Bronchial hypersecretion or failure to clear secretions Bronchitis, bronchiectasis Cystic fibrosis Primary ciliary dyskinesia aspiration, or focal auscultatory findings should have posteroanterior (PA) and lateral chest radiographs obtained. Generalized hyperinflation, indicated by flattening of the diaphragms and an increased anteroposterior (AP) chest diameter, suggests diffuse obstruction of the small airways. Hyperinflation in association with patchy densities due to atelectasis is often seen in asthma and mistaken for pneumonia. Localized hyperinflation, especially on expiratory views, suggests localized bronchial obstruction (foreign body or an anatomic anomaly). Dysphagia leading to aspiration and airway inflammation can present with persistent wheezing. This is best assessed with a videofluoroscopic swallowing study. Gastroesophageal reflux may aggravate asthma and may lead to wheezing in very young children, especially if it is associated with aspiration.
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SEE CHAPTER 78.
Tracheomalacia is a floppy trachea due to lack of structural integrity of the tracheal wall. The tracheal cartilaginousrings normally extend through an arc of approximately320°, maintaining rigidity of the trachea during changesin intrathoracic pressure. With tracheomalacia, the cartilaginous rings may not extend as far around the circumference (leaving the membranous posterior trachea widerthan usual), may be completely absent, or may be presentbut damaged. These abnormalities can result in excessivecollapse of the trachea, most pronounced during expiration.Tracheomalacia may be congenital (tracheoesophageal fistula or bony dysplasia syndromes) or acquired (long-termmechanical ventilation). Tracheomalacia must be differentiated from extrinsic tracheal compression by masses or vascular structures. Localized tracheomalacia may persist afterthe trachea has been relieved of extrinsic compression. Viralinfections may exacerbate tracheomalacia, leading to coarseexpiratory wheezing and barky cough. The expiratory noisesof tracheomalacia are often mistakenly ascribed to asthmaor bronchiolitis, and the barky cough is often misdiagnosed as croup.
With tracheomalacia, the tracheal collapse may only be apparent during forced exhalation or with cough. It is commonly aggravated by respiratory infections. The airway collapse may cause recurrent coarse expiratory wheeze and a prolonged expiratory phase. Secretions may be retained behind the segment of malacia, predisposing to infection. Infants with severe tracheomalacia may completely collapse their tracheas during agitation, resulting in cyanotic episodes that resemble breath-holding spells. The voice is normal, as is inspiratory effort. In older children, the hallmark sign is a brassy, barky cough due to the vibration of the tracheal walls. This cough can be loud and persistent and is often misdiagnosed as croup.
Infants with mild to moderate tracheomalacia usually require no intervention. Tracheomalacia improves with airway growth as the lumen increases in diameter and the tracheal wall becomes more firm. The treatment of older symptomatic children is geared toward treating any precipitating cause for cough and providing supportive care. Antibiotics may be necessary to treat concurrent infection. Children, especially infants, with severe tracheomalacia may require tracheostomy tubes to administer continuous positive airway pressure (CPAP), which serves to stent open the airway. Custom-length tracheostomy tubes have been used to stent open the airway when CPAP fails. Surgically placed airway stents are problematic in children because the stents cannot grow and thus serve as a source of fixed stenosis and obstruction.
SEE CHAPTER 128.