Tuberculosis in infants: a retrospective study in China

Area of Science:

• Pediatrics
• Infectious Diseases
• Public Health

Background:

• Tuberculosis (TB) remains a significant global health challenge, especially in high-burden countries.
• Infant tuberculosis (TB) presents unique diagnostic and clinical challenges.
• Understanding the specific epidemiology of infant TB is crucial for effective control strategies.

Purpose of the Study:

• To describe the demographics, clinical characteristics, and microbiologic findings of infant tuberculosis (TB) in a high TB burden country.
• To evaluate the diagnostic performance of routine TB tests in infants.
• To identify common clinical presentations and sites of extrapulmonary TB (EPTB) in infants.

Main Methods:

• A retrospective review of 115 infants (≤2 years old) diagnosed with TB between February 2007 and June 2015.
• Analysis of demographic data, clinical presentations, and diagnostic test results (pathology, acid-fast bacilli smear, mycobacterial culture, PPD, T-SPOT.TB).
• Comparison of clinical characteristics and time to hospital admission across different TB types.

Main Results:

• The majority of infants were male (73.0%), with a mean age of 10.1 months.
• Extrapulmonary TB (EPTB) was more common (64.4%) than pulmonary TB, with tuberculous lymphadenitis (61 cases) being the most frequent site, particularly axillary lymph nodes (54 cases).
• Routine TB diagnostic tests demonstrated low sensitivity (e.g., mycobacterial culture 26.2%, PPD 49.2%, T-SPOT.TB 46.7%).

Conclusions:

• Infant TB in this high-burden setting is predominantly extrapulmonary, with a high proportion of tuberculous lymphadenitis.
• The low sensitivity of conventional TB diagnostic tests in infants underscores the urgent need for improved diagnostic tools.
• An association between axillary lymph node TB and BCG vaccination in infants in China warrants further investigation.