Plastic Bronchitis in Children
Introduction to Plastic Bronchitis in Children
Plastic bronchitis is a rare but potentially life-threatening condition characterized by the formation of large, branching bronchial casts that obstruct the airways. It primarily affects children, especially those with underlying cardiopulmonary conditions. The term "plastic" refers to the cohesive and rubber-like consistency of the casts, not their composition.
Key points:
- Incidence: Rare, exact prevalence unknown
- Age of onset: Typically in children, but can occur in adults
- Gender predilection: No significant difference
- First described: 1901 by Bettmann
Etiology of Plastic Bronchitis
The etiology of plastic bronchitis is multifactorial and often associated with underlying conditions:
- Cardiac conditions:
- Fontan circulation (most common)
- Other congenital heart diseases
- Respiratory conditions:
- Asthma
- Cystic fibrosis
- Allergic bronchopulmonary aspergillosis
- Lymphatic disorders:
- Lymphangiectasia
- Lymphangiomatosis
- Infections:
- Influenza
- Bacterial pneumonia
- Idiopathic cases (no identifiable cause)
Pathophysiology of Plastic Bronchitis
The pathophysiology of plastic bronchitis involves complex interactions between the lymphatic system, bronchial mucosa, and inflammatory processes:
- Cast formation:
- Accumulation of proteinaceous material in the airways
- Fibrin exudation and mucin production
- Incorporation of inflammatory cells and cellular debris
- Lymphatic involvement:
- Abnormal lymphatic drainage or leakage into airways
- Increased central venous pressure (in Fontan circulation)
- Inflammatory cascade:
- Release of pro-inflammatory cytokines
- Recruitment of inflammatory cells
- Increased mucus production
- Airway obstruction:
- Progressive cast formation leading to partial or complete obstruction
- Impaired mucociliary clearance
Clinical Presentation of Plastic Bronchitis
The clinical presentation of plastic bronchitis can vary from mild respiratory symptoms to acute respiratory distress:
- Respiratory symptoms:
- Chronic cough (often productive)
- Wheezing
- Dyspnea
- Chest pain
- Expectoration of casts:
- Large, branching bronchial casts (pathognomonic)
- May be accompanied by hemoptysis
- Acute presentations:
- Sudden onset of respiratory distress
- Cyanosis
- Hypoxemia
- Associated symptoms:
- Fever (if infectious etiology)
- Fatigue
- Weight loss (in chronic cases)
Diagnosis of Plastic Bronchitis
Diagnosis of plastic bronchitis requires a high index of suspicion and a combination of clinical, radiological, and pathological findings:
- Clinical evaluation:
- Detailed history (including underlying conditions)
- Physical examination (auscultation for decreased breath sounds)
- Imaging studies:
- Chest X-ray: Atelectasis, infiltrates, or hyperinflation
- CT scan: Tree-in-bud opacities, bronchial filling defects
- MRI lymphangiography: Evaluate lymphatic anomalies
- Bronchoscopy:
- Visualization and removal of casts
- Bronchoalveolar lavage for cytology and microbiology
- Cast analysis:
- Gross examination: Branching, rubbery appearance
- Histopathology: Classification into inflammatory or acellular types
- Additional tests:
- Pulmonary function tests
- Echocardiography (to evaluate cardiac function)
- Serum IgE and eosinophil count (if allergic etiology suspected)
Treatment of Plastic Bronchitis
Treatment of plastic bronchitis is multifaceted and depends on the underlying etiology:
- Acute management:
- Airway clearance: Bronchoscopic removal of casts
- Supportive care: Oxygen therapy, mechanical ventilation if needed
- Pharmacological interventions:
- Mucolytics: N-acetylcysteine, dornase alfa
- Bronchodilators: Beta-2 agonists
- Corticosteroids: Systemic or inhaled
- Antibiotics: If bacterial infection suspected
- Management of underlying conditions:
- Cardiac: Optimization of Fontan circulation
- Respiratory: Asthma control, cystic fibrosis management
- Lymphatic: Thoracic duct ligation, embolization
- Novel therapies:
- Inhaled tissue plasminogen activator (tPA)
- Aerosolized heparin
- Sirolimus (for lymphatic anomalies)
- Supportive measures:
- Chest physiotherapy
- Nutritional support
- Psychosocial support for patients and families
Prognosis of Plastic Bronchitis
The prognosis of plastic bronchitis varies depending on the underlying etiology and treatment response:
- Mortality:
- Historically high (up to 50% in some series)
- Improved with modern management techniques
- Recurrence:
- Common, especially in cardiac-related cases
- May require long-term management
- Factors influencing prognosis:
- Underlying condition (cardiac vs. non-cardiac)
- Frequency and severity of exacerbations
- Timely diagnosis and intervention
- Response to treatment
- Long-term outcomes:
- Potential for chronic respiratory impairment
- Impact on quality of life
- Need for ongoing medical surveillance
Plastic Bronchitis in Children
- What is plastic bronchitis?
A rare condition characterized by the formation of large, branching bronchial casts - What is the composition of bronchial casts in plastic bronchitis?
Mucin, fibrin, cellular debris, and inflammatory cells - What are the two main types of bronchial casts in plastic bronchitis?
Inflammatory (cellular) and acellular (mucoid) casts - What congenital heart condition is most commonly associated with plastic bronchitis?
Fontan procedure for single ventricle physiology - What is the most common presenting symptom of plastic bronchitis?
Productive cough with expectoration of branching bronchial casts - What is the characteristic radiographic finding in plastic bronchitis?
Atelectasis or airspace opacities due to bronchial obstruction - What is the gold standard for diagnosing plastic bronchitis?
Bronchoscopy with visualization and removal of bronchial casts - What is the role of chest CT in evaluating plastic bronchitis?
To assess the extent of bronchial obstruction and rule out other causes - What is the primary acute treatment for plastic bronchitis?
Bronchoscopic removal of casts - What mucolytic agent is commonly used in the treatment of plastic bronchitis?
Dornase alfa (DNase) - What is the role of tissue plasminogen activator (tPA) in treating plastic bronchitis?
Inhaled tPA can help break down fibrin in casts - What is the role of bronchodilators in managing plastic bronchitis?
To relieve associated bronchospasm and improve airflow - What is the significance of lymphatic abnormalities in plastic bronchitis?
They can contribute to cast formation, especially in post-Fontan patients - What imaging modality is used to evaluate lymphatic abnormalities in plastic bronchitis?
Dynamic contrast-enhanced magnetic resonance lymphangiography - What is the role of thoracic duct ligation in treating plastic bronchitis?
It can be effective in cases associated with lymphatic abnormalities - What is the prognosis for children with plastic bronchitis?
Variable, depending on underlying cause and response to treatment - What is the role of inhaled corticosteroids in managing plastic bronchitis?
They may help reduce airway inflammation in some cases - What is the significance of cast analysis in plastic bronchitis?
It can help determine the underlying etiology (inflammatory vs. acellular) - What is the role of pulmonary function testing in plastic bronchitis?
To assess for obstructive patterns and monitor disease progression - What is the importance of airway clearance techniques in managing plastic bronchitis?
They help mobilize and expel bronchial casts - What is the role of N-acetylcysteine in treating plastic bronchitis?
As a mucolytic agent to help break down casts - What is the significance of hemoptysis in plastic bronchitis?
It can occur due to airway injury from cast formation or removal - What is the role of bronchial artery embolization in plastic bronchitis?
It may be considered in cases with significant hemoptysis - What is the importance of nutritional support in managing plastic bronchitis?
To maintain overall health and support the immune system - What is the role of hypertonic saline in treating plastic bronchitis?
As an osmotic agent to help hydrate and mobilize bronchial secretions - What is the significance of recurrent pneumonia in plastic bronchitis?
It can occur due to chronic airway obstruction and requires prompt treatment - What is the role of bronchial thermoplasty in treating plastic bronchitis?
It is not typically used; its role in plastic bronchitis is not established - What is the importance of infection control in managing plastic bronchitis?
To prevent respiratory infections that can exacerbate cast formation - What is the role of extracorporeal membrane oxygenation (ECMO) in severe plastic bronchitis?
As a temporary support measure in life-threatening cases unresponsive to other treatments - What is the significance of cast recurrence in plastic bronchitis?
It indicates the need for ongoing management and possible adjustment of treatment strategy
External Resources
- Plastic Bronchitis: New Insights and a Classification Scheme - Comprehensive review article from Pediatric Pulmonology
- Plastic Bronchitis - Children's Hospital of Philadelphia - Patient and family information from a leading pediatric center
- Plastic Bronchitis: New Therapeutic Frontiers - American Journal of Respiratory and Critical Care Medicine article on emerging treatments
- Plastic Bronchitis in Children: A Systematic Review and Meta-Analysis - Journal of Pediatrics meta-analysis on clinical features and outcomes
