Menieres Disease

Theresa Pitt, Aud.D., F.S.H.A.A., Audiology Services in S.E. Ireland.

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(Acknowledgements to the Otolaryngology Department at the University of Washington)
Meniere's Disease
Meniere's disease, first described in 1861 by the French physician Prosper Meniere, is characterized by multiple symptoms, all associated with excessive fluid in the inner ear involving both the hearing and balance organs. Excessive fluid in the cochlea (hearing organ) = cochlear hydrops. Excessive fluid in the semicircular canals (balance organ) results in dizziness and is vestibular hydrops. Almost all Meniere's patients have both cochlear and vestibular hydrops.

NORMAL HEARING:
Sound travels along the external ear canal, causing the eardrum to vibrate. Three small bones of the middle ear (malleus, incus, and stapes) conduct this vibration from the ear drum to the cochlea of the inner ear, causing waves of fluid in the cochlea to stimulate its delicate hearing cells (hair cells). Movement of the hair cells generates an electrical current in the auditory nerve, which in turn transmits signals to the brain. Through various interconnections these signals are recognized as sound.

SYMPTOMS:
The symptoms of Meniere's are dizzy spells (vertigo) associated with hearing loss, tinnitus, and a feeling of fullness in the ear. These spells occur to varying degrees and last from 20 minutes to a full day. About 80 percent of patients with Meniere's experience the problem in only one ear. Meniere's can occur at any age but it most frequently begins between the ages of 30 and 50. The cause of Meniere's is unknown. Possible contributors are stress, excessive salt intake, and, occasionally, endocrine problems, such as low thyroid function, abnormal glucose (sugar) metabolism, or an inability to handle fats (high cholesterol and/or triglycerides.) Uncommon disorders that mimic Meniere's are auto-immune labyrinthitis, syphilis, head injury, or viral infection of inner ear.

EVALUATIONS:
Tests determine the existence and cause of Meniere's in each patient, though it is not necessary to perform all the tests listed below in every case. Tests are:

Auditory: pure tones and speech discrimination
Glycerol: changes in loudness and/or clarity after drinking glycerine (A positive result is specific for active Meniere's; a negative result may indicate inactive Meniere's, especially when the hearing loss has been present for some time.
Electronystagmography: balance canal function as seen through eye movements
General health evaluation
Auditory brainstem response(ABR) and Otoacoustic emission tests
Balance testing
Antibody measurement
Glucose (sugar) metabolism
Blood: (evaluating for systemic infection)
Magnetic resonance imaging of the inner ear and hearing nerve

MEDICAL MANAGEMENT:
1. No smoking: Patients must abstain from tobacco totally. Nicotine is toxic to the inner ear. Continued use may render all treatments listed below ineffective.
2. Low sodium (low salt) diet: To decrease the amount of fluid in the inner ear, patients are placed on a low sodium diet. This means no additional salt in cooking or at the table.
3. Diuretic: A diuretic is advisable to decrease the body's sodium and water content, but some diuretics decrease potassium excessively. To prevent this, patients should eat potassium-rich foods every day. Good sources of potassium are salt substitutes, orange juice, bananas, dried fruits, raisins, cantaloupe, nectarines, potatoes, and salt-free peanuts. Occasionally, severe weakness and "flulike" symptoms may be caused by potassium loss. It is important for patients with these symptoms to be checked promptly by a physician.
4. No caffeine: Caffeine products (for example, coffee, tea, cola beverages, and chocolate) should not be used by patients with Meniere's. Numerous patients have reported attacks within minutes of caffeine use. Decaffeinated products are fine.
5. Stress avoidance: Episodes of Meniere's frequently occur at times of severe stress and fatigue or immediately following such episodes. Patients should try to avoid situations that produce undue stress. At times, professional counselling is necessary to help patients with stressful problems.
6. Watch for food allergy: In certain patients, episodes of Meniere's are caused by specific foods (for example, chocolate, red wine, wheat, beer, shellfish, and milk products). While this is uncommon, it is desirable to keep a list of foods ingested at the meal preceding each episode to see if any particular food is consistently present.
7. Innovar Therapy: Some patients with frequent vertigo attacks are helped by an intravenous injection of Innovar. This is a potent anesthetic agent and must be given in hospital as a one-time treatment.

PROGNOSIS:
By using these forms of medical management, the disease can be controlled in about 70 percent of patients. This means that attacks of vertigo will be prevented or will be minimal, if they occur. Unfortunately, tinnitus (head noises) seldom disappears. If treatment is started while a patient's hearing is still fluctuating, it is sometimes improved by medical management and may be stabilized in the more advanced disease. In some patients, however, hearing loss will continue to worsen. It is important to remember that Meniere's involves both ears in only 20 percent of patients, and if it is going to involve both ears, it usually does so in the first 2 or 3 years. Medical management is usually effective within 2 months; if not the case, surgery may be considered. A low sodium diet is continued until there are no episodes of dizziness for 2 years, although the diuretic treatment can usually be discontinued a year after the last episode of dizziness.

SURGICAL TREATMENTS:
There are many surgical treatments for Meniere's disease, if and when surgery becomes necessary. The most successful treatments are:
1. Endolymphatic sac surgery. When hearing in the involved ear is good but dizzy spells continue in spite of medical management, an endolymphatic sac surgery is sometimes chosen. The sac is a part of the inner ear that absorbs fluid and extends into the mastoid process behind the ear.Sac involvement in Meniere's is poorly understood but may increase fluid absorption. Performed under general anesthesia, this surgery initially relieves the dizziness in about 75 percent of patients. Long-term relief is achieved in 50-60 percent of cases. Hearing is usually not affected. These results are very similar to a placebo operation. Hearing occasionally improves after surgery but in about 4 percent of patients, hearing worsens as a complication of the surgery. Tinnitus is not usually changed and dizziness is unusual immediately after surgery. Patients are hospitalized overnight.
2. Vestibular nerve section. This procedure is definitive (like labyrinthectomy) but it preserves hearing in over 90 percent of cases. It is a more serious operation, requiring an incision behind the ear and 5 to 7 days in the hospital. Risks include meningitis and a leak of spinal fluid. Control of vertigo is achieved in 95 percent of cases.
3. Labyrinthectomy In patients with severe Meniere's uncontrolled by medical management and where hearing is no longer adequate for communication, a labyrinthectomy has a 95 percent success rate in eliminating major spells. General anesthetia is necessary. Following surgery, there is no hearing or balance function in the operated ear. Patients are usually dizzy after surgery, but gradually stabilize as the unoperated ear takes over the balance function. The dizziness usually lasts 3 to 5 days, but may persist for several weeks. In elderly patients, it is occasionally prolonged. Tinnitus may not be changed by the surgery, in fact, it may worsen. Hearing is totally and permanently destroyed in the operated ear.
Other Resources on Vestibular Disorders on the Internet are on the Adresses page of this Site


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