Bronchomalacia

Bronchomalacia is weakness of the bronchial wall cartilage causing excessive collapse of the main, lobar or segmental bronchi during expiration, often coexisting with tracheomalacia (tracheobronchomalacia).

• Primary (congenital) and secondary (acquired) forms mirror tracheomalacia: prematurity, congenital heart disease with vascular compression (dilated pulmonary arteries, left atrial enlargement), tracheoesophageal fistula, bronchopulmonary dysplasia, prolonged ventilation, chronic infection, relapsing polychondritis, COPD, Mounier-Kuhn, post transplantation (anastomotic), external compression by masses, chronic inflammation.
• Localised (left main bronchus most common) or diffuse.
• Consequences: air trapping, atelectasis, bronchiectasis, recurrent pneumonia, chronic cough, respiratory failure.
• Prevalence in children with chronic respiratory symptoms undergoing bronchoscopy 1 to 2%.

• Persistent monophonic wheeze unresponsive to bronchodilators and steroids, chronic wet cough, recurrent bronchitis or pneumonia, dyspnoea, exercise intolerance, atelectasis, apnoeic spells in infants, failure to thrive.
• Adults: chronic cough, haemoptysis, breathlessness, mimicking asthma or COPD.
• Examination: localised expiratory wheeze, rhonchi, reduced air entry, expiratory stridor.

• Flexible bronchoscopy in spontaneously breathing patient with dynamic assessment during quiet breathing and cough: collapse of the bronchial lumen over 50% during expiration (grade mild 50 to 75%, moderate 75 to 90%, severe over 90%); pulsatile external compression indicates vascular cause.
• Dynamic expiratory CT (inspiratory and end expiratory) with 3D reconstruction, airway volumetry; or cine MRI.
• Spirometry: obstructive; flow volume loop; bronchodilator non-responsive.
• CT angiography or echocardiography for vascular compression; swallow study; reflux evaluation.
• Microbiology of bronchoalveolar lavage.

• Conservative (most infants and mild cases): treat infection and aspiration, optimise airway clearance (chest physiotherapy, hypertonic saline 3% nebulised), positive airway pressure (CPAP 5 to 10 cmH2O or bilevel), avoid bronchodilators if they worsen wheeze, anti-reflux therapy (omeprazole 20 mg), nutrition; most paediatric cases improve by 2 to 3 years as airway grows.
• Prophylactic azithromycin 10 mg/kg three times weekly for recurrent infections; immunisations.
• Bronchoscopic stenting (silicone) in severe, symptomatic adult or paediatric disease as a trial; complications limit use.
• Surgical intervention: bronchopexy, aortopexy for vascular compression, relief of vascular ring or enlarged pulmonary artery (pulmonary artery repositioning), tracheobronchoplasty with mesh splinting in adults, resection of destroyed lobe in bronchiectasis.
• Tracheostomy with home ventilation for severe disease; lung transplant rarely.
• Treat underlying conditions (relapsing polychondritis, COPD).
• Regular follow up with bronchoscopy and lung function; avoid smoking and irritants.