Selected causes of bronchiectasis with their reported prevalence
| Aetiology of bronchiectasis | Proportion of adult patients affected | Typical clinical features |
| Idiopathic | 20–60% | Variable presentation |
| Post-infective | 20–40% | History of severe infection in the affected lobe(s) or historical infection# |
| Post-TB | <2% in developed countries Dominant cause in Eastern Europe, Asia and possibly other regions | History of TB with cavitation and lung damage |
| ABPA | 1–10% | History of asthma, sputum plugs, wheezing, response to corticosteroids and demonstration of specific allergy to Aspergillus Central bronchiectasis |
| CTD | 1–10% | Evidence of systemic CTD (most frequently rheumatoid arthritis) |
| Immunodeficiency | <5% | May be evidence of nonpulmonary infections or unusual microorganisms |
| CF | <1% in “non-CF” adult clinics | Upper lobe bronchiectasis, extrapulmonary features, male infertility, malabsorption Isolation of P. aeruginosa, S. aureus or NTM |
| PCD | <2% but may be underestimated due to limited testing | Middle or lower lobe disease, history of otitis media and rhinosinusitis, early age of onset |
| Yellow nail syndrome | <1% | Yellow nails, pleural effusion |
| Tracheobronchomegaly | <1% | Characteristic radiological appearance of tracheal dilatation and central bronchiectasis |
| NTM infection | 2–50% | Middle lobe nodular bronchiectatic disease More common in females May be scoliosis, pectus excavatum and low BMI |
| HIV infection | <1% | No characteristic phenotype |
| Haematological malignancy | <1% | Frequent respiratory tract infections |
| AATD | <1% | Paraseptal emphysema, airflow obstruction |
| Inhaled foreign body | <1% | Single lobe disease |
| COPD¶ | 2–60% | Mild bilateral lower lobe disease with empysema and history of cigarette smoking |
| Asthma¶ | 1–50% | Not well described |
| Gastro-oesophageal reflux or aspiration¶ | N/A | Bilateral lower lobe or isolated right lower lobe bronchiectasis Not clearly identified as an aetiology |
BMI: body mass index; N/A: not available. #: reverse causation and recall bias make these estimates unreliable; ¶: whether these are true causes of bronchiectasis is debated. Prevalence rate data were extracted from [1, 12, 15–19].