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Published on: February 16, 2020
Subclinical Tuberculosis in Children: Diagnostic Strategies for Identification Reported in a 6-year National
Nora Fritschi1, Ante Wind2, Jürg Hammer3
1Mycobacterial and Migrant Health Research Group, University of Basel Children's Hospital Basel and Department of Clinical Research, University of Basel, Basel, Switzerland.
Insights
Subclinical tuberculosis (TB) is common in children, often detected through contact tracing. Screening asymptomatic children requires a combination of immunodiagnostic tests, imaging, and molecular testing for accurate diagnosis.
Area of Science:
- Pediatrics
- Infectious Diseases
- Public Health
Background:
- Subclinical tuberculosis (TB) is defined as TB disease without recognizable symptoms.
- Identifying factors and diagnostic strategies for subclinical TB is crucial, especially in low-prevalence settings.
Purpose of the Study:
- To identify factors associated with subclinical TB in children.
- To evaluate diagnostic strategies for subclinical TB in a low-burden, high-resource country.
Main Methods:
- Data collected from December 2013 to November 2019 via the Swiss Pediatric Surveillance Unit (SPSU).
- Included children with culture/molecular confirmed TB or treated with ≥3 antimycobacterial drugs.
- Analyzed 138 children with TB disease, focusing on 43 subclinical cases.
Main Results:
- 31% (43/138) of children with TB had subclinical disease.
- Subclinical TB was diagnosed at a younger median age (3.7 years) compared to symptomatic TB (9.7 years).
- Contact exposure was the primary reason for investigation in 72.1% of subclinical cases; diagnostic methods varied, with "immunodiagnostic + chest radiography" being most common (44.2%).
Conclusions:
- A significant proportion of pediatric TB cases are subclinical.
- Non-symptom-based case finding is vital for exposed children and those from high-TB-prevalence areas.
- Recommended screening for asymptomatic children includes immunodiagnostic testing, imaging, and subsequent culture/molecular testing.
Background:
Subclinical tuberculosis (TB) is well recognized and defined as a disease state with absent or nonrecognized symptoms. The study identifies factors associated with subclinical TB and diagnostic strategies in a low-burden, high-resource country.
Methods:
Data were collected between December 2013 and November 2019 through the Swiss Pediatric Surveillance Unit (SPSU). Children with culture/molecular confirmed TB, or who were treated with ≥3 antimycobacterial drugs, were included.
Results:
A total of 138 (80%) children with TB disease were included in the final analysis, of which 43 (31%) were subclinical. The median age of children with subclinical compared to symptomatic TB was 3.7 (interquartile range [IQR] 2.2-7) and 9.7 (IQR 2.7-14.3) years, respectively (P = .003). The cause of investigation for TB was recorded in 31/43 (72.1%) of children with subclinical TB and included contact exposure in 25 (80.6%) of children. In children with subclinical TB, diagnosis was made by a combination of the following abnormal/confirming results: culture/molecular + immunodiagnostic + chest radiography in 12 (27.9%) cases, immunodiagnostic + chest radiography in 19 (44.2%) cases, culture/molecular + chest radiography in 2 (4.7%) cases, culture + immunodiagnostic in 1 (2.3%) case, chest radiography only in 8 (18.6%) cases, and immunodiagnostic only in 1 (2.3%) case.
Conclusions:
A notable proportion of children with TB had subclinical disease. This highlights the importance of non-symptom-based TB case finding in exposed children and refugees from high-TB-prevalence settings. TB screening in these asymptomatic children should therefore include a combination of immunodiagnostic testing and imaging followed by culture and molecular testing.
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