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Indian Pediatr 2013;50: 803-804 |
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Tuberculosis - A Quest Towards Objectivity
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A Gupta
Department of Pediatrics and Neonatology, Fortis
Hospital and Research Centre, Faridabad, India.
Email:
[email protected]
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I read with interest "updated National Guidelines for pediatric
tuberculosis in India, 2012" and appreciate the effort made to clarify
certain grey areas of interpretation like weight loss or no weight gain
besides presenting the contents as flow diagrams for ready reference
[1]. I would like to draw attention to certain points requiring further
clarification to enable a clinician to use these guidelines practically
and effectively in a wider range of situations.
According to figure 1a and 1b, a symptomatic sputum
negative patient undergoes chest X-ray and TST. Following this, the
possible results would be in six ways as per the outcome of these two
investigations.
Chest X-ray can be read as: (a) Highly
suggestive of tuberculosis, (b) Non- specific shadows (c)
Normal; TST can be read as: (i) Positive, (ii) Negative.
Though most of the possible scenarios are dealt with properly, it does
not provide an approach for (a+ii) that is highly suggestive XRC and TST
negative. Similarly it does not justify the use of TST when XRC shows
non- specific shadows as no decision is based on TST results whether
positive or negative.
CT scan is a useful diagnostic modality in children
when tuberculosis is suspected and the radiographic findings are normal
or inconclusive [2]. Chest CT can help to identify enlarged, calcified,
necrotic mediastinal lymph nodes, which are less frequently found in
community acquired bacterial pneumonia and frequently obscured by thymic
shadows on chest radiographs of children [3]. It may also detect
pulmonary parenchymal lesions not otherwise visualized on chest
radiographs [4]. Therefore, a TST positive, sputum negative clinical
suspect in such scenario may be subjected to CT scan chest as first
investigation (wherever possible) before taking on other investigation
for alternate diagnosis.
As tuberculin skin test is defined with the use of
tuberculin 2 TU and its procurement is difficult outside government
supply, it would be useful to share the manufacturer of such product.
References
1. Kumar A, Gupta D, Sharath BN, Singh V, Sethi GR,
Prasad J. Updated National Guidelines for pediatric tuberculosis in
India, 2012. Indian Pediatr. 2013;50:301-13.
2. Kim WS, Moon WK, Kim IO, Lee HJ, Im JG, Yeon KM,
et al. Pulmonary tuberculosis in children: evaluation with CT. Am
J Roentgenol. 1997;168:1005-9.
3. Peng SS, Chan PC, Chang YC, Shih TT. Computed
tomography of childrenwith pulmonary Mycobacterium
tuberculosis infection. J Formos Med Assoc. 2011; 110:744-9.
4. Swaminathan S, Raghavan A, Datta M, Paramasivan
CN, Saravanan KC. Computerized tomography detects pulmonary lesions in
children with normal radiographs diagnosed to havetuberculosis. Indian
Pediatr. 2005; 42:258-61.
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Reply
The author has raised the issue about
dealing with children with highly suggestive radiology, who
are TST negative. With certainty it is spelt out in the
diagnostic algorithm that a presumptive pediatric TB case
with TST negative and chest X-ray findings suggestive
of TB should be diagnosed based on X-ray findings;
because the TST suffers from lack of sensitivity and
specificity, and there are operational issues concerned with
performing the test efficiently. In view of radiation risk
and issues pertaining to CT interpretation (low specificity
and inter observer variability) [1,2] it is neither
necessary nor appropriate to recommend CT scan as first line
investigation. However, the algorithm has identified
situations where an expert opinion is needed and they may
ask for more detailed investigations including CT chest.
Varinder Singh and BN Sharath
Email: [email protected]
References
1. Andronikou S, Brauer B, Galpin J,
Brachmeyer S, Lucas S, Joseph E, et al. Interobserver
variability in the detection of mediastinal and hilar lymph
nodes on CT in children with suspected pulmonary
tuberculosis. Pediatr Radiol. 2005;35:425-8.
2. de Jong PA, Nievelstein RJ. Normal mediastinal and
hilar lymph nodes in children on multi-detector row chest
computed tomography. Eur Radiol. 2012;22:318-21.
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