Post-TB Sequelae: Chest X-Ray Findings

1. Parenchymal Changes

Fibro-calcific Changes (most common)

• The hallmark of healed post-primary TB
• Irregular, dense opacities with or without calcification, typically in the upper lobes (apical and posterior segments)
• Combined fibrosis and calcification = "fibro-calcific change"
• Associated volume loss of the affected lobe with compensatory hyperinflation of adjacent lung

Ghon Focus / Ranke Complex

• A Ghon focus = residual well-defined rounded or irregular opacity (with or without calcification) from healed primary TB
• Heterogeneous, irregular nodal calcification in the ipsilateral hilum or mediastinum
• Ghon focus + ipsilateral calcified lymph node = Ranke complex
• Calcification of the Ghon focus occurs in ~15% of cases

Tuberculoma

• Rounded soft-tissue density, usually 1-4 cm, often with central or irregular calcification (in 20-30%)
• Smooth, well-defined margins; frequently stable for years
• Satellite nodules present in up to 80% of cases
• May be solitary or multiple

Thin-Walled (Residual) Cavity

• After cavitary TB resolves, a thin-walled, air-filled cavity may persist without active disease
• Wall thickness < 2 mm; no surrounding consolidation
• Clinically significant as a site for aspergilloma formation

Aspergilloma (Mycetoma)

• A fungus ball (Aspergillus) colonising an existing TB cavity or bronchiectatic space
• CXR: rounded opacity within a cavity, often with an "air crescent sign" (air cap between the ball and cavity wall)
• Changes position with posture (pathognomonic when present)

Cicatrization Collapse (Destroyed Lung)

• The most severe parenchymal sequela
• Complete or near-complete destruction of a lobe or entire lung from prolonged cavitation, endobronchial spread, and fibrosis
• CXR shows: dense opacification, marked volume loss, ipsilateral mediastinal and tracheal shift, crowded ribs, and compensatory emphysema on the opposite side
• More often unilateral

2. Airway Disease

Bronchiectasis

• Common and characteristic sequela; occurs by destruction and fibrosis of parenchyma with irreversible secondary bronchial dilatation (traction bronchiectasis)
• Location in the apical and posterior segments of the upper lobes is highly suggestive of tuberculous origin
• CXR: tram-track opacities, ring shadows, crowded vascular markings; better seen on CT

Tracheobronchial Stenosis

• Results from healed endobronchial TB or extrinsic compression by calcified lymph nodes
• CXR may show lobar atelectasis or air-trapping; can be subtle on plain film, better assessed on CT

3. Pleural / Chest Wall Changes

Pleural Thickening

• Common residual finding; may be unilateral or bilateral
• Ranges from mild apical capping to extensive fibrous pleural rind (fibrothorax)
• CXR: blunted costophrenic angle, dense band along the chest wall

Pleural Calcification

• Dense, often irregular calcification along the visceral and/or parietal pleura
• Often associated with old tuberculous empyema
• "Eggshell" pattern or broad sheet of calcification is characteristic

Fibrothorax

• Extensive pleural fibrosis encasing the entire lung
• CXR: marked volume loss, scoliosis, and ipsilateral mediastinal shift; ipsilateral ribs are crowded

Empyema Necessitatis

• Rare: direct spread of infection through chest wall to soft tissues
• CXR: soft-tissue mass at chest wall, often with rib involvement

4. Vascular Changes

Rasmussen Aneurysm

• Pseudoaneurysm of a pulmonary artery branch that traverses or is adjacent to a tuberculous cavity
• CXR: a nodular opacity within or adjacent to a cavity (the aneurysm itself)
• Can rupture and cause massive haemoptysis
• Best characterised on contrast-enhanced CT

5. Mediastinal / Lymph Node Changes

Calcified Mediastinal/Hilar Lymph Nodes

• Heterogeneous, irregular, often stippled calcification in hilar and mediastinal nodes
• Usually asymptomatic residual finding
• Rarely can compress adjacent bronchi causing atelectasis or broncholithiasis

Summary Table

Clinical Pearls

• Upper lobe location of fibrosis, cavitation, bronchiectasis, or calcification is the strongest indicator of a tuberculous aetiology
• Residual thin-walled cavities and bronchiectatic spaces are the most common sites for superimposed aspergilloma
• Cicatrization collapse can make it difficult to assess for residual active disease radiologically - CT and bronchoscopy are required
• Mediastinal tracheal shift toward the side of volume loss is an important sign of post-primary sequelae and should not be confused with a mediastinal mass
• Some findings (mild pleural fibrosis, calcified nodes) are incidental and asymptomatic; others like fibrothorax and destroyed lung cause significant respiratory compromise