Congenital Tracheomalacia

Congenital tracheomalacia is abnormal softness of the tracheal wall, which allows excessive collapse of the airway during expiration, with narrowing of the lumen of more than 50%. It may be isolated (primary) or secondary to external compression or associated anomalies.

It is the most common congenital tracheal anomaly in infants. Primary disease results from immature tracheal cartilage and is more frequent in preterm infants. Secondary forms are associated with oesophageal atresia and tracheo oesophageal fistula, vascular rings, mediastinal masses, Larsen syndrome and chondrodysplasias.

Most isolated cases improve by 18 to 24 months as the cartilage matures.

Pathophysiology.

Weak cartilage and a lax posterior membrane make the airway collapsible, and during expiration the intrathoracic pressure exceeds airway pressure. The airway narrows and airflow is limited, causing a monophonic wheeze or barking cough.

Crying, feeding and coughing increase intrathoracic pressure and worsen symptoms. Secretion retention causes recurrent infection.

• Expiratory stridor or monophonic wheeze from the first weeks, louder with agitation, feeding, crying or respiratory infection, and relieved in sleep or with neck extension.
• Barking or honking cough, recurrent infections, and noisy breathing that does not respond to bronchodilators.
• Severe forms: apnoea, cyanosis and life threatening events ("dying spells"), especially after oesophageal atresia repair, and difficulty weaning from ventilation.

Red flags.

• Cyanotic or apnoeic episodes, or failure to wean from ventilation.
• Feeding difficulty, aspiration or failure to thrive.
• Recurrent pneumonia, or associated anomalies (tracheo oesophageal fistula, vascular ring, cardiac disease).

• Flexible bronchoscopy with the child breathing spontaneously, which is the best test to visualise dynamic airway collapse and to find associated lesions.
• Dynamic CT or MRI with cine imaging if a bronchoscope is not available or for assessing external compression, with CT angiography for vascular rings.
• Barium swallow for vascular ring and fistula, echocardiography for associated cardiac anomaly, and assessment of reflux and aspiration.
• Lung function testing in older children.

Differential diagnosis. Laryngomalacia, vascular ring, bronchomalacia, foreign body, subglottic stenosis, asthma, tracheo oesophageal fistula and cystic fibrosis.

• Mild to moderate disease: reassurance and observation, with prompt treatment of respiratory infections and avoidance of tobacco smoke. Bronchodilators can worsen the collapse and should be avoided unless there is asthma.
• Treat associated reflux and aspiration, and ensure nutrition and immunisation.
• Respiratory support: CPAP or positive end expiratory pressure splints the airway during illness, and humidified high flow oxygen can be used.
• Surgical options for severe or life threatening disease: aortopexy (anterior tracheal suspension), posterior tracheopexy after oesophageal atresia, relief of vascular compression, external splinting, internal stent (silicone or biodegradable), or tracheostomy with long term ventilation.

Monitoring. Growth, symptoms, frequency of respiratory infection, and bronchoscopy if symptoms persist beyond 2 years.

Referral and escalation. Refer to paediatric ENT or airway surgery for apnoeic spells, failure to wean, recurrent pneumonia or persistent severe symptoms.