[Electron microscopic investigation of connective tissue in vestibular ganglion and nerve in morbus Menière]

The three faces of vestibular ganglionitis

We present temporal bone and clinical evidence that common syndromes of recurrent vertigo are caused by a viral infection of the vestibular ganglion. In the present series, histopathologic and radiologic changes in the vestibular ganglion and meatal ganglion were consistent with a viral inflammation of ganglion cells in cases of Meniere's disease, benign paroxysmal positional vertigo, and vestibular neuronitis. Clinical observations of multiple neuropathies involving cranial nerves V, VII, and VIII on the same side in patients with recurrent vertigo are best explained by a cranial polyganglionitis caused by a neurotrophic virus, which is reactivated by a stressful event later in life. The reactivation of the latent virus may manifest as one of the above vertigo syndromes, depending on the part of the vestibular ganglion that is inflamed, the type and strain of the virus, and host resistance.

Immunohistochemical findings in the vestibular ganglion from a patient with Menière's disease

Immunofluorescent staining techniques were performed on a series of cryostat sections of the vestibular ganglion taken during ganglionectomy from a patient with Menière's disease. The direct technique using FITC-labelled antiserum proved the presence of immunoglobulins in the patient's blood vessels and endoneural connective tissue. Preincubation with unlabelled antiserum blocked this reaction. An additional positive reaction of ganglion cells was demonstrated by incubating tissue with the patient's serum. These findings prove antibodies in the patient's serum against the autologous ganglion cells. The vestibular ganglion from a patient with dizziness following a skull base fracture served as a control specimen. No autoimmune reaction was found in the ganglion cells when incubation was carried out with the patient's serum. A positive reaction in the blood vessels and connective tissue was less pronounced. The findings of the present study underline the occurrence of immunological reactions in the vestibular ganglion of patients with Menière's disease. A subsequent degeneration of ganglion cells could provoke clinical Menière's attacks.

The incidence of fibrosis in the vestibular ganglia in Menière's disease

The vestibular ganglia in 11 temporal bones from subjects with known premortem unilateral Meniere's disease were studied for evidence of increased fibrosis. Tissue sections were treated with Gomori's trichrome stain and were examined independently by each of seven persons experienced in histological study. The averaged ratings for the amount of fibrous tissue in the vestibular ganglia showed no significant differences for ears with Meniere's disease, the opposite uninvolved ears, and the controls.

A functional and histological study of the combined effects of gentamicin and aminooxyacetic acid on the organ of Corti of the guinea pig

Aminooxyacetic acid (AOAA) is a transaminase inhibitor that has been shown to protect the inner ear from loud noises. This study was done to determine if it can also protect against the cochleotoxic action of gentamicin. Four groups of guinea pigs were injected with gentamicin in doses approximating a clinical therapeutic dose and then in ototoxic doses. Thereafter animals were treated with parenteral AOAA. The effect on hearing was investigated using Preyer's reflex measurements. All animals were sacrificed and their cochleas were examined histologically using the surface preparation technique and mid-modiolar semithin sections. Histocochleograms were plotted to compare the effects of treatment in the animal groups. There was no difference seen among the groups tested. Cochlear damage was nearly equal in all animals, and AOAA was not found to protect the cochlea against gentamicin-induced ototoxicity of gentamicin. The mechanism of the ototoxicity produced is discussed on the basis of the findings. Additionally, hair cell degeneration was studied after therapeutic doses of gentamicin. Changes seen were found to be equal to or less than 5% of the hair cells and were scattered throughout the entire cochlea.