2005 OPEN FORUM Abstracts
PLASTIC BRONCHITIS: A CASE STUDY
Gary Oldenburg, RRT, John Browning, RRT, Anthony Bilenki, RRT, Joseph Dwyer, RRT, Pedro A. Mendez-Tellez, MD. Johns Hopkins Medicine, Baltimore, Maryland
Introduction: Plastic bronchitis is a rare condition characterized by the formation of long, branching mucoid bronchial casts that may lead to airway obstruction. Plastic bronchitis is usually associated with underlying pulmonary diseases like bronchiectasis, cystic fibrosis, bronchial asthma, and allergic bronchopulmonary aspergillosis. Plastic bronchitis may also be associated with other systemic diseases like congenital heart defects and acute chest crisis in sickle cell disease. We report the case of a patient with chronic plastic bronchitis who presented with worsening respiratory failure, refractory to medical therapy.
Case Review: A 40-year-old Caucasian female presented with plastic bronchitis secondary to an unknown etiology. The patient had multiple admissions with mucous plugging and cast formation refractory to steroid inhalation, heparin, alpha dornase, antibiotics, and bronchodilators. This patient has undergone several bronchoscopies for the removal of the mucous plugs. This patient did suffer oxygenation problems which were not resolved by CPAP. Once intubated, a bronchoscopy was performed to remove the mucous plugs and casts. The patient was then extubated and able to return to room air. Extensive diagnostic procedures including open lung biopsy did not reveal the etiology of this condition. The patient was discharged from hospital with decreasing frequency of bronchial casts being expectorated. The patient continues on home regimen of prednisone, potassium iodide, bronchodilators, diuretics, and spironolactone.
Discussion: Plastic bronchitis is also termed "cast bronchitis", "fibrinous bronchitis", "pseudo-membranous bronchitis" and "Hoffman's bronchitis". Plastic bronchitis is associated with the formation of large bronchial casts which lead to airway obstruction mimicking foreign body aspiration or status asthmaticus and may present as acute, life-threatening respiratory failure. Bronchial casts have been associated with many conditions but the mechanisms of cast formation and bronchial plugging remain unclear. Bronchial casts can be of different consistency depending on the underlying pathology and may be divided into two types: Type I or inflammatory casts, consisting mainly of fibrin with a dense eosinophilic inflammatory infiltrate and Type II or acellular casts, consisting mainly of mucin with little or no cellular infiltrate. Type I casts occur in inflammatory diseases of the lung and type II casts usually occur in children with congenital heart disease following surgery.
In both group of patients, the acute mortality is high, close to 50%, secondary to airway obstruction. Long-term mortality has been reported up to 16% in patients with respiratory diseases and 29% in patients with cardiac defects. Patients categorized by underlying disease included 31% with asthma/allergic disease, 40% with underlying cardiac defects, and 29% other. The treatment of plastic bronchitis is limited and represented by endoscopic extraction of the casts. Adjunctive treatments may include airway humidification and chest physio-therapy after extraction of the casts, antibiotics, steroids, and N-acetyl-cysteine. There have been reports of success with a variety of agents including aerosolized thrombolytic agents like urokinase and recombinant tissue plasminogen and intra-tracheal recombinant human DNase.
Conclusions: Although the patient was treated with all known therapies against plastic bronchitis, the condition continues. Medications and interventions associated with improvement of the pulmonary condition as well as maneuvers designed to remove and facilitate expectoration can be beneficial. The patient did benefit from bronchoscopy to relieve symptoms. Although her symptoms did improve, it has not been identified with any specific treatment regimen. Optimal treatment for this condition remains unclear.