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SELECTED ARTICLES FROM THE RECENT LITERATURE 2006
9/29/06
Small airway involvement in asthma
Summary
Background - There has been a recent increasing interest in and debate about the involvement of the peripheral small airways in asthma.
Findings - This subject was recently reviewed by Tulic and Hamid. Previously, the focus of investigation of the pathophysiology of asthma involved the larger central airways. More recent studies have evidence of inflammatory changes and remodeling in the smaller peripheral airways and even the lung parenchyma of chronic asthmatics, sometimes more prominent than occuring in the larger airways. This peripheral airways involvement may be associated with prominent local production of several Th2 cytokines and result in a significant proportion of the overall airflow obstruction in asthma. If remodeling occurs in the smaller airways in asthma this can affect the response to customary anti-asthma treatment and overall prognosis.
Reference
Clin Chest Med 2006;27:41-52
Editor's Comments
The extent of small airways involvement in the pathophysiology of asthma appears to depend on what instrument one uses to investigate asthma. Sensitive pathologic and immunopathologic approaches find frequent involvement. Yet, airflow obstruction in asthma most commonly assessed in asthma by the FEV-1 is due predominantly to obstruction in the larger, more central airways. However, recent studies (reviewed by Wenzel and others) have shown that the FEV-1 impairment is not a consistently good predictor of asthma severity (as expressed in asthma exacerbation frequency, nocturnal asthma quality of life). Thus, smaller airway involvement may also play a role in the overall pathophysiology of asthma.
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