Small airways are usually defined as non-cartilaginous airways with an internal diameter of less than 2 mm. Located at a transitional zone between larger airways and lung interstitium, small airways may be affected in a wide variety of pathophysiological conditions.
Small airways diseases, excluding asthma and COPD, are associated with:
- airway infections
- connective tissue diseases
- inflammatory bowel diseases
- bone marrow and lung transplantation
- common variable immunodeficiency disorders (CVID)
- diffuse panbronchiolitis
- diseases related to environmental exposures to pollutants, allergens and drugs.
The diagnostic approach often involves a computed tomography scan and pulmonary function tests.
Treatment of small airways diseases is not well established due to the wide variety of causal factors and their often late diagnosis. Better and earlier identification should improve the possibilities to propose earlier treatments.
Small airways diseases, excluding asthma and COPD: an overview. Eur Respir Rev June 1, 2013 vol. 22 no. 128 131-147.
Image source: Lungs, Wikipedia, public domain.