Autoimmune Inner Ear Disease - Causes, Symptoms and Treatment

Introduction:

Autoimmune sudden sensorineural hearing loss, also known as autoimmune inner ear disease, is a condition caused due to the body’s immune reaction against its own cells, mainly affecting the inner ear wall. This cell-mediated immune reaction acts against the cells of the inner ear or protein present in the inner ear. It is a rare disease that progresses gradually over months and is hard to diagnose. It can be present in association with other disorders as secondary autoimmune conditions. Hence, it is important to rule out other autoimmune diseases to confirm the diagnosis. Its occurrence is mainly involving both ears, though not necessarily at the same time. The peculiar characteristic of progression over weeks or months rejects the other differential diagnoses like hearing loss due to trauma or old age. Thorough patient history, evaluation, medical tests, and some imaging is necessary to confirm the autoimmune sudden sensorineural hearing loss. Treatment of this disease mainly includes immunosuppressive agents to stop the progression of the disease and assistive hearing devices and cochlear implants to improve hearing ability.

What Is Autoimmune Sudden Sensorineural Hearing Loss?

It is an immune system malfunction, where the body’s own immune cells attack the inner ear causing hearing loss. It is a rare, rapidly progressing disease with unknown etiology. It can happen primarily or in association with other autoimmune diseases (a secondary autoimmune inner ear disease) and usually involve both ears eventually.

What Are the Types of Autoimmune Sudden Sensorineural Hearing Loss?

• Primary: It is present independently and not associated with any other condition.

• Secondary: It is present in association with other autoimmune disorders.

What Are the Other Autoimmune Diseases Associated With Secondary Autoimmune Sudden Sensorineural Hearing Loss?

• Cogan's Syndrome: It is a rare autoimmune disease that affects both eyes and ears that is characterized by recurrent ocular inflammation and hearing loss, which can result in deafness if not treated.

• Wegener’s Granulomatosis: It is a rare disorder that results in inflammation of blood vessels of the nose, throat, sinuses, lungs, and kidneys.

• Relapsing Polychondritis: It is an uncommon degenerative condition of the cartilage in the body.

• Lyme Disease: It is considered a tick-borne illness, and the causative agent is borrelia bacteria. This disease is characterized by a bull’s eye rash, flu-like symptoms, joint pain, and weakness.

• Systemic Lupus Erythematosus (SLE): SLE (systemic lupus erythematosus) is an autoimmune inflammatory condition that affects joints, skin, blood cells, kidneys, heart, and lungs.

• Polyarteritis Nodosa: It is a not-so-common disorder that is characterized by generalized inflammation, weakness, and damaged arteries. Mostly the small and medium-sized arteries are affected.

• Sjogren’s Syndrome: It is an immune disorder that predominantly causes dry eyes and dry mouth.

What Are the Symptoms of Autoimmune Sudden Sensorineural Hearing Loss?

Common symptoms of autoimmune sudden sensorineural hearing loss are:

• Progressive hearing loss in both ears over weeks to months, which may and may not be at the same time.

• Loss of balance or dizziness.

• Tinnitus or ringing sound in the ears.

• Fluctuating hearing.

• Ear fullness.

• Eustachian tube obstruction due to inflammation of the inner ear causing conductive hearing loss.

• Secondary symptoms due to associated autoimmune disease (tiredness, muscle pain, swelling, redness, fever, etc.).

What Are the Causes of Autoimmune Sudden Sensorineural Hearing Loss?

The causes of autoimmune sudden sensorineural hearing loss can be:

• Autoimmunity Against the Inner Ear: The body’s malfunctioning immune system forms autoantibodies and immune complexes against the inner ear. This will eventually cause the destruction of inner ear cells and result in bilateral hearing loss.

• Autoimmunity Against Cochlin: The body’s immune system forms antibodies against the cochlin protein, which is present in the inner ear wall. Destruction of this protein leads to damage to the inner war wall.

• Dilation of Endolymphatic Sac: As an immune response, the endolymphatic sac (structure present in the inner ear) present in the inner ear may dilate and cause hearing loss.

How to Diagnose Autoimmune Sudden Sensorineural Hearing Loss?

Apart from clinical signs and symptoms, different medical tests are done to diagnose autoimmune sudden sensorineural hearing loss, such as,

• Erythrocyte Sedimentation Rate: It is used as a general indicator in case of inflammation.

• Rheumatoid Factor: It is used as a marker for rheumatoid arthritis and other autoimmune disorders.

• Antinuclear Antibody Titer: It is used to detect lupus and other related autoimmune disorders.

• Quantitative Immunoglobulin Determination: This is a test used to find immunodeficiencies by assessing the quantitative determination of different immunoglobulins.

• A Leukocyte Migration Inhibition Test: This test helps reveal the sensitivity of lymphocytes and the cell-mediated immunity to a particular antigen.

To rule out any other underlying cause for sensorineural hearing loss, other commonly used medical tests are:

• Complete Blood Count: It is helpful to rule out hemolytic disorders or leukemia.

• The Fluorescent Treponemal Antibody Absorption (Fta-Abs) Test: It is done for the identification of antibodies against the bacteria which causes syphilis.

• Magnetic Resonance Imaging (MRI): For brain and cerebellopontine angle help to detect the presence of vascular lesions and space-consuming lesions.

• Lipid Profile: It is done to check for any dyslipidemias. Dyslipidemia refers to abnormally elevated levels of lipids or cholesterol in the circulation.

What Is the Treatment for Autoimmune Sudden Sensorineural Hearing Loss?

A team of different specialists should work and treat autoimmune sudden sensorineural hearing loss. Different treatment approaches should be evaluated based on the progression of the disease, and care should be taken to evaluate the side effects of immunosuppressant agents.

Different therapies used are:

• Steroids: Corticosteroids are mainly used in the treatment of immunosuppression and their effect on the modulation of sodium transport. Although, they also possess the risk of steroid-associated adverse effects.

• Non-steroidal Immunosuppressants: In non-responsive patients with steroid therapy or with unacceptable side effects of steroid therapy, alternative immunosuppressive approaches are used. Cyclophosphamide is used as an effective drug in such cases; however, more research is needed to evaluate its side effects.

• Methotrexate: It is used in Prednisone-sparing treatment as an adjunct to other drug therapies.

• Cytokine Modulation: Blocking of tumor necrosis factor-alpha (TNF - alpha), both systemically and locally, has been used successfully as a treatment for autoimmune sudden hearing loss.

• Cell Modulation: Rituximab has been used as an effective drug in the treatment.

• Plasmapheresis: The procedure has shown some success in improving the hearing capacity of the ears.

• Hearing Aids: Assistive hearing devices can be used to improve hearing ability.

• Cochlear Implantation: Patients who can no longer hear from hearing devices are evaluated for cochlear implantation.

Conclusion:

Autoimmune sudden sensorineural hearing loss happens because of the body’s immune reaction against inner ear cells. Clinical symptoms, history of disease progression, and certain tests can help to diagnose the autoimmune sudden sensorineural hearing loss, also known as autoimmune inner ear disease. It can be treated efficiently with Corticosteroids, though other drug therapies are also found to be effective to some extent. Hearing aids or cochlear implantation can be helpful in some cases to improve hearing ability.