Influence of computed tomographic dimensions of the nasopharynx on middle ear effusion and inflammation in pugs and French bulldogs with brachycephalic airway syndrome

Abstract

To compare the prevalence of middle ear abnormalities in pugs and in French bulldogs and evaluate the influence of nasopharyngeal dimensions on middle ear effusion. Retrospective study. Thirty pugs and 30 French bulldogs with brachycephalic airway syndrome and no known history of ear disease. Computed tomographic (CT) studies were reviewed for middle ear effusion, mucosal contrast enhancement, signs of osteitis, and tympanic wall thickness. Soft palate thickness and cross-sectional areas of the nasopharynx at the opening of the auditory tube were measured and normalized to each individual's skull index before statistical comparison between breeds. Statistical dependence of middle ear abnormalities and nasopharyngeal dimensions was assessed by using Spearman's rank correlation tests. Middle ear effusion was observed in 17 of 30 (56.7%) French bulldogs and five of 30 (16.7%) pugs. Contrast enhancement of the tympanic bulla was noted in 25 of 60 (41.6%) French bulldog ears and three of 60 (5.0%) pug ears. The cross-sectional airway dimensions (difference [Δ] = 0.31 cm2 , P < .0001) and soft palate thickness (Δ = 0.44 cm, P < .0001) were reduced in pugs compared with in French bulldogs. Weak correlations were detected between soft palate thickness and nasopharyngeal dimensions and presence of tympanic bulla effusion (r = 0.324 and r = 0.198, respectively) or contrast enhancement (r = 0.270 and r = 0.199, respectively). Middle ear effusion and inflammation were more common in French bulldogs than in pugs and did not seem related to nasopharyngeal dimensions. French bulldogs with brachycephalic airway syndrome seem predisposed to middle ear effusion and inflammation.