Endobronchial Tuberculosis

Endobronchial tuberculosis is tuberculous infection of the tracheobronchial tree, confirmed by bronchoscopy. It is found in about 10 to 40% of patients with pulmonary tuberculosis, and is more common in young women.

Healing often leaves bronchial stenosis, with lobar collapse, bronchiectasis and chronic disability, so early recognition matters. It can occur with a normal chest radiograph.

Pathophysiology. Infection reaches the bronchial wall by direct spread from cavities or infected sputum, by lymphatics or haematogenously, and by erosion of caseous lymph nodes into the airway. Inflammation, ulceration and granulation lead to oedema, then fibrosis and stenosis.

Bronchoscopic types are active caseous, oedematous hyperaemic, fibrostenotic, tumour like, granular, ulcerative and non-specific bronchitic.

Persistent cough with sputum, localised wheeze, haemoptysis, chest pain, dyspnoea, fever and weight loss. Stridor occurs with tracheal disease. Examination may show localised wheeze and reduced breath sounds.

Stridor, severe haemoptysis and respiratory failure need urgent assessment.

• Bronchoscopy with inspection, biopsy, brushing and washing: the key test, showing oedema, ulcers, granulations, caseous material or stenosis.
• Sputum smear is positive in about half to 80%, and bronchial wash for nucleic acid amplification (Xpert MTB/RIF), culture and drug susceptibility.
• Biopsy histology for granuloma and acid fast bacilli.
• CT chest: bronchial wall thickening and narrowing, lymph node enlargement, collapse and cavities. Chest radiograph may be normal.
• HIV test and diabetes screening.
• Spirometry with flow volume loop for central airway obstruction.

Differential diagnosis.

• Lung cancer
• Sarcoidosis
• Foreign body
• Fungal infection
• Granulomatosis with polyangiitis
• Bronchial anthracofibrosis
• Carcinoid tumour

• First line therapy: rifampicin 10 mg/kg (maximum 600 mg), isoniazid 5 mg/kg (maximum 300 mg), pyrazinamide 25 mg/kg and ethambutol 15 mg/kg daily for 2 months, then rifampicin and isoniazid daily for 4 months, with pyridoxine 10 to 25 mg daily. Extend to 9 months if the response is slow or disease is severe, and manage drug resistance with a specialist regimen.
• Adjunctive corticosteroid: prednisolone 0.5 to 1 mg/kg daily (maximum 40 to 60 mg) for 4 to 8 weeks then tapered, in selected patients with oedematous or obstructing disease, with antituberculosis cover. Evidence is limited.
• Bronchoscopic treatment of stenosis: balloon dilatation (best in the first weeks of disease), cryotherapy, laser, and silicone stents for fibrostenotic disease, with repeat treatment as needed. Surgery (sleeve resection or lobectomy) for severe, refractory stenosis or destroyed lobe.
• Infection control: respiratory isolation until sputum is no longer infectious, and contact screening.
• Monitor liver function, visual acuity and colour vision (ethambutol), and treat adverse effects.

Complications and prognosis. Bronchial stenosis (common), lobar collapse, bronchiectasis and, rarely, bronchial perforation or tracheoesophageal fistula. Early treatment lowers stenosis.

Monitoring. Repeat bronchoscopy at 2 months and at the end of treatment, and spirometry at the end of treatment and at 6 to 12 months.

Referral and escalation. Refer to a respiratory physician and an interventional pulmonologist. Refer urgently for central airway obstruction.