Timothy C. Hain, MD Page last modified: March 8, 2013 Spanish version.
AIED defined How common is it ?Diagnosis Treatment
Autoimmune inner ear disease or "AIED" consists of a syndrome of progressive hearing loss and/or dizziness which is caused by antibodies or immune cells which are attacking the inner ear.
The classic picture is reduction of hearing accompanied by tinnitus (ringing, hissing, roaring) which occurs over a few months. Variants are bilateral attacks of hearing loss and tinnitus which resemble Meniere's disease, and attacks of dizziness accompanied by abnormal blood tests for self-antibodies. About 50% of patients with AIED have imbalance.
The immune system is complex and there are several ways that it can damage the inner ear. Both allergy and traditional "autoimmune disease" such as Ankylosing spondylitis, Behcet's, Systemic Lupus Erythematosis (SLE), Sjoegren's syndrome (dry eye syndrome), Cogan's disease, ulcerative colitis, Wegener's granulomatosis, relapsing polychondritis, rheumatoid arthritis, and scleroderma (Amor-Dorado, 2008; Armin Deroee et al, 2009) can cause or be associated with AIED.
Allergy involving the inner ear is traditionally felt to be food related, but there is presently no agreement as to the importance of food allergy.
Ankylosing spondylitis (AS) is a progressive bone disease associated with fusion of the spine. Persons with severe cases of AS may be disabled because of their lack of flexibility. Although one might expect AS to be associated with conductive hearing loss, AS has been reported to be associated with a sensorineural hearing loss in about 28% of patients ( Alatas, Yazgan et al. 2005 )
Susac syndrome (microangiopathy of ear, brain and eye) is a disorder in which deafness, reduced vision, and encephalopathy may all present simultaneously. The encephalopathy manifests with headache, confusion, memory loss, behavioral changes, dysarthria and occasional mutism. The hearing loss is usually bilateral and accompanied by tinnitus and vertigo. According to Susac, it is generally a low-frequency sensorineural loss, resembling that of Meniere's disease. The reduced vision is caused by retinal artery occlusions. MRI images, which are invariably abnormal, reveal multifocal white matter lesions, including the corpus callosum (Susac et al, 2004). This is an unusual location for a white matter lesion as it is not found in the more common types of demyelinating disease, such as MS. Treatment is with immunosuppresants (Clement et al, 2003).
Not all individuals with bilateral sensorineural hearing loss have autoimmune disease. Genetic defects, infections, toxins, advanced age, noise exposure, and conditions of mysterious origin all account for some cases.
How Common is Autoimmune Inner Ear Disease ?
AIED is rare, probably accounting for less than 1% of all cases of hearing impairment or dizziness. The precise incidence is controversial. About 16% of persons with bilateral Meniere's disease, and 6% of persons with Meniere's disease of any variety may be due to immune dysfunction.
What Causes Autoimmune Inner Ear Disease ?
The cause of AIED is generally assumed to be related to either antibodies or immune cells that cause damage to the inner ear. There are several theories as to how these might arise, analogously to other putatative autoimmune disorders:
Bystander damage: In this theory damage to the inner ear causes cytokines to be released which provoke, after a delay, additional immune reactions. This theory might explain the attack/remission cycle of disorders such as Meniere's disease. There is evidence for cytokines in the cochlea including interleukin-1A, TNF-alpha, NFkB P65 and P50, and IkBa (Adams, 2002). Drugs that block TNF such as etanercept (see treatment section) seem to be potentially effective in AIED (Rahmen et al, 2001). The endolymphatic sac lumen expresses TNF-alpha (Satoh et al, 2003), which may be another way wherebye Meniere's disease is linked to AIED. Other autoimmune disorders such as Crohn's disease also seem to be linked to TNF, and other ear diseases such as otosclerosis also are linked to TNF-alpha. (Karosi, Konya et al. 2005)
Cross-reactions: In this theory, antibodies or rogue T-cells cause accidental inner ear damage because the ear shares common antigens with a potentially harmful substance, virus or bacteria that the body is fighting off. This is presently the favored theory of AIED. COCH5B2 has recently been reported to be a target antigen in AIED (Boulassel et al, 2001).
Intolerance: The ear, like the eye may be only an partially "immune privileged" locus, meaning that the body may not know about all of the inner ear antigens, and when they are released (perhaps following surgery or an infection), the body may wrongly mount an attack on the "foreign" antigen.
In the eye, there is a syndrome called "sympathetic ophthalmia", where following a penetrating injury to one eye, the other eye may go blind. The corresponding situation in the ear would be to go deaf in one ear, following trauma or surgery performed on the opposite ear. This theory is not presently in favor for the ear. Nevertheless, over about 20 years of practice the author of this page has seen several patients who develop ear disease in a delayed fashion in the opposite ear treated for an acoustic neuroma, including one patient following gamma knife "surgery". Another interpretation of this observation is that there might be a chronic CSF leak, as these are known to impair hearing on both sides.
There have also been cases reported of development of AIED in the opposite ear after surgery for Meniere's disease (Ochoa and Weider, 2003), 11 years after a temporal bone fracture (ten Cate and Bachor, 2005), and in 2 of 148 patients after stapes surgery (Richards et al, 2002). The author has also seen this occur as a late complication in persons who have had operations for perilymphatic fistula. Lacking much organized data other than the stapes study, and considering our personal observations, we suspect that this occurs in about 1% of patients in which inner ear antigen is released into the body. A systematic error in this reasoning is that in nearly all situations, a CSF leak could also be present.
Genetic factors: There is evidence that genetically controlled aspects of the immune system may increase or otherwise be associated with increased susceptibility to common hearing disorders such as Menieres disease. Bernstein and associates reported that 44% of patients with Menieres, otosclerosis and striatal presbyacusis had one particular extended MHC haplotype (Dqw2-Dr3-c4Bsf-C4A0-G11: 15-Bf:0.4-C2a-HSP70:7.5-TNF), compared to only 7% of controls. Sudden hearing loss in Koreans that does not recover is also associated with HLA-DRB1*04, DQA1 03 and 05 (Yeo et al, 1999; Yeo et al, 2001). The author has also found an association (in the US) with certain types of HLA-types and variants of vertigo in caucasians (unpublished). On the other hand, a recent study by Lopez-Escamez and others performed in Spain found no difference in HLA antigens between 54 patients with definate MD and 534 normal controls (Lopez Escamez et al, 2002). The genetic background of HLA studies is important and it is possible that one group might find HLA differences which are not found in another.
These data are thus conflicted. If there is indeed an association with HLA, at least in certain populations, it would suggest that more of Menieres disease and other progressive syndromes may be caused by immune dysfunction than is presently generally thought. It is important to remember that HLA-typing is relevant when considered in the context of the patient's genetic background. In other words, studies of Korean subjects for example, such as reported by Yeo, may not apply to persons of non-Korean ethnicity.
How is the diagnosis of Autoimmune Inner Ear Disease made?
The diagnosis is based on history, findings on physical examination, blood tests, the results of hearing and vestibular tests, MRI scans, and response to immunosuppressive medications. The usual clinical picture is a subacute bilateral progressive sensorineural hearing loss.
|Patient with a hearing loss that partially responded to steroids over several weeks.|
Steroid responsiveness is the most useful method of making the diagnosis, and ordinarily the diagnosis is made by observing a bilateral progressive sensorineural hearing loss that responds to sterods.
Other tests may be proposed based on the clinical situation.
As auditory neuropathy can present with a progressive bilateral sensorineural hearing loss, ABR testing should be done in persons with enough hearing for the test to be practical. Otoacoustic emmission tests should be done in those in whom ABR testing cannot be done. MRI scans ot the brain are useful to diagnose Susac's syndrome (see above), as well as to exclude possible confounding disorders, such as acoustic neuroma.
While specific tests for autoimmunity to the inner ear would be desirable, at this writing (7/2004) there are none that are both commercially available and proven to be useful. (Garcia Berrocal et al, 2002). Here is a partial list of blood tests.
A small study recently suggested that FDG PET scans may be useful in AIED. (Mazlumzadeh et al, 2003). More investigation of this modality is needed before it's role in diagnosis can be defined. The cost is clearly prohibitive.
As there are no specific tests for AIED, a common approach is to look for other evidence for autoimmune involvement.
Blood tests for autoimmune disorders, ordered from most to least useful, include:
Blood tests for conditions that resemble autoimmune disorders, again from most to least useful, include:
Recently it has been suggested that blood levels of TNF, tumor necrosis factor, is both diagnostic and predictive of treatment response (Svarkic, 2012). As TNF is a nonspecific inflammatory cytokine, we are dubious as we think that TNF should logically be elevated in many conditions.
MRI testing is mainly done to exclude other entities, but occasionally enhancement is seen of the cochlea.
How is Autoimmune Inner Ear Disease Treated ?
In cases with a classic rapidly progressive bilateral hearing impairment, a trial of steroids (prednisone or dexamethasone) for 4 weeks may be tried. In persons with response to steroids, in most cases a chemotherapy type of medication such as Cytoxan will be used over the long term (Sismanis et al , 1994; Sismanis et al, 1997), as long term high-dose steroids can result in severe side effects. While often patients are converted over to methotrexate, this has been shown ineffective by Harris (2003).
In the author's practice, persons who respond to steroids are considered for treatment with Enbrel (see below), but this is presently not commonly used.
Plasmapheresis may be beneficial (Luetje and Berliner, 1997; Hussain et al, 2005). Plasmapheresis requires periodic visits using a machine similar to a dialysis unit.
Methotrexate, a chemotherapy and arthritis drug, has been shown to be ineffective in a large multicenter study (Harris et al, 2003).
Intravenous immunoglobulin has been reported successful in a single case with scleroderma (Deroee et al, 2009).
We have one patient with RA and AIED who is doing very well on Orencia ( Abatacept). This is a drug approved for rheumatoid arthritis, that prevents T-cell activation. We are not sure if it is a generally good drug for AIED, and as it is expensive and difficult to prescribe due to insurance company restrictions, we may never know. This type of drug would seem a good choice for autoimmune disorders mediated by cellular immunity.
Etanercept (Enbrel) is a promising agent for treatment of AIED (Rahmen et al, 2001; Wang et al, 2003). Enbrel is an anti-TNF (tumor necrosis factor) drug. TNF is an inflammatory cytokine (see above). Wang et al recently reported that etanercept given acutely in sterile experimental labyrinthitis resulted in much better hearing results in an animal model. On the other hand, Cohen et al (2005) reported that Enbrel was no better than placebo in persons with chronic AIED in restoring hearing lost to the disease. We don't feel that this is surprising or very meaningful, as we would not expect that Enbrel could cause hair cells to spring back to life from the dead. In our clinical practice, we have had generally very good results in our patients with steroid responsive, progressing AIED and we feel that because of the study design (chronic hearing loss, no requirement for steroid response), that Enbrel is still worth trying.
Enbrel is given as an subcutaneous injection once/week, usually between 25 and 50 units. Enbrel has generally been well tolerated but according to the manufacturer's information, people on Enbrel have developed serious infections (2%), nervous system disorders, and depression/personality disorders (1%).
A related agent, (infliximab) Remicade, was not found useful for AIED, but this study was based on only a handful of cases (Pyykko et al, 2002). Remicade is also not suitable for home use. There are newer agents that are in the drug pipeline that will need to be tested for their efficacy. Of the newer anti-TNF drugs, the most interesting is Humira, which is another anti-TNF drug, which was recently approved by the FDA (12/2002). It is not known so far whether this drug is useful in AIED.
Drugs already available in the world that are also anti-TNF agents include thalidomide, pentoxifylline (a vasodilator used for poor circulation), and rolipram (an antidepressant available in Japan and Europe). These drugs have not been tried in AIED.
None of these drugs has an official FDA indication for AIED. There recently has been some concern about these drugs affecting other health problems such as how well the body fights infection or kills tumor cells. In controlled studies of all TNF-alpha blocking drugs, more cases of lymphoma have been noted in treated patients than controls. Lymphomas are also often seen with use of other immunosuppresants including azathiprine and/or mercaptopurine. It is also generally felt that when these drugs are in use there should be increased vigilance for reactivation of tuberculosis.
Another significant problem with use of Enbrel as well as related drugs is it's very high cost and lack of uniform insurance coverage. This is an expensive drug, and insurance companies often simply balk at paying for it, saying that it is experimental. If one has an autoimmune disease where Enbrel is already approved, there generally is no problem. However, you may be out of luck if you don't have an "indicated" disease such as rheumatoid arthritis or psoriasis.
In animals, attempts have been made to treat variants of AIED with oral collagen (Kim et al, 2001). Relapsing polychondritis is a disorder in which there may be antibodies to collagen and acquired deafness.
Autoimmune inner ear disease is rare, making it difficult to study. One can speculate that there might be effective treatments that simply have not been discovered. For example, there are numerous potential treatments that have not been tried in a formal way. Gamma globulin infusions, given monthly, are useful in numerous autoimmune disorders. This treatment is very expensive, which limits its use. Immune modulating drugs such as are used for treatment of MS (beta-interferon, alpha-inteferon, copaxone) have not been tried in AIED, to this author's knowledge. Other medications that have coincidental suppression of immune responses, such as minocycline, or other anti-TNF drugs (see above), might be tried.
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