Bronchial Stenosis

Fixed narrowing of the bronchial lumen from intrinsic disease of the wall, scarring, or compression from outside, giving obstruction, impaired drainage and recurrent distal infection.

• Causes: endobronchial tuberculosis (bronchial stenosis develops in 10 to 40% of patients with endobronchial disease), anastomotic stricture after lung transplantation (5 to 15%), prolonged intubation or tracheostomy, sarcoidosis, granulomatosis with polyangiitis, inflammatory bowel disease, radiotherapy, aspiration of caustic material or foreign body, carcinoid or other benign tumours, amyloidosis, fibrosing mediastinitis and congenital stenosis (rare).
• Mechanism: granulation and fibrosis of the bronchial wall, with luminal narrowing and loss of cartilage support.
• Burden: tuberculosis remains the most frequent cause worldwide, including in sub-Saharan Africa; younger women are over-represented.

Persistent localised monophonic wheeze that does not respond to bronchodilators, chronic or recurrent cough, breathlessness, haemoptysis, recurrent pneumonia in the same lobe, fever and weight loss with tuberculosis.

• Stridor if the stenosis involves the trachea or main bronchi.
• Signs: reduced breath sounds, localised wheeze, volume loss.
• Differential diagnosis: asthma, chronic obstructive pulmonary disease, endobronchial tumour, foreign body, mucus plug, tracheobronchomalacia, lung cancer with nodal compression, fibrosing mediastinitis.
• Complications: post-obstructive pneumonia, lung abscess, bronchiectasis, lobar collapse, destroyed lung, respiratory failure when main airways are involved, and haemoptysis.

Chest X-ray: lobar collapse, hyperinflation, bronchiectasis, volume loss.

• CT chest with multiplanar and virtual bronchoscopy reconstruction: length, severity (percentage lumen narrowing), wall thickening, distal lung, nodes, and external compression.
• Flexible bronchoscopy: site, length, extent (more than 50% narrowing is significant), mucosa (oedematous, ulcerated, granular, fibrostenotic), with biopsy, brushings and washings for culture, acid-fast smear, Xpert MTB/RIF, histology (granulomas, vasculitis, tumour).
• Flow-volume loop: fixed obstruction (flattening of both inspiratory and expiratory limbs); spirometry with FEV1 reduction.
• Blood tests: HIV test, antineutrophil cytoplasmic antibody, angiotensin converting enzyme, serum calcium, immunoglobulins, inflammatory markers; tuberculin or interferon gamma release testing.
• Perfusion scan or CT to assess whether the distal lung is functioning before intervention.

Treat the cause:

• Tuberculosis: isoniazid 5 mg/kg (maximum 300 mg), rifampicin 10 mg/kg (maximum 600 mg), pyrazinamide 25 mg/kg (maximum 2 g) and ethambutol 15 mg/kg daily for 2 months, then isoniazid and rifampicin daily for 4 months (extend to 9 months in extensive endobronchial disease), with pyridoxine 10 to 25 mg daily. Prednisolone 0.5 mg/kg daily (usual 30 to 40 mg) for 4 to 6 weeks then tapered may reduce stenosis; evidence is limited.
• Sarcoidosis: prednisolone 30 to 40 mg daily for 4 to 6 weeks, then taper over 6 to 12 months, with methotrexate 10 to 15 mg weekly with folic acid 5 mg weekly as a steroid sparing agent.
• Granulomatosis with polyangiitis: prednisolone 1 mg/kg daily with rituximab 375 mg/m2 weekly for 4 weeks or 1 g twice 2 weeks apart, specialist-led.

```{=html} <!-- --> ``` - Treat distal infection: co-amoxiclav 625 mg three times daily for 7 to 14 days, or doxycycline 200 mg then 100 mg daily; sputum culture directed therapy.

• Bronchoscopic management (in a centre with rigid bronchoscopy), for symptomatic stenosis with viable distal lung:
  • Balloon bronchoplasty: radial expansion balloon inflated stepwise to 3 to 5 atmospheres for 30 to 60 seconds, repeated sessions every 1 to 4 weeks.
  • Electrocautery or laser radial incisions of the fibrotic ring followed by balloon dilatation, or cryotherapy for granulation tissue.
  • Topical mitomycin C 0.4 mg/mL applied for 4 to 5 minutes to reduce recurrence (evidence limited).
  • Silicone stent (preferred in benign disease because it can be removed) for recurrent stenosis, left for 6 to 12 months and then removed; complications are migration, mucus plugging, granulation and infection. A metal stent is avoided in benign disease because it cannot be removed safely.
• Surgery (sleeve resection, bronchoplasty, lobectomy or pneumonectomy) for failed endoscopic treatment, long segment stenosis, or destroyed distal lung with recurrent infection; success rates for sleeve resection are about 80 to 90% with an operative mortality of about 3 to 5%.
• Airway clearance and humidification: chest physiotherapy, hypertonic saline 7% 4 mL twice daily after salbutamol.
• Lung transplant anastomotic stricture: balloon dilatation, stent, and adjusting immunosuppression under the transplant team.
• Special groups: children (congenital and post-intubation stenosis, specialised paediatric bronchoscopy and slide tracheoplasty; weight-based antituberculosis dosing with isoniazid 10 mg/kg, rifampicin 15 mg/kg, pyrazinamide 35 mg/kg, ethambutol 20 mg/kg); pregnancy (antituberculosis drugs are acceptable with pyridoxine, avoid streptomycin; defer interventions where possible); HIV (antiretroviral therapy within 2 weeks for CD4 less than 50 cells/microlitre and by 8 weeks otherwise, with dolutegravir 50 mg twice daily during rifampicin); renal impairment (adjust ethambutol and pyrazinamide); hepatic impairment (monitor liver tests weekly for 2 weeks).
• Red flags: stridor, haemoptysis, lobar collapse, respiratory failure, fever with distal infection, rapidly reducing FEV1.
• Follow-up: bronchoscopy at 4 to 6 weeks after intervention and then at 3, 6 and 12 months; spirometry and flow-volume loop at each visit; chest X-ray or CT with new symptoms; stent review every 3 months; liver tests monthly during antituberculosis treatment.