Is tracheomalacia (weakening of the tracheal cartilage) known to cause cough?

Tracheomalacia as a Cause of Cough

Yes, tracheomalacia is a known cause of cough, with cough being one of the two most common symptoms observed in almost all patients with airway malacia. 1, 2

Pathophysiology and Mechanism

Tracheomalacia is characterized by:

• Flaccidity of the airways due to structural weakness of the tracheal walls
• Loss of cartilaginous integrity resulting in excessive collapse during breathing
• Significant narrowing of the coronal diameter during forced expiration or coughing (>50% in patients with tracheomalacia compared to <40% in healthy individuals) 1, 2

The cough in tracheomalacia occurs due to:

• Airway irritation from the excessive collapse
• Impaired clearance of secretions
• Stimulation of the cough reflex by the dynamic narrowing of the airway 1

Clinical Presentation

Patients with tracheomalacia typically present with:

• Chronic cough, often described as a characteristic "barking" cough 3, 4
• Expiratory wheezing (present in almost all patients) 1, 2
• Dyspnea, particularly with exertion 5
• Recurrent respiratory infections due to poor secretion clearance 6
• In severe cases, episodes of cyanosis or life-threatening events 3

Diagnostic Approach

The diagnosis of tracheomalacia as a cause of cough requires:

1. Bronchoscopy (gold standard):

   • Shows coronal narrowing >50% during coughing in patients with tracheomalacia 2
   • Allows direct visualization of the excessive airway collapse

2. Dynamic CT scanning:

   • Recommended as first-line imaging to evaluate airway collapse during breathing 2
   • Can demonstrate the characteristic crescentic narrowing of the trachea

3. Pulmonary function tests:

   • May provide clues about excessive airway collapse 2
   • Flow-volume curves showing characteristic flattening of the expiratory limb

Clinical Pearls and Pitfalls

Important considerations:

• Tracheomalacia is often misdiagnosed as asthma, COPD, or recurrent respiratory infections 7
• It should be considered in patients with chronic cough that persists despite appropriate treatment for common causes 1
• The airway collapse seen in COPD does not represent true tracheomalacia 1

Severity classification:

• Mild: 26-50% collapse
• Moderate: 51-75% collapse
• Severe: >75% collapse 2

Management Options

Treatment depends on severity:

1. Mild cases:

   • Often require only conservative management
   • Cough suppressants and optimization of airway clearance 5, 6

2. Moderate to severe cases:

   • Specific therapy aimed at the etiology of tracheomalacia
   • Mechanical interventions may include:
     • Surgical resection of the affected airway segment
     • Insertion of an airway prosthesis (stent)
     • Continuous positive-pressure breathing
     • Tracheostomy in severe cases 1, 2

3. Surgical options for severe symptomatic cases:

   • Tracheoplasty
   • Posterior or anterior tracheopexy
   • Aortopexy 3, 6

When evaluating a patient with chronic cough, tracheomalacia should be considered as a potential cause, especially when the cough persists after evaluation for common causes or when the diagnostic evaluation suggests an uncommon cause may be contributing 1.