Expiratory central airway collapse - an overlooked entity?: Two case reports

Area of Science:

• Pulmonology
• Respiratory Medicine
• Thoracic Surgery

Background:

• Expiratory central airway collapse, including excessive dynamic airway collapse (EDAC), involves inward bulging of the tracheobronchial posterior membrane or cartilage.
• EDAC is often misdiagnosed as common obstructive lung disorders due to non-specific symptoms and low clinical awareness.
• EDAC may be an independent risk factor in chronic obstructive pulmonary disease and asthma, and can occur without apparent obstructive lung disease.

Observation:

• Two patients presented with idiopathic chronic cough and dyspnea, respectively, unresponsive to standard treatments like bronchodilators and inhaled corticosteroids.
• Bronchoscopy revealed excessive collapse of the tracheobronchial posterior membrane in both patients.
• Excessive central airway collapse was also visualized on expiratory CT in one patient, with spirometry showing disproportionate obstruction relative to breathlessness.

Findings:

• Both patients were diagnosed with excessive dynamic airway collapse (EDAC).
• Treatment involved N-acetylcysteine and adjustable positive expiratory pressure (PEP) valves.
• Patient 1 experienced near-complete resolution of chronic cough, and Patient 2 showed significant improvement in dyspnea.

Implications:

• These cases suggest EDAC can be an unexpected but significant cause of respiratory symptoms.
• Treatment modification targeting EDAC led to improved quality of life for both patients.
• Further research into EDAC as a distinct clinical entity and its management is warranted.