What is Autoimmune Inner Ear Disease?
According to www.american-hearing.org, Autoimmune Inner Ear Disease is defined as a syndrome of progressive hearing loss and/or dizziness that is caused by antibodies or immune cells which are attacking the inner ear. In most cases, there is a reduction of hearing accompanied by tinnitus (ringing, hissing, roaring) which occurs over a few months. Variants are bilateral attacks of hearing loss and tinnitus that resemble Meniere’s disease, and attacks of dizziness accompanied by abnormal blood tests for antibodies. About 50% of patients with AIED have symptoms related to balance (dizziness or unsteadiness).
How Can The Immune System Affect Your Ears?
The immune system is complex and there are several ways that it can damage the inner ear. Both allergy and traditional autoimmune diseases can cause or be associated with AIED.
AIED will manifest as a 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.
Testing For AIED
Because of the difficulty in the differential diagnosis of AIED, many have proposed the use of lab tests to assist in the medical diagnosis, such as:
- 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
- Various steroid trials
Autoimmune Inner Ear Disease Treatment
Steroids: There are several protocols for treatment of AIED. In cases with a classic rapidly progressive bilateral hearing impairment, a trial of steroids (prednisone or dexamethasone) for four weeks may be tried. This treatment is inexpensive, but if effective, it is difficult to maintain because of steroid side effects.
Plasmapheresis: It has also been reported recently that plasmapheresis may be beneficial in AIED (Bianchin et al 2010). Plasmapheresis is expensive, must be done periodically (usually monthly), and intrinsically it is only suitable for disorders mediated by antibodies.
Cochlear Implant: Cochlear implantation can be successful in AIED, and it may be indicated when there is acquired bilateral deafness.
Cell and Gene Therapy: Cell therapy involves transplantation of individual stem cells capable of developing into inner ear cells in the ear canal. Gene therapy is the introduction of new genes into native cells, allowing the cells to produce new proteins that improve their ability to function.