Chronic Bronchitis and COPD.
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Chronic Bronchitis and COPD.
Am J Respir Crit Care Med. 2012 Nov 29;
Authors: Kim V, Criner GJ
Abstract
Chronic bronchitis is a common but variable phenomenon in COPD. It has numerous clinical consequences, including an accelerated decline in lung function, greater risk of the development of airflow obstruction in smokers, a predisposition to lower respiratory tract infection, higher exacerbation frequency, and worse overall mortality. Chronic bronchitis is caused by overproduction and hypersecretion of mucus by goblet cells, which leads to worsening airflow obstruction by lumenal obstruction of small airways, epithelial remodeling, and alteration of airway surface tension predisposing to collapse. Despite its clinical sequelae, little is known about the pathophysiology of chronic bronchitis and goblet cell hyperplasia in COPD, and treatment options are limited. In addition, it is becoming increasingly apparent that in the classic COPD spectrum, with emphysema on one end and chronic bronchitis on the other, most patients lie somewhere in the middle. It is known now that many patients with severe emphysema can develop chronic bronchitis, and small airway pathology has been linked to worse clinical outcomes, such as increased mortality and lesser improvement in lung function after lung volume reduction surgery. However, in recent years, a greater understanding of the importance of chronic bronchitis as a phenotype to identify patients with a beneficial response to therapy has been described. Herein we review the epidemiology of chronic bronchitis, the evidence behind its clinical consequences, the current understanding of the pathophysiology of goblet cell hyperplasia in COPD, and current therapies for chronic bronchitis.
PMID: 23204254 [PubMed - as supplied by publisher]