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  • • Bronchiectasis is characterized by chronic cough productive of purulent sputum.
  • • Chest radiography demonstrates abnormally dilated airways and mucous plugging, characterized by “ring” shadows, “gloved finger” shadows, or air-filled cystic spaces that may include fluid levels.
  • • Spirometry reveals a pattern of airflow obstruction.
  • • Cystic fibrosis is one of the most common causes of bronchiectasis. The classic CF phenotype includes chronic sinopulmonary disease, pancreatic exocrine insufficiency, and abnormal sweat chloride levels.

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Bronchiectasis is a pathological description of abnormally dilated, distorted thick-walled medium-sized bronchi that are chronically inflamed and infected by bacteria. The essential clinical feature is chronic production of purulent sputum. Bronchiectasis is not a single disease, but a pathological entity now recognized to be associated with many different conditions. The process occurs in airways that have sustained inflammatory injury with subsequent loss of structural integrity of muscle, elastic tissue, and bronchial cartilage. These abnormal dilated airways are susceptible to bacterial colonization, which leads to neutrophil influx. Proteolytic neutrophil products further damage lung tissue and disrupt ciliary function, and this continued bronchial wall damage predisposes to further colonization with bacteria.

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Cystic fibrosis (CF) is the most common inherited disorder among whites in the United States, affecting one in 3200. One in 25 is a carrier of the disease. The disease is caused by mutations in a single gene, called the cystic fibrosis transmembrane conductance regulator (CFTR), and is inherited in an autosomal recessive fashion. Defective chloride transport across epithelial cells leads to dehydrated secretions and exocrine gland dysfunction. Although multiple organs are affected, the progression of bronchiectasis is the most common cause of death and disability. Over 800 mutations in the gene that encodes CFTR have been described, with the most common mutation, δF508, seen in 66% of CF chromosomes.

Barker AF: Bronchiectasis. N Engl J Med 2002;346:1383.   [PubMed: 11986413] (A recent review of bronchiectasis that provides an excellent overview of the subject.)

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Bronchiectasis is caused by a variety of insults to the airways. A number of congenital and/or hereditary factors predispose certain individuals to develop it, but bronchiectasis is not present at birth. Primary or secondary infections are the most frequently identified initiating factor in patients predisposed to bronchiectasis. Other proinflammatory insults such as inhalation of toxins, aspiration of gastric contents, abnormal immune responses (such as autoimmune diseases), or environments exposures (tobacco smoke) can accelerate the lung disease. Damage to the bronchial mucosa and accompanying impairment of host defense eventually lead to chronic infection of the airways regardless of the initial insult. A persistent inflammatory response is established resulting in chronic sputum production and perpetuation of airway injury. The most clearly defined mechanism resulting in bronchiectasis is mutation of CFTR in CF.

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CFTR functions as a cyclic adenosine monophosphate (cAMP)-regulated chloride channel located in the apical membranes of epithelia affected by CF. This defect leads to excess absorption of salt and water at airway surfaces, dehydrating secretions ...

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