Otologic manifestations of experimental rhinovirus infection.

Episodes of acute otitis media are commonly associated with viral upper respiratory tract infections. Rhinoviruses account for approximately 40% of these infections, and were previously shown to alter eustachian tube function and middle ear pressures. However, progression to otitis media has not been prospectively documented. In the present study, changes in tympanometric pressures and otoscopic findings resulting from experimental intranasal rhinovirus type-39 inoculation were documented in 60 adult volunteers. Fifty-seven (95%) subjects became infected and 34 (60%) of these had a clinical cold. Prior to viral inoculation, 3 (5%) subjects had middle ear pressures of less than -100 mm H2O and two of these subjects developed middle ear effusions following infection. In all, 22 (39%) subjects developed middle ear pressures of less than -100 mm H2O. No subject with normal middle ear pressures prior to infection developed evidence of effusion. This study extends the otologic manifestations of rhinovirus infection to include otitis media. Furthermore, these results support the hypothesized relationship between upper respiratory tract infections, eustachian tube dysfunction, and otitis media.

Eustachian tube function in the ferret.

The role of viral upper respiratory tract infections (URI) in the pathogenesis of otitis media (OM) may be related to Eustachian tube (ET) dysfunction. Preliminary experimental evidence suggests that the ferret may be an appropriate animal for modeling of pathophysiologic process related to URI's and ET dysfunction. In an effort to determine the applicability of this animal model, normal ET function was evaluated in 10 ferrets using the inflation-deflation and forced-response testing protocols. The results indicate that the ET of the ferret functions as a small-scale version of its rhesus monkey and human counterparts. The ET-middle ear (ME) system could maintain applied positive and negative ME pressures in all instances. Nearly complete swallow-induced pressure equilibrations were demonstrated in all ears tested. Elevated passive function parameters suggested a small tubal lumen. The efficiency of the tubal dilatory mechanism as expressed by the normalizing calculation (R0/RA) was shown to be quite similar to that in primates and man. These findings suggest that the ferret's ET functions in a manner similar to humans and is, therefore, an appropriate animal to study the pathogenesis of otitis media in the context of ET dysfunction.