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TB Mantoux Interpretation — RACP Paediatrics MCQ

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ModerateInfectious DiseaseTB Mantoux InterpretationRACP Paediatrics

A 6-year-old Aboriginal child in the Northern Territory presents with painful cervical lymphadenopathy, fever, and a BCG scar. His family recently arrived from a country with high TB burden. Mantoux test is 18 mm. What does this result indicate in this context?

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Correct answer: E — Latent TB infection or active TB disease requiring further investigation

In the context of TB exposure and symptoms, a Mantoux ≥10 mm (or ≥5 mm if immunocompromised/close contact) is considered positive regardless of BCG status. BCG typically causes reactions <10 mm and its effect wanes over time. This child requires CXR, sputum/gastric aspirate, and consideration of treatment for LTBI or active TB.

Reference: Therapeutic Guidelines – 2024 – Antibiotic: Tuberculosis Screening