The endolymphatic sac as the immunocompetent organ of the inner ear

Relapsing autoimmune inner ear disease with significant response to methotrexate and azathioprine combination therapy: A case report and mini literature review

RATIONALE

Autoimmune inner ear disease typically presents with bilateral hearing loss that progresses over weeks or months though its mechanisms are unknown. Corticosteroids are the first-line treatment, but their responses are variable and relapses are frequent. Thus, many experts have sought to replace corticosteroids with immunosuppressive agents.

PATIENT CONCERNS

A 35-year-old woman experienced a progressive hearing impairment, initially on the left side and later becoming bilateral. Her response to corticosteroid monotherapy was temporary, and there have been two relapse episodes over several months.

DIAGNOSES

Autoimmune inner ear disease was considered due to evidence of autoimmunity combined with a clinical course of bilateral and recurrent sensorineural hearing loss and a partial response to corticosteroid therapy.

INTERVENTIONS

The patient received a 3-day mini-pulse of methylprednisolone at 250 mg/d, followed by 12 mg/d maintenance, and concurrently began an azathioprine regimen gradually increasing to 100 mg/day as a corticosteroid-sparing agent.

OUTCOMES

Three weeks after immunosuppressive therapy, hearing and pure-tone audiometry improved, and after 7 weeks, methylprednisolone was tapered to 8 mg/d. The dosage was further reduced by adding methotrexate at 7.5 mg/week, resulting in a reduction to 4 mg/d as maintenance therapy after 4 weeks.

LESSONS

For patients who are unresponsive to corticosteroids or experience difficulty tolerating them, a combination therapy of methotrexate and azathioprine is recommended as a viable alternative as this regimen is well-tolerated and yields positive outcomes.

The Role of Autoimmunity in the Pathogenesis of Sudden Sensorineural Hearing Loss

Sudden sensorineural hearing loss (SSHL) is a clinically common acute symptom in otolaryngology. Although the incidence of SSHL has increased around the world in recent years, the etiology of the disease is still unclear. It has been reported that infections, ototoxic drugs, membrane labyrinth rupture, carcinomas, circulatory system diseases, autoimmune diseases, brain lesions, mental diseases, congenital or inherited diseases, and so on, are all risk factors for SSHL. Here, we discuss the autoimmune mechanisms behind SSHL, which might be induced by type II–IV allergic reactions. We also introduce the main immunosuppressive medications that have been used to treat SSHL, which will help us to identify potential targets for immune therapy.

Intratympanic Steroids for Idiopathic Sudden Sensorineural Hearing Loss

Objectives:

We undertook to evaluate the effectiveness of intratympanic (IT) steroid injections for treating idiopathic sudden sensorineural hearing loss (ISSHL) by performing a retrospective case series study in a private otology practice.

Methods:

A total of 21 eligible patients with ISSHL were included. We defined ISSHL as a hearing loss of 20 dB or more at at least 3 consecutive audiometric frequencies that develops within 72 hours or less and cannot be attributed to any commonly identifiable cause of sudden hearing loss. Three IT injections of 0.4 mL of 62.5 mg/mL methylprednisolone solution were administered 1 week apart. The end point for the study was a clinically significant change in audiometric values, with a positive response determined to be a 10-dB or greater improvement in the 4-tone pure tone average and/or a 15% or greater improvement in the word discrimination score. Audiometric data were recorded just before therapy and 1 week after the last IT treatment. The potentially confounding variables recorded included age, sex, “prompt treatment” (defined as treatment within 14 days from onset), concurrent or prior treatment with oral steroids, and severity of hearing loss.

Results:

The overall response rate to the IT steroid protocol was 67% (14 of 21 patients), with a 95% confidence interval of 43% to 85%. Backward stepwise logistic regression identified “prompt treatment” as the only variable that significantly affected the outcome. The response rate of the “prompt treatment” cohort was 91% (10 of 11 patients), with a 95% confidence interval of 59% to 100%.

Conclusions:

These findings support the use of IT steroids as an early intervention in the treatment of ISSHL.

Rezidivierende Tiefton-Hörverluste ohne Schwindel – ein eigenes Krankheitsbild?

BACKGROUND

Besides the typical attacks of dizziness, recurrent low-frequency sensory hearing loss--together with mostly low-frequency tinnitus--is also a characteristic sign of Menière's disease. It is therefore often assumed to be a prodromal sign of Menière's disease, even without dizziness.

METHODS

During our longitudinal study, which was started in 1995, we reported that there were 81 patients with recurrent low-frequency hearing loss with no initial vertigo in the first suspense year of 1999. After a further 6 years, we investigated 46 (57%) of these original 81 patients in the second suspense year, 2005, for new components of vertigo, with the questions of development of Menière's disease and further development of the patients' hearing ability and psychic situation in mind.

RESULTS

In all, 12 (26%) of the 81 former patients suffered from vertigo, but only 4 (9%) had developed the typical signs of full-blown Menière's disease with the typical labyrinthine vertigo. Of the 12 patients who suffered from vertigo, 6 (13% of the 81 with vertigo) were diagnosed with psychogenic vertigo, 1 (1%) suffered from benign and treatable paroxysmal positional vertigo and 1 (1%) had developed vertigo after acoustic neurinoma surgery.

CONCLUSIONS

We conclude from our observations that, although almost every patient with Menière's disease suffers from recurrent low-frequency hearing loss, only a few patients with recurrent hearing loss develop Menière's disease. However, many patients with low-frequency sensory hearing loss develop anxiety leading to psychogenic dizziness in fearful expectation of "imminent" Menière's disease. We found that 26% of the patients had persisting bilateral normacusis in the low-frequency ranges, while 34% had unilateral hearing loss that was sufficiently severe to affect their lives and 39%, bilateral hearing loss; however, none of the patients became completely deaf.

Autoimmune vestibulo-cochlear disorders

Autoimmune vestibulo-cochlear disorders (AVCD) represent a group of syndromes with overlapping clinical features, manifesting as sensorineural hearing loss, often associated with vertigo, tinnitus, and aural fullness, and believed to be caused by an autoimmune mechanism. Although definitive evidence of a classic "autoimmune process" is still lacking, substantial indirect evidence has accumulated to strongly indicate such a pathogenesis. Rapidly progressing AVCD is analogous to rapidly progressive glomerulonephritis in that inner ear inflammation progresses to severe, irreversible damage within 3 months of onset (and often much more quickly). Thus patients with rapidly progressive AVCD are treated with a sense of urgency. Prompt treatment with corticosteroids and other antirheumatic/immunosuppressive agents can preserve hearing and vestibular functions. We are not aware of any randomized controlled clinical trials evaluating the efficacy of antirheumatic/immunosuppressive agents in AVCD. In this article we review reports of various therapies that have been tried in this condition and our experience of etanercept therapy in AVCD.