How do we know drug-resistant TB in children is increasing?

Photo by varsheshIs there an increasing number of children in the high prevalence countries contracting the drug resistant strain?

Can these TB resistant strains in children be diagnosed? Has anyone proven it?

Childhood TB (or Primary TB) is a 'self-limiting' disease. Nobody knows if or when a child has primary TB, since the child shows no symptoms.

Primary TB could be detected, if contact tracing is carried out vigilantly. The source of infection is usually a close family member (house contact) who is coughing up sputum containing live tubercle bacilli and who is not (yet) under chemotherapy for TB.

The finding of hilar glandular enlargement plus the very presence of a source of infection and the absence of clinical symptoms (child is healthy,? no symptoms of asthma, bronchitis, whooping cough, etc) could indicate primary or childhood TB.

The characteristic signs of primary TB on chest X ray, are the presence of a primary affect, an infiltrate (too small to be visible on X ray) in the lung tissue, and an adjacent enlarged hilar lymphnode(s) which is likely more visible.

After BCG however, chest X ray may not show the characteristics of primary TB, pleural or miliary TB. To diagnose childhood or primary TB, after BCG, tuberculin tests are not helpful, neither are sero-diagnostic tests.

It is difficult to collect sputum from small children as they do not expectorate. Gastric washings are traumatic to the child. Besides, primary TB is paucibacillar, containing very few TB bacilli if any.

It is more difficult to carry out sensitivity testing for (multi-) drug resistant M tuberculosis and as far as extreme-drug resistant sensitivity testing is concerned it is impossible to diagnose MDR- or XDR-TB even in the most sophisticated TB laboratories where second-line drugs are not used or available.

However, it must be stressed, that children are not excluded from having post-primary TB. Characteristics can be found similar to those adults showing radiographical lesions consistent with progressive pulmonary tuberculosis. In such case, sputum examination may be positive and sensitivity tests can be carried out in a well established bacterial laboratories.

Bobby Ramakant-CNS

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