Inner Ear Dysfunction in Thyroid Disease: A Scoping Review

Area of Science:

• Otolaryngology
• Endocrinology
• Internal Medicine

Background:

• Sensorineural hearing loss (SNHL) and vestibular disorders are influenced by various factors, including thyroid diseases.
• Hypothyroidism and autoimmune thyroiditis can impact inner ear function via hormonal, immune, and vascular pathways.
• Potential links exist between thyroid dysfunction and conditions like Meniere's disease (MD) and benign paroxysmal positional vertigo (BPPV).

Purpose of the Study:

• To review and synthesize scientific evidence on the association between thyroid disorders and inner ear dysfunction.
• To evaluate the correlation between hypothyroidism, hyperthyroidism, and auditory/vestibular impairments.
• To identify gaps in knowledge regarding the pathophysiological mechanisms involved.

Main Methods:

• A systematic literature review was conducted following PRISMA guidelines.
• Searches were performed across PubMed, Scopus, and Google Scholar databases.
• Thirty studies investigating thyroid disorders and inner ear dysfunction were included.

Main Results:

• A significant correlation was found between hypothyroidism and hearing impairment.
• Evidence suggests a link between hyperthyroidism and inner ear disorders, especially concerning autoimmunity.
• A notable association exists between thyroid disease and Meniere's disease, though supporting studies are fewer.

Conclusions:

• Hypothyroidism is clearly correlated with auditory function impairment.
• A substantial body of evidence supports an association between thyroid disease and vestibular disorders.
• Further research is required to fully understand the autoimmune, vascular, and metabolic mechanisms underlying these correlations.