When cough is due to Active TB, the CXR is always abnormal.
- Suspect when findings occur in the apex, also in upper lobes.
- Cavities are strongly suspect; nodular infiltrates too.
- A myriad of other readings are possible.
- “Calcified granuloma” doesn’t count — it’s a marker for Latent TB (by definition asymptomatic).
BEWARE if radiologist finds “scars of old granulomatous disease”
- Interpretation is impossible unless also present on a prior film, & now unchanged.
- If no old film, consider active TB.
Diagnose Active TB by sputum tests for acid-fast bacteria (AFB).
- The PPD isn’t helpful (20% of patients have false-negative skin tests).
- Positive PPD identifies Latent TB (asymptomatic).
Suspect Active TB among patients at risk:
Risks for Being Infected with TB
|Risks for Reactivating TB