Post-Tuberculosis Lung Disease

Post-tuberculosis lung disease is chronic structural and functional lung damage that persists after microbiological cure of tuberculosis. It affects a large share of survivors, with abnormal spirometry in about a third to a half, and it is a major cause of chronic respiratory disease in Africa and Asia.

It includes airflow obstruction, restriction, bronchiectasis, fibrocavitary scarring, destroyed lung, pleural thickening, tracheobronchial stenosis, chronic pulmonary aspergillosis and pulmonary hypertension. Disability and early death are increased even after cure.

Pathophysiology. Granulomatous inflammation, caseation and cavitation destroy parenchyma and distort airways, and healing by fibrosis leaves bronchiectasis, traction and scarring. Residual cavities are colonised by Aspergillus. Delayed diagnosis, extensive disease, recurrent episodes, HIV, smoking, and biomass smoke add to the damage.

Chronic cough with sputum, exertional dyspnoea, wheeze, recurrent chest infection and haemoptysis, with reduced exercise capacity and weight loss. Examination may show hyperinflation, crackles, tracheal deviation, and signs of cor pulmonale.

Massive haemoptysis, respiratory failure or new fever with weight loss (possible relapse or drug resistant tuberculosis) needs urgent assessment.

• History of treated tuberculosis, with documented bacteriological cure.
• Spirometry with bronchodilator testing: obstructive, restrictive or mixed pattern. Full lung function and diffusing capacity, and a 6-minute walk test with oxygen saturation.
• Chest radiograph and CT: fibrosis, cavities, bronchiectasis, volume loss, pleural thickening, aspergilloma and tracheobronchial stenosis.
• Sputum for acid fast bacilli and nucleic acid amplification to exclude relapse or resistant disease, and culture for nontuberculous mycobacteria and fungi.
• Aspergillus IgG and total IgE when cavities are present.
• Echocardiography for pulmonary hypertension and cor pulmonale, and HIV status.

Differential diagnosis.

• Active or relapsed tuberculosis, including drug resistance
• COPD from smoking
• Nontuberculous mycobacterial disease
• Chronic pulmonary aspergillosis
• Lung cancer in scarred lung
• Bronchiectasis from other causes

• Confirm cure and exclude active disease before treating sequelae. Treat relapse or drug resistance with specialist input.
• Airflow obstruction: tiotropium 5 micrograms (two inhalations) once daily or a long acting beta agonist, with salbutamol 100 micrograms as needed, and an inhaled corticosteroid only for asthma features or eosinophils over 300 cells/microlitre.
• Bronchiectasis: airway clearance, antibiotic treatment of exacerbations directed by culture (amoxicillin-clavulanate 625 mg three times daily for 10 to 14 days), and azithromycin 250 mg daily or 500 mg three times weekly for frequent exacerbations after excluding nontuberculous mycobacteria.
• Chronic pulmonary aspergillosis: itraconazole 200 mg orally twice daily (with a blood level of 0.5 to 4 mg/L after 2 weeks) or voriconazole 200 mg twice daily for 6 to 12 months or longer. Monitor liver function and interactions with rifampicin, and avoid rifamycins during azole treatment.
• Haemoptysis: tranexamic acid 500 mg to 1 g orally three times daily for up to 5 days (or 1 g intravenously every 8 hours), and bronchial artery embolisation for repeated or massive bleeding.
• Pulmonary rehabilitation, nutritional support, vaccination against influenza, pneumococcus and COVID-19, and cessation of smoking, with stove and fuel changes to cut biomass smoke exposure.
• Long term oxygen when PaO2 is 7.3 kPa or less (8.0 kPa with cor pulmonale).
• Surgery (lobectomy or pneumonectomy) for localised destroyed lung, large aspergilloma or intractable haemoptysis in fit patients.
• HIV care with antiretroviral therapy and screening for further tuberculosis.

Monitoring. Spirometry and symptom review every 6 to 12 months, imaging when symptoms change, and Aspergillus IgG and itraconazole levels during antifungal therapy.

Referral and escalation. Refer to a respiratory physician for complex disease, chronic pulmonary aspergillosis, haemoptysis or oxygen need, and to a thoracic surgeon for localised disease.