ARNOLD-Australasian Registry Network for Orphan Lung Disease

References

Anti-inflammatory properties of macrolides. Wagner T. Burns JL. Pediatric Infectious Disease Journal. 26(1):75-6, 2007 Jan.

Bronchiolitis: the pathologist's perspective. Visscher DW. Myers JL. Proceedings of the American Thoracic Society. 3(1):41-7, 2006.

Chronic cough due to nonbronchiectatic suppurative airway disease (bronchiolitis)ACCP evidence-based clinical practice guidelines. Brown KK. Chest. 129(1 Suppl):132S-137S, 2006 Jan.

Radiologic and pathologic features of bronchiolitis. Pipavath SJ. Lynch DA. Cool C. Brown KK. Newell JD. American Journal of Roentgenology. 185(2):354-63, 2005 Aug.

Bronchiolitis

 

Dr Margaret Wilsher, Auckland DHB Respiratory Services, New Zealand

What is it?: Bronchiolitis is a term for inflammation of, or diseases affecting, the small airways or bronchioles.

What are the causes of bronchiolitis?: Bronchiolitis can occur as a primary disorder or as part of a wider disease process. These are the most common causes;

• Viral infection
• Connective tissue diseases such as rheumatoid arthritis and Sjogrens syndrome
• Inflammatory bowel diseases such as Crohn’s disease and Ulcerative colitis
• Post lung or bone marrow transplantation
• Ingestion or inhalation of toxic material (rare)
• Idiopathic or unknown cause such as “Japanese” panbronchiolitis

How does bronchiolitis present?: Bronchiolitis can present acutely in the context of viral infection. Patients will have cough, breathlessness and wheezing. Sputum may or not be present. When bronchiolitis occurs as part of a systemic disease the respiratory symptoms usually develop over weeks to months. On listening to the chest, the doctor may hear typical end inspiration squeaks and crackles.

What tests are helpful in diagnosis?: The CXR is not very useful but a high resolution CT scan of the chest will often show typical changes and this test may be all that is required for diagnosis. There are two distinct patterns: one characterized by plugging of the very small airways with mucus and cellular debris (exudative) and the other reflecting trapping of gas in the lungs (obliterative). The latter pattern usually reflects chronically scarred small airways. Breathing tests can be useful and in acute viral bronchiolitis, blood oxygen tests may reflect respiratory failure. Sometimes a bronchoscopy with biopsy and sampling of lung fluid (bronchoalveolar lavage) can help with the diagnosis. Only rarely is surgical lung biopsy indicated.

Treatment: Exudative bronchiolitis usually responds well to a class of anti-inflammatory antibiotics called macrolides. Prednisone is often not very helpful. When bronchiolitis occurs in the post lung transplant setting it usually does not respond to increased immunosuppression. Management centres on treating any underlying infection, aggressively managing gastro-oesophageal reflux disease (which may contribute) and initiating a macrolide antibiotic such as azithromycin. Often the damage caused by obliterative bronchiolitis cannot be reversed but it may be possible to prevent further damage if the underlying cause is identified.