The spectrum of nonasthmatic inflammatory airway diseases in adults.

When the airways are overwhelmed by noxious particles, gases, or microorganisms, inflammatory and immune responses occur that may cause permanent structural changes. One consequence may be an overproduction of mucus and this may overwhelm mucociliary clearance mechanisms and cause a chronic cough phlegm syndrome. The expectorated mucus is usually clear or white (mucoid) but when it becomes infected, the mucus may become purulent and have a yellow or green color. Diseases associated with chronic productive cough discussed in this article include chronic bronchitis, bronchiectasis, and infectious and noninfectious bronchiolitis and their diagnosis and treatment.