Pathogenesis of Meniere's disease and Meniere's syndrome

Therapeutic Response of Meniere's Disease Utilizing Sorbus domestica

Introduction Meniere's disease (MD) is a chronic condition characterized by episodic attacks of vertigo, fluctuating hearing loss, and tinnitus. MD can impart a significant socioeconomic impact with associated progressive hearing loss. First-line therapies consist of diuretics and antihistamines, with second-line therapies including intratympanic steroids and pulse therapy. Third-line treatments include endolymphatic sac surgery (ELSS) followed by intratympanic gentamicin injection and/or vestibular neurectomy. The gemmotherapy Sorbus domestica's inherent properties to regulate venous circulation and lymphatic drainage have been utilized in the European literature for the treatment of MD and the patients in this study. Methods Patients presenting for rehabilitation at Pulaski Health and Rehabilitation Facility with a history of vertigo were examined and, through history and specific exam, to define MD. This resulted in six patients whose symptoms and exam were consistent with MD and interfered with their therapeutic progression. These patients were offered and accepted treatment with Sorbus domestica for their MD. Results All patients responded with either resolution or significant improvement in their symptoms and hearing loss. Treatment also resulted in an improved and probably shortened rehabilitative course. All patients had no adverse reactions and were supplied with resources for continual treatment upon discharge. Conclusion Sorbus domestica is a safe and viable treatment option for MD. It has been useful, especially in treatment-resistant diseases, without side effects and can be utilized in initial cases with improvement or resolution of hearing loss.

Hydropic Ear Disease: Correlation Between Audiovestibular Symptoms, Endolymphatic Hydrops and Blood-Labyrinth Barrier Impairment

Research Objective: To investigate the correlation between clinical features and MRI-confirmed endolymphatic hydrops (EH) and blood-labyrinth barrier (BLB) impairment. Study Design: Retrospective cross-sectional study. Setting: Vertigo referral center (Haga Teaching Hospital, The Hague, the Netherlands). Methods: We retrospectively analyzed all patients that underwent 4 h-delayed Gd-enhanced 3D FLAIR MRI at our institution from February 2017 to March 2019. Perilymphatic enhancement and the degree of cochlear and vestibular hydrops were assessed. The signal intensity ratio (SIR) was calculated by region of interest analysis. Correlations between MRI findings and clinical features were evaluated. Results: Two hundred and fifteen patients with MRI-proven endolymphatic hydrops (EH) were included (179 unilateral, 36 bilateral) with a mean age of 55.9 yrs and median disease duration of 4.3 yrs. Hydrops grade is significantly correlated with disease duration (P < 0.001), the severity of low- and high-frequency hearing loss (both P < 0.001), and the incidence of drop attacks (P = 0.001). Visually increased perilymphatic enhancement was present in 157 (87.7%) subjects with unilateral EH. SIR increases in correlation with hydrops grade (P < 0.001), but is not significantly correlated with the low or high Fletcher index (P = 0.344 and P = 0.178 respectively). No significant differences were found between the degree of EH or BLB impairment and vertigo, tinnitus or aural fullness. Conclusion: The degree of EH positively correlates with disease duration, hearing loss and the incidence of drop attacks. The BLB is impaired in association with EH grade, but without clear contribution to the severity of audiovestibular symptoms.

Is Menière's Disease a Contraindication to Stapedectomy?

OBJECTIVE

Review surgical outcomes of stapedectomy for otosclerosis in patients with Menierè's disease.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

Patients with otosclerosis and Menière's disease undergoing stapedectomy between 2010 and 2017.

INTERVENTION

Stapedectomy.

MAIN OUTCOME MEASURES

Pre- and postoperative hearing and complications. Hearing was measured by air conduction (AC) and bone conduction (BC) pure-tone frequency, pure-tone averages (PTA), air-bone gap (ABG), and word recognition scores (WRS).

RESULTS

Among 1,499 patients with otosclerosis, the incidence of concomitant Menière's disease was 1.7%. Fifteen patients with otosclerosis and Menière's disease underwent stapedectomy, 12 primary and three revisions. Mean AC PTA was 43 dB preoperatively, and 25 dB postoperatively (p = 0.0007), while the ABG improved on average from 20 to 5 dB (p = 0.0001). There was no significant difference in BC PTA or WRS postoperatively. Two patients experienced fluctuation of hearing in the postoperative period, one of which resolved with a course of steroids. The mean follow-up time was 41 months.

CONCLUSIONS

In patients with otosclerosis and Menière's disease, stapedectomy provides excellent hearing outcomes in a majority of patients. As is characteristic of Menière's disease, some patients will continue to experience fluctuating hearing postoperatively, which may progress to severe sensorineural hearing loss. Menière's disease may not be an absolute contraindication to stapes surgery.

Autoimmune vertigo: an update on vestibular disorders associated with autoimmune mechanisms

The role of the immune system in mediating cochleovestibular pathologies has received increasing attention in recent years. Autoimmune vertigo may be an invalidating condition and may worsen the quality of life of affected patients, especially in the cases of delayed diagnosis. Since the etiopathogenesis is still not clear, also the treatment is not yet completely delineated. According to the clinical presentation, autoimmune vertigo can present as an isolated disorder or in association with systemic autoimmune diseases. The main feature in autoimmune vertigo is the presence of an abnormal immune response, in either absence or presence of systemic autoimmune disease, directed against delicate components of the inner ear. This may determine a functional or anatomical alteration, with an inflammatory reaction often devastating for hearing and balance. Being the exact pathogenesis unknown, the diagnosis of autoimmune vertigo is based either on clinical criteria or on a positive response to steroids. The earlier the diagnosis is made, the sooner the therapy can be installed, giving a chance to the recovery of inner ear damages. Corticosteroids represent the most effective and universally accepted treatment, even if other immunomodulatory drugs are now having a more extensive use. HIGHLIGHTS: Vertigo is relatively frequent in autoimmune diseases; however, it is often misdiagnosed or attributed to central nervous system alterations rather to specific inner ear involvement. Vertigo and other audiovestibular symptoms may be the first manifestation of an autoimmune disease and if correctly addressed could significantly contribute to early diagnosis of the underlying autoimmune disease. Early diagnosis of immune-related vertigo can lead to prompt initiation of targeted therapy with elevate chances of preventing irreversible damages to the inner ear. The presence of alternating phases of well-being and disabling symptoms in patients with vertigo should always been considered, as they could suggest an underlying autoimmune condition.

Intratympanic Sustained-Exposure Dexamethasone Thermosensitive Gel for Symptoms of Ménière's Disease: Randomized Phase 2b Safety and Efficacy Trial

OBJECTIVE

To evaluate safety and efficacy of a single intratympanic injection of OTO-104, sustained-exposure dexamethasone, in patients with unilateral Ménière's disease.

STUDY DESIGN

Randomized, double-blind, placebo-controlled, Phase 2b study over 5 months.

SETTING

Fifty-two academic and community otolaryngology centers.

PATIENTS

One hundred fifty four patients (77 per group) aged 18 to 85 years inclusive.

INTERVENTION

Single intratympanic injection of OTO-104 (12 mg dexamethasone) or placebo.

MAIN OUTCOME MEASURES

Efficacy (vertigo) and safety (adverse events, otoscopy, audiometry, tympanometry).

RESULTS

Primary endpoint (change from baseline in vertigo rate at Month 3) was not statistically significant (placebo [-43%], OTO-104 [-61%], P = 0.067). Improvements with OTO-104 were observed in prospectively defined secondary endpoints number of days with definitive vertigo, (Month 2 [P = 0.035], Month 3 [P = 0.030]), vertigo severity (Months 2-3, P = 0.046) and daily vertigo counts (Month 2, P = 0.042), and in some Short Form-36 (SF-36) subscales (Month 2 bodily pain P = 0.039, vitality P = 0.045, social functioning P = 0.025). No difference in tinnitus loudness or tinnitus handicap inventory (THI-25) was observed. OTO-104 was well tolerated; no negative impact on safety compared with placebo. Persistent tympanic membrane perforation was observed in two OTO-104 treated patients at study end.

CONCLUSION

OTO-104 was well-tolerated, did not significantly affect change from baseline in vertigo rate, but did reduce number definitive vertigo days, vertigo severity, and average daily vertigo count compared with placebo during Month 3. Results provide insight into analyzing for a vertigo treatment effect and support advancing OTO-104 into Phase 3 clinical trials for the treatment of Ménière's disease symptoms.

Tone Burst Electrocochleography for the Diagnosis of Clinically Certain Meniere's Disease

The technique of transtympanic electrocochleography was initially developed as an objective hearing threshold test by Eggermont. Gibson et al. (1977) claimed that an enlarged direct current component of the action potential (AP) called the summating potential (SP) is an indication of endolymphatic hydrops, later confirmed by Coates who proposed an SP/AP ratio measure. This led to numerous publications using diagnostic ratios of 0.33-0.35. The insensitivity led to an eventual disenchantment with the test as a reliable objective test for Meniere's disease. It was further confused by audiologists employing remote canal or ear drum electrodes which give a response about one-fourth of the magnitude obtained by an electrode in contact with the cochlea. Subsequently Gibson stated that an SP/AP ratio of <0.5 is not diagnostic for hydrops. He then showed that a tone burst stimulus gave the test a significantly higher sensitivity and specificity, which has been supported by others. On MRI inner ear imaging with gadolinium hydrops can be seen, but the quality of images and what is seen may vary according to brand of scanner, settings, mode of gadolinium administration, and the possibility that gadolinium entry may favor the vestibule. Transtympanic tone burst electrocochleography is to date the simplest, cheapest and most sensitive technique for detecting cochlear endolymphatic hydrops to confirm a diagnosis of Meniere's disease.

A three-dimensional analysis of the endolymph drainage system in Ménière disease

OBJECTIVES/HYPOTHESIS

To measure the volume of the endolymph drainage system in temporal bone specimens with Ménière disease, as compared with specimens with endolymphatic hydrops without vestibular symptoms and with nondiseased specimens STUDY DESIGN: Comparative human temporal bone analysis.

METHODS

We generated three-dimensional models of the vestibular aqueduct, endolymphatic sinus and duct, and intratemporal portion of the endolymphatic sac and calculated the volume of those structures. We also measured the internal and external aperture of the vestibular aqueduct, as well as the opening (if present) of the utriculoendolymphatic (Bast's) valve and compared the measurements in our three study groups.

RESULTS

The volume of the vestibular aqueduct and of the endolymphatic sinus, duct, and intratemporal endolymphatic sac was significantly lower in the Ménière disease group than in the endolymphatic hydrops group (P <.05). The external aperture of the vestibular aqueduct was also smaller in the Ménière disease group. Bast's valve was open only in some specimens in the Ménière disease group.

CONCLUSIONS

In temporal bones with Ménière disease, the volume of the vestibular aqueduct, endolymphatic duct, and intratemporal endolymphatic sac was lower, and the external aperture of the vestibular aqueduct was smaller as compared with bones from donors who had endolymphatic hydrops without vestibular symptoms and with nondiseased bones. The open status of the Bast's valve in the Ménière disease group could be secondary to higher retrograde endolymph pressures caused by smaller drainage systems. These anatomic findings could correlate with the reason that some patients with hydrops develop clinical symptoms, whereas others do not.

LEVEL OF EVIDENCE

N/A Laryngoscope, 127:E170-E175, 2017.

Diagnostic Value of Vestibular Evoked Myogenic Potentials in Endolymphatic Hydrops: A Meta-Analysis

In this study, we evaluated the clinical diagnostic value of vestibular evoked myogenic potentials (VEMPs) for endolymphatic hydrops (EH) by systematic review and Meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio and area under summary receiver operating characteristic curves (AUC) were calculated. Subgroup analysis and publication bias assessment were also conducted. The pooled sensitivity and the specificity were 49% (95% CI: 46% to 51%) and 95% (95% CI: 94% to 96%), respectively. The pooled positive likelihood ratio was 18.01 (95% CI: 9.45 to 34.29) and the pooled negative likelihood ratio was 0.54 (95% CI: 0.47 to 0.61). AUC was 0.78 and the pooled diagnostic odds ratio of VEMPs was 39.89 (95% CI: 20.13 to 79.03). In conclusion, our present meta-analysis has demonstrated that VEMPs test alone is not sufficient for Meniere’s disease or delayed endolymphatic hydrops diagnosis, but that it might be an important component of a test battery for diagnosing Meniere’s disease or delayed endolymphatic hydrops. Moreover, VEMPs, due to its high specificity and non-invasive nature, might be used as a screening tool for EH.

A Genetic Murine Model of Endolymphatic Hydrops: The Phex Mouse

Animal models of endolymphatic hydrops (ELH) provide critical insight into the pathophysiology of Meniere's disease (MD). A new genetic murine model, called the Phex mouse, circumvents prior need for a time and cost-intensive surgical procedure to create ELH. The Phex mouse model of ELH, which also has X-linked hypophosphatemic rickets, creates a postnatal, spontaneous, and progressive ELH whose phenotype has a predictable decline of vestibular and hearing function reminiscent of human MD. The Phex mouse enables real-time histopathologic analysis to assess diagnostic and therapeutic interventions as well as further our understanding of ELH's adverse effects. Already the model has validated electrocochleography and cervical vestibular evoked myogenic potential as useful diagnostic tools. New data on caspase activity in apoptosis of the spiral ganglion neurons may help target future therapeutic interventions. This paper highlights the development of the Phex mouse model and highlights its role in characterizing ELH.

A mouse model validates the utility of electrocochleography in verifying endolymphatic hydrops

Endolymphatic hydrops (ELH) is a disorder of the inner ear that causes tinnitus, vertigo, and hearing loss. An elevated ratio of the summating potential (SP) to the action potential (AP) measured by electrocochleography has long been considered to be the electrophysiological correlate of ELH-related clinical conditions, such as Meniere's disease, but in vivo confirmation and correlation between an elevated SP/AP ratio and ELH has not yet been possible. Confirming this relationship will be important to show that elevated SP/AP ratio is indeed diagnostic of ELH. Here, we sought to confirm that an elevated SP/AP ratio is associated with ELH and test the hypothesis that severity of ELH and hearing loss would also correlate with the SP/AP ratio in vivo using the Phex(Hyp-Duk)/Y mouse model of postnatal ELH. In addition, we describe a minimally invasive approach for electrocochleography in mice. Auditory brainstem responses and electrocochleography data were collected from controls and Phex(Hyp-Duk)/Y mutants at postnatal day 21 and the mice (all male) were euthanized immediately for cochlear histology. Our results show that (1) the SP/AP ratio was significantly elevated in mice with histological ELH compared to controls, (2) the SP/AP ratio was not correlated with the severity of histological ELH or hearing loss, and (3) the severity of hearing loss correlated with the severity of histological ELH. Our study demonstrates that an elevated SP/AP ratio is diagnostic of ELH and that the severity of hearing loss is a better predictor of the severity of ELH than is the SP/AP ratio.

Chronic daily headaches secondary to greater auricular and lesser occipital neuromas following endolymphatic shunt surgery

In head and neck surgery, peripheral sensory nerves are at risk for traumatic injury. These injuries are known to be peripheral triggers of chronic headaches if left untreated or unrecognised. We report the case of a patient that presented with a severe headache, nausea and emesis of 2 years duration following endolymphatic shunt placement for Meniere's disease. Nerve blockade suggested a peripheral trigger, and surgical exploration of the incision site revealed traumatic neuromas of the greater auricular and lesser occipital nerves. Subsequent nerve resection yielded complete symptomatic relief. This is the first case report of a peripherally triggered migraine headache due to the development of neuromas of the greater auricular and lesser occipital nerves, also representing a previously unreported complication of endolymphatic shunt placement. It is recommended that in patients presenting with intractable migraines and a history of head and neck surgery, diagnostic nerve blockage be used to assess for neuromas.

Immunohistochemical localization and mRNA expression of aquaporins in the macula utriculi of patients with Meniere's disease and acoustic neuroma

Meniere's disease is nearly invariably associated with endolymphatic hydrops (the net accumulation of water in the inner ear endolymphatic space). Vestibular maculae utriculi were acquired from patients undergoing surgery for Meniere's disease and acoustic neuroma and from autopsy (subjects with normal hearing and balance). Quantitative immunostaining was conducted with antibodies against aquaporins (AQPs) 1, 4, and 6, Na(+)K(+)ATPase, Na(+)K(+)2Cl co-transporter (NKCC1), and alpha-syntrophin. mRNA was extracted from the surgically acquired utricles from subjects with Meniere's disease and acoustic neuroma to conduct quantitative real-time reverse transcription with polymerase chain reaction for AQP1, AQP4, and AQP6. AQP1 immunoreactivity (-IR) was located in blood vessels and fibrocytes in the underlying stroma, without any apparent alteration in Meniere's specimens when compared with acoustic neuroma and autopsy specimens. AQP4-IR localized to the epithelial basolateral supporting cells in Meniere's disease, acoustic neuroma, and autopsy. In specimens from subjects with Meniere's disease, AQP4-IR was significantly decreased compared with autopsy and acoustic neuroma specimens. AQP6-IR occurred in the sub-apical vestibular supporting cells in acoustic neuroma and autopsy samples. However, in Meniere's disease specimens, AQP6-IR was significantly increased and diffusely redistributed throughout the supporting cell cytoplasm. Na(+)K(+)ATPase, NKCC1, and alpha-syntrophin were expressed within sensory epithelia and were unaltered in Meniere's disease specimens. Expression of AQP1, AQP4, or AQP6 mRNA did not differ in vestibular endorgans from patients with Meniere's disease. Changes in AQP4 (decreased) and AQP6 (increased) expression in Meniere's disease specimens suggest that the supporting cell might be a cellular target.

A mouse model with postnatal endolymphatic hydrops and hearing loss

Endolymphatic hydrops (ELH), hearing loss and neuronal degeneration occur together in a variety of clinically significant disorders, including Meniere's disease (MD). However, the sequence of these pathological changes and their relationship to each other are not well understood. In this regard, an animal model that spontaneously develops these features postnatally would be useful for research purposes. A search for such a model led us to the Phex Hyp-Duk mouse, a mutant allele of the Phex gene causing X-linked hypophosphatemic rickets. The hemizygous male (Phex Hyp-Duk/Y) was previously reported to exhibit various abnormalities during adulthood, including thickening of bone, ELH and hearing loss. The reported inner-ear phenotype was suggestive of progressive pathology and spontaneous development of ELH postnatally, but not conclusive. The main focuses of this report are to further characterize the inner ear phenotype in Phex Hyp-Duk/Y mice and to test the hypotheses that (a) the Phex Hyp-Duk/Y mouse develops ELH and hearing loss postnatally, and (b) the development of ELH in the Phex Hyp-Duk/Y mouse is associated with obstruction of the endolymphatic duct (ED) due to thickening of the surrounding bone. Auditory brainstem response (ABR) recordings at various times points and histological analysis of representative temporal bones reveal that Phex Hyp-Duk/Y mice typically develop adult onset, asymmetric, progressive hearing loss closely followed by the onset of ELH. ABR and histological data show that functional degeneration precedes structural degeneration. The major degenerative correlate of hearing loss and ELH in the mutants is the primary loss of spiral ganglion cells. Further, Phex Hyp-Duk/Y mice develop ELH without evidence of ED obstruction, supporting the idea that ELH can be induced by a mechanism other than the blockade of longitudinal flow of endolymphatic fluid, and occlusion of ED is not a prerequisite for the development of ELH in patients.