Contemporary perspectives on the pathophysiology of Meniere's disease: implications for treatment

Trends in Procedural Management of Meniere's Disease: Analysis of a National Insurance Claims Database

Objective

This study used a national insurance claims database to analyze trends in procedural management of Meniere's disease.

Study Design

Retrospective cohort analysis.

Setting

Database study using United States inpatient and outpatient insurance claims submitted from January 2003 to December 2021.

Subjects and Methods

The Merative MarketScan Commercial and Medicare Claims Databases were queried for adults (≥18 years) with a diagnosis of Meniere's Disease according to International Classification of Diseases codes. Patients receiving procedures per Current Procedural Terminology codes for endolymphatic sac surgery, vestibular nerve section, labyrinthectomy, and intratympanic dexamethasone or gentamicin were identified. Temporal trends were analyzed by calculating annual percent change (APC) in the proportion of patients receiving procedures using Joinpoint regression.

Results

A total of 16,523 unique patients with MD receiving procedural management were identified. From 2003 to 2021, the proportion of patients managed with intratympanic dexamethasone increased (APC 1.76 [95% CI 1.53-1.98], P < .001). The proportion of patients receiving intratympanic gentamicin increased from 2003 to 2015 (APC 4.43 [95% CI 1.29-7.66], P = .008) but decreased from 2015 to 2021 (APC -10.87 [95% CI -18.31 to -2.76], P = .013). The proportion of patients receiving endolymphatic sac surgery (APC: -10.20 [95% CI -11.19 to -9.20], P < .001) and labyrinthectomy (APC: -6.29 [95% CI -8.12 to -4.42], P < .001) decreased from 2003 to 2021.

Conclusion

From 2003 to 2021, there has been an increase in the use of intratympanic dexamethasone and a decrease in the use of intratympanic gentamicin, endolymphatic sac surgery, and labyrinthectomy for procedural management of Meniere's Disease.

Placebo effect in randomized controlled trials for Meniere's disease: A meta-analysis

PURPOSE

Meniere's Disease is a condition known for its recurrent vertigo, fluctuating sensorineural hearing loss, aural fullness, and tinnitus. Previous studies have demonstrated significant influence of placebo treatments. Our objective was to quantify the magnitude of the placebo effect in randomized controlled trials for Meniere's Disease.

MATERIALS AND METHODS

A systematic review was performed by searching PubMed, SCOPUS, CINAHL, and Cochrane databases from inception through September 27, 2022. Data extraction, quality rating, and risk of bias assessment were performed by two independent reviewers. A meta-analysis of mean differences with 95 % confidence interval, weighted summary proportions, and proportion differences were calculated using random and fixed effects models.

RESULTS

A total of 15 studies (N = 892) were included in the review. Significant improvement was seen in the functional level scores of the pooled placebo groups, with a mean difference of -0.6 points, (95%CI: -1.2 to -0.1). There was no difference in pure tone audiometry, speech discrimination score, or vertigo frequency at 1 and 3 months for the placebo group. Patient-reported vertigo episodes were improved in 52.5 % (95%CI: 39.2 to 65.5) of the placebo group and was significantly less than the pooled experimental group (90.1 %, 95%CI: 39.2 to 65.5, p < 0.001).

CONCLUSIONS

The placebo effect in Meniere's Disease trials is associated with some symptomatic improvement in subjective outcomes, such as patient reported vertigo episodes. However, the clinical significance is questionable across other outcomes measures, especially when analyzing objective data. The extent and strength of the placebo effect continues to be a hurdle in the search for better treatment options.

Diagnostic Role of Combined Electrocochleography and Pure-Tone Audiometry Monitoring During Dehydrating Test in Ménière's Disease: A Case Series

OBJECTIVES

To evaluate the diagnostic role of combined electrocochleography and pure-tone audiometry monitoring during dehydrating test in Ménière's disease and consider its suitability as a diagnostic tool to differentiate those patients with unclear differential diagnosis and therefore identify those with clear endolymphatic hydrops responsive to dehydrating test. To study the efficacy of dehydrating therapy on vertiginous symptoms and hearing loss in patients with Ménière's disease.

STUDY DESIGN

Prospective case series.

SETTINGS

University hospital, secondary referral center.

PATIENTS

Thirty patients, 20 women and 10 men, age range of 25 to 75 years, matching the criteria for definite Ménière's disease according to the Barany Society classification.

INTERVENTION

Diagnostic. During an active phase of the disease, electrocochleography and pure-tone audiometry were performed, and repeated at 30th, 45th, and 60th minutes after intramuscular injection of 40 mg furosemide and 40 mg methylprednisolone.

MAIN OUTCOME MEASURE

Data related to symptoms, electrocochleography, and pure-tone audiometry during the dehydrating test were collected at different times and statistically analyzed.

RESULTS

After the administration of dehydrating therapy, we observed that both summating potential and action potential ratio and summating potential and action potential area ratio were normalized in 21 of 30 subjects. Furthermore, pure-tone audiometry thresholds improved significantly. An improvement of ear fullness was also observed, whereas tinnitus unchangeably persisted.

CONCLUSIONS

The monitoring of the electrocochleography and pure-tone audiometry thresholds during dehydrating tests with furosemide and methylprednisolone could allow to detect an improvement of instrumental features and clinical symptoms related to endolymphatic hydrops, and therefore, it could be used as a diagnostic tool in the identification of those patients affected by Ménière's disease with unclear differential diagnosis.

Hearing Outcomes Following Endolymphatic Duct Blockage Surgery and Factors Associated with Improved Audition at Two Years Follow-Up

Objective: To evaluate hearing outcomes at 2 years post endolymphatic duct blockage (EDB) surgery, with an analysis of factors that may predict hearing improvement. Study Design: Retrospective comparative study. Setting: Tertiary care center. Subjects: Definite Ménière's Disease (MD) patients undergoing EDB for refractory disease. Methods: Chart review was conducted to assign cases to one of the three hearing outcome groups (deteriorated, stable, and improved). All cases that met our inclusion criteria were selected. Preoperative data collected were audiograms, bithermal caloric tests, preoperative vertigo episodes, history of previous ear surgery for Ménière, intratympanic steroid injections (ITS) and intraoperative endolymphatic sac (ELS) tear or opening. Postoperative data collected at 24 months were audiograms, vertigo episodes and bithermal caloric testing. Results: Preoperative vertigo episodes, caloric paresis and history of surgery, ITS injections or ELS integrity, as well as postoperative vertigo class distribution and caloric paresis changes were not different between our groups. Preoperative word recognition score (WRS) was lowest in the improved hearing group (p = 0.032). The persistence of tinnitus at 2 years postoperatively was associated with deteriorated hearing (p = 0.033). Conclusions: There are no strong predictors of hearing improvement on presentation pre-EDB, but low preoperative WRS may be the best estimator available. Therefore, ablative interventions should be considered very carefully in patients presenting with low WRS, as they may benefit more from EDB; there is a fair chance of a good hearing outcome with EDB surgery. Persistence of tinnitus can reflect deteriorating audition. Vertigo control and hearing preservation are independent outcomes of EDB surgery, making it desirable as an early intervention for refractory MD cases.

Magnetic resonance imaging of endolymphatic hydrops in Ménière's disease: A comparison of the diagnostic value of multiple scoring methods

Objectives

To compare three methods of scoring endolymphatic hydrops in patients with Ménière's disease in order to assess the correlation between endolymphatic hydrops and auditory characteristics.

Methods

A retrospective study of 97 patients with unilateral definite Ménière's disease (DMD) who underwent contrast-enhanced three-dimensional fluid attenuated inversion recovery (3D FLAIR) MRI. Each patient was scored by the Inner Ear Structural Assignment Method (IESAM), the Saccule to utricle area ratio (SURI), and the Four Stage Vestibular Hydrops Grading (FSVH), according to their corresponding axial images. Cohen's Kappa and intra-class correlation coefficient were used for consistency testing, combined with binary logistic regression analysis, to compare the sensitivity and specificity of the three methods. The degree of hydrops in different stages of MD was compared. The correlation between endolymphatic hydrops in the inner ear sub-units and hearing thresholds was further analyzed.

Results

The intra- and inter-reader reliability for the scoring of endolymphatic hydrops were excellent. The IESAM had a high diagnostic value for identifying definite Ménière's disease (sensitivity: 86.6%, specificity: 97.9%). The hearing thresholds were correlated with the degree of endolymphatic hydrops. Stages 3 and 4 were more significant for the severity of hydrops than stage 1. Within the subgroups of the Ménière's disease patients, compared with the non-hydrops group and the pure vestibular hydrops (V group), the cochlear combined vestibular hydrops group (CV group) had significantly higher auditory thresholds. The amplitude ratio of electrocochleogram was significantly higher in the affected ear than in the healthy ear.

Conclusion

The IESAM is a more sensitive and specific diagnostic scoring method for the diagnosis of DMD. Diagnostic imaging may improve the detection of inner ear hydrops which is correlated with severity of hearing loss. A comprehensive evaluation of the inner ear sub-unit structures maybe necessary.

Expression of circadian clock genes in leukocytes of patients with Meniere's disease

Objectives

The underlying etiology of Meniere's disease (MD) is not completely clear, but the precipitated triggers may alter the circadian clock in patients with MD. This study aims to survey the expression of circadian clock genes in peripheral blood (PB) leukocytes of MD patients.

Methods

We investigated the expression of nine circadian clock genes in the PB leukocytes of patients with MD and normal controls using real‐time quantitative reverse transcriptase‐polymerase chain reaction (qRT‐PCR).

Results

We observed significantly lower expression of PER1 gene and higher expression of CLOCK gene in MD patients than those in normal controls (p < 0.05). PER1 did not associate with the degree of dizziness handicap in the patients with MD, but a lower expression of PER1 was significantly correlated with higher pure tone average (PTA) and speech reception threshold of the affected ear (p < 0.05). Patients with PTA > 30 dB had significantly lower PER1 expression than those with PTA ≤30 dB in the affected ear (p < 0.05). Our qRT‐PCR result was validated by fewer positively stained leukocytes for PER1 protein in the MD patients using the immunocytochemical study.

Conclusion

Our study implies the alteration of the circadian clock in patients with MD. In particular, the downregulation of PER1 correlated with the degree of hearing loss in the affected ear. PER1 in PB leukocytes may be a potential marker for the progression of hearing loss in MD.

Association between Statin Use and Meniere's Disease: Results from a National Health Screening Cohort

The protective effects of statins against inner ear diseases have been suggested. This study investigated the relationship between previous statin use and the occurrence of Meniere’s disease (MD). Participants ≥40 years old in the Korean National Health Insurance Service-Health Screening Cohort 2002–2015 were enrolled. A total of 7734 MD participants were matched with 38,670 comparison participants. The dates of statin prescriptions for the 2 years before the onset of MD were examined. A conditional logistic regression analysis was performed to estimate the odds ratios (ORs) of statin use for MD. Regarding the different types of statins, lipophilic statins, but not hydrophilic statins, were associated with lower odds of MD in the <65 year-old group (adjusted OR = 0.81, 95% CI = 0.68–0.97, p = 0.023). Prior statin use did not show association with MD in the adult population. Regarding the different types of statins, lipophilic statin use was related to a lower rate of MD in a middle-aged population.

Effectiveness of endolymphatic duct blockage versus endolymphatic sac decompression in patients with intractable Ménière's disease: study protocol for a double-blinded, randomised controlled trial

INTRODUCTION

Outcomes of surgery for Ménière's disease (MD) remain discordant. Recently, a new surgical procedure in which the endolymphatic duct is clipped was proposed. To date, only one prospective trial assessing this technique was published, yielding promising results. This protocol describes a prospective, double-blinded, randomised controlled trial that will be carried out to assess the effectiveness of this surgical intervention.

METHODS

Eighty-four patients with intractable MD will be recruited from 13 hospitals in the Netherlands. Intraoperatively, randomisation will determine whether endolymphatic duct blockage (EDB) or endolymphatic sac decompression (ESD) will be performed. Randomisation will be 1:1 stratified for gender and duration of MD (recent-onset versus mature MD). All participants receive vestibular rehabilitation after surgery. Patients are followed up during 1 year after surgery. Follow-up visits will take place at 1 week, 3 months, 6 months and 12 months after surgery. The main study endpoint is proportion of patients who are free of vertigo spells at 12 months postoperatively. Secondary parameters include cumulative number of vertigo bouts, co-intervention, tinnitus, hearing, quality of life, cost effectiveness and a budget impact analysis. Total duration of the study is 4 years.

ANALYSIS

The primary analysis will follow the intention-to-treat principle. For the primary outcome, a χ² test will be performed. Secondary outcomes will be analysed using a linear mixed model (EDB versus decompression group) at the different time measurement point.

ETHICS AND DISSEMINATION

This study was reviewed and approved by a board of specialists before funding was obtained, as well as by the Medical Research Ethics Committee Leiden-The Hague-Delft and the boards of all participating centres. Results of this study will be published in international peer-reviewed scientific journals and will be presented on (inter)national scientific conferences and meetings.

TRIAL REGISTRATION NUMBERS

NL9095 and ISRCTN12074571; Pre-Results.

Otorhinolaryngological adverse effects of urological drugs

PURPOSE

To describe the otorhinolaryngological adverse effects of the main drugs used in urological practice.

MATERIALS AND METHODS

A review of the scientific literature was performed using a combination of specific descriptors (side effect, adverse effect, scopolamine, sildenafil, tadalafil, vardenafil, oxybutynin, tolterodine, spironolactone, furosemide, hydrochlorothiazide, doxazosin, alfuzosin, terazosin, prazosin, tamsulosin, desmopressin) contained in publications until April 2020. Manuscripts written in English, Portuguese, and Spanish were manually selected from the title and abstract. The main drugs used in Urology were divided into five groups to describe their possible adverse effects: alpha-blockers, anticholinergics, diuretics, hormones, and phosphodiesterase inhibitors.

RESULTS

The main drugs used in Urology may cause several otorhinolaryngological adverse effects. Dizziness was most common, but dry mouth, rhinitis, nasal congestion, epistaxis, hearing loss, tinnitus, and rhinorrhea were also reported and varies among drug classes.

CONCLUSIONS

Most of the drugs used in urological practice have otorhinolaryngological adverse effects. Dizziness was most common, but dry mouth, rhinitis, nasal congestion, epistaxis, hearing loss, tinnitus, and rhinorrhea were also reported. Therefore, doctors must be aware of these adverse effects to improve adherence to the treatment and to minimize damage to the health of patients.

Clinical Practice Guideline: Ménière's Disease Executive Summary

OBJECTIVE

Ménière's disease (MD) is a clinical condition defined by spontaneous vertigo attacks (each lasting 20 minutes to 12 hours) with documented low- to midfrequency sensorineural hearing loss in the affected ear before, during, or after one of the episodes of vertigo. It also presents with fluctuating aural symptoms (hearing loss, tinnitus, or ear fullness) in the affected ear. The underlying etiology of MD is not completely clear, yet it has been associated with inner ear fluid volume increases, culminating in episodic ear symptoms (vertigo, fluctuating hearing loss, tinnitus, and aural fullness). Physical examination findings are often unremarkable, and audiometric testing may or may not show low- to midfrequency sensorineural hearing loss. Imaging, if performed, is also typically normal. The goals of MD treatment are to prevent or reduce vertigo severity and frequency; relieve or prevent hearing loss, tinnitus, and aural fullness; and improve quality of life. Treatment approaches to MD are many, and approaches typically include modifications of lifestyle factors (eg, diet) and medical, surgical, or a combination of therapies.

PURPOSE

The primary purpose of this clinical practice guideline is to improve the quality of the diagnostic workup and treatment outcomes of MD. To achieve this purpose, the goals of this guideline are to use the best available published scientific and/or clinical evidence to enhance diagnostic accuracy and appropriate therapeutic interventions (medical and surgical) while reducing unindicated diagnostic testing and/or imaging.

Clinical Practice Guideline: Ménière's Disease

OBJECTIVE

Ménière's disease (MD) is a clinical condition defined by spontaneous vertigo attacks (each lasting 20 minutes to 12 hours) with documented low- to midfrequency sensorineural hearing loss in the affected ear before, during, or after one of the episodes of vertigo. It also presents with fluctuating aural symptoms (hearing loss, tinnitus, or ear fullness) in the affected ear. The underlying etiology of MD is not completely clear, yet it has been associated with inner ear fluid (endolymph) volume increases, culminating in episodic ear symptoms (vertigo, fluctuating hearing loss, tinnitus, and aural fullness). Physical examination findings are often unremarkable, and audiometric testing may or may not show low- to midfrequency sensorineural hearing loss. Conventional imaging, if performed, is also typically normal. The goals of MD treatment are to prevent or reduce vertigo severity and frequency; relieve or prevent hearing loss, tinnitus, and aural fullness; and improve quality of life. Treatment approaches to MD are many and typically include modifications of lifestyle factors (eg, diet) and medical, surgical, or a combination of therapies.

PURPOSE

The primary purpose of this clinical practice guideline is to improve the quality of the diagnostic workup and treatment outcomes of MD. To achieve this purpose, the goals of this guideline are to use the best available published scientific and/or clinical evidence to enhance diagnostic accuracy and appropriate therapeutic interventions (medical and surgical) while reducing unindicated diagnostic testing and/or imaging.

Clinical Practice Guideline: Sudden Hearing Loss (Update)

OBJECTIVE

Sudden hearing loss is a frightening symptom that often prompts an urgent or emergent visit to a health care provider. It is frequently but not universally accompanied by tinnitus and/or vertigo. Sudden sensorineural hearing loss affects 5 to 27 per 100,000 people annually, with about 66,000 new cases per year in the United States. This guideline update provides evidence-based recommendations for the diagnosis, management, and follow-up of patients who present with sudden hearing loss. It focuses on sudden sensorineural hearing loss in adult patients aged ≥18 years and primarily on those with idiopathic sudden sensorineural hearing loss. Prompt recognition and management of sudden sensorineural hearing loss may improve hearing recovery and patient quality of life. The guideline update is intended for all clinicians who diagnose or manage adult patients who present with sudden hearing loss.

PURPOSE

The purpose of this guideline update is to provide clinicians with evidence-based recommendations in evaluating patients with sudden hearing loss and sudden sensorineural hearing loss, with particular emphasis on managing idiopathic sudden sensorineural hearing loss. The guideline update group recognized that patients enter the health care system with sudden hearing loss as a nonspecific primary complaint. Therefore, the initial recommendations of this guideline update address distinguishing sensorineural hearing loss from conductive hearing loss at the time of presentation with hearing loss. They also clarify the need to identify rare, nonidiopathic sudden sensorineural hearing loss to help separate those patients from those with idiopathic sudden sensorineural hearing loss, who are the target population for the therapeutic interventions that make up the bulk of the guideline update. By focusing on opportunities for quality improvement, this guideline should improve diagnostic accuracy, facilitate prompt intervention, decrease variations in management, reduce unnecessary tests and imaging procedures, and improve hearing and rehabilitative outcomes for affected patients.

METHODS

Consistent with the American Academy of Otolaryngology-Head and Neck Surgery Foundation's "Clinical Practice Guideline Development Manual, Third Edition" (Rosenfeld et al. Otolaryngol Head Neck Surg. 2013;148[1]:S1-S55), the guideline update group was convened with representation from the disciplines of otolaryngology-head and neck surgery, otology, neurotology, family medicine, audiology, emergency medicine, neurology, radiology, advanced practice nursing, and consumer advocacy. A systematic review of the literature was performed, and the prior clinical practice guideline on sudden hearing loss was reviewed in detail. Key Action Statements (KASs) were updated with new literature, and evidence profiles were brought up to the current standard. Research needs identified in the original clinical practice guideline and data addressing them were reviewed. Current research needs were identified and delineated.

RESULTS

The guideline update group made strong recommendations for the following: (KAS 1) Clinicians should distinguish sensorineural hearing loss from conductive hearing loss when a patient first presents with sudden hearing loss. (KAS 7) Clinicians should educate patients with sudden sensorineural hearing loss about the natural history of the condition, the benefits and risks of medical interventions, and the limitations of existing evidence regarding efficacy. (KAS 13) Clinicians should counsel patients with sudden sensorineural hearing loss who have residual hearing loss and/or tinnitus about the possible benefits of audiologic rehabilitation and other supportive measures. These strong recommendations were modified from the initial clinical practice guideline for clarity and timing of intervention. The guideline update group made strong recommendations against the following: (KAS 3) Clinicians should not order routine computed tomography of the head in the initial evaluation of a patient with presumptive sudden sensorineural hearing loss. (KAS 5) Clinicians should not obtain routine laboratory tests in patients with sudden sensorineural hearing loss. (KAS 11) Clinicians should not routinely prescribe antivirals, thrombolytics, vasodilators, or vasoactive substances to patients with sudden sensorineural hearing loss. The guideline update group made recommendations for the following: (KAS 2) Clinicians should assess patients with presumptive sudden sensorineural hearing loss through history and physical examination for bilateral sudden hearing loss, recurrent episodes of sudden hearing loss, and/or focal neurologic findings. (KAS 4) In patients with sudden hearing loss, clinicians should obtain, or refer to a clinician who can obtain, audiometry as soon as possible (within 14 days of symptom onset) to confirm the diagnosis of sudden sensorineural hearing loss. (KAS 6) Clinicians should evaluate patients with sudden sensorineural hearing loss for retrocochlear pathology by obtaining magnetic resonance imaging or auditory brainstem response. (KAS 10) Clinicians should offer, or refer to a clinician who can offer, intratympanic steroid therapy when patients have incomplete recovery from sudden sensorineural hearing loss 2 to 6 weeks after onset of symptoms. (KAS 12) Clinicians should obtain follow-up audiometric evaluation for patients with sudden sensorineural hearing loss at the conclusion of treatment and within 6 months of completion of treatment. These recommendations were clarified in terms of timing of intervention and audiometry and method of retrocochlear workup. The guideline update group offered the following KASs as options: (KAS 8) Clinicians may offer corticosteroids as initial therapy to patients with sudden sensorineural hearing loss within 2 weeks of symptom onset. (KAS 9a) Clinicians may offer, or refer to a clinician who can offer, hyperbaric oxygen therapy combined with steroid therapy within 2 weeks of onset of sudden sensorineural hearing loss. (KAS 9b) Clinicians may offer, or refer to a clinician who can offer, hyperbaric oxygen therapy combined with steroid therapy as salvage therapy within 1 month of onset of sudden sensorineural hearing loss.

DIFFERENCES FROM PRIOR GUIDELINE

Incorporation of new evidence profiles to include quality improvement opportunities, confidence in the evidence, and differences of opinion Included 10 clinical practice guidelines, 29 new systematic reviews, and 36 new randomized controlled trials Highlights the urgency of evaluation and initiation of treatment, if treatment is offered, by emphasizing the time from symptom occurrence Clarification of terminology by changing potentially unclear statements; use of the term sudden sensorineural hearing loss to mean idiopathic sudden sensorineural hearing loss to emphasize that >90% of sudden sensorineural hearing loss is idiopathic sudden sensorineural hearing loss and to avoid confusion in nomenclature for the reader Changes to the KASs from the original guideline: KAS 1-When a patient first presents with sudden hearing loss, conductive hearing loss should be distinguished from sensorineural. KAS 2-The utility of history and physical examination when assessing for modifying factors is emphasized. KAS 3-The word "routine" is added to clarify that this statement addresses nontargeted head computerized tomography scan that is often ordered in the emergency room setting for patients presenting with sudden hearing loss. It does not refer to targeted scans, such as temporal bone computerized tomography scan, to assess for temporal bone pathology. KAS 4-The importance of audiometric confirmation of hearing status as soon as possible and within 14 days of symptom onset is emphasized. KAS 5-New studies were added to confirm the lack of benefit of nontargeted laboratory testing in sudden sensorineural hearing loss. KAS 6-Audiometric follow-up is excluded as a reasonable workup for retrocochlear pathology. Magnetic resonance imaging, computerized tomography scan if magnetic resonance imaging cannot be done, and, secondarily, auditory brainstem response evaluation are the modalities recommended. A time frame for such testing is not specified, nor is it specified which clinician should be ordering this workup; however, it is implied that it would be the general or subspecialty otolaryngologist. KAS 7-The importance of shared decision making is highlighted, and salient points are emphasized. KAS 8-The option for corticosteroid intervention within 2 weeks of symptom onset is emphasized. KAS 9-Changed to KAS 9A and 9B. Hyperbaric oxygen therapy remains an option but only when combined with steroid therapy for either initial treatment (9A) or salvage therapy (9B). The timing of initial therapy is within 2 weeks of onset, and that of salvage therapy is within 1 month of onset of sudden sensorineural hearing loss. KAS 10-Intratympanic steroid therapy for salvage is recommended within 2 to 6 weeks following onset of sudden sensorineural hearing loss. The time to treatment is defined and emphasized. KAS 11-Antioxidants were removed from the list of interventions that the clinical practice guideline recommends against using. KAS 12-Follow-up audiometry at conclusion of treatment and also within 6 months posttreatment is added. KAS 13-This statement on audiologic rehabilitation includes patients who have residual hearing loss and/or tinnitus who may benefit from treatment. Addition of an algorithm outlining KASs Enhanced emphasis on patient education and shared decision making with tools provided to assist in same.

Investigations of the Microvasculature of the Human Macula Utricle in Meniere's Disease

The integrity and permeability of the blood labyrinthine barrier (BLB) in the inner ear is important to maintain adequate blood supply, and to control the passage of fluids, molecules and ions. Identifying the cellular and structural components of the BLB, the vascular endothelial cells (VECs), pericytes, and the perivascular basement membrane, is critical to understand the pathophysiology of the inner ear microvasculature and to design efficient delivery of therapeutics across the BLB. A recent study of the normal and pathological ultrastructural changes in the human macula utricle microvasculature demonstrated that the VECs are damaged in Meniere’s disease (MD), and further studies identified oxidative stress markers (iNOS and nitrotyrosine) in the VECs. Using fluorescence microscopy, the microvasculature was studied in the macula utricle of patients diagnosed with MD that required transmastoid labyrinthectomy for intractable vertigo (n = 5), and patients who required a translabyrinthine approach for vestibular schwannoma (VS) resection (n = 3). Normal utricles (controls) were also included (n = 3). VECs were identified using rabbit polyclonal antibodies against the glucose transporter-1 (GLUT-1) and pericytes were identified using mouse monoclonal antibodies against alpha-smooth muscle actin (α-SMA). Immunofluorescence (IF) staining was made in half of the utricle and flat mounted. The other half was used to study the integrity of the BLB using transmission electron microscopy (TEM). GLUT-1-IF, allowed delineation of the macula utricle microvasculature (located in the stroma underneath the sensory epithelia) in both MD and VS specimens. Three sizes of vessels were present in the utricle vasculature: Small size (<15 μm), medium size (15–25 μm) and large size >25 μm. α-SMA-IF was present in pericytes that surround the VECS in medium and thick size vessels. Thin size vessels showed almost no α-SMA-IF. AngioTool software was used for quantitative analysis. A significant decreased number of junctions, total vessel length, and average vessel length was detected in the microvasculature in MD specimens compared with VS and control specimens. The deeper understanding of the anatomy of the BLB in the human vestibular periphery and its pathological changes in disease will enable the development of non-invasive delivery strategy for the treatment of hearing and balance disorders.

FGF23 and its role in X-linked hypophosphatemia-related morbidity

Background

X-linked hypophosphatemia (XLH) is an inherited disease of phosphate metabolism in which inactivating mutations of the Phosphate Regulating Endopeptidase Homolog, X-Linked (PHEX) gene lead to local and systemic effects including impaired growth, rickets, osteomalacia, bone abnormalities, bone pain, spontaneous dental abscesses, hearing difficulties, enthesopathy, osteoarthritis, and muscular dysfunction. Patients with XLH present with elevated levels of fibroblast growth factor 23 (FGF23), which is thought to mediate many of the aforementioned manifestations of the disease. Elevated FGF23 has also been observed in many other diseases of hypophosphatemia, and a range of animal models have been developed to study these diseases, yet the role of FGF23 in the pathophysiology of XLH is incompletely understood.

Methods

The role of FGF23 in the pathophysiology of XLH is here reviewed by describing what is known about phenotypes associated with various PHEX mutations, animal models of XLH, and non-nutritional diseases of hypophosphatemia, and by presenting molecular pathways that have been proposed to contribute to manifestations of XLH.

Results

The pathophysiology of XLH is complex, involving a range of molecular pathways that variously contribute to different manifestations of the disease. Hypophosphatemia due to elevated FGF23 is the most obvious contributor, however localised fluctuations in tissue non-specific alkaline phosphatase (TNAP), pyrophosphate, calcitriol and direct effects of FGF23 have been observed to be associated with certain manifestations.

Conclusions

By describing what is known about these pathways, this review highlights key areas for future research that would contribute to the understanding and clinical treatment of non-nutritional diseases of hypophosphatemia, particularly XLH.

Good Clinical Approach: Delphi Consensus for the Use of Betahistine in Menière's Disease

Menière's disease is a disorder of the inner ear that causes vertigo, tinnitus, fullness, and hearing loss. Several pharmacological treatments are available, but none of them has shown significant results. Betahistine has been largely used but its effect on the main symptoms of Menière's disease remains unclear. In order to improve clinical appropriateness and to reduce the heterogeneity of the therapeutic approaches for Menière's disease, we proposed a European Consensus Conference on Betahistine's prescription. A group of European experts in vestibular disorders completed a questionnaire, prepared by opinion leaders, on the use of betahistine in Menière's disease. The Delphi method was used as an iterative investigation method in order to increase and establish the consensus. While betahistine was considered useful to reduce the number of the vertigo attacks during the intercritical phase of the disease, its use during attacks was considered helpful only when associated with other drugs. Betahistine was not considered useful for preventing hearing loss. The experts support the use of betahistine during the intercritical phase of the disease to reduce the number and severity of vertigo episodes. They also defined the parameters for a good clinical approach to evaluate the efficacy of betahistine treatment for Menière's disease.

Endolymphatic hydrops in idiopathic intracranial hypertension: prevalence and clinical outcome after lumbar puncture. Preliminary data

Idiopathic intracranial hypertension is characterized by raised intracranial pressure (ICP) without any underlying pathology, presenting with (IIH) or without papilledema (IIHWOP). Headache, often on daily basis, is the most frequent symptom. Among audiovestibular symptoms, tinnitus and dizziness are commonly reported, while vertigo and hearing impairment are infrequent reports. Endolymphatic hydrops (ELH) is the typical histopathologic feature of Ménière disease, a condition featured by episodes of vertigo, dizziness, fluctuating hearing loss, tinnitus, and aural fullness. Evidences suggest that ICP is transmitted to inner ear. The aim of this study is to investigate the prevalence of ELH symptoms in IIH/IIHWOP and the relationship between the raised ICP and ELH. The prevalence of chronic headache and of ELH symptoms was investigated in a consecutive series of IIH/IIHWOP patients, and a standard audiometry with hearing threshold measurement (pure-tone average-PTA) was performed. Differences in chronic headache and ELH symptoms prevalence and changes of PTA threshold were calculated after ICP normalization by lumbar puncture (LP). Thirty-one patients (17 with IIH and 14 with IIHWOP) were included. Before LP, chronic headache was present in 93.5%. The percentages of patients reporting tinnitus, dizziness, vertigo, and aural fullness were 67.7, 77.4, 22.6, and 61.3%, respectively. Headache frequency as well as ELH symptoms and PTA significantly improved after LP. The improvement of PTA and of ELH symptoms observed after LP in this series of IIH/IIHWOP patients indicates that a raised ICP, a condition known to be involved in the progression and refractoriness of migraine pain, has also a role in ELH. We propose that intracranial hypertension may represent the shared pathogenetic step explaining the large epidemiological comorbidity between migraine and vestibular symptoms, at present conceptualized as "vestibular migraine."

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.

Circulating steroids negatively correlate with tinnitus

While not a disease entity in itself; symptoms of tinnitus (from Latin tinnio - clink) accompany a number of diseases. Tinnitus prevalence increases with age, deteriorates one's quality of life, and may even result in suicidal behavior. Tinnitus develops in response to a variety of risk factors, otoxic substances, noise exposure, hearing disorders, and psychological alterations. Tinnitus is closely related to mood, depression, and psychological state. In the present study, we focused on alterations of the steroid metabolome and particularly neuroactive, neuroprotective, and immunomodulatory steroids in patients with tinnitus. The study group consisted of 28 patients without evidence of an organic cause of tinnitus as well as without associated diseases or the effect of ototoxic medications. All patients underwent a complete audiological assessment and laboratory tests including routine biochemical markers and quantification of circulating steroids using gas chromatography/mass spectrometry and immunoassays. To rule out a pathology in the cerebellopontine angle area, CT scan or MRI were performed. To diagnose stem lesions, evoked potentials were also measured. Pearson's correlations and multivariate regression were used to assess any links between tinnitus intensity and frequency on the one hand, and steroid levels on the other. Results indicated a significant and consistent negative correlation between tinnitus indices and intensity of adrenal steroidogenesis. The circulating steroid metabolome including hormones and neuroactive, neuroprotective, and immunomodulatory steroids negatively correlates with the degree of tinnitus due to hypothalamo-pituitary-adrenal axis malfunction. Our results may help explain the pathophysiology of tinnitus and improve its diagnosis. However, further studies are needed to verify our postulation.

The blood labyrinthine barrier in the human normal and Meniere's disease macula utricle

The ultrastructural organization of the blood labyrinthine barrier (BLB) was investigated in the human vestibular endorgan, the utricular macula, using postmortem specimens from individuals with documented normal auditory and vestibular function and surgical specimens from patients with intractable Meniere’s disease. Transmission electron microscopic analysis of capillaries located in the normal human utricular stroma showed vascular endothelial cells with few pinocytotic vesicles, covered by a smooth and uniform basement membrane surrounded by pericyte processes. Meniere’s disease specimens revealed differential ultrastructural pathological changes in the cellular elements of the microvasculature. With moderate degeneration of the BLB, there were numerous vesicles within the vascular endothelial cells (VECs), with increased numbers at the abluminal face, pericyte process detachment and disruption of the perivascular basement membrane surrounding the VECs. With severe degeneration of the BLB, there was severe vacuolization or frank apparent necrosis of VECs and loss of subcellular organelles. A higher severity of BLB degenerative changes was associated with a higher degree of basement membrane thickening and edematous changes within the vestibular stroma. This study presents the first ultrastructural analysis of the capillaries constituting the BLB in the human vestibular macula utricle from normal and Meniere’s disease.

The physiologic role of corticosteroids in Ménière's disease

Multiple options exist to manage Ménière's disease (MD), ranging from dietary modifications to ablative surgery. Corticosteroids (CS) have long been used to manage MD, but their exact mechanism for disease alleviation is relatively uncertain. Glucocorticoid receptors have been shown to exist in the human inner ear and several studies propose they influence mechanisms of blood flow, fluid regulation, and ion regulation, with recent evidence describing the latter two. Corticosteroids have been shown to upregulate aquaporins and ion channels in the inner ear, and may have a positive effect on labyrinthine blood flow. Additionally, processes have been described in genomic and non-genomic manners. This text will review the literature on the actions of CS on the inner ear relevant to MD.

The Intimate Relationship between Vestibular Migraine and Meniere Disease: A Review of Pathogenesis and Presentation

Vestibular migraine (VM) has only recently been recognized as a distinct disease entity. One reason is that its symptoms overlap greatly with those of other vestibular disorders, especially Meniere disease (MD). The pathophysiology of neither VM nor MD is entirely elucidated. However, there are many theories linking migraine to both disorders. We reviewed the current understanding of migraine, VM, and MD and described how VM and MD are similar or different from each other in terms of pathophysiology and presentation, including hypotheses that the two share a common etiology and/or are variants of the same disease.

It is 2015: What are the best diagnostic and treatment options for Ménière’s disease?

Ménière’s disease (MD) is a common cause of recurrent vertigo. Its pathophysiology is still unclear and controversial. The most common histological finding in postmortem temporal bone studies of patients is endolymphatic hydrops (EH). However, not all cases of hydrops are associated with MD and it may represent the end point of various etiologies. The diagnostic criteria for MD have undergone changes during the past few decades. A recent collaboration among specialty societies in United States, Europe and Japan has given rise to a new set of guidelines for the diagnosis and classification of MD. The aim is to develop international consensus criteria for MD that would help improve the quality of data collected from patients. The diagnosis of MD can be difficult in some cases as there is no gold standard for testing. Previous use of audiometric data and electrocochleography are poorly sensitive as screening tools. Recently magnetic resonance imaging as a diagnostic tool for identifying EH has gained popularity in Asia and Europe. Vestibular evoked myogenic potentials are also used but lack specificity. Finally, the treatment for MD has improved with the introduction of intratympanic treatments with steroids and gentamicin as well as less invasive treatment with the Meniett device.

Surgery for vertigo: 10-year audit from a contemporary vertigo clinic

OBJECTIVE

To present the profile of patients undergoing surgical treatment for vertigo at a contemporary institutional vertigo clinic.

STUDY DESIGN

A retrospective analysis of clinical charts.

METHODS

The charts of 1060 patients, referred to an institutional vertigo clinic from January 2003 to December 2012, were studied. The clinical profile and long-term outcomes of patients who underwent surgery were analysed.

RESULTS

Of 1060 patients, 12 (1.13 per cent) were managed surgically. Of these, disease-modifying surgical procedures included perilymphatic fistula repair (n = 7) and microvascular decompression of the vestibular nerve (n = 1). Labyrinth destructive procedures included transmastoid labyrinthectomy (n = 2) and labyrinthectomy with vestibular nerve section (n = 1). One patient with vestibular schwannoma underwent both a disease-modifying and destructive procedure (translabyrinthine excision). All patients achieved excellent vertigo control, classified as per the American Academy of Otolaryngology - Head and Neck Surgery 1995 criteria.

CONCLUSION

With the advent of intratympanic treatments, surgical treatments for vertigo have become further limited. However, surgery with directed intent, in select patients, can give excellent results.

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.

Oral steroid treatment for hearing improvement in Ménière's disease and endolymphatic hydrops

OBJECTIVE

To determine the effect of oral steroid treatment on hearing in unilateral Ménière's disease and endolymphatic hydrops patients.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary referral center.

PATIENTS

All patients presenting during the 2010 calendar year with confirmed unilateral Ménière's disease or endolymphatic hydrops. Those with a first visit and second visit audiogram (n = 58) were included in the analysis of oral steroid treatment effect.

INTERVENTION

Steroid treatment for hearing loss.

MAIN OUTCOME MEASURE

Change in hearing, as defined by change in affected ear threshold values or speech discrimination score from pretreatment visit to posttreatment visit.

RESULTS

Hearing (threshold, speech discrimination score) in patients' affected ear did not significantly change from first visit to second visit after treatment with steroids relative to patients who did not receive steroid treatment.

CONCLUSION

The results of this and other studies would indicate that a Ménière's disease or endolymphatic hydrops patient is unlikely to experience an improvement in hearing from a short course of oral steroid. Clinically observed temporary improvement did not sustain over several months. Further work to elucidate the mechanisms underlying hearing loss in hydrops, perhaps focusing on the dendrite damage noted in animal models of hydrops, is warranted.

Is allergy related to Meniere's disease?

Meniere's disease (MD) is characterized by episodic rotational vertigo, fluctuating sensorineural hearing loss, aural pressure, and tinnitus. The cause of MD is thought to be multifactorial, with anatomic and genetic contributions. Allergy is thought to be one of the possible extrinsic factors that, when combined with underlying intrinsic factors, may lead to MD. We review the epidemiologic associations of MD and allergy and review the recent literature on the association of allergy and MD.

Recurrent spontaneous attacks of dizziness

PURPOSE OF REVIEW

This article describes the common causes of recurrent vertigo and dizziness that can be diagnosed largely on the basis of history.

RECENT FINDINGS

Ninety percent of spontaneous recurrent vertigo and dizziness can be explained by six disorders: (1) Ménière disease is characterized by vertigo attacks, lasting 20 minutes to several hours, with concomitant hearing loss, tinnitus, and aural fullness. Aural symptoms become permanent during the course of the disease. (2) Attacks of vestibular migraine may last anywhere from minutes to days. Most patients have a previous history of migraine headaches, and many experience migraine symptoms during the attack. (3) Vertebrobasilar TIAs affect older adults with vascular risk factors. Most attacks last less than 1 hour and are accompanied by other symptoms from the posterior circulation territory. (4) Vestibular paroxysmia is caused by vascular compression of the eighth cranial nerve. It manifests itself with brief attacks of vertigo that recur many times per day, sometimes with concomitant cochlear symptoms. (5) Orthostatic hypotension causes brief episodes of dizziness lasting seconds to a few minutes after standing up and is relieved by sitting or lying down. In older adults, it may be accompanied by supine hypertension. (6) Panic attacks usually last minutes, occur in specific situations, and are accompanied by choking, palpitations, tremor, heat, and anxiety. Less common causes of spontaneous recurrent vertigo and dizziness include perilymph fistula, superior canal dehiscence, autoimmune inner ear disease, otosclerosis, cardiac arrhythmia, and medication side effects.

SUMMARY

Neurologists need to venture into otolaryngology, internal medicine, and psychiatry to master the differential diagnosis of recurrent dizziness.

Functional variants of MIF, INFG and TFNA genes are not associated with disease susceptibility or hearing loss progression in patients with Ménière's disease

Variability in acute immune response genes could determine susceptibility or prognosis for Ménière's disease (MD). The cytokines tumor necrosis factor α (TNFα), macrophage migration inhibitory factor (MIF) and interferon γ (INFγ) are proinflammatory cytokines of the innate immune response. These cytokines mediate inflammation and have been previously associated with the inflammatory process in several autoimmune diseases. We investigated the association between functional allelic variants of MIF (rs35688089), IFNG (rs2234688) and TNFA (rs1800629) in patients with MD. In addition to testing these variants for an association with disease, we also tested for an association with clinical aspects of disease progression, such as persistence of vertigo and the sensorineural hearing loss. A total of 580 patients with diagnosis of definite MD, according to the diagnostic scale of the American Academy of Otolaryngology-Head and Neck Surgery, and 552 healthy controls were included. DNA samples from a set of 291 American patients were used to confirm the results obtained in the MIF gene in our Spanish cohort. Although we found a significant association with the allele containing five repeats of CATT within the MIF gene in patients with MD in the Spanish cohort [corrected p = 0.008, OR = 0.69 (95 % CI, 0.54-0.88)], this finding could not be replicated in the American set. Moreover, no genetic associations for variants in either the TNFA or IFNG genes and MD were found. These results support the conclusion that functional variants of MIF, INFG, and TFNA genes are not associated with disease susceptibility or hearing loss progression in patients with MD.

Distinct mutations in STXBP2 are associated with variable clinical presentations in patients with familial hemophagocytic lymphohistiocytosis type 5 (FHL5)

Familial hemophagocytic lymphohistiocytosis (FHL) is a genetically determined hyperinflammatory syndrome caused by uncontrolled immune response mediated by T-lymphocytes, natural killer (NK) cells, and macrophages. STXBP2 mutations have recently been associated with FHL5. To better characterize the genetic and clinical spectrum of FHL5, we analyzed a cohort of 185 patients with suspected FHL for mutations in STXBP2. We detected biallelic mutations in 37 patients from 28 families of various ethnic origins. Missense mutations and mutations affecting 1 of the exon 15 splice sites were the predominant changes detectable in this cohort. Patients with exon 15 splice-site mutations (n = 13) developed clinical manifestations significantly later than patients with other mutations (median age, 4.1 year vs 2 months) and showed less severe impairment of degranulation and cytotoxic function of NK cells and CTLs. Patients with FHL5 showed several atypical features, including sensorineural hearing deficit, abnormal bleeding, and, most frequently, severe diarrhea that was only present in early-onset disease. In conclusion, we report the largest cohort of patients with FHL5 so far, describe an extended disease spectrum, and demonstrate for the first time a clear genotype-phenotype correlation.

Clinical Practice Guideline

Objective. Sudden hearing loss (SHL) is a frightening symptom that often prompts an urgent or emergent visit to a physician. This guideline provides evidence-based recommendations for the diagnosis, management, and follow-up of patients who present with SHL. The guideline primarily focuses on sudden sensorineural hearing loss (SSNHL) in adult patients (aged 18 and older). Prompt recognition and management of SSNHL may improve hearing recovery and patient quality of life (QOL). Sudden sensorineural hearing loss affects 5 to 20 per 100,000 population, with about 4000 new cases per year in the United States. This guideline is intended for all clinicians who diagnose or manage adult patients who present with SHL.

Purpose. The purpose of this guideline is to provide clinicians with evidence-based recommendations in evaluating patients with SHL, with particular emphasis on managing SSNHL. The panel recognized that patients enter the health care system with SHL as a nonspecific, primary complaint. Therefore, the initial recommendations of the guideline deal with efficiently distinguishing SSNHL from other causes of SHL at the time of presentation. By focusing on opportunities for quality improvement, the guideline should improve diagnostic accuracy, facilitate prompt intervention, decrease variations in management, reduce unnecessary tests and imaging procedures, and improve hearing and rehabilitative outcomes for affected patients.

Results. The panel made strong recommendations that clinicians should (1) distinguish sensorineural hearing loss from conductive hearing loss in a patient presenting with SHL; (2) educate patients with idiopathic sudden sensorineural hearing loss (ISSNHL) about the natural history of the condition, the benefits and risks of medical interventions, and the limitations of existing evidence regarding efficacy; and (3) counsel patients with incomplete recovery of hearing about the possible benefits of amplification and hearing-assistive technology and other supportive measures. The panel made recommendations that clinicians should (1) assess patients with presumptive SSNHL for bilateral SHL, recurrent episodes of SHL, or focal neurologic findings; (2) diagnose presumptive ISSNHL if audiometry confirms a 30-dB hearing loss at 3 consecutive frequencies and an underlying condition cannot be identified by history and physical examination; (3) evaluate patients with ISSNHL for retrocochlear pathology by obtaining magnetic resonance imaging, auditory brainstem response, or audiometric follow-up; (4) offer intratympanic steroid perfusion when patients have incomplete recovery from ISSNHL after failure of initial management; and (5) obtain follow-up audiometric evaluation within 6 months of diagnosis for patients with ISSNHL. The panel offered as options that clinicians may offer (1) corticosteroids as initial therapy to patients with ISSNHL and (2) hyperbaric oxygen therapy within 3 months of diagnosis of ISSNHL. The panel made a recommendation against clinicians routinely prescribing antivirals, thrombolytics, vasodilators, vasoactive substances, or antioxidants to patients with ISSNHL. The panel made strong recommendations against clinicians (1) ordering computerized tomography of the head/brain in the initial evaluation of a patient with presumptive SSNHL and (2) obtaining routine laboratory tests in patients with ISSNHL.

Physiopathology of the cochlear microcirculation

Normal blood supply to the cochlea is critically important for establishing the endocochlear potential and sustaining production of endolymph. Abnormal cochlear microcirculation has long been considered an etiologic factor in noise-induced hearing loss, age-related hearing loss (presbycusis), sudden hearing loss or vestibular function, and Meniere's disease. Knowledge of the mechanisms underlying the pathophysiology of cochlear microcirculation is of fundamental clinical importance. A better understanding of cochlear blood flow (CoBF) will enable more effective management of hearing disorders resulting from aberrant blood flow. This review focuses on recent discoveries and findings related to the physiopathology of the cochlear microvasculature.

Oxidative stress, redox homeostasis and cellular stress response in Ménière's disease: role of vitagenes

Ménière's disease (MD) is characterized by the triad of fluctuating hearing loss, episodic vertigo and tinnitus, and by endolymphatic hydrops found on post-mortem examination. Increasing evidence suggests that oxidative stress is involved in the development of endolymphatic hydrops and that cellular damage and apoptotic cell death might contribute to the sensorineural hearing loss found in later stages of MD. While excess reactive oxygen species (ROS) are toxic, regulated ROS, however, play an important role in cellular signaling. The ability of a cell to counteract stressful conditions, known as cellular stress response, requires the activation of pro-survival pathways and the production of molecules with anti-oxidant, anti-apoptotic or pro-apoptotic activities. Among the cellular pathways conferring protection against oxidative stress, a key role is played by vitagenes, which include heat shock proteins (Hsps) as well as the thioredoxin/thioredoxin reductase system. In this study we tested the hypothesis that in MD patients measurable increases in markers of cellular stress response and oxidative stress in peripheral blood are present. This study also explores the hypothesis that changes in the redox status of glutathione, the major endogenous antioxidant, associated with abnormal expression and activity of carbonic anhydrase can contribute to increase oxidative stress and to disruption of systemic redox homeostasis which can be associated to possible alterations on vulnerable neurons such as spiral ganglion neurons and consequent cellular degeneration. We therefore evaluated systemic oxidative stress and cellular stress response in patients suffering from Meniere's disease (MD) and in age-matched healthy subjects. Systemic oxidative stress was estimated by measuring protein oxidation, such as protein carbonyls (PC) and 4-hydroxynonenal (HNE) in lymphocytes of MD patients, as well as ultraweak luminescence (UCL) as end-stable products of lipid oxidation in MD plasma and lymphocytes, as compared to age-matched controls, whereas heat shock proteins Hsp70 and thioredoxin (Trx) expression were measured in lymphocytes to evaluate the systemic cellular stress response. Increased levels of PC (P < 0.01) and HNE (P < 0.05) have been found in lymphocytes from MD patients with respect to control group. This was paralleled by a significant induction of Hsp70, and a decreased expression of Trx (P < 0.01), whereas a significant decrease in both plasma and lymphocyte ratio reduced glutathione GSH) vs. oxidized glutathione (GSSG) (P < 0.05) were also observed. In conclusion, patients affected by MD are under condition of systemic oxidative stress and the induction of vitagenes Hsp70 is a maintained response in counteracting the intracellular pro-oxidant status generated by decreased content of GSH as well as expression of Trx. The search for novel and more potent inducers of vitagenes will facilitate the development of pharmacological strategies to increase the intrinsic capacity of vulnerable ganglion cells to maximize antidegenerative mechanisms, such as stress response and thus cytoprotection.