Inrtoduction:
Bronchiectasis is a disease that causes localized, irreversible dilatation of part of the bronchial tree. Involved bronchi are dilated, inflamed, and easily collapsible, resulting in airflow obstruction and impaired clearance of secretions. Bronchiectasis is associated with a wide range of disorders, but it usually results from necrotizing bacterial infections, such as infections caused by the Staphylococcus or Klebsiella species or Bordetella pertussis.
Pathogenesis:
Dilation of the bronchial walls results in airflow obstruction and impaired clearance of secretions because the dilated areas disrupt normal air pressure in the bronchial tubes, causing sputum to pool inside the dilated areas instead of being pushed upward. The pooled sputum provides an environment conducive to the growth of infectious pathogens, and these areas of the lungs are thus very vulnerable to infection. The more infections that the lungs experience, the more damaged the lung tissue and alveoli become. When this happens, the bronchial tubes become more inelastic and dilated, creating a self-perpetuating cycle of further damage to the lungs.
There are both congenital and acquired causes of bronchiectasis. Kartagener syndrome, which affects the mobility of cilia in the lungs, aids in the development of the disease. Another common genetic cause is cystic fibrosis, in which a small number of patients develop severe localized bronchiectasis. Young's syndrome, which is clinically similar to cystic fibrosis, is thought to significantly contribute to the development of bronchiectasis. This is due to the occurrence of chronic, sinopulmonary infections. Patients with alpha 1-antitrypsin deficiency have been found to be particularly susceptible to bronchiectasis, for unknown reasons. Other less-common congenital causes include primary immunodeficiencies, due to the weakened or nonexistent immune system response to severe, recurrent infections that commonly affect the lung.
Treatment:
Treatment of bronchiectasis is aimed at controlling infections and bronchial secretions, relieving airway obstruction, and preventing complications. This includes the prolonged usage of antibiotics to prevent detrimental infections, as well as eliminating accumulated fluid with postural drainage and chest physiotherapy. Surgery may also be used to treat localized bronchiectasis, removing obstructions that could cause progression of the disease.
Inhaled steroid therapy that is consistently adhered to can reduce sputum production and decrease airway constriction over a period of time, and help prevent progression of bronchiectasis. One commonly used therapy is beclometasone dipropionate, which also used in asthma treatment. Use of inhalers such as albuterol (salbutamol), fluticasone (Flovent/Flixotide) and ipratropium (Atrovent) may help reduce likelihood of infection by clearing the airways and decreasing inflammation.
