Chronic Obstructive Disease of Small Airways

The clinical, radiological, pathophysiological, and morphological features of seven patients with chronic airways obstruction characterized by chronic cough and expectoration are described. All had a reticular pattern on their chest roentgenogram. None had severe or extensive emphysema. Hypercapnia was chronic in four and transient in two. The lungs were not hyperinflated, but residual volume was increased. Pulmonary function tests showed airways obstruction. Mucous plugging, narrowing, and peribronchial fibrosis were variably present. The only morphological abnormality common to all was inflammation of small bronchi and bronchioles. These morphologic lesions may be principally responsible for the functional and possibly the roentgenographic abnormalities in these patients. Similar abnormalities are seen in small airways of patients dying from chronic bronchitis and emphysema and may be responsible for many of the functional derangements in these disorders.