Excessive Dynamic Airway Collapse

Excessive dynamic airway collapse (EDAC) refers to a dynamic form of central airway obstruction that is frequently seen in bronchoscopies but often goes unnoticed as bronchoscopies when done are with intention to diagnose infections, masses, etc., unless one keeps his eyes and observation open it is missed. It would be seen as forward bulging of the posterior membrane of the tracheobronchial tree. There will be a decrease of more than 50% of the cross-sectional area of the tracheobronchial tree. This can also be diagnosed by dynamic cross-sectional imaging of the tracheobronchial tree. Sometimes, this term is used as a synonym for tracheobronchomalacia. They are not because in tracheobronchomalacia there is weakness of cartilage of the tracheobronchial tree. This can be patchy or uniform. Relapsing polychondritis is one of the primary forms of EDAC. Secondary forms of EDAC can occur in chronic obstructive pulmonary disease (COPD) and other peripheral airway diseases. These disease entities are probably underdiagnosed because they present with a variety of nonspecific symptoms like patients with other obstructive ventilatory disorders such as asthma and COPD and recurrent chest infections mistakenly treated as bronchiectasis. The most common symptoms of these patients are persistent dry cough all through the day with frequent worsening at night. Routine investigations will appear normal, and spirometry shows obstructive airway abnormalities that may or may not be reversible. X-ray chest may appear normal. Computed axial tomography scans may show the trachea and airways to be compressed horizontally. This finding should alert a clinician to think of EDAC as one of the abnormalities. Bronchoscopies are performed for an intractable cough to rule out foreign bodies or diagnose an underlying Aspergillus sensitization. One should keep in mind and look for this important finding during bronchoscopy. Current therapeutic management depends on extent, airway, and severe abnormalities noted on clinical abnormalities. Continuous positive airway pressure is one of the accepted means of treating, and surgeries such as trachebronchopexy and aortopexy have been tried. In relapsing polychondritis, Y tubes have been tried. In secondary EDAC, bronchodilators have been tried. The reason for the identification of this problem is to inform the patient about the illness and the limitations of treatment. Endoluminal stent insertion can improve symptoms and pulmonary function in patients with central airway obstruction and should be considered for patients with symptoms refractory to conservative therapy. Several open surgical procedures have also been performed over the years, including tracheostomy, airway splinting, tracheal resection, and, more recently, external tracheal stents. Endobronchial laser therapy, resorbable stents, the application of grafting materials used to support the collapsed airway as well as the use of cartilage regeneration techniques are investigational. Their use in humans remains to be assessed. Future studies should compare therapeutic interventions and outcomes such as functional status, ventilatory function, and bronchoscopic and radiologic appearances to define the costs and benefits of individual and combined treatment modalities. This editorial is to highlight the important common symptom, a computed tomography chest finding, and bronchoscopy finding that can go unnoticed.