Tracheomalacia

Tracheomalacia is weakness of the tracheal cartilage and/or posterior membranous wall, causing excessive dynamic collapse (over 50% reduction in cross sectional area) of the trachea during expiration.

• Primary (congenital, in infants): tracheal cartilage immaturity, associated with prematurity, tracheoesophageal fistula repair, vascular rings, Mounier-Kuhn syndrome, connective tissue disorders (Ehlers Danlos, Marfan), Larsen syndrome, mucopolysaccharidoses, relapsing polychondritis.
• Secondary (acquired in adults): prolonged intubation or tracheostomy, chronic obstructive lung disease/chronic bronchitis, recurrent infection, extrinsic compression (goitre, vascular ring, mediastinal mass, aortic aneurysm), relapsing polychondritis, radiation, smoking.
• Excessive dynamic airway collapse (EDAC): posterior membrane invagination (over 70%) with preserved cartilage.
• Severity by percentage collapse: mild (under 75% collapse), moderate (75 to 90%), severe (over 90%, wall contact).
• Prevalence in adults with COPD 4 to 23%, in bronchoscopy for symptoms.

• Infants: expiratory stridor or biphasic stridor, barking or "seal like" cough, recurrent respiratory infections, apnoea or cyanotic spells (dying spells), feeding difficulty, symptoms worsen with crying, agitation, cough, feeding and respiratory infection; improve when quiet; usually resolve by 18 to 24 months.
• Adults: chronic cough (barking), dyspnoea, wheeze not responding to bronchodilators, sputum retention, recurrent infections, orthopnoea, voice change; symptoms worse on forced expiration/cough.
• Examination: expiratory wheeze (monophonic), stridor, tracheal tug.

• Dynamic CT chest (inspiratory and end expiratory/forced expiratory images, 4D) showing collapse over 50% (crescent or saber sheath).
• Flexible bronchoscopy during spontaneous breathing, with coughing: direct visualisation of tracheal collapse (gold standard); avoid general anaesthesia with positive pressure which masks collapse.
• Dynamic MRI for children (no radiation).
• Spirometry: flow volume loop with variable intrathoracic obstruction (expiratory flow limitation).
• Evaluate coexisting lesions: oesophagram, echocardiography, CT angiography for vascular rings, laryngoscopy for laryngomalacia.
• Assess for respiratory failure, reflux, sleep studies.

• Mild/moderate and infants: conservative: humidified air, treat infection and reflux (omeprazole 1 mg/kg), positive pressure support (CPAP 6 to 10 cmH2O) to splint the airway, avoid irritants, smoking cessation, optimise COPD treatment, chest physiotherapy; bronchodilators may worsen collapse by reducing smooth muscle tone.
• Adults: trial of stenting with silicone stent (assess symptomatic response before surgery; complications include migration, mucus plugging, granulation); non invasive ventilation with CPAP/bilevel.
• Surgical options for severe symptomatic disease:
  • Membranous tracheoplasty (tracheobronchoplasty) with polypropylene mesh splinting of the posterior wall (marked improvement in 80%) in adults.
  • Aortopexy or posterior tracheopexy in infants with severe collapse due to vascular compression, 3D printed bioresorbable splints.
  • Tracheostomy with long tube bypassing the malacic segment, home ventilation.
  • Resection for focal disease.
• Treat the underlying disease: relapsing polychondritis (prednisolone 0.5 to 1 mg/kg, methotrexate, tocilizumab), goitre resection, vascular ring division.
• Respiratory infection treatment promptly (antibiotics, secretion clearance).
• Follow up with serial bronchoscopy and spirometry; most infantile cases resolve by 2 years.