The Pathogenesis of secondary forms of Autoimmune Inner Ear Disease (AIED): advancing beyond the audiogram data

ABSTRACT

Introduction

Autoimmune Inner Ear Disease (AIED) can be of a primary or secondary type. To date, a clear pathogenesis of the disease is still not available. Focusing on the secondary forms of AIED, the aim of this review is to (i) assess and describe the hearing involvement in patients affected by autoimmune diseases, (ii) describe the possible association between clinical features (among serological/laboratory data and disease activity/duration) and hearing impairment, (iii) show evidence connecting the AIED types with various etiopathogenetic mechanisms.

Areas covered

A PRISMA-compliant systematic review was performed. Medline, Cochrane, Embase, and Cinahl were searched from 1 January 2015 through to 5 August 2020. Overall, 16 studies (involving 1043 participants) were included in the review. The data in the literature suggested that bilateral mild-to-moderate sensorineural hearing loss is a commonly reported clinical symptom of AIED.

Expert opinion

Patients with systemic autoimmune disorders present a cochlear injury which might be associated with the humoral and/or cellular immune response against the inner ear. To date, AIED pathogenesis remains an open issue, due to the rarity of these clinical entities and due to the difficulties in investigating the inner ear immunology, considering the inner ear inaccessibility for tissue sampling.

KEYWORDS:

• Autoimmune disease
• AIED
• hearing loss
• immune system
• inner ear

Article highlights

• In the secondary AIED cases, most of the inner ear injuries could be related to vascular atrophy, loss of hair cells and spiral ganglion neurons.

• So far, the proposed mechanisms involved in the inner ear damage are: i) immune complex-mediated vasculitis and micro-infarctions of the inner ear, ii) cochlear nerve neuritis; iii) direct immune pro-inflammatory T or B cells response against inner ear proteins/antigens; and iv) drug-induced ototoxicity.

• A middle ear disorder can be present in Juvenile Idiopathic Arthritis (JIA), Rheumatoid Arthritis (RA), Granulomatosis with Polyangiitis (GPA) and Eosinophilic Granulomatosis with Polyangiitis (EGPA), due to the inflammatory involvement of the synovium of the ossicular chain’s joints (JIA and RA) and to chronic granulomatous and effusive otitis media (GPA and EGPA).

• A bilateral mild-to-moderate sensorineural hearing loss is commonly reported in patients with Sjögren syndrome (SS), Systemic Sclerosis (SSc), RA, and Systemic Lupus Erythematosus (SLE).

• Vestibular symptoms represent an underestimated issue in patients with AIED and vestibular investigations should be further implemented.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.