Extrapulmonary TB Infectiousness — SCE Infectious Diseases MCQ

Instant feedback + full explanation. One question, done properly.

EasyTuberculosisExtrapulmonary TB InfectiousnessSCE Infectious Diseases

A 30-year-old woman with HIV (CD4 350, VL <50 on ART) presents with a 3 cm painless axillary lymph node. FNA shows acid-fast bacilli. GeneXpert detects M. tuberculosis without Rifampicin resistance. She has no pulmonary symptoms and her chest X-ray is normal. Is she infectious?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: A — Extrapulmonary TB (lymph node) without pulmonary involvement is generally NOT infectious — she does not require respiratory isolation

TB infectiousness is determined by the site of disease and the ability to aerosolise M. tuberculosis. Pulmonary TB (especially smear-positive cavitary disease) is the primary infectious form. Extrapulmonary TB (lymph node, bone, genitourinary, etc.) without concurrent pulmonary involvement is generally NOT infectious to others and does not require respiratory isolation. However, draining sinuses from lymph node TB are potentially infectious through direct contact. This patient with isolated cervical lymph node TB and normal CXR is not infectious and does not need airborne precautions.

Reference: NICE NG33 2016 – TB; UKHSA 2024 – TB IPC guidance