Recent advances in viral inner ear disorders.

PURPOSE OF REVIEW: To highlight the recent advances in the understanding of the diagnosis and management of viral inner ear disorders. Congenital sensorineural hearing loss (cSNHL), sudden sensorineural hearing loss (SSNHL), Ménière's disease, and vestibular neuritis/viral labyrinthitis are discussed. RECENT FINDINGS: Cytomegalovirus infection during pregnancy is an under-recognized cause of hearing loss and central nervous system disease amongst the general population. Prevention of maternal infection and treatment of affected newborns with ganciclovir are promising interventions. Recent evidence in SSNHL patients has resulted in recommendations against viral serology or the use of antivirals. There appears to be an increased risk of SSNHL in patients with comorbid hypertension and diabetes. The viral hypothesis of Ménière's disease remains unproven. In patients with an acute episode of vestibular neuritis, there is presently not sufficient evidence to support the routine use of corticosteroids or antiviral medications. SUMMARY: cSNHL remains the most clearly defined of the viral inner ear disorders. The evidence for viral involvement in SSNHL, Ménière's disease, and vestibular neuritis is indirect and equivocal. This review highlights the recent advancements in the diagnosis and management of these disorders.

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%).

Herpes virus and Ménière's disease.

OBJECTIVE: The main goal of this study was to examine the vestibular ganglia from patients with intractable classic Ménière's disease (MD) for the presence or absence of DNA from three neurotropic viruses herpes simplex virus 1 and 2 (HSV1, HSV2) and varicella zoster virus (VZV) and to investigate the hypothesis that MD is associated with virus reactivation within Scarpa's ganglion. STUDY DESIGN: Polymerase chain reaction (PCR) was performed with nested primer sets specific for viral genomic DNA of HSV1, HSV2 and VZV in biopsies of the ganglion scarpae of patients with MD who underwent vestibular neurectomy. Included were patients with MD classified as definite MD according to American Academy of Otolaryngology/Head and Neck Surgery criteria. The ganglion scarpae and ganglion geniculi harvested at autopsy from patients without history of MD or facial palsy served as control specimens. RESULTS: No viral DNA was detected in the vestibular ganglion of 7 patients with definite MD. In 34% of the vestibular ganglia of the control group we detected either HSV1 or VZV. Only one Scarpa's ganglion had both viruses present at the same time. Thirty-two out of 34 ganglia from the geniculate segment of the facial nerve contained either HSV1 and/or VZV genomic DNA. Eight specimens contained both viruses simultaneously. Altogether viral DNA was found in 94% of ganglia. Viral genomic DNA of HSV2 was not detected. CONCLUSION: Although HSV and VZV appear to be present in many ganglion cells throughout the human body, we were unable to find genomic DNA of these viruses in patients with definite MD and disabling vertigo, who underwent vestibular neurectomy. Based on these results, reactivation of HSV1 and VZV in the vestibular ganglion does not seem to play a role in the pathogenesis of MD.

Do viruses cause inner ear disturbances?

The association of viral infection to inner ear disease is controversial. Experiments on animals show that several viruses are capable of causing hearing loss, if applied into the perilymph. Some of these have specific affinity to the cellular type of the inner ear, as sensory epithelia and cochlear nerve. Some viruses as adenoviruses and Coxsackie virus B have specific CAR receptors that are identified in different cell types, whereas other act by attaching onto nonspecific cellular surface receptors. Some viruses such as varicella zoster virus (VZV) do not cause disease in rodents. We assessed 273 patients with clinical, serological, neuro-otologic and endoscopic evaluations. Of the 273 patients, 43 served as control subjects. The patients either had Ménière's disease (n = 158), recurrent vertigo of unknown etiology (n = 56), or hearing loss (n = 17). Antibodies against neurotropic and common viruses were evaluated. VZV, influenza B, CBV5 and RSV titers were significantly elevated in patients with inner ear disease when compared with the control group. In analyzing the internal relationship, VZV and influenza B were intercorrelated. We did not find a correlation between hearing loss and viral titers. In conclusion, VZV, Coxsackie virus B5 and influenza B virus may be the main causes of inner ear disorder. The spiral and Scarpa's ganglion are potential sites harboring viral DNA for possible latent infection.

Inner ear and facial nerve complications of acute otitis media with focus on bacteriology and virology.

CONCLUSION: Among 20 patients with inner ear complications and/or peripheral facial palsy secondary to acute otitis media (AOM) a proven or probable bacteriological cause was found in 13 (65%). In seven patients (35%), a proven or probable viral cause was found. Only two of the patients (10%), with a proven bacterial AOM and a clinical picture of a purulent labyrinthitis in both, together with a facial palsy in one, had a substantial degree of dysfunction. Although the number of patients in this study is relatively low our findings show that inner ear complications and facial palsy due to AOM can be of both bacterial and viral origin. Severe sequelae were found only where a bacterial origin was proven. OBJECTIVES: Inner ear complications and/or peripheral facial palsy secondary to AOM are rare. The general understanding is that they are due to bacterial infections. However, in some of these patients there are no clinical or laboratory signs of bacterial infections and they have negative bacterial cultures. During recent years different viruses have been isolated from the middle ear or serologically proven in AOM patients and are thought to play a pathogenetic role. We suggest that in some cases of AOM complications from the inner ear and the facial nerve can be caused by viruses. The purpose of our study was to analyze infectious agents present in patients with inner ear complications and/or facial palsy arising from AOM. PATIENTS AND METHODS: The medical records of 20 patients who had inner ear complications and/or facial palsy following AOM ( unilateral in 18, bilateral in 2) between January 1989 and March 2003 were evaluated. Bacterial cultures were carried out for all patients. Sera from 12 of the patients were stored and tested for a battery of specific viral antibodies. In three patients, investigated between November 2002 and March 2003, viral cultures were also performed on samples from the middle ear and nasopharynx. RESULTS: Nineteen patients had inner ear symptoms. Eight of them had a unilateral sensorineural hearing loss and vertigo, three had vertigo as an isolated symptom and one, with bilateral AOM, had bilateral sensorineural hearing loss. Seven patients had a combination of facial palsy and inner ear symptoms (unilateral sensorineural hearing loss in three, unilateral sensorineural hearing loss and vertigo in two, bilateral sensorineural hearing loss and vertigo in one, with bilateral AOM, and vertigo alone in one). One patient had an isolated facial palsy. Healing was complete in 11 of the 20 patients. In seven patients a minor defect remained at follow-up (a sensorineural hearing loss at higher frequencies in all). Only two patients had obvious defects (a pronounced hearing loss in combination with a moderate to severe facial palsy (House-Brackman grade 4) in one, distinct vestibular symptoms and a total caloric loss in combination with a high-frequency loss in the other. Eight patients had positive bacteriological cultures from middle ear contents: Streptococcus pneumoniae in two, beta-hemolytic Streptococcus group A in two, beta-hemolytic Streptococcus group A together with Staphylococcus aureus in one, Staph. aureus alone in one and coagulase-negative staphylococci (interpreted as pathogens) in two. In the 12 patients with negative cultures, there was a probable bacteriological cause due to the outcome in SR/CRP and leukocyte count in five. In four patients serological testing showed a concomitant viral infection that was interpreted to be the cause (varicella zoster virus in two, herpes simplex virus in one and adenovirus in one.) In three there was a probable viral cause despite negative viral antibody test due to normal outcome in SR/CRP, normal leukocyte count, serous fluid at myringotomy and a relatively short pre-complication antibiotic treatment period.

Incidence of virus infection as a cause of Meniere's disease or endolymphatic hydrops assessed by electrocochleography.

Meniere's disease (MD) may follow viral infection such as by neurotropic viruses known to invade the endolymphatic sac (ES) and provoke endolymphatic hydrops (EH). The objective of this study was to investigate whether neurotropic viruses may cause infection of the inner ear and provoke EH. Antiviral immunoglobulin (IgG) assay against herpes simplex 1 (HSV1), herpes simplex 2 (HSV2), adenovirus (ADV), varicella zoster virus (VZV) and cytomegalovirus (CMV) were performed in 109 patients with an advanced stage of MD and compared with those obtained from 26 patients operated on because of vestibular schwannoma (VS), who served as a control group, to evaluate whether there is an association between the IgG levels and the ECoGs summating potential/action potential ratio (SP/AP ratio) in the MD group. In MD patients, the IgG titre against VZV and ADV were significantly higher than in the control (schwannoma) group. However, no correlation was found between the IgG levels against ADV and VZV with the SP/AP ratio. Neurotropic viruses such VZV and ADV may play a role in the pathogenesis of MD, despite the absence of association between the levels of IgG titres and the SP/AP ratio.

Herpes simplex virus and Meniere's disease.

OBJECTIVE/HYPOTHESIS: This study was designed to investigate the hypothesis that Meniere's disease is associated with herpes simplex virus (HSV) reactivation in the vestibular ganglion. STUDY DESIGN: Case control study. METHODS: Vestibular ganglia were obtained from archival surgical pathology specimens from patients undergoing vestibular neurectomy for vertigo caused by Meniere's disease. All patients met criteria for classification as definite Meniere's disease according to American Academy of Otolaryngology/Head and Neck Surgery (AAO-HNS) criteria. Control specimens were obtained from willed body donors. Sections from each ganglion were studied for prevalence of viral DNA using a nested polymerase chain reaction designed to amplify the HSV DNA polymerase gene. Quantitative analysis determined the number of viral copies per standard unit of ganglionic DNA. RESULTS: HSV DNA was more prevalent in paraffin embedded ganglia from patients with Meniere's disease (100%) than in fresh-frozen control ganglia (81%) (P =.02). Fixation and paraffin embedding substantially reduced recovery of HSV virus in selected control specimens. Quantitative analysis found no correlation between viral copy number in control ganglia processed frozen versus formalin fixed and paraffin embedded. CONCLUSIONS: HSV is more commonly isolated from vestibular ganglia of patients with Meniere's disease than the general population. The routine histologic preparation of formalin fixation and paraffin embedding significantly altered the quantity of virus detected though not in a predictable manner. The study provides supportive evidence for a viral etiology in Meniere's disease.

Detection of viral DNA in the endolymphatic sac in Ménière's disease by in situ hybridization.

The main purpose of this study is to search for a viral etiology in Ménière's disease by examining the presence or absence of herpes family virus DNA in the endolymphatic sac (ES) using the in situ hybridization method. This was a prospective study with the ES from 10 patients with Ménière's disease and from 7 control cases without any pre-mortem ear diseases except a case of acoustic tumor. These 10 patients underwent the ES surgery. The presence of herpes family virus DNA, such as herpes simplex virus types 1 and 2 (HSV1&2), varicella-zoster virus (VZV), Epstein-Barr virus (EBV) and human cytomegalovirus (CMV), was examined using the in situ hybridization method. Serum antibody titers against these viruses just before the ES surgery were studied in these patients. Of the 10 specimens from the patients with Ménière's disease, 7 were positive for VZV, 4 for EBV, 1 for CMV and none for HSV1&2, although the serum antibody titers against these viruses did not show any significant elevation in these patients just before the ES surgery. This result suggests that the viral DNA in the ES is inactive and is present in a latent form. From the statistical analysis, it can be postulated that VZV infection in early childhood may reach the ES and play a role in the pathogenesis of Ménière's disease (p = 0.0235). The double infection with both VZV and EBV tended to be another candidate for the pathogenesis of Ménière's disease (p = 0.0557).

Herpesvirus DNA in peripheral blood mononuclear cells of some patients with Meniere's disease.

Herpes simplex virus-1 (HSV) or varicella zoster virus (VZV) DNA was detected by nested polymerase chain reaction in peripheral blood mononuclear cells of patients with Meniere's disease (one of 28 patients for HSV-1, 2 of 28 patients for VZV) during acute illness (within 5 days after onset). On the other hand, neither HSV-1 DNA or VZV DNA was detected in PBMCs of 50 age- and sex-matched healthy individuals and 50 pregnant women. These findings may imply that reactivation of HSV- 1 or VZV may be associated with the development of some cases of Meniere's disease.

Detection of viral DNA in vestibular ganglia tissue from patients with Menière's disease.

OBJECTIVE: The main goal of this study was to examine the vestibular ganglia from 11 patients with intractable classic Menière's disease (MD) for the presence or absence of DNA from three neurotropic viruses (herpes simplex virus, cytomegalovirus, and varicella zoster virus) using exquisitely sensitive molecular biologic techniques. STUDY DESIGN: This was a prospective controlled study with vestibular ganglia from patients with MD and from patients with small vestibular schwannomas undergoing resection. Polymerase chain reaction was used for viral DNA detection from the ganglia along with known positive and negative polymerase chain reaction control subjects. SETTING: The study was performed in an academic tertiary referral center. PATIENTS: Patients for inclusion had medically uncontrolled MD, including documented fluctuating sensorineural hearing loss, episodic vertigo, and tinnitus who elected to undergo vestibular nerve section. Control patients were undergoing vestibular schwannoma removal. INTERVENTIONS: The intervention was vestibular nerve section with removal of vestibular ganglion. MAIN OUTCOME MEASURES: The presence or absence of viral DNA (herpes simplex virus, cytomegalovirus, and varicella zoster virus) in vestibular ganglion tissues detected by polymerase chain reaction. RESULTS: No viral DNA was detected in the vestibular ganglia of patients with MD (p = 0.028) nor in the control group. The likelihood of a type II or beta type error was < 10%. CONCLUSIONS: In patients with MD requiring surgical intervention, infection with herpes simplex virus, cytomegalovirus, or varicella zoster virus of the vestibular ganglia does not appear to play a major role in the pathoetiology of the disease.

Herpes simplex virus antibodies in the perilymph of patients with Menière disease.

OBJECTIVE: To evaluate the presence of IgG antibodies directed to herpes simplex virus (HSV) in the perilymph of patients with Menière disease. DESIGN: Antibodies to HSV, Epstein-Barr virus, cytomegalovirus, and measles virus were analyzed in serum and perilymph samples by enzyme-linked immunosorbent assay. Total IgG and albumin in serum and perilymph samples were measured by nephelometer analysis. The relation of specific antivirus IgG in the perilymph vs the serum was expressed as an index. PATIENTS: Perilymph and serum samples from 7 patients with long-standing, disabling Menière disease were collected during therapeutic vestibulotomy. Perilymph and serum samples from 7 patients with otosclerosis and 2 recipients of cochlear implants were used as controls. RESULTS: Compared with the corresponding serum sample, the perilymph from the patients with Menière disease disclosed a higher level of specific anti-HSV IgG. An elevated level of specific anti-measles virus IgG in the perilymph was detected in patients with otosclerosis. Patients of all groups showed no variation of specific anti-Epstein Barr virus IgG and anti-cytomegalovirus IgG in the serum or in the perilymph. CONCLUSIONS: Our results show the presence of HSV IgG in the perilymph of patients with Menière disease and support the hypothesis that HSV may play an important role in the etiopathogenesis of Menière disease.

Molecular and cellular pathology of Meniere's disease.

The etiopathogenesis of Meniere's disease has remained controversial since the early 1900s. Many investigators have studied the molecular and cellular pathology of the inner ear in patients with this disorder. Three basic pathologic mechanisms have emerged; fibrosis of the endolymphatic sac and vestibular epithelia, altered glycoprotein metabolism, and immune-mediated inner ear disease. This article reviews the current understanding of these three basic pathologic processes.

Patients with Meniére's disease possess IgE reacting with herpes family viruses.

OBJECTIVE: To determine if patients with Meniere's disease possess serum IgE specific for herpes simplex virus (HSV) type 1, HSV type 2, Epstein-Barr virus, and/or cytomegalovirus. DESIGN: A modified radioallergosorbent test method was employed wherein each serum sample was processed with recombinant protein A to remove competing non-IgE antibodies, and HSV-1, HSV-2, cytomegalovirus, and Epstein-Barr viral proteins were used as potential antigens. PATIENTS: Ten patients with long-standing active Meniere's disease were tested. Ten age- and gender-matched patients with allergic rhinitis but without Meniere's disease served as control subjects. RESULTS: IgE specific for HSV-1, HSV-2, Epstein-Barr virus, and/or cytomegalovirus was found in the serum sample of nine of 10 patients with Meniere's disease but only in four of 10 control serum samples. Of the positive subjects tested, seven patients with Meniere's disease were positive for IgE for at least three viruses compared with only two control subjects. CONCLUSIONS: (1) Most patients with Meniere's disease possess virus-specific IgE in their serum samples; (2) four viruses of the herpes family are capable of inducing such IgE-mediated sensitization; and (3) latent virus-specific, IgE-mediated inflammation may be an important factor in the initiation and/or sustenance of Meniere's disease.

Detection of viral DNA in endolymphatic sac tissue from Menière's disease patients.

Neurotropic viruses have been postulated to play a role in the development of Menière's disease (MD). The purpose of this study was to evaluate the endolymphatic sacs of patients undergoing surgery for MD in a single-blind study for evidence of herpes simplex virus (HSV), varicella zoster (VZ), or cytomegalovirus (CMV) DNA. Polymerase chain reaction (PCR) was used as the method of detection because of its sensitivity, specificity, and applicability to fresh, as well as fixed tissues. Twenty-two patients with MD and 11 control patients with vestibular schwannomas had a portion of the endolymphatic sac removed at the time of surgery. The specimens were then evaluated for herpes simplex type and 2, varicella zoster, and cytomegalovirus DNA. Herpes simplex virus DNA was detected in 2 of the 22 extracts from the endolymphatic sacs obtained from patients with MD. There was no evidence of a positive signal obtained with any of the other viral DNA probes when PCR was performed on the control tissue extracts or the other MD tissue extracts. These results do not demonstrate a significant difference and do not statistically support the postulate that ongoing viral infection in the endolymphatic sac is a frequent factor in the development of Menière's disease.