Which radiological finding is pathognomonic for endobronchial tuberculosis on chest X-ray?

Explanation

## Endobronchial Tuberculosis — Radiological Features **Key Point:** Segmental or lobar atelectasis due to bronchial obstruction is the hallmark radiological finding of endobronchial TB (EBTB). The disease involves the mucosa of the bronchi, causing stenosis and collapse of distal lung parenchyma. ### Pathophysiology Endobronchial TB results from: 1. Erosion of a caseous focus into an adjacent bronchus 2. Mucosal inflammation and ulceration 3. Bronchial stenosis → air trapping or atelectasis 4. Risk of bronchial spread to other segments ### Radiological Findings in EBTB | Finding | Frequency | Significance | |---------|-----------|-------------| | **Segmental/lobar atelectasis** | Most common | Pathognomonic when present | | Bronchial wall thickening | Common | Seen on CT, not always on CXR | | Cavitation | Variable | May or may not be present | | Hilar/mediastinal lymphadenopathy | Frequent | Often accompanies EBTB | | Air bronchograms | Less common | Suggests consolidation, not typical EBTB | **High-Yield:** Segmental atelectasis in TB (especially in the **right upper lobe or superior segment of right lower lobe**) should raise suspicion for EBTB. This is a classic NEET PG finding. **Clinical Pearl:** EBTB is a form of active TB and requires anti-tuberculous therapy. It carries a risk of bronchial stenosis and bronchiectasis if untreated. ### Why Other Findings Are Not Pathognomonic - **Lobar consolidation with air bronchograms** → seen in primary TB, secondary TB, and other pneumonias - **Cavitary lesion** → seen in secondary TB but not specific to endobronchial disease - **Miliary pattern** → indicates hematogenous dissemination, not endobronchial involvement