Autoimmune Inner Ear Disease

February 2006

Barbara "Barbie" Bell-Lehmkuhler

Brian McCabe, MD, first described autoimmune sensorineural hearing loss in his landmark 1979 paper. McCabe described a series of 18 patients whose "clinical pattern did not fit with known entities and thus seemed to merit distinctive categorization." Since that time, autoimmune inner ear disease (AIED) or immune-mediated sensorineural hearing loss, has taken its place as a cause of sensorineural hearing loss and vestibular symptoms.

AIED occurs when the body's immune system attacks cells in the inner ear that are mistaken for a virus or bacteria. AIED is a rare disease occuring in less than 1% of the 28 million Americans with a hearing loss. It can happen in isolation (as just labyrinthine disease) or as part of other systemic autoimmune disorders. Twenty percent of patients have other autoimmune diseases, such as rheumatoid arthritis or lupus.

The exact clinical description can vary somewhat; however, most agree that the syndrome follows a fairly typical course. AIED will manifest as rapidly progressing, sensorineural hearing loss that is most commonly bilateral. Typically, it begins unilaterally and ultimately affects the other ear, and it can occur suddenly. Word recognition is usually disproportionately poor. Vestibular symptoms can have a fluctuating course during the active phase of disease. Additionally, tinnitus, as a ringing, roaring, or hissing noise, may be present. Diagnosis can be difficult because AIED can mimic other ear disorders. In any patient with presumed AIED, it is essential to rule out other causes of progressive sensorineural hearing loss, such as acoustic neuroma, neurosyphilis, and Meniere's, as well as other metabolic conditions.

Because of the difficulty in the differential diagnosis of AIED, many have proposed the use of lab tests to assist in the medical diagnosis. McCabe originally recommended an "immune screen" to include

• Erythrocyte sedimentation rate, which is a general indicator of inflammation;
• Rheumatoid factor, which is a marker for rheumatoid arthritis and other autoimmune diseases;
• Anti-nuclear antibody titer, to check for lupus and other autoimmune diseases;
• quantitative immunoglobulin determination; and
• A leukocyte migration inhibition test.

Later, Campbell and Klemens (2000) listed other medical tests they commonly use to detect AIED:

• CBC (complete blood count) to check for leukemia or other hemolytic disorders;
• FTA/ABS blood screen for syphilis;
• MRI, with contrast, of brain and cerebellopontine angle to check for MS, vascular lesions, and space-occupying lesions;
• Lymphocyte blast transformation to check for inner ear antigen, which may underlie AIED (the efficacy of this test is controversial);
• Rheumatoid factor and anti-nuclear antibody, as mentioned above;
• Lipid panel to check for dylipemias; and
• Steroid trial.

Many have also cited the use of the test for heat shock protein-70 (HSP-70). Positive response on this test correlates well to how well a patient will respond to steroids (Derebery, 2001).

Ultimately, many diagnose AIED by the positive response to steroid treatment. Steroids (dexamethasone, prednisone, prednisolone) are often used for the treatment of AIED. High doses, often in doses of 40-80 gm/day, may be useful in the initial management of AIED. Unfortunately, hearing improvement is rarely sustained and unacceptable side effects from the corticosteroid therapy soon follow (Matteson et al., 2003). Other agents such as Methotrexate (a chemotherapeutic agent) and immune modifying drugs such as Enbrel or Imuran are used and are being investigated. Reportedly, 6% of the AIED patients progress to the point of profound loss. Most do extremely well with an implant.

As mentioned above, 20% of patients have other autoimmune diseases. Here is a list of some of the systemic immune diseases that have been known to have AIED:

• Cogan's syndrome-this syndrome includes ocular inflammation and associated vestibulo-auditory dysfunction,
• Relapsing polychondritis,
• Systemic lupus erythematosus,
• Wegener's granulomatosis,
• Polyarteritis nodosa,
• Sjogren's syndrome, and
• Lyme disease.

About the Author

Barbie Bell has been a practicing clinical audiologist for 20 years now. She got her start at the House Ear Clinic in Los Angeles immediately after grad school. In 1993, she moved to the Denver metro area where she continues to work clinically at RidgeGate Hearing Clinic. Barbie has also done software training for a hearing aid manufacturer and now works part time as a professional reviewer of audiograms with Associates in Acoustics. She is pursuing her AuD from Central Michigan University with hopes of graduating in the spring of 2006.

References

Campbell, K.C., & Klemens, J. J. (2000). Sudden hearing loss and autoimmune inner ear disease. Journal of the American Academy of Audiology, 11, 361–367.

Derebery, J. (2001, November 26). Interview with Jennifer Derebery, M.D, House Ear Clinic, Autoimmune Inner Ear Disease. Audiology Online. Available from http://www.audiologyonline.com/interview/displayarchives.asp?interview_id=92.

Matteson, E. L., Fabry, D. A., Strome, S. E., Driscoll, C. L., Beatty, C. W., & McDonald, T. J. (2003). Autoimmune inner ear disease: Diagnostic and therapeutic approaches in a multidisciplinary setting. Journal of the American Academy of Audiology, 14, 225–230.

McCabe, B. (1979). Autoimmune sensorineural hearing loss. Annals of Otolgy, Rhinology and Laryngology, 88,585–589.