Auditory tube and middle ear mucosa in nonpurulent otitis media.

Most functional disturbances within the auditory tube can be shown and documented morphologically. In the case of a blocked tube we demonstrated changes on the tubal lining as well as in the adjacent salivary glands. Complete obliteration of the lumen is a very rare instance. A lack of ventilation already produces a vacuum within the tympanic cleft, followed by a typical effusion out of the altered mucosa. Anaerobic conditions favor hypertransformation and metaplastic transformation of the epithelium. The missing clearance makes the middle ear discharge a great challenge to the mucosa. Granulation tissue proliferates, an enzyme production starts, phagocytes help to eliminate the tympanic content. If the auditory tube is blocked long enough, the result is the atelectatic tympanum, filled by scar tissue, granulations with fatty degeneration or dystrophic calcification. The ossicular chain is fixed, if not destroyed or interrupted. A retraction pocket within the eardrum membrane, often a reason for secondary acquired cholesteatoma, is very dangerous.