Bronchiectasis

Bronchiectasis is a term that describes damage to the walls of the large airways, or bronchial tubes, of the lung. Inflammation due to infection or other causes destroys the smooth muscles that allow the bronchial tubes to be elastic and prevents secretions that are normally made by lung tissue to be cleared.

Normal branching of the airways of the lung demonstrates a gentle taper that occurs at each branch point, like the branches of a tree. This tapering results in decreased resistance in the larger branches, enabling mucus or other objects to be funneled to the larger airways and eventually, with a cough, ejected out through the mouth. Loss of this normal anatomic tapering of the airways by damage due to inflammation causes the walls of the airways to be irregularly shaped. Secretions tend to pool in the distorted airways rather than be expelled, and these stagnant secretions are a breeding ground for bacterial growth. These bacteria, in turn, cause further irritation and inflammation, airway damage, and hence more secretions, initiating a "vicious cycle" of damage. This increases the risk of infections to spread directly into the airspaces of the lungs resulting in pneumonia.

Bronchiectasis is a form of chronic obstructive pulmonary disease (COPD) which also includes emphysema and chronic bronchitis. Bronchiectasis can be present alone, but usually more than one of the aforementioned components of COPD coexist in the same person.

Congenital bronchiectasis may occur due to a genetic defect such as occurs in cystic fibrosis. Usually, the disease Alpha-1 antiprotease (alpha 1- antitrypsin) deficiency results in emphysema, but bronchiectasis can occur as well in this condition. An embryologic defect in the airway cilia, so-called immotile cilia syndrome, is another cause of bronchiectasis and is often associated with situs inversus, in which the major organs are in a reversed position (for example, the heart is on the right).

Pediatric lung infections may ultimately lead to lung destruction and bronchiectasis later in life. Therefore prevention is an important part of treatment, including adequate immunizations and avoidance of secondhand smoke and other toxic fumes.

Bronchiectasis is characterized by an increased amount of sputum production (mucus produced and coughed up from the lung), recurrent infections, and gradual loss of lung function leading to shortness of breath.

Source: MedicineNet.com
http://www.medicinenet.com/bronchiectasis/article.htm