Intratympanic Steroid Treatments May Improve Hearing via Ion Homeostasis Alterations and Not Immune Suppression

Intratympanic dexamethasone in Manières disease and symptom control

BACKGROUND

Manières disease (MD) is a chronic inner ear disease characterized by recurrent vertigo and fluctuation in auditory symptoms. Vertigo spells have a sudden onset and are difficult for patients to handle. Therefore, treating a patient with MD is still a challenge for clinicians.

AIMS

This study aims to analyse the short-term effects of intratympanic dexamethasone (ITD) on the various symptoms of unilateral MD.

MATERIALS AND METHODS

The study comprised 27 patients with unilateral MD and severe vertigo who failed medication therapy. Treatment was with ITD as an alternative to destructive therapy. Treatment is evaluated after four months.

RESULTS

Significant improvements were measured with Dizziness Handicap Inventory (DHI), Tinnitus Handicap Inventory (THI), frequency of vertigo attacks longer than 20 min, Functional Level Scale (FLS), and tinnitus sensation measured by the Analog Visual Scale (AVS). Patients with severe symptoms grading with DHI and THI experienced the most improvement. Patients have achieved substantial vertigo control in 73%.

CONCLUSION

ITD application shows improvement in controlling vertigo and tinnitus in patients under exacerbation in MD.

SIGNIFICANCE

It is a promising non-destructive addition to the 'stepwise treatment concept' in MD and can be used as a first-line treatment in vertigo control.

Conditional Ablation of Glucocorticoid and Mineralocorticoid Receptors from Cochlear Supporting Cells Reveals Their Differential Roles for Hearing Sensitivity and Dynamics of Recovery from Noise-Induced Hearing Loss

Endogenous glucocorticoids (GC) are known to modulate basic elements of cochlear physiology. These include both noise-induced injury and circadian rhythms. While GC signaling in the cochlea can directly influence auditory transduction via actions on hair cells and spiral ganglion neurons, evidence also indicates that GC signaling exerts effects via tissue homeostatic processes that can include effects on cochlear immunomodulation. GCs act at both the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR). Most cell types in the cochlea express both receptors sensitive to GCs. The GR is associated with acquired sensorineural hearing loss (SNHL) through its effects on both gene expression and immunomodulatory programs. The MR has been associated with age-related hearing loss through dysfunction of ionic homeostatic balance. Cochlear supporting cells maintain local homeostatic requirements, are sensitive to perturbation, and participate in inflammatory signaling. Here, we have used conditional gene manipulation techniques to target Nr3c1 (GR) or Nr3c2 (MR) for tamoxifen-induced gene ablation in Sox9-expressing cochlear supporting cells of adult mice to investigate whether either of the receptors sensitive to GCs plays a role in protecting against (or exacerbating) noise-induced cochlear damage. We have selected mild intensity noise exposure to examine the role of these receptors related to more commonly experienced noise levels. Our results reveal distinct roles of these GC receptors for both basal auditory thresholds prior to noise exposure and during recovery from mild noise exposure. Prior to noise exposure, auditory brainstem responses (ABRs) were measured in mice carrying the floxed allele of interest and the Cre recombinase transgene, but not receiving tamoxifen injections (defined as control (no tamoxifen treatment), versus conditional knockout (cKO) mice, defined as mice having received tamoxifen injections. Results revealed hypersensitive thresholds to mid- to low-frequencies after tamoxifen-induced GR ablation from Sox9-expressing cochlear supporting cells compared to control (no tamoxifen) mice. GR ablation from Sox9-expressing cochlear supporting cells resulted in a permanent threshold shift in mid-basal cochlear frequency regions after mild noise exposure that produced only a temporary threshold shift in both control (no tamoxifen) f/fGR:Sox9iCre+ and heterozygous f/+GR:Sox9iCre+ tamoxifen-treated mice. A similar comparison of basal ABRs measured in control (no tamoxifen) and tamoxifen-treated, floxed MR mice prior to noise exposure indicated no difference in baseline thresholds. After mild noise exposure, MR ablation was initially associated with a complete threshold recovery at 22.6 kHz by 3 days post-noise. Threshold continued to shift to higher sensitivity over time such that by 30 days post-noise exposure the 22.6 kHz ABR threshold was 10 dB more sensitive than baseline. Further, MR ablation produced a temporary reduction in peak 1 neural amplitude one day post-noise. While supporting cell GR ablation trended towards reducing numbers of ribbon synapses, MR ablation reduced ribbon synapse counts but did not exacerbate noise-induced damage including synapse loss at the experimental endpoint. GR ablation from the targeted supporting cells increased the basal resting number of Iba1-positive (innate) immune cells (no noise exposure) and decreased the number of Iba1-positive cells seven days following noise exposure. MR ablation did not alter innate immune cell numbers at seven days post-noise exposure. Taken together, these findings support differential roles of cochlear supporting cell MR and GR expression at basal, resting conditions and especially during recovery from noise exposure.

The role of the stria vascularis in neglected otologic disease

The stria vascularis (SV) has been shown to play a critical role in the pathogenesis of many diseases associated with sensorineural hearing loss (SNHL), including age-related hearing loss (ARHL), noise-induced hearing loss (NIHL), hereditary hearing loss (HHL), and drug-induced hearing loss (DIHL), among others. There are a number of other disorders of hearing loss that may be relatively neglected due to being underrecognized, poorly understood, lacking robust diagnostic criteria or effective treatments. A few examples of these diseases include autoimmune inner ear disease (AIED) and/or autoinflammatory inner ear disease (AID), Meniere's disease (MD), sudden sensorineural hearing loss (SSNHL), and cytomegalovirus (CMV)-related hearing loss (CRHL). Although these diseases may often differ in etiology, there have been recent studies that support the involvement of the SV in the pathogenesis of many of these disorders. We strive to highlight a few prominent examples of these frequently neglected otologic diseases and illustrate the relevance of understanding SV composition, structure and function with regards to these disease processes. In this study, we review the physiology of the SV, lay out the importance of these neglected otologic diseases, highlight the current literature regarding the role of the SV in these disorders, and discuss the current strategies, both approved and investigational, for management of these disorders.

Progression of endolymphatic hydrops and vertigo during treatment in Meniere's disease

BACKGROUND

Patients with Meniere's disease (MD) receive treatment to reduce vertigo.

PURPOSE

To explore the fluctuation of vertigo symptoms and the changes in endolymphatic hydrops (EHs) in MD patients during long-term regular medication.

MATERIALS AND METHODS

We enrolled MD patients who had received two magnetic resonance imaging with intravenous contrast agents.

RESULTS

Of the 42 patients in the study, 18(42.9%) had progressive EHs and 3(7.1%) had remission. The change value of the signal intensity ratio (SIR; cochlear perilymph/cerebellum) on the affected side (1.2) was larger than that on the healthy side (0.9), but there was no statistical difference. Among the 30 patients followed up, two patients had complete control of vertigo, two patients had substantial control, and three patients had worse control. The other 23 patients had insignificant control of vertigo symptoms before and after treatment. The correlation between the progression of cochlear and vestibular hydrops and the improvement of vertigo symptoms in MD patients was not significant.

CONCLUSIONS AND SIGNIFICANCE

In treated patients with MD, EHs may progress or relieve over the long course of the disease. But there was no correlation between the development of EHs and changes in vertigo symptoms.

Intratympanic corticosteroids for sudden sensorineural hearing loss

BACKGROUND

Idiopathic sudden sensorineural hearing loss (ISSNHL) is common, and defined as a sudden decrease in sensorineural hearing sensitivity of unknown aetiology. Systemic corticosteroids are widely used, however their value remains unclear. Intratympanic injections of corticosteroids have become increasingly common in the treatment of ISSNHL.

OBJECTIVES

To assess the effects of intratympanic corticosteroids in people with ISSNHL.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Trials Register; CENTRAL (2021, Issue 9); PubMed; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials (search date 23 September 2021).

SELECTION CRITERIA

We included randomised controlled trials (RCTs) involving people with ISSNHL and follow-up of over a week. Intratympanic corticosteroids were given as primary or secondary treatment (after failure of systemic therapy).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods, including GRADE to assess the certainty of the evidence. Our primary outcome was change in hearing threshold with pure tone audiometry. Secondary outcomes included the proportion of people whose hearing improved, final hearing threshold, speech audiometry, frequency-specific hearing changes and adverse effects.

MAIN RESULTS

We included 30 studies, comprising 2133 analysed participants. Some studies had more than two treatment arms and were therefore relevant to several comparisons. Studies investigated intratympanic corticosteroids as either primary (initial) therapy or secondary (rescue) therapy after failure of initial treatment. 1. Intratympanic corticosteroids versus systemic corticosteroids as primary therapy We identified 16 studies (1108 participants). Intratympanic therapy may result in little to no improvement in the change in hearing threshold (mean difference (MD) -5.93 dB better, 95% confidence interval (CI) -7.61 to -4.26; 10 studies; 701 participants; low-certainty). We found little to no difference in the proportion of participants whose hearing was improved (risk ratio (RR) 1.04, 95% CI 0.97 to 1.12; 14 studies; 972 participants; moderate-certainty). Intratympanic therapy may result in little to no difference in the final hearing threshold (MD -3.31 dB, 95% CI -6.16 to -0.47; 7 studies; 516 participants; low-certainty). Intratympanic therapy may increase the number of people who experience vertigo or dizziness (RR 2.53, 95% CI 1.41 to 4.54; 1 study; 250 participants; low-certainty) and probably increases the number of people with ear pain (RR 15.68, 95% CI 6.22 to 39.49; 2 studies; 289 participants; moderate-certainty). It also resulted in persistent tympanic membrane perforation (range 0% to 3.9%; 3 studies; 359 participants; very low-certainty), vertigo/dizziness at the time of injection (1% to 21%, 3 studies; 197 participants; very low-certainty) and ear pain at the time of injection (10.5% to 27.1%; 2 studies; 289 participants; low-certainty). 2. Intratympanic plus systemic corticosteroids (combined therapy) versus systemic corticosteroids alone as primary therapy We identified 10 studies (788 participants). Combined therapy may have a small effect on the change in hearing threshold (MD -8.55 dB better, 95% CI -12.48 to -4.61; 6 studies; 435 participants; low-certainty). The evidence is very uncertain as to whether combined therapy changes the proportion of participants whose hearing is improved (RR 1.27, 95% CI 1.15 to 1.41; 10 studies; 788 participants; very low-certainty). Combined therapy may result in slightly lower (more favourable) final hearing thresholds but the evidence is very uncertain, and it is not clear whether the change would be important to patients (MD -9.11 dB, 95% CI -16.56 to -1.67; 3 studies; 194 participants; very low-certainty). Some adverse effects only occurred in those who received combined therapy. These included persistent tympanic membrane perforation (range 0% to 5.5%; 5 studies; 474 participants; very low-certainty), vertigo or dizziness at the time of injection (range 0% to 8.1%; 4 studies; 341 participants; very low-certainty) and ear pain at the time of injection (13.5%; 1 study; 73 participants; very low-certainty).  3. Intratympanic corticosteroids versus no treatment or placebo as secondary therapy We identified seven studies (279 participants). Intratympanic therapy may have a small effect on the change in hearing threshold (MD -9.07 dB better, 95% CI -11.47 to -6.66; 7 studies; 280 participants; low-certainty). Intratympanic therapy may result in a much higher proportion of participants whose hearing is improved (RR 5.55, 95% CI 2.89 to 10.68; 6 studies; 232 participants; low-certainty). Intratympanic therapy may result in lower (more favourable) final hearing thresholds (MD -11.09 dB, 95% CI -17.46 to -4.72; 5 studies; 203 participants; low-certainty). Some adverse effects only occurred in those who received intratympanic injection. These included persistent tympanic membrane perforation (range 0% to 4.2%; 5 studies; 185 participants; very low-certainty), vertigo or dizziness at the time of injection (range 6.7% to 33%; 3 studies; 128 participants; very low-certainty) and ear pain at the time of injection (0%; 1 study; 44 participants; very low-certainty).  4. Intratympanic plus systemic corticosteroids (combined therapy) versus systemic corticosteroids alone as secondary therapy We identified one study with 76 participants. Change in hearing threshold was not reported. Combined therapy may result in a higher proportion with hearing improvement, but the evidence is very uncertain (RR 2.24, 95% CI 1.10 to 4.55; very low-certainty). Adverse effects were poorly reported with only data for persistent tympanic membrane perforation (rate 8.1%, very low-certainty).

AUTHORS' CONCLUSIONS

Most of the evidence in this review is low- or very low-certainty, therefore it is likely that further studies may change our conclusions.   For primary therapy, intratympanic corticosteroids may have little or no effect compared with systemic corticosteroids. There may be a slight benefit from combined treatment when compared with systemic treatment alone, but the evidence is uncertain. For secondary therapy, there is low-certainty evidence that intratympanic corticosteroids, when compared to no treatment or placebo, may result in a much higher proportion of participants whose hearing is improved, but may only have a small effect on the change in hearing threshold. It is very uncertain whether there is additional benefit from combined treatment over systemic steroids alone. Although adverse effects were poorly reported, the different risk profiles of intratympanic treatment (including tympanic membrane perforation, pain and dizziness/vertigo) and systemic treatment (for example, blood glucose problems) should be considered when selecting appropriate treatment.

Safety and Efficacy of Intratympanic Alpha-Lipoic Acid Injection in a Mouse Model of Noise-Induced Hearing Loss

Alpha-lipoic acid (ALA) is an antioxidant with oto-protective effects. In the present study, the safety and effectiveness of ALA therapy after noise-induced hearing loss was confirmed based on the administration method. The safety of intratympanic ALA (IT-ALA) was evaluated with oto-endoscopy and middle ear mucosa morphologic study. Perilymph ALA concentrations according to the administration routes were compared, and the efficacy of ALA was investigated through hearing tests and cochlear histological studies. The middle ear mucosa was swollen 1 week after IT-ALA but completely recovered within 3 weeks. ALA concentration in the perilymph was significantly higher in the IT-ALA group. Recovery of organ of Corti morphology and hearing levels were predominant in the IT-ALA group compared with the intraperitoneal injection group (IP-ALA) and showed similar rescue effects in the IT-dexamethasone group (IT-DEX). Interleukin-1 beta and nuclear factor-kappa B expression was significantly downregulated in the IT-ALA group. IT-ALA showed better cochlear recovery from acoustic trauma with higher inner ear penetration rate than IP-ALA. The rescue effect of IT-ALA after noise-induced hearing loss was similar to IT-DEX; however, the ALA and DEX mechanisms are different. IT-ALA appears to be another safe and effective treatment modality after acoustic trauma and comparable to IT-DEX.

Duration of symptom control following intratympanic dexamethasone injections in Meniere’s disease

Purpose

Intratympanic (IT) injections of corticosteroids have emerged as a non-ablative alternative to gentamicin in the management of refractory Meniere’s disease. However, currently, the duration of the symptom control achieved via intratympanic corticosteroids is under reported.

Methods

We retrospectively reviewed the notes of all patients who underwent IT injections of dexamethasone for the treatment of definite Meniere’s disease at a single tertiary referral university centre over a 6-year period. We included demographic information, the number of procedures patients required, duration of symptom-control achieved (time interval between repeat IT injections), and the presence of co-morbidities, with a focus on the presence of autoimmune disease.

Results

We identified 27 patients who underwent a total of 42 procedures; 23/27 (85.2%) patients demonstrated clinical response with a median period of symptom control of 14.5 months (range 1–64, IQR 10.25). The median longest asymptomatic period per patient was 19 months (range 11–64, IQR: 18). Interestingly, all patients with autoimmune disease (7/27) demonstrated a clinical response; autoimmune disease was found to be a statistically significant predictor of response to treatment (p = 0.002). In patients who received repeated treatment following disease relapse, there was no difference in duration of symptom-control achieved.

Conclusions

IT steroids can provide an effective alternative to gentamicin ablation. Symptom control is achieved for a median of 14.5 months, and treatment can be repeated with no loss of efficacy. Those patients who have an underlying autoimmune co-morbidity are more likely to demonstrate a clinical response to therapy, which may provide insight into the underlying pathophysiology of Meniere’s disease.

Dexamethasone does not affect endolymphatic hydrops (EH) in patients with Meniere’s disease within 24 h, and intratympanic administration of gadolinium plus dexamethasone simplifies high-quality imaging of EH using a novel protocol of 7 minutes

Background

Intratympanic administration of gadolinium chelate allows for a better visualization of endolymphatic hydrops (EH) using MRI than intravenous injection and was recently further improved to facilitate high-quality imaging of EH in 7 min. The aim of the present study was to simplify the intratympanic administration protocol by mixing gadolinium chelate with therapeutic dexamethasone and to evaluate the effects of this mixture on the visualization of EH in MRI.

Materials and methods

In an in vitro study, the potential impact of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) on the stability of dexamethasone was evaluated by analyzing dynamic changes in dexamethasone with high-performance liquid chromatography (HPLC) after mixing with Gd-DTPA. Ten patients with definite Meniere's disease (MD) were recruited to study the potential interference of dexamethasone on MRI visualization of EH, and 49 patients with MD were recruited to evaluate the effect of intratympanic injection of Gd-DTPA mixed with dexamethasone on MRI of EH using a 3T MR machine and a novel heavily T2-weighted 3-dimensional fluid-attenuated inversion recovery reconstructed using a magnitude plus zero-filled interpolation (hT₂FLAIR-MZFI) sequence.

Results

The retention times and peak area of dexamethasone in HPLC were not modified by the addition of Gd-DTPA. EH grading in the cochlea and vestibule was not influenced in any ear by intratympanic injection of dexamethasone. Excellent inner ear images were obtained from all patients, and EHs with various grades were displayed. There were significant correlations between diagnosis and cochlear EH (p < 0.01, Spearman's Rho), between diagnosis and vestibular EH (p < 0.01, Spearman's Rho), and between cochlear and vestibular EH (p < 0.01, Spearman's Rho). The distribution of Gd-DTPA plus dexamethasone negatively correlated with the grade of vestibular EH. Injury of the endolymph-perilymph barrier was detected in one cochlea and three vestibules of 59 inner ears with MD.

Conclusions

Intratympanic administration of Gd-DTPA plus dexamethasone yielded high-quality MRI images of EH in patients with MD using a novel 7-min protocol and simplified the clinical application. Intratympanic administration of Gd-DTPA plus dexamethasone might be used to test its therapeutic effect in future work.

Level of evidence

3.

[Corticosteroids for acute sensorineural hearing loss treatment. The contemporary state of problem. Literature review. Part 1]

The article presents modern literary data relating to the expediency of the purpose of glucocorticosteroids in sudden sensorineural hearing loss (SSHL) of various genes. In detail, the radar molecular mechanisms and the anatomo-physiological features of the exposure to the inner ear, side effects, the introduction methods, their comparative efficacy and modern schemes of the SSHL.

[Glucocorticosteroids in the treatment of acute neurosensory hearing loss. The current state of the problem. Part 2]

Modern literature data are presented on the choice of a drug for hormonal therapy in acute neurosensory hearing loss of various origins, the doses used for systemic therapy, the features and methods of intratympanic administration of glucocorticosteroids, and the evaluation of the effectiveness of treatment with this group of drugs.

Intratympanic steroid versus gentamicin for treatment of refractory Meniere's disease: A meta-analysis

PURPOSE

Intratympanic steroid injections (ITSI) have become a promising treatment for refractory Meniere's disease due to less cochleovestibular damage. However, whether ITSI would be a good alternative to intratympanic gentamicin injections (ITGI) for refractory Meniere's disease still remains controversial. Here we intended to compare the therapeutic effect of ITSI and ITGI in patients with Meniere's disease refractory to conservative treatments, in terms of vertigo control and hearing outcomes, via a meta-analysis.

METHODS

Using MEDLINE, PubMed, and EMBASE databases, we calculated pooled odds ratio (OR) estimates of vertigo control rate (i.e., class A according to AAO-HNS guideline) and standardized mean differences (SMD) of spell count, pure tone audiometry (PTA) threshold and speech discrimination score (SDS) with a 95% confidence interval (CI). The trim-and-fill method and sensitivity analysis were used as post-hoc analyses to verify the integrity of the quantitative analysis results. Furthermore, subgroup analyses were performed according to steroid type (methylprednisolone versus dexamethasone) and follow-up period (>1-year versus <1-year).

RESULTS

Five studies involving 332 patients with refractory unilateral Meniere's disease were included. In the pooled analysis, those treated with ITGI showed higher ORs than those treated with ITSI in terms of vertigo control rate (OR: 2.39, 95% CI: 0.84-6.79, P = 0.102) and spell counts (SMD: 0.24, 95% CI: -0.12-0.59, P = 0.195), but it did not reach statistical significance. However, a substantial amount of heterogeneity (I² = 71.0%, Q = 13.79, P = 0.008) and publication bias was found, suggesting a significant small-study effect. Additionally, ITSI elicited better hearing outcomes of the mean PTA threshold (SMD: 3.08, 95% CI: -1.18-7.35) and mean SDS (SMD: 11.15, 95% CI: -23.21-0.90) compared with ITGI, although no statistical significance. In subgroup analysis, the difference in vertigo control rate between ITGI and ITSI was not significant, regardless of the follow-up period and steroid type. Further, methylprednisolone appeared to be superior to dexamethasone for vertigo control. No significant complications from either treatment were reported in the literature.

CONCLUSION

The results of this study further refine the recently proposed efficacy of ITSI for the treatment of refractory Meniere's disease, demonstrating the comparable value of ITGI on vertigo control as well as better hearing preservation. Collectively, ITSI could be a safe and the effective treatment for refractory Meniere's disease. However, the current evidence on efficacy of ITSI for refractory Meniere's disease needs to be further clarified, given the substantial heterogeneity and potential biases.

Impact of Systemic versus Intratympanic Dexamethasone Administration on the Perilymph Proteome

Glucocorticoids are the first-line treatment for sensorineural hearing loss, but little is known about the mechanism of their protective effect or the impact of route of administration. The recent development of hollow microneedles enables safe and reliable sampling of perilymph for proteomic analysis. Using these microneedles, we investigate the effect of intratympanic (IT) versus intraperitoneal (IP) dexamethasone administration on guinea pig perilymph proteome. Guinea pigs were treated with IT dexamethasone (n = 6), IP dexamethasone (n = 8), or untreated for control (n = 8) 6 h prior to aspiration. The round window membrane (RWM) was accessed via a postauricular approach, and hollow microneedles were used to perforate the RWM and aspirate 1 μL of perilymph. Perilymph samples were analyzed by liquid chromatography-mass spectrometry-based label-free quantitative proteomics. Mass spectrometry raw data files have been deposited in an international public repository (MassIVE proteomics repository at https://massive.ucsd.edu/) under data set # MSV000086887. In the 22 samples of perilymph analyzed, 632 proteins were detected, including the inner ear protein cochlin, a perilymph marker. Of these, 14 proteins were modulated by IP, and three proteins were modulated by IT dexamethasone. In both IP and IT dexamethasone groups, VGF nerve growth factor inducible was significantly upregulated compared to control. The remaining adjusted proteins modulate neurons, inflammation, or protein synthesis. Proteome analysis facilitated by the use of hollow microneedles shows that route of dexamethasone administration impacts changes seen in perilymph proteome. Compared to IT administration, the IP route was associated with greater changes in protein expression, including proteins involved in neuroprotection, inflammatory pathway, and protein synthesis. Our findings show that microneedles can mediate safe and effective intracochlear sampling and hold promise for inner ear diagnostics.

Lesion-specific prognosis by magnetic resonance imaging in sudden sensorineural hearing loss

BACKGROUND

High signals in the inner ear of idiopathic sudden sensorineural hearing loss (ISSNHL) on magnetic resonance imaging (MRI) have been reported, but no quantitative evaluation has yet been done.

OBJECTIVES

To evaluate hearing outcomes and cochlear signal intensities on 3-T heavily T₂-weighted three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging (hT₂W-3D-FLAIR) in patients with ISSNHL.

MATERIALS AND METHODS

Twenty-nine patients with ISSNHL were included. Patients underwent hT₂W-3D-FLAIR with intravenous gadolinium injection and pure tone audiometry (PTA) at initial visits and 3 months later. Signal intensity ratios (SIRs) were measured in the basal or apical-middle turns of the affected cochlea. A statistical analysis of relationships between SIRs and the average hearing levels (HLs) at low (125, 250, and 500 Hz) and high (2, 4, and 8 kHz) tone frequencies was performed.

RESULTS

Hearing improvements at high-tone frequencies in ears with HLs ≥60 dB were significantly worse in those with high SIRs at the basal turns on pre-contrast images. Similarly, hearing improvements at low-tone frequencies in ears with HLs ≥60 dB were significantly worse in those with high SIRs at the apical-middle turns on post-contrast images.

CONCLUSIONS AND SIGNIFICANCE

High SIRs on hT₂W-3D-FLAIR indicate cochlear disturbances with severe ISSNHL and could provide lesion-specific prognostic information.

A Case of Incus Necrosis Following Oral and Intratympanic Steroid Administration for Sensorineural Hearing Loss

OBJECTIVE

Intratympanic (IT) steroid injections are often used for the treatment of inner ear pathologies, including sudden sensorineural hearing loss. IT steroids are also commonly used in conjunction with or in case of systemic steroid therapy failure. They are viable options for patients who cannot endure side effects or are at high risk of complications from systemic therapy. The duration of treatment, strength, and type of steroid, and number of IT injections are important factors that impact possible treatment complications. Reported complications, though uncommon, include tympanic membrane perforation, otalgia, vertigo, otitis media, and acne. In this report, we explore a novel case of incus necrosis associated with oral and/or IT steroid administration.

STUDY DESIGN

Clinical Capsule Report.

SETTING

Tertiary Academic Center.

PATIENT

We present a case of a 70-year-old male with sudden sensorineural hearing loss who developed incus necrosis and conductive hearing loss following treatment with oral and intratympanic steroids.

INTERVENTION

The patient underwent a left tympanoplasty with ossicular chain reconstruction to treat the conductive component of his hearing loss.

RESULTS

The left tympanoplasty almost fully-resolved the conductive component of his hearing loss. However, intraoperative and CT assessment of the temporal bone revealed resorption of the long process of the incus, with otherwise normal-appearing ossicles.

CONCLUSION

We report the first case of possible steroid-induced necrosis of the long process of the incus. Owing to its tenuous blood supply, the incus may be predisposed to steroid-induced osteonecrosis similar to that of the femoral head.

Intratympanically Delivered Steroids Impact Thousands More Inner Ear Genes Than Systemic Delivery

Objectives:

Glucocorticoids are given for sensorineural hearing loss, but little is known of their molecular impact on the inner ear. Furthermore, in spite of claims of improved hearing recovery with intratympanic delivery of steroids, no studies have actually documented the inner ear molecular functions that are enhanced with this delivery method.

Methods:

To assess steroid-driven processes in the inner ear, gene chip analyses were conducted on mice treated systemically with the glucocorticoids prednisolone or dexamethasone or the mineralocorticoid aldosterone. Other mice were given the same steroids intratympanically. Inner ears were harvested at 6 hours and processed on the Affymetrix 430 2.0 Gene Chip for expression of its 34 000 genes. Results were statistically analyzed for up or down expression of each gene against control (untreated) mice.

Results:

Analyses showed approximately 17 500 genes are normally expressed in the inner ear and steroids alter expression of 55% to 82% of these. Dexamethasone changed expression of 9424 (53.9%) inner ear genes following systemic injection but 14 899 ear genes (85%) if given intratympanically. A similar pattern was seen with prednisolone, as 7560 genes were impacted by oral delivery and 11 164 genes (63.8%) when given intratympanically. The mineralocorticoid aldosterone changed expression of only 268 inner ear genes if given orally, but this increased to 10 124 genes (57.9%) if injected intratympanically. Furthermore, the glucocorticoids given actually impacted more inner ear genes via the mineralocorticoid receptor than the glucocorticoid receptor.

Conclusions:

Thousands of inner ear genes were affected by steroids, and this number increased significantly if steroids were delivered intratympanically. Also, the impact of glucocorticoids on inner ear mineralocorticoid functions is more substantial than previously known. Thus, the application of therapeutic steroids for hearing loss needs to be reassessed in light of their more comprehensive impact on inner ear genes. Furthermore, simply ascribing the efficacy of steroids to immunosuppression no longer appears to be warranted.

Aminoglycoside-Induced Cochleotoxicity: A Review

Aminoglycoside antibiotics are used as prophylaxis, or urgent treatment, for many life-threatening bacterial infections, including tuberculosis, sepsis, respiratory infections in cystic fibrosis, complex urinary tract infections and endocarditis. Although aminoglycosides are clinically-essential antibiotics, the mechanisms underlying their selective toxicity to the kidney and inner ear continue to be unraveled despite more than 70 years of investigation. The following mechanisms each contribute to aminoglycoside-induced toxicity after systemic administration: (1) drug trafficking across endothelial and epithelial barrier layers; (2) sensory cell uptake of these drugs; and (3) disruption of intracellular physiological pathways. Specific factors can increase the risk of drug-induced toxicity, including sustained exposure to higher levels of ambient sound, and selected therapeutic agents such as loop diuretics and glycopeptides. Serious bacterial infections (requiring life-saving aminoglycoside treatment) induce systemic inflammatory responses that also potentiate the degree of ototoxicity and permanent hearing loss. We discuss prospective clinical strategies to protect auditory and vestibular function from aminoglycoside ototoxicity, including reduced cochlear or sensory cell uptake of aminoglycosides, and otoprotection by ameliorating intracellular cytotoxicity.

Repeated courses of intratympanic dexamethasone injection are effective for intractable Meniere's disease

CONCLUSION

Intra-tympanic dexamethasone injection (ITD) could serve as a first-line intra-tympanic (IT) treatment for Meniere's disease (MD), regardless of hearing level. Even if the response to initial ITD course was unsatisfactory, a repeated course may be beneficial with some patients.

OBJECTIVES

This study examined the effect of repeated courses of ITD administered on demand and investigated the possibility of ITD as an initial IT treatment for medically intractable MD patients.

METHOD

Fifty-one patients who had been diagnosed with definite MD and given course(s) of ITD treatment were included. Vertigo control, pure tone average and functional disability scores were evaluated against the American Academy of Otolaryngology-Head and Neck Surgery guidelines for MD.

RESULTS

Vertigo disappeared or was substantially controlled in 58.8% and 23.5% of the patients, respectively, after the first ITD course. A repeated course further raised the complete vertigo control rate by 15.7% and intra-tympanic gentamycin injection could be postponed or avoided in 78.6% of the patients who required repeated IT treatment. Hearing was unchanged after the first course of ITD (p > .05). No significant differences were detected in the clinical profiles or laboratory findings between patients receiving single course of ITD and those on multiple courses (p > .05).

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.

Sudden Sensorineural Hearing Loss: Primary Care Update

The primary care physician's role in recognizing sudden sensorineural hearing (SSNHL) loss and delivering initial treatment is critical in the management of the syndrome. This role involves recognizing its clinical symptoms, distinguishing it from conductive hearing loss with the Weber tuning fork or the Rauch hum test, and urgent administration of high dose oral corticosteroids. Diagnosis and treatment should not be delayed for audiometric testing or referral to otolaryngology. This paper provides an update on the initial evaluation and treatment of this syndrome based on the literature and clinical guideline recommendations.