Plastic bronchitis is a rare condition characterized by the formation of large endobronchial casts that obstruct the tracheobronchial tree. The inspissated casts obstruct the airways and can result in an acute life threatening airway emergency. Patients may require therapeutic bronchoscopy for cast removal. We describe the use of bronchoscopic cryotherapy in the removal of the airway casts in a patient with plastic bronchitis.
A 51 year-old male, life time nonsmoker, presented for evaluation of chronic cough productive of thick mucous plugs and dyspnea. The patient had severe bouts of dyspnea and required multiple hospitalizations, including intensive care unit monitoring for hypoxemic respiratory failure. A severe episode necessitated endotracheal intubation and mechanical ventilation. A chest radiograph showed opacification of the left hemithorax and computerized tomography of the chest confirmed occlusion of the left mainstem bronchus with collapse of the left lung. Flexible bronchcoscopy demonstrated tenacious secretions occluding the left mainstem bronchus. The casts were too thick to be suctioned through the bronchoscope and too friable to be grasped and removed with forceps. The use of fiberoptic bronchoscopic cryotherapy probe was used to remove a large left mainstem cast en bloc. This resulted in dramatic improvement in oxygenation and ventilation, and allowed for rapid extubation. Pathological analysis of the bronchial cast revealed acellular material consisting of fibrin and mucous with minimal inflammation and no eosinophils. A comprehensive evaluation for allergic bronchopulmonary aspergillosis, atopic diseases, cardiac disease, disorders of lymphatic drainage, and immunodeficiencies and vasculitidies was unrevealing. A clinical diagnosis of idiopathic plastic bronchitis was made. The patient required several bronchoscopies utilizing the cryoprobe to remove recurrent airway casts and relieve symptoms.
The prevalence of plastic bronchitis is unknown and is likely under recognized as a disease entity. The most common associated diseases are cyanotic congenital heart disease, atopic conditions, and sickle cell acute chest syndrome. A new classification system of plastic bronchitis has been proposed and includes 1. structural congenital heart disease and mucin predominant casts, 2. lymphatic disorders and chylous casts, 3. asthma, atopy and eosinophilic casts, and 4. sickle cell acute chest syndrome with fibrinous casts. The natural history of plastic bronchitis depends on the associated disease and the type of cast. The treatment of plastic bronchitis includes bronchodilators, inhaled mucolytics, airway clearance techniques, and antibiotics. Other therapeutic options include inhaled heparin, dornase alfa and tissue plasminogen alpha. It may necessary to mechanically remove the airway casts if the patient presents with life threatening respiratory distress and hypoxemia. Urgent therapeutic bronchoscopy may be lifesaving. In our patient, cryotherapy allowed for the airway cast to be frozen and removed en bloc. This allowed the patient to be extubated and significantly improved gas exchange.
Plastic bronchitis is an uncommon disease that can lead to acute endobronchial obstruction and life threatening acute respiratory failure. This case demonstrates the utility of bronchoscopic cryoprobe therapy to remove the large obstructing airway casts of a patient with plastic bronchitis.
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