DISCUSSION
Epidimiology:
Koch discovered the tubercle bacillus in 1882. The world wide incidence
of TB is increasing. Between 2000-2020 one billion will be newly infected,
200 million will develop the disease, and 35 million will die.
HIV is one of the major predisposing factors leading to an increase
of TB. In the developing counties Up to 40% cases are pediatric while
in the developed countries less than 5% of all cases are, but it is
also increasing.
CRITERIA
FOR THE DIAGNOSIS OF
PULMONARY TUBERCULOSIS
American Academy of Pediatric:
Two or more of the following:
–
History of close contact with a known or suspected infectious case of
TB
–
Radiographic finding compatible with TB
–
Positive tuberculin skin test defined below:
±
5mm
–
(a)
in close contact with known or suspected infectious case
–
Or
(b) suspected of having TB on the basis of a chest radiogram
–
Or (c) have clinical evidence on physical examination or laboratory
assessment that would include TB as a working diagnosis (eg,meningitis,
hepatosplenomegaly )
–
Or (d) immunosupressive conditions including HIV and sever malnutrition
–
Or (e) immunosupressive therapy eg corticosteriods
–
Or (f) features suggestive of HIV but unknown HIV status
± 10mm
In children at increase risk of dissemination
–
Less
than 4years
–
Or other medical risk factors (Diabetes, Chronic renal failure, malnutrition)
± 15mm
–
Any child with or without risk factors
WHO
criteria:
Mantoux
test positive if it is >10 mm (no BCG) or 15 mm (with BCG)
British Thoracic Society:
Mantoux test 10TU will considered positive if 5-14 mm (no BCG) or >15mm
(with BCG)
PCR:
PCR is used for rapid detection of AFB. It has high specificity but
the sensitivity is significantly less than that of the culture. 39%
of children with no radiological or clinical evidence of TB had positive
PCR. PCR alone is insufficient to diagnose TB in children.
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