Inflammatory changes reflected in middle ear effusion in otitis media.

Otitis media (OM) is an extremely wide-spread disease, and the presence of middle ear effusion (MEE) is a common phenomena in OM. The analyses of MEE provide important information for better understanding of etiology and evaluation of inflammatory stages of the middle ear cavity. Well investigated etiologic factors of OM have included negative pressures within the middle ear cavity secondary to Eustachian tube dysfunction, and bacterial or viral infection. It is quite conceivable that the biochemical, cytological and immunochemical products found in the middle ear mucosa (MEM) and MEE during OM may contribute to the clinical course of the disease. The sources of these inflammatory components include: inflamed epithelial cells of MEM, cells of the subepithelial space, vasogenic origins, bacterial and/or inflammatory cell products in MEE. In animal studies (serous otitis media [SOM] and purulent otitis media [POM]), interesting correlations between sequential biochemical and cytological findings have been observed. The vasodilation, increased blood vessel permeability, and the release of intracellular products both from inflamed middle ear mucosa and inflammatory cells are determining factors for the biochemical changes of MEE. Recently, the importance of the role of the subepithelial space (SES) in the pathogenesis of various types of OM has been emphasized in human studies. A strong cellular-immune response with proliferation of fibroblasts, collagen fibers, plasma cells, lymphocytes, macrophages, along with an increase in capillary networks have been characterized with SES changes in OM. Analysis of MEE by biochemical and immunochemical markers (prostaglandins, immunoglobulins, intracellular enzymes) have reflected inflammatory changes in the MEM of various types and stages of OM.(ABSTRACT TRUNCATED AT 250 WORDS)