What causes bronchiectasis?
Infectious causes:
- Bacterial: e.g. pertussis, staphylococcal and other bacterial pneumonia, Mycoplasma, Chlamydia, whooping cough, tuberculosis
- Viral: e.g. measles, adenovirus, influenza, respiratory syncytial virus (RSV), parainfluenza virus, Epstein-Barr virus, cytomegalovirus
- Fungal: e.g. Aspergillus, Candida, Cryptococcus
- Parasitic: e.g. Strongyloides, Ascaris, hookworm, Schistosoma mansoni
- Mycobacterial: e.g. Mycobacterium tuberculosis, Mycobacterium avium complex
Immune-mediated causes:
- Primary ciliary dyskinesia: a group of inherited conditions that affect the structure and function of cilia, the tiny hair-like structures that help to clear mucus from the airways.
- Allergic bronchopulmonary aspergillosis: a condition that develops in people who have an allergy to the fungus Aspergillus fumigatus.
- Cystic fibrosis: a genetic condition that affects the lungs, pancreas, and other organs.
- Immunodeficiency: e.g. HIV, hypogammaglobulinaemia, common variable immunodeficiency
Congenital abnormalities:
- Tracheobronchomalacia: softening of the trachea and bronchi
- Bronchial atresia: congenital narrowing or absence of a bronchus
- Congenital lobar emphysema: over-inflation of one or more lobes of the lung
- Congenital cystic adenomatoid malformation (CCAM): a rare lung malformation that is present at birth
- Kartagener syndrome: a rare genetic disorder that affects the cilia, leading to bronchiectasis and other respiratory problems
Obstructive causes:
- Aspiration: this is when food, drink, or other objects enter the lungs, which can cause inflammation and damage to the airways.
- Tumors: benign or malignant tumors in the lungs or airways can block the flow of air and cause bronchiectasis.
- Foreign bodies: objects such as toys, food, or insects can become lodged in the airways and cause bronchiectasis.
- Strictures: these are narrowings of the airways that can be caused by inflammation, scarring, or tumors.
Drug-induced bronchiectasis:
- Certain drugs, such as methotrexate, amiodarone, nitrofurantoin, and cocaine, can cause bronchiectasis.
Idiopathic bronchiectasis:
- In some cases, the cause of bronchiectasis is unknown. This is known as idiopathic bronchiectasis.