Tracheal stenosis in the cat: anatomopathologic repercussions on the pulmonary parenchyma

Abstract

A calibrated stenosis of the trachea was performed in 6 young cats and 1 old one (TS cats); the animals were observed for 8 or 15 weeks thereafter. The percentage of macrophages in bronchoalveolar lavage fluid was greater in the TS cats than in the controls. An irregular distribution of pulmonary lesions was found. 4 TS cats presented with a real emphysema with tracheobronchial inflammation, a parenchymatous infection which was histologically shown or quantified in lavage fluid (Haemophilus (10(8]. They exhibited episodes of hypoventilation which followed in quick succession. The alveolar section of the TS emphysematous lung was equal or greater (up to 88% of the lung surface observed) than that of both the same-aged controls (81.5%) and of an old emphysematous cat (88 months). The alveoli were more homogeneous (lower deviation). TS lung was characterized by a higher amount of dry tissue protein but hydroxyproline varied individually. A possible synergy between infection and ventilatory obstruction may be a tentative explanation for the etiogeny of this emphysema which appears to be secondary to tracheal stenosis.