production of thin sputum, severe and forceful cough
• Factors affecting tuberculosis disease development

  • Immunity status
  • Nutritional status
  • Intercurrent illness
  • Length of time of exposure
  • Number of bacteria inhaled
  • Age at infection
• Primary infection


  The initial infection, including the parenchymal pulmonary focus and the regional lymph nodes
• Reactivation


  Pulmonary tuberculosis which occurs after 1 year of infection, usually characterized by cavitations
• Disseminated and meningeal tuberculosis are early manifestations, often occurring within 2-6 months of acquisition
• Significant lymph node or endobronchial tuberculosis usually appears within 3-9 months
• Lesions of the bones and joints take several years to develop, and renal lesions become evident decades after infection
• Extra-pulmonary manifestations are more common in children than adults (25-35% of children vs 10% of immunocompetent adults)
• The risk for dissemination of M. tuberculosis is very high in HIV-infected persons, and reinfection can also occur in persons with advanced HIV or AIDS
• Diagnostic methods for tuberculosis

  • X-rays
  • Tuberculin skin test
  • Culture
  • Biopsy
  • PCR
  • DNA finger printing
  • Ziel Nielson stain
  • Flourochrome stain
  • T-cell based interferon-gamma assays (QuantiFERON-TB gold, T-SPOT.TB)
  • Sputum acid-fast bacilli (AFB) smear
• Chest X-ray


  No shadow is typical for tuberculosis, and 40% of patients diagnosed as having TB by X-Ray alone may not have active TB disease
• Tuberculin skin test (PPD)


  Based on the delayed hypersensitivity which develops after infection, measurement done after 48 to 72 hours, transient reactions within 24 hours are considered negative, results based on measurement of induration (not erythema)
• Causes of false negative PPD test


  • Severe protein-energy malnutrition
  • Measles
  • Overwhelming tuberculosis
  • Wrong techniques
  • HIV
  • Steroids
  • Cancer
• Causes of false positive PPD test

  • Atypical mycobacterial infections
  • Hypersensitivity to constituents
  • BCG vaccination
• Criteria for tuberculosis diagnosis in children


  • Positive PPD
  • Compatible radiology
  • Contact history
  • Symptom complex
  • Acid-fast bacilli
  • Miliary pattern on chest X-ray
  • Biopsy
  • Culture
  • Positive PPD in unvaccinated children under 5 years of age
• Types of tuberculosis


  • Latent tuberculosis infection
  • Tuberculosis disease (extra-pulmonary, pulmonary - primary, reactivation, progressive primary)
• Tuberculosis lymphadenitis (Scrofula)


  Common sites are cervical lymph nodes, occasionally axillary and groin lymph nodes, mostly unilateral, TST (PPD) positive in 80% of patients but chest X-ray is normal in 70% of patients
• Primary pulmonary tuberculosis


  The primary complex includes the parenchymal pulmonary focus and the regional lymph nodes, approximately 70% of lung foci are subpleural, all lobar segments of the lung are at equal risk for initial infection, the hallmark is the relatively large size of the regional lymphadenitis compared with the relatively small size of the initial lung focus
• Symptoms of primary pulmonary tuberculosis in children

  • Nonproductive cough and mild dyspnea are the most common symptoms, severe symptoms like fever, cough with sputum production, weight loss, and night sweats are less common, 50% of infants and children with radiographically moderate to severe pulmonary tuberculosis have no physical findings
• Progressive primary pulmonary tuberculosis

  A rare but serious complication where the primary focus enlarges steadily and develops a large caseous center, characterized by high fever, severe cough with sputum production, weight loss, and night sweats
• Primary complex


  Includes the parenchymal pulmonary focus and the regional lymph nodes
• Approximately 70% of lung foci are subpleural