Primary complex is the site where the Tuberculosis
Bacilli infect for first time. Usually the area is located in upper part of lower lobe of lung / lower part of upper lobe of lung / at the apex of lung. When TB bacilli are inhaled, it get into the lung. The bacilli multiply in the site until it is attenuated by body protection mechanism -the cell mediated immunity (CMI). The bacilli become dormant and stay there for life long. The chance of reactivation of the bacilli from primary complex to develop tuberculosis disease is very less (usually 5 to 10%) in normal healthy individual during some phase of life with low body defence (like - malnutrition
, steroid therapy, immunosuppression
). However, the chance of reactivation is more (about 30%) in people with HIV. Primary complex usually produce no symptoms or mild symptoms (like - cough). However, primary tuberculosis may not be limited in complex (GOHN FOCUS / SIMON FOCUS) and directly progress to full disease of tuberculosis - pulmonary and extrapulmonary.
Primary Complex is detected in Chest X-ray PA (postero-anterior) view as a small opacity at the area involved (apex / lower part of upper lobe / upper part of lower lobe). But some cases (about 15%) may not be detected in Chest X-ray.
Other test for TB is the Tuberculin test or Mantoux test
. Extract from TB bacilli (sterilized culture) is injected intradermally (between the layers of skin) and the area is observed after 48/72 hrs. A person exposed to TB bacilli will show a reaction (induration / redness of area ). The diameter area is measured and interpreted (the size of area is correlated with person's clinical feature, history of TB exposure, travelling history to TB dominant areas, HIV infections etc). However, the test has false positivity (BCG vaccinated person) and false negativity (Miliary TB).
I do not know how the primary tuberculosis was detected (by chest X-ray only, or along with tuberculin test).The opacity of Primary TB complex in lung if present, usually persists for life. If the primary tuberculosis diagnosis was right - drugs should be continued for 6 months.
You should go for a tuberculin test (if not done already). Tuberculin test positive in a child with no history of BCG vaccination
suggest an infection with TB bacilli. Such children need therapy for six months.
Tuberculosis bacilli are well known for their nature of developing drug resistance
in case of inadequate / incomplete therapy.
As your pediatrician
already examined the child and suggested to stop therapy, he /she may be right. But if the diagnosis of primary TB was correct, it would be wise to get your child examined by Tuberculosis expert / Chest medicine Specialist doctor before discontinuing therapy.