Treatment of cast bronchitis with low-dose oral azithromycin

Cast or plastic bronchitis is an unusual disorder that is rarely encountered in the pediatric population. It is characterized by the expectoration of large, branching plugs of airway debris. These "casts" conform to the shape of portions of the tracheobronchial tree, and give the disorder its name. Cast bronchitis is typically seen in association with several primary pulmonary disorders and cyanotic congenital heart disease. It can be classified as inflammatory or acellular, based on the histologic characteristics of the casts. The presence of large, obstructive plugs filling the airways of lobes or entire lungs can result in a variety of clinical signs and symptoms, and may ultimately lead to respiratory failure and death. Conventional treatment of cast bronchitis has focused on the clearance of obstructing material from the airways combined with therapy for any underlying cardiopulmonary disease. Unfortunately, this approach has not proven very effective, and patient mortality remains high. We report on a case in which a patient with cast bronchitis was treated with long-term, low-dose oral azithromycin. This therapy resulted in clinical, spirometric, and radiographic improvement of the patient.