Tuberculosis remains one of the world’s leading infectious killers. The chest radiograph is often the first clue, and recognising the main patterns helps clinicians isolate patients and send the right samples early.
Primary tuberculosis
Seen most often in children, primary TB typically shows hilar or mediastinal lymphadenopathy, sometimes with consolidation in any lobe and a pleural effusion.
Post-primary (reactivation) tuberculosis
This favours the apical and posterior segments of the upper lobes and the superior segments of the lower lobes. Cavitation indicates active, often highly infectious disease. On CT, a “tree-in-bud” pattern suggests endobronchial spread.
Key patterns:
- Upper-zone consolidation with cavitation
- Hilar lymphadenopathy, especially in children
- Miliary pattern – innumerable tiny nodules of 1–3 mm
- Pleural effusion
Immunosuppression changes the picture
In people with advanced HIV infection, TB often looks atypical — lower-zone disease, lymphadenopathy and little cavitation — and the chest film may even be normal.
“Imaging raises the suspicion; microbiology makes the diagnosis.”
Sputum testing with rapid molecular assays should follow any suspicious film.
This article is for education only and does not replace clinical judgement or local guidelines.
