Stapediovestibular ankylosis in an HIV/HCV-copositive patient.

To the best of the author's knowledge, no case of a patient with stapediovestibular ankylosis who was also coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) has been previously described in the literature. This report describes the case of a 36-year-old woman who was diagnosed with all three conditions. The clinical diagnosis of stapes fixation was based on otoscopic, audiometric, tympanometric, and surgical findings. Stapedectomy was performed, and perilymph and serum samples were obtained and tested for anti-HIV and anti-HCV antibodies. While the titers of anti-HCV antibodies in the serum and perilymph were of similar magnitude, there were almost 16 times more anti-HIV antibodies in the serum than in the perilymph. This case offered a unique opportunity to study the titers of anti-HIV/HCV antibodies in both the blood serum and perilymph. Data relating to these titers may provide new insights into the mechanisms of stapediovestibular ankylosis and inner ear immunology.

Superior Versus Inferior Vestibular Neuritis: Are There Intrinsic Differences in Infection, Reactivation, or Production of Infectious Particles Between the Vestibular Ganglia?

HYPOTHESIS: Intrinsic differences in neurons of the vestibular ganglia result in the increased likelihood of superior vestibular ganglion involvement in vestibular neuritis. BACKGROUND: Vestibular neuritis is hypothesized to result from herpes simplex type I (HSV1) infection or reactivation in vestibular ganglia. Involvement of the inferior vestibular ganglion is extremely rare in patients with vestibular neuritis. METHODS: Primary cultures of rat superior and inferior vestibular ganglion neurons (VGNs) were cultivated separately. Neurons were lytically and latently infected with HSV1 with a US11-green fluorescent protein (GFP) chimera. Percentage lytic infection and baseline reactivation was assessed by microscopy for GFP fluorescence. Trichostatin-A (TSA) was used to stimulate HSV1 reactivation. Virion production was assessed by viral titers. Relative numbers of latency-associated (LAT) transcripts were determined by real-time reverse-transcription polymerase chain reaction (real-time RT-PCR). RESULTS: Lytic infection rates were equivalent between the two ganglia (p > 0.05). Lytic infections yielded similar amounts of plaque-forming units (p > 0.05). Relative amounts of LAT transcripts did not differ between latently infected superior and inferior VGNs. Latently infected cultures showed no differences in rates of baseline and TSA-induced HSV1 reactivation (p > 0.05). Production of virions was not significantly different between reactivated, latently infected superior versus inferior VGNs (p = 0.45). CONCLUSION: Differences in prevalence of superior and inferior vestibular neuritis do not result from intrinsic differences in HSV1 infection or virion production of these neurons. Other factors, such as the length and width of the bony canal containing the ganglia and nerves, account for the greater involvement of the superior vestibular ganglion in vestibular neuritis.

Inner ear lesions in congenital cytomegalovirus infection of human fetuses.

Congenital cytomegalovirus (CMV) infection is the leading cause of non-hereditary congenital sensorineural hearing loss (SNHL). The natural course and the pathophysiology of inner ear lesions during human fetal CMV infection have not yet been reported. Inner ear lesions were investigated in six CMV-infected fetuses aged 19-35 postconceptional weeks and correlated with central nervous system (CNS) lesions. All the fetuses had high viral loads in the amniotic fluid and severe visceral and CNS lesions visible by ultrasound. Diffuse lesions consisting of both cytomegalic cells containing inclusion bodies and inflammation were found within all studied structures including the inner ear, brain, other organs, and placenta, suggesting hematogenous dissemination. Cochlear infection was consistently present and predominated in the stria vascularis (5/6), whereas the supporting cells in the organ of Corti were less often involved (2/6). Vestibular infection, found in 4/6 cases, was florid; the non-sensory epithelia, including the dark cells, were extensively infected. The endolymphatic sac was infected in 1 of 3 cases. The severity of inner ear infection was correlated with the CNS lesions, confirming the neurotropism of CMV. This study documenting infection of the structures involved in endolymph secretion and potassium homeostasis in fetuses with high amniotic fluid viral loads suggests that potassium dysregulation in the endolymphatic compartment of the inner ear may lead to secondary degeneration of the sensory structures. In addition, the occurrence of SNHL depends on the intensity and duration of the viral infection and inflammation.

Auditory and vestibular defects induced by experimental labyrinthitis following herpes simplex virus in mice.

CONCLUSION: Our herpes simplex virus (HSV) labyrinthitis mouse model suggests that HSV infection induces vestibular neuritis and sudden deafness. OBJECTIVE: Viral labyrinthitis has been postulated to play a role in vestibular neuritis and sudden deafness. We established a mouse model to investigate the pathogenesis of HSV-induced labyrinthitis. The relationship between HSV infection and apoptosis in the labyrinth was assessed. METHODS: HSV types 1 and 2 were inoculated into the middle ear of mice, and the function of the cochlear and vestibular nerves was assessed. Histopathological changes were examined with hematoxylin and eosin staining. Anti-HSV immunohistochemistry staining and TUNEL staining were done to investigate the relationship between HSV-infected cells and apoptotic cells. RESULTS: Hearing loss and vestibular dysfunction were observed in all mice after inoculation of HSV type 1 or 2. In the cochlear duct, columnar epithelial cells in the stria vascularis were infected with HSV, but only a portion of the infected cells underwent apoptosis. In contrast, many uninfected cells in the spiral organ of Corti were apoptotic. Vestibular dysfunction was observed when vestibular ganglion cells were largely infected, but not apoptotic. These findings recapitulate sudden deafness and vestibular neuritis described in patients.

Naturally-occurring canine herpesvirus-1 infection of the vestibular labyrinth and ganglion of dogs.

Although the involvement of herpesviruses in vestibular disease of humans has been recognised for many years, knowledge of such a link in companion animal species is restricted to cats. This study was conducted to assess the prevalence of canine herpesvirus-1 (CaHV-1) infection of the vestibular labyrinth (VL) and vestibular ganglion (VG) of dogs by PCR. 'Field' herpesvirus was detected in the VL of 17% and in the VG of 19% of 52 dogs, respectively. None of the 11 dogs with infected VG and/or VL exhibited signs of vestibular disease, whereas clinical signs in the remaining three animals were attributable to intra-cranial neoplasia. As reported for other species, the putative role of herpesvirus infection in canine vestibular disease requires further elucidation.

Evidence of feline herpesvirus-1 DNA in the vestibular ganglion of domestic cats.

In humans, herpes simplex virus type-1 has recently been detected in the vestibular ganglion (VG) and labyrinth (VL) and may be associated with vestibular signs. Feline herpesvirus-1 (FHV-1) is widespread amongst cat populations and affects many different tissues. The aim of this pilot study was to investigate the presence of FHV-1 DNA in the VG and VL of randomly selected domestic cats using PCR. FHV-1 DNA was detected in the VG of 14% of the cats. There was no detectable FHV-1 DNA in the VL of any cat. None of the infected cats had vestibular signs related to the VG infection.

Ménière's disease is a viral neuropathy.

Morphological and clinical evidence supports a viral neuropathy in Ménière's disease (MD). Quantitative examination of 11 sectioned temporal bones (TBs) from 8 patients with a history of MD revealed a significant loss of vestibular ganglion cells in both the endolymph hydropic (EH) and non-EH ears. Transmission electron microscopy of vestibular ganglion cells excised from a patient with MD revealed viral particles enclosed in transport vesicles. Antiviral treatment controlled vertigo in 73 of 86 patients with vestibular neuronitis (85%) and 32 of 35 patients with MD (91%).

[Varicella-zoster infection with isolated cochleovestibular affectation (without facial palsy)]. / Infección por herpes zoster con afectación cocleovestibular aislada (sin parálisis facial).

Otological complications of Ramsay Hunt syndrome include facial paralysis, tinnitus, hearing loss, vertigo, dysgeusia, and skin eruption. The lower cranial nerves sometimes are affected by this neuritis. A case is reported of a man without immune-system impairment who had a cranial mononeuritis with unilateral involment of the VIII and VII cranial nerves after infection with varicella-zoster without herpetic lesions.

Expression of adeno-associated virus integrated transgene within the mammalian vestibular organs.

HYPOTHESIS: Adeno-associated virus (AAV) is a suitable viral vector for transgene expression within the mammalian vestibular organs. BACKGROUND: In vivo introduction and expression of a foreign gene within the cochlear tissues have been established using a variety of viral vectors and guinea pig as the animal model. However, the vestibular neuroepithelia of the mammalian inner ear as a potential target for transgene expression remain to be investigated. METHODS: Transgene expression was assessed within the vestibular neuroepithelia of guinea pigs after intracochlear infusion of the recombinant AAV vector with the aid of an osmotic minipump. Evaluation of the transgene within the vestibular apparatus focused on its duration of expression from 2-24 weeks after intracochlear AAV infusion using immunohistochemistry. RESULTS: In the AAV-beta-galactosidase (beta-gal)-infused animals, the sensory hair cells as well as the supporting epithelial cells of cristae and maculae were positive for the transgene expression. The relative level of beta-gal expression was noted to decrease progressively over time. Transduction of the vestibular neuroepithelia also was observed in the contralateral ear, a finding that has been documented previously in AAV-integrated transgene expression in the cochlea. CONCLUSION: This study reports the first demonstration of introduction and long-term transgene expression within the vestibular neuroepithelia. The ability to express a foreign gene with the vestibular system allows the possibility of experimental and therapeutic application of gene therapy technology to address vestibular function and dysfunction.

Ultrastructural findings in the vestibular end-organs of AIDS cases.

Neurotologic manifestations are apparent in human immunodeficiency virus (HIV) infection, but are poorly understood. Symptoms related to the vestibular system include episodes of vertigo, imbalance, ataxia, and nausea. Although patients present more often with hearing impairment, vestibular complaints are described and electrophysiologic studies indicate vestibular dysfunction in HIV-infected patients. Whether the disease involvement includes the central, or the peripheral nervous system has not been established. Ultrastructural analysis of vestibular end-organs obtained from HIV autopsy cases revealed pathologic changes in the labyrinth wall, the epithelial lining, and the receptor maculae and cristae. Cytologic changes in hair cells included inclusion bodies, viral-like particles, and hair bundle malformations. Epithelial lining cells, supporting cells, and connective tissue cells had inclusions and viral-like particles. These findings are consistent with those of a previous cochlear study demonstrating intracellular viral-like particles with the morphologic characteristics of HIV. Further cytologic evaluation of decalcified temporal bones and immunohistochemical analysis of freshly harvested HIV-infected temporal bones may provide further insight into the pathogenesis of viral-induced hearing loss and vestibular impairment.