Pulmonary Tuberculosis

Overview

Surgery was historically the primary treatment for pulmonary tuberculosis (PTB) — collapse therapy, thoracoplasty, and plombage were widely used before the antibiotic era. With the discovery of streptomycin in 1943 and subsequent introduction of combination chemotherapy, surgery retreated to a secondary role. In the current era, surgery is indicated for sequelae of PTB, complications, and drug-resistant disease.

Pulmonary tuberculosis is caused by Mycobacterium tuberculosis — a rod-shaped, aerobic, acid-fast bacillus characterised by slow multiplication and the capacity for dormancy over decades. The lung is the most commonly affected organ, accounting for approximately 80% of all TB.

Pathogenesis

Primary pulmonary TB

Following airborne infection, a subpleural granuloma forms in the distal airways — the Ghon focus. When accompanied by tubercular lymphangitis and hilar lymphadenopathy, this constitutes the Ghon complex. On healing, the calcified subpleural lesion with calcified hilar lymph node forms the Ranke complex. In immunocompromised patients, primary TB may progress to consolidation, lymphadenopathy, pleural effusion, or miliary disease.

Post-primary (reactivation) TB

Reactivation usually occurs within two years of primary infection, typically affecting upper lobe parenchyma. It leads to cavitation and consolidation. Healing produces fibrosis, scarring, volume loss, traction bronchiectasis, and potential pleural involvement.

Surgical indications

A multidisciplinary approach — infectious disease specialists, respiratory physicians, radiologists, and thoracic surgeons — is essential for timing and patient selection, particularly in drug-resistant disease.

Surgical management of PTB sequelae

Destroyed lung

Complete parenchymal destruction in end-stage TB, more commonly affecting the left lung. Pathogenesis involves chronic inflammation, cicatrisation atelectasis, fibrosis, cavitation, and repeated secondary infection. Indications for pneumonectomy include recurrent infections, haemoptysis, failure to thrive, and recurrent TB.

Persistent cavity

Most tubercular cavities resolve with chemotherapy. Persistent cavities may be thin-walled (mimicking bullae) or thick-walled. Chronic cavities risk relapsing TB, aspergilloma formation, and Rasmussen aneurysm. Indications for surgery: haemoptysis, aspergilloma, and persistence despite adequate chemotherapy. Anatomical resection (lobectomy) is preferred over wedge excision.

Tracheobronchial stenosis

Left main bronchus is most commonly involved. Pathogenesis: healed endobronchial TB causes submucosal granuloma, ulceration, and stricture. Management depends on the extent of airway involvement and condition of the lung parenchyma. Isolated stenosis with preserved lung may be managed with bronchoscopic dilatation (recurrence is common). Parenchyma-sparing bronchoplastic procedures are preferred for limited disease; lobectomy or pneumonectomy for destroyed or significantly diseased lung.

Broncholithiasis

Calcified tubercular lymph nodes eroding into the bronchial lumen, causing obstruction. Mobile broncholiths may be removed bronchoscopically. Fixed broncholiths require bronchotomy, removal, and repair.

Drug-resistant PTB — surgical role

The 2021 WHO updated definition of XDR-TB defines it as MDR/RR-TB with additional resistance to any fluoroquinolone plus at least one of bedaquiline or linezolid. The previous definition (resistance to any fluoroquinolone + one of the second-line injectables) is now superseded.

Surgical resection as an adjunct to chemotherapy may provide better outcomes in selected cases — particularly where drug therapy alone is unlikely to achieve sputum negativity or where there is localised resectable disease. Pre-operative optimisation to achieve sputum negativity or reduced bacillary load is strongly desirable before elective resection.

Non-tuberculous mycobacteria (NTM)

NTM (also known as MOTT — mycobacteria other than tuberculosis) are ubiquitous environmental organisms. Both immunosuppressed and immunocompetent hosts may be affected. MAC (M. avium complex), M. kansasii, and M. abscessus are the most common respiratory pathogens.

Surgical indications in NTM: relapse or re-infection with localised resectable disease; persistent positive cultures despite adequate chemotherapy; or destroyed lung parenchyma (bronchiectasis, fibrocavitary disease).