Alaska Tuberculosis Program Manual - Epidemiology - State of Alaska

Radiologic abnormalities in children with active TB may, in the short term,
worsen on treatment before they improve. Usually there has been some
response by two months, but even at the end of a satisfactory course of
treatment there may be residual lymphadenopathy or scarring.
Magnetic resonance (MR) or computed tomography (CT) scans are generally not necessary
unless there is a questionable abnormality on the plain film and further definition is required.
MR and CT imaging may be very helpful in the evaluation of suspected active CNS disease or
bone and joint disease. MR and CT imaging can also be helpful in the evaluation of
endobronchial disease and disease in other sites, such as the intra or extrathoracic lymph
nodes, pericardium and peritoneum. 34
Bacteriologic Testing
The gold standard for diagnosing TB disease in children is isolation of M. tuberculosis by culture
from specimens of gastric aspirates, sputum, bronchial washings, pleural fluid, cerebrospinal
fluid (CSF), urine, other body fluids, or a biopsy specimen.
For many children with pulmonary TB, culture confirmation is not needed. Diagnosis is made on
the basis of a positive TST, clinical and radiographic findings suggestive of TB, and history of
contact with an identified adult source case. The drug-susceptibility test results from the source
case’s TB isolate can be used to guide the optimal treatment for the child. However, cultures
should be obtained from the child if the source patient is unknown or has a drug-resistant
organism and if the child is immunocompromised or has extrapulmonary TB.
Gastric Aspirates
For infants and young children with suspected pulmonary TB, the best specimen to obtain for
culture is an early morning gastric aspirate obtained using a naso-gastric tube before the child
arises and before peristalsis empties the stomach of the respiratory secretions swallowed
overnight. Three consecutive morning gastric aspirates yield M. tuberculosis in 30% to 50% of
cases; the yield from infants is as high as 70%.
Curry International Tuberculosis Center has guidelines for the collection of
gastric aspirates, available at
http://currytbcenter.ucsf.edu/products/product_details.cfm?productID=ONL-
10
Sputum Collection
For older children collection of spontaneously produced or induced sputum is often possible.
The combination of sputum induction and gastric aspirate has yielded the organism in up to
90% of cases. In older children or adolescents, sputum induction is preferable to bronchoscopy.
Bronchoscopy
The culture yield is lower from bronchoscopy specimens than from properly obtained gastric
aspirates. Most
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A L A S K A T U B E R C U L O S I S P R O G R A M M A N U A L Diagnosis and Treatment of LTBI and TB Disease in Children 9.22
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