We investigated the effects of pepsin/hydrochloric acid and bile acids on eustachian tube function and eustachian tube mucosa in 40 Sprague-Dawley rats. The animals were randomly assigned to groups of 10: one group received pepsin/hydrochloric acid (pepsin/HCl group), another received human bile (human bile group), a third received a mixture of pepsin/HCl and human bile (combination group), and the fourth received isotonic saline solution (control group). Test solutions were applied transnasally three times a day for 10 days. Passive opening pressures and passive closing pressures were measured digitally at baseline and then on days 3, 5, and 10. After 10 days, the rats were sacrificed and histologic changes in the eustachian tube mucosa were analyzed. At study's end, we observed that the increases in passive opening pressures and passive closing pressures in all three experimental groups were significantly greater than those of the control group. Moreover, the increases in passive opening and closing pressures were significantly greater in the combination group than in both the pepsin/HCl and the human bile groups. In the tympanic orifice, the degree of lymphocyte and polymorphonuclear leukocyte infiltration was significantly higher in all three experimental groups than in the control group. In the nasopharyngeal orifice, lymphoid follicle formation was significantly more common in the human bile group than in the control group; also, the presence of subepithelial vasodilation and subepithelial edema was significantly more common in the pepsin/HCl and combination groups than in the controls. Of the three experimental solutions tested, the combination of pepsin/HCl and human bile was the most injurious to eustachian tube function. Reflux of bile acids causes eustachian tube dysfunction, and this damage worsens with the introduction of an acidic compound.

Retrospective chart review of 248 children (1-19 years old) with tinnitus who presented to a tertiary pediatric hospital between 2006 and 2011, looking at which cofactors are predictors of pediatric tinnitus. In our review, we extracted demographics, symptoms, historical data, imaging, and laboratory results; we compared with the general population. Eighty-seven percent had normal hearing. Age distribution, noise exposure, and frequency of psychiatric diagnoses in our cohort were consistent with previous reports. We found a lower incidence of otitis media and the same prevalence of dizziness, asthma, and hearing loss as the general population, a lower prevalence of Eustachian tube dysfunction, otitis media, headaches, and higher incidence of rhinosinusitis. Lack of patient reporting and objective testing complicate the ability to detect pediatric tinnitus. We revealed a gap in the literature regarding rhinosinusitis as a cofactor, imaging during diagnosis, and if psychiatric diagnoses are associated with tinnitus in younger children.

We propose that the complex formed by the Pharyngeal Recess and Eustachian Tube, acts as an acoustic passageway for sounds originating inside the body: sounds made by one's voice, breathing, mastication, one's heartbeats. The antagonistic effect of two sets of muscles, one innervated by the trigeminal nerve, the other by the vagal nerve and cervical plexus, enables the body to modulate transmission of sound via this passageway and hence modulate the awareness of body sounds. Impairment of this system can be due to local factors, such as adhesions over the pharyngeal recess or inflammation inside the pharyngeal recess and/or Eustachian tube; or to tensions of the muscles involved, related to other causes. Dysfunction of the system can lead to symptoms related to increased or decreased awareness of body sounds, such as autophony, hearing of pulsating sounds and clicks in the ear; sensory symptoms related to increased activation of the nerves such as fullness feeling in the ear, facial pain, burning mouth syndrome, globus pharyngeus, pharyngeal pain; and symptoms related to inappropriate muscular contraction such as masticatory and cervical muscle tensions, bruxism, and tension type headache. The functioning of this acoustic passageway is related to the concept of the Trigeminocervical complex. The concept of Vagocervical complex is proposed.