There are many causes of bronchiectasis - some are acquired and others you may be born with (congenital). The following is a list of the most important and/or common ones.
Infections can damage the airways and cause bronchiectasis. They may also be a consequence which in turn can lead to worsening bronchiectasis. Examples include:
Viral infections (measles, adenovirus, influenza),
Bacterial infections (Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella),
Mycobacterial infections (tuberculosis, Mycobacterium avium complex) and
Fungal infections (histoplasmosis).
Persons with immune deficiencies, such as antibody deficiencies, are more likely to have repeated lung infections which can damage the airways and cause bronchiectasis.
Chronic pulmonary aspiration occurs when a person inhales oral or stomach material into his/her lungs. If severe or recurrent, aspiration can lead to inflammation of the airways and cause bronchiectasis. The aspiration can occur from:
Impaired ability to swallow (oropharyngeal dysphagia) which may cause saliva or food to enter the lung.
Gastroesophageal reflux disease (GERD) which occurs when the valve of smooth muscle between the esophagus and the stomach does not function properly, and allows stomach contents (acid and non-acid) to flow back up into the esophagus. The stomach contents may enter your lungs and irritate the airways. Some signs and symptoms of GERD include: heartburn or sour taste in mouth, but many (possibly up to 30%) of people with GERD may have no symptoms ("silent" GERD).
Rheumatoid arthritis, Lupus, Sjogren's syndrome and Wegener's granulomatosis are examples of rheumatologic, autoimmune or connective tissue diseases that can cause bronchiectasis.
Cystic fibrosis causes impaired drainage of mucus and bacteria from the airways and leads to recurrent lung infection and bronchiectasis. Classic cystic fibrosis is obvious at birth, but there are forms of cystic-fibrosis that may not be recognized until adulthood.
Primary ciliary dyskinesia impairs the ability small hairs called cilia to clear mucus and bacteria from the airways. Recurrent lung infections can occur and cause bronchiectasis.
Alpha-1 Antitrypsin Deficiency or Anomaly. Alpha-1 antitrypsin is a protein that moderates inflammation that occurs during an infection. Persons who are deficient in alpha-1 antitrypsin or who have an abnormal protein may be more likely to have recurrent lung infections that cause bronchiectasis.
Obstruction of the Airways
Obstructed airways trap mucous and infection behind the obstruction which can damage the airways and cause bronchiectasis.