Objectives: Bacteria and viruses are rarely isolated from the middle ear fluid in cases of otitis media with effusion (OME). However, since endotoxins are often detected in such effusions, it is suspected that patients with OME have a previous history of gram-negative infection. Recently, fungi have drawn attention as microorganisms that cause chronic sinusitis. We investigated the involvement of fungi in the formation of middle ear effusions of patients with OME and eosinophilic otitis media, in which patients have viscous middle ear effusions and a history of adult bronchial asthma indicating definite involvement of eosinophils.
Methods: Middle ear effusions and nasal secretions were collected from patients with eosinophilic otitis media (7 patients) or OME (12 patients), and smears were prepared for methenamine silver staining. The remaining specimens were embedded in Epon and stained with toluidine blue for observation under a light microscope, and ultrathin sections were prepared for examination under an electron microscope.
Results: Fungal hyphae were detected in the middle ear fluid in all of the patients with eosinophilic otitis media or OME. Charcot-Leyden crystals (CLCs) were observed in 6 of the 7 patients with eosinophilic otitis media. In regard to the findings in the nasal secretions, fungal hyphae were also detected in the nasal secretions of all patients, whereas CLCs were detected in only 1 patient with eosinophilic otitis media.
Conclusions: It was clarified by use of the methenamine silver staining method that fungi were present in the middle ear fluid in 100% of the studied cases of eosinophilic otitis media or OME. Whether fungi are also present in the middle ear cavity of normal persons is unknown, but the possibility that they may contribute as a cause of both diseases cannot be excluded. Particularly in eosinophilic otitis media, the observation of numerous CLCs in the middle ear fluid suggests that many eosinophils have degenerated. The eosinophil granule proteins released from the degenerated eosinophils can cause epithelial injury of the middle ear. The possibility that fungi induce the eosinophils in the middle ear also cannot be excluded.