Bronchiectasis is a type of chronic lung disease. It is most often caused due to an infection or other condition that causes injury to the walls of the airways or prevents clearing of mucus from the airways.
Risk factors of bronchiectasis: It can be caused due to congenital problems (problem present from birth) or acquired diseases (that is diseases which occur after birth) which affect the lungs or the airways.
Some problems which increase the risk of bronchiectasis are:
- Cystic fibrosis: This is the leading cause of bronchiectasis (especially in developed countries such as United States). In cystic fibrosis, viscid mucous secretion accumulates in the airways as it not cleared properly. Accumulation of secretion makes the person prone to infection and repeated infections and injures to the walls of the airways and leads to bronchiectasis.
- Primary ciliary dyskinesia: This is a type of congenital disorder in which the lung's cilia are not functioning properly. The cilia help to clear the mucus from the airways. As the cilia are 'immotile' i.e. not moving it allows mucus to accumulate in the lower airways and get infected. Repeated infections injure the walls of the airways and increase the risk of bronchiectasis.
Some conditions or disease which increase the risk of bronchiectasis are:
- Childhood infections such as measles, whooping cough, adenovirus, M. Pneumoniae, and certain other infections such as pneumonia and TB (tuberculosis). These conditions may cause damage to the airways, making the person prone to repeated infections and slowly lead to bronchiectasis.
- Retained inhaled foreign object in the airways or a tumour can prevent the clearing of mucus from the airways. This increases the risk of repeated infections and subsequently, bronchiectasis.
- Exposure to chemical irritants (e.g. aspiration pneumonia or ammonia inhalation) can cause airway inflammation, mucus accumulation and later on, bronchiectasis.
- Immunodeficiency disorders such as HIV and AIDS or over-response (allergic bronchopulmonary aspergillosis) also increase the risk of bronchiectasis. Allergic bronchopulmonary aspergillosis which is caused due to allergic reaction to a fungus called aspergillus can cause swelling in the airways, repeated infection, accumulation of mucus in the airways and finally bronchiectasis.
- Lung fibrosis due to connective tissue disease and idiopathic pulmonary fibrosis can cause inflammation of the airways and 'traction bronchiectasis'.
All these disorders cause inflammation, accumulation of mucus in the airways and infection and this becomes a vicious cycle. Repeated infections and lung damage which leads to bronchiectasis, generally starts many years or months before the symptoms of bronchiectasis may become evident.
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