Summary about Disease
Diffuse panbronchiolitis (DPB) is a chronic, progressive inflammatory lung disease primarily affecting the respiratory bronchioles. It's characterized by inflammation and thickening of the walls of these small airways, leading to airflow obstruction and increased susceptibility to infections. It is more prevalent in individuals of East Asian descent, particularly in Japan. Without treatment, DPB can lead to significant morbidity and mortality, including bronchiectasis and respiratory failure.
Symptoms
Common symptoms include:
Chronic cough, often productive of purulent sputum
Excessive sputum production
Dyspnea (shortness of breath), particularly with exertion
Wheezing
Crackles (rales) heard upon auscultation of the lungs
Sinusitis
Nasal congestion
Causes
The exact cause of DPB is not fully understood, but it is believed to be multifactorial, involving:
Genetic Predisposition: DPB is strongly associated with specific HLA (human leukocyte antigen) alleles, particularly HLA-B54:01.
Environmental Factors: Environmental exposures may play a role, but these are not well-defined.
Immune Dysfunction: Abnormal immune responses likely contribute to the chronic inflammation and airway damage.
Medicine Used
The primary treatment for DPB is long-term, low-dose macrolide antibiotics, such as:
Erythromycin
Clarithromycin
Azithromycin These antibiotics are used for their anti-inflammatory and immunomodulatory effects rather than solely for their antibacterial properties. Other potential treatments could include expectorants and mucolytics.
Is Communicable
DPB is generally considered not communicable. It is not caused by an infectious agent that can be transmitted from person to person.
Precautions
While DPB itself is not communicable, individuals with DPB should take precautions to minimize the risk of respiratory infections, which can exacerbate their condition:
Vaccination against influenza and pneumococcal pneumonia
Frequent handwashing
Avoiding close contact with individuals who are sick
Smoking cessation (if applicable)
Avoiding exposure to environmental irritants
How long does an outbreak last?
DPB is a chronic disease, not an acute outbreak. Symptoms persist and progressively worsen over time if left untreated. Macrolide treatment is typically long-term, often continued for years, to manage the condition and prevent disease progression.
How is it diagnosed?
Diagnosis typically involves a combination of:
Clinical History and Physical Examination: Assessment of symptoms and listening to lung sounds.
Chest Radiography: May show hyperinflation, increased bronchovascular markings, and nodular shadows.
High-Resolution Computed Tomography (HRCT) of the Chest: The most important diagnostic tool, revealing diffuse centrilobular nodules, bronchial wall thickening, and tree-in-bud opacities.
Pulmonary Function Tests: Show obstructive pattern (reduced FEV1/FVC ratio).
Sputum Culture: To identify any bacterial infections.
Bronchoscopy with Bronchoalveolar Lavage (BAL): May be performed to rule out other conditions and assess inflammation.
Timeline of Symptoms
The timeline of DPB symptoms is typically progressive:
Early Stage: Initial symptoms may be mild and intermittent, such as a chronic cough with sputum production, sometimes attributed to a common cold or bronchitis.
Progressive Stage: Over time, the cough becomes more persistent and productive, dyspnea develops with exertion, and wheezing may occur.
Advanced Stage: Without treatment, airflow obstruction worsens, leading to significant shortness of breath, respiratory failure, bronchiectasis, and increased susceptibility to infections. The rate of progression can vary among individuals.
Important Considerations
Early diagnosis and treatment are crucial to slow disease progression and improve outcomes.
Long-term macrolide therapy is the cornerstone of treatment, but adherence to the medication regimen is essential.
Monitoring for macrolide resistance is important, as prolonged use can lead to the development of resistant bacteria.
Management of secondary infections is necessary.
Regular follow-up with a pulmonologist is essential to monitor disease progression and adjust treatment as needed.
Lung transplantation may be considered in severe cases that do not respond to medical therapy.
Screening family members of affected individuals may be considered, particularly those of East Asian descent, due to the genetic predisposition.