Mucosal injuries following intratympanic applications of chlorhexidine gluconate in the cat.

We investigated the morphological changes of the middle ear mucosa of the cat exposed to two different concentrations of the disinfectant, chlorhexidine gluconate. In the high concentration (2%) group, notable destructive changes were found on the mucosal surfaces in the tympanic cavity and were especially most severe in that area lined with few ciliated cells under normal conditions. Cilia were twisted and decreased in length in this site. At the tympanic orifice of the eustachian tube, cilia were distributed densely and showed little destructive changes on the surface. In the clinical concentration (0.05%) group, mucosal injuries generally seemed more slight when compared with those in the high concentration group. However, a decrease in the number of cilia or actual loss of cilia was one of the features in this group. Infrequent defects of the superstructures of the epithelial cells were noted on the mucosal surface, but these injuries appeared to spare the basal lamina. In both groups, there were no calcified pathologies seen and no complete obliterations by thickened mucosa or granulations. Deterioration of the ciliary system by chlorhexidine gluconate seems to produce subsequent cell destruction of the middle ear mucosa.