Middle Ear Effusions Produced Experimentally in Dogs: III. Further studies concerning the pathogenesis of the effusions

Abstract

Middle ear effusions were produced in dogs by cauterizing the nasophar-yngeal orifices of the eustachian tube. Cauterization of the actual tubal orifice was essential for producing the effusion. Injury to the contiguous wall of the nasopharynx, no matter how close to the tubal opening, did not result in an effusion. Serous, seropurulenl, purulent and mucopurulent effusions were obtained in approximately one-half of the cauterized ears. These revealed characteristics similar to those seen in human effusions. Positive bacterial cultures were obtained from approximately three-fourths of the effusions. A high percentage of streptococci were cultured concomi-tantly from the middle ear effusions and the corresponding nasopharynges. Differences in the cytologic and physical characteristics of the effusions are attributed to individual immunologic responses.

These studies were performed under grant B969, National Institute of Neurological Diseases and Blindness, National Institutes of Health, Public Health Service.