Bronchiolar emphysema (diffuse bronchiolectasis)--so-called muscular cirrhosis of the lungs.

Eleven autopsied cases of bronchiolar emphysema are reported. In all, both lungs were involved. Their pleural surfaces were finely bosselated, presenting an appearance resembling that of the liver in Laennec's cirrhosis. The lungs were firm, they cut with increased fibrous resistance, and the cut surfaces were honeycombed with cysts.Microscopically, the cysts originated in terminal bronchioles. Their walls were thickened with fibrous tissue, elastic fibres and prominent smooth muscle. Areas of lung parenchyma were replaced by fibrous tissue rich in elastic fibres.The etiology of this disease is unknown. Inherent weakness of the myoelastic wall of the respiratory bronchiole, hypoplasia of the distal segment of the respiratory unit, and superimposed recurrent respiratory infections probably are essential in its pathogenesis. The pulmonary changes cause interference with hemorespiratory gaseous exchange.Death was due to respiratory failure in seven cases, to cardiac failure in three and to superimposed staphylococcal pneumonia in one.