Congenital Bronchomalacia

Congenital bronchomalacia is abnormal softness of the wall of one or more bronchi with excessive expiratory collapse of more than 50% of the lumen. It frequently coexists with tracheomalacia (tracheobronchomalacia), and the left main bronchus is most commonly involved.

Primary disease is due to cartilage immaturity and is common in preterm infants and in conditions such as Larsen syndrome and chondrodysplasias. Secondary disease arises from compression by vascular rings, enlarged left atrium or pulmonary arteries, mediastinal masses, and after prolonged ventilation.

Most infants improve with growth by 2 to 3 years.

Pathophysiology.

Deficient bronchial cartilage allows the airway to collapse as pleural pressure rises in expiration. Air trapping, atelectasis and impaired clearance of secretions result.

Localised malacia may cause lobar hyperinflation or collapse and recurrent infection in the affected segment.

• Persistent monophonic wheeze or coarse rattling that does not respond to bronchodilators, worse with infection, crying or feeding.
• Recurrent lower respiratory infections, persistent cough, and recurrent or persistent atelectasis.
• Hyperinflation of the affected lung, tachypnoea, and in severe cases cyanotic episodes and ventilator dependence.

Red flags.

• Recurrent pneumonia in the same lobe or atelectasis.
• Apnoea, cyanotic spells, or ventilator dependence.
• Wheeze unresponsive to treatment, associated congenital heart disease or syndromic features.

• Flexible bronchoscopy with spontaneous breathing is the best diagnostic test, showing dynamic collapse on expiration or coughing. Record the site and degree.
• Dynamic CT or MRI of the airway, with CT angiography for vascular compression. Bronchography is rarely used.
• Chest X-ray (hyperinflation, atelectasis), echocardiography, and evaluation of reflux and aspiration.
• Rule out cystic fibrosis, primary ciliary dyskinesia and immune deficiency in children with recurrent infection.

Differential diagnosis. Asthma, tracheomalacia, foreign body, bronchiolitis, cystic fibrosis, primary ciliary dyskinesia, extrinsic compression and bronchial stenosis.

• Supportive care for most children: airway clearance physiotherapy, prompt antibiotics for infection (for example amoxicillin-clavulanate 22.5 mg/kg of the amoxicillin component every 12 hours), immunisation including influenza and pneumococcal vaccines, and avoidance of tobacco smoke.
• Avoid bronchodilators and ipratropium unless concomitant asthma is documented, since they may worsen collapse.
• Respiratory support: CPAP, positive end expiratory pressure or high flow therapy during illness. Long term ventilation through a tracheostomy for severe disease.
• Surgery for compression (division of vascular ring, aortopexy), bronchial stenting, or resection of a severely affected lobe, in selected children with life threatening symptoms.
• Treat gastro oesophageal reflux, aspiration and allergies.

Monitoring. Symptom frequency, growth, imaging for persistent atelectasis, and repeat bronchoscopy if surgery is considered.

Referral and escalation. Refer to paediatric respiratory and airway surgery services for recurrent infections, atelectasis, hypoxaemia or a need for respiratory support.