What Is Meniere's Disease? What Causes Meniere's Disease?

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Main Category: Ear, Nose and Throat
Also Included In: Hearing / Deafness
Article Date: 15 Sep 2009 - 3:00 PDT

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Meniere's disease (Ménière's disease) is a condition with vertigo, tinnitus (ringing, buzzing, noises in the ears) and progressive deafness. Meniere's disease is caused by a dysfunction of the endolymphatic sac (semi-circular canals) in the inner ear - also known as the labyrinth. The labyrinth is a system of small fluid-filled channels that send signals of sound and balance to the brain. It is an unpredictable disease that requires various types of treatment.

It is estimated at approximately 1 in every 1,000 people suffers from Meniere's disease. The disease can develop at any age, but more commonly does so when the patient is aged between 40 and 60.

According to the National Institute of Deafness and Other Communication Disorders approximately 615,000 Americans in the USA have the disease.

The disease is named after Prosper Meniere (1799-1862), a French physician who first reported that vertigo was caused by inner ear disorders in an article published in 1861.

What are the signs and symptoms of Meniere's disease?

Symptoms vary from person-to-person. Symptoms can occur suddenly, and their frequency and duration differ. A symptom is something the patient feels or detects, such as dizziness, while a sign is something other people, including a doctor, may notice, such as a rash.

The principle symptoms include:

• Vertigo - usually the most striking Meniere's disease symptom, which includes:
  
  
  • A feeling that you are spinning, even when you are stationary.
  • Dizziness
  • Vomiting
  • Nausea
  • Irregular heartbeats (palpitations)
  • Sweating
  
  An episode of vertigo may last from a few minutes to a number of hours. As it is difficult to predict when a vertigo attack may occur, patients should have their vertigo medication handy at all times. Vertigo can interfere with driving, operating heavy machinery, climbing ladders/scaffolding, and swimming.


• Tinnitus - you sense noise or ringing, buzzing, roaring, whistling or hissing in your ear, which is generated from inside your body. You will be more aware of it either during quiet times or when you are tired.


• Hearing loss - hearing loss may fluctuate, especially early on in the course of the disease. The patient may also be especially sensitive to loud sounds. Eventually, most people experience some degree of long-term hearing loss.

The three stages of Meniere's disease

• Early stage - sudden and unpredictable episodes of vertigo. Often the patient will experience nausea, dizziness and vomiting during the episodes. An episode may last from about 20 minutes to a full 24 hours. During episodes there will be some hearing loss, which returns to normal after it is over. The ear may feel uncomfortable and blocked, with a sense of fullness or pressure (aural fullness). Tinnitus is also common.


• Middle stage - vertigo episodes continue, but are usually less severe. Tinnitus and hearing loss, on the other hand, get worse. Some patients during this stage may experience periods of complete remission - symptoms just go away and seem to have gone forever. These periods of remission can last several months.


• Late stage - vertigo episodes become even less frequent, and in some cases never come back. Balance problems, though, continue. Patients will feel especially unsteady when it is dark and they have less visual input to help maintain balance. Hearing and tinnitus typically get progressively worse.

The following symptoms are also possible (known as secondary symptoms)

• Anxiety, stress, depression - because of Meniere's disease's unpredictability many patients become, anxious, depressed and stressed. The disease can have a detrimental impact on the sufferer's work, especially if they have to climb ladders or operate machinery. As hearing gets progressively worse the patient may find it more difficult to interact with other people.
  
  
  Some people cannot drive, further limiting their independence, job prospects, freedom and access to social contacts. It is important for patients who experience stress, anxiety and/or depression to tell their doctor.

What causes Meniere's disease?

Experts believe the disease is caused by an abnormality in the composition and/or amount of fluid in the inner ear. However, they do not know what factors cause these inner-ear changes.

In the inner ear there is a cluster of connected passages and cavities - a labyrinth. The outer part of the inner ear is where the bony labyrinth is. Inside there is a soft structure of membrane (membranous labyrinth), which is a smaller version of the bony labyrinth with a similar shape.

The membranous labyrinth contains endolymph - a fluid. The membranous labyrinth has hair-like sensors that respond to the fluid's movement. The sensors create nerve impulses that travel to the brain. Different parts of the inner ear are actively involved in various types of sensory perception:

• Our ability to detect our own acceleration movement in any direction comes from sensors in a portion of the membrane in the vestibule (the center section of the labyrinth).


• Three loops (semicircular canals) branch off from one side of the vestibule. The sensors in the semicircular canals help us maintain balance; they sense our own rotational motion.


• On the other side of the vestibule is the cochlea (a structure shaped like a snail) - this is the hearing part of the inner ear. Bones in the middle ear vibrate and create waves in the inner ear fluid - the sensors in the cochlea interpret these waves and translate them into impulses which are sent to the brain.

For all of the sensors in the inner ear to work properly, the fluid has to be at the right pressure, volume and chemical composition. Certain factors present in Meniere's disease alter the properties of the inner ear fluid, which cause the disease's symptoms.

Meniere's disease very rarely affects both ears.

How is Meniere's disease diagnosed?

Unfortunately, no single test exists for a quick Meniere's disease diagnosis. The GP (general practitioner, primary care physician) will interview and examine the patient, ask about their medical and family history, and consider the signs and symptoms.

The doctor will ask questions regarding:

• How severe the symptoms are
• How often symptoms occur
• What medications the patient has been taking
• Past ear problems
• The patient's general health
• The patient's history of infectious diseases or allergies
• Any family history of inner ear problems

All three primary symptoms must be present for a diagnosis of Meniere's disease to be possible:

• Vertigo - two or more episodes, at least 20 minutes long, within a single attack.


• Tinnitus and/or aural fullness.


• Hearing loss - the patient should be referred to an ENT (ear nose and throat) specialist to determine the extent of the hearing loss before diagnosis can be established.

Several other diseases and conditions have similar symptoms, making it harder to diagnose Meniere's disease, including ear infections and some migraines. Usually, diagnosis is established after some time has passed and a pattern of recurrent attacks develops and is observed.

Establishing extent of hearing loss

• Audiogram - this exam determines the extent of hearing loss caused by the disease. An audiometer produces tones of varying loudness and pitch. The patient listens with headphones and indicates when he/she hears a sound, or when a sound is not longer present.
  
  The test only works if the patient has normal hearing in one ear - the specialist can then make a comparison. An audiogram may not be so effective during the early stage because hearing loss is usually temporary.
  
  The test may also determine whether the hearing problem is in the inner ear or the nerve that connects the inner ear to the brain (auditory nerve).

Balance assessment - Many people with Meniere's disease have some degree of ongoing balance problems, even when their sense of balance appears to return to normal between episodes of vertigo.

• Electronystagmography (ENG) - this assesses eye movement to evaluate balance function. Muscles that control eye movement are linked to balance-related sensors in the inner ear - it is this link that allows people to turn their head while focusing their eyes steadily on a single point.
  
  Electrodes are placed on the skin near the eyes and on the patient's forehead. Warm and cool water or air is introduced into the ear canal. Involuntary eye movements in response to this simulation are measured. Abnormalities may indicate an inner ear problem.


• Rotary-chair testing - this test also measures inner ear movement by assessing eye movement. It is usually better tolerated than the ENG. The patient sits in a chair in a small, dark booth. Electrodes are placed near the eyes and a computer-guided chair rotates gently back and forth at varying speeds. The movement stimulates the inner balance system and causes nystagmus (eye movements) that are recorded by a computer and monitored with an infrared camera.
  
  Rotary chair testing does not provide specific diagnostic information about each ear individually - unlike the ENG.


• VEMP (vestibular evoked myogenic potentials) testing - this test measures the function of the sensors in the vestibule of the inner ear that detects acceleration movement. These sensors are slightly sensitive to sound. When exposed to sound the neck muscles contract at varying degrees. VEMP testing can indirectly measure inner ear function.


• Posturography - this test determines which part of the balance system the patient relies on the most, and which may cause problems. The patient wears a safety harness, stands barefoot on a special platform and has to keep his/her balance under various conditions. We rely on various senses for balance, including vision, inner ear, or sensations in our skin, muscles, tendons and joints.

A doctor may wish to rule out other possible diseases and conditions, such as a brain tumor or multiple sclerosis. In order to do so, the following tests may be ordered:

• MRI (magnetic resonance imaging) scan - a magnetic field and radio waves created a 3-D image of the brain on a computer screen (monitor).


• CT (computerized tomography) scan - many X-ray images produce cross-sectional images of internal structures of the body.


• Auditory brainstem response audiometry - a computerized measure of auditory function using responses produced by the auditory nerve at the brainstem. This test is also known as brainstem evoked response audiometry. This test can determine whether a tumor is disrupting the function of the auditory nerves.

What are the treatment options for Meniere's disease?

Although there is no cure, there is treatment that can help the patient manage some of the symptoms of Meniere's disease.

Medications for vertigo - the individual may be prescribed medication to be taken during an episode of vertigo to reduce the intensity of an attack. These may include:

• Motion sickness drugs - examples include meclizine (Antivert) or diazepam (Valium). They may help with the spinning sensation, as well as nausea and vomiting.


• Drugs for nausea - prochlorperazine has been shown to be effective in the treatment of nausea during a vertigo episode.

Diuretics - a combination of triamterene and hydrochlorothiazide (Dyazide, Maxzide) will reduce fluid retention. By reducing the amount of fluid the body retains the patient's fluid volume and pressure in the inner ear may improve, resulting in less severe and less frequent Meniere's disease symptoms.

Long-term diuretic medication may deplete body levels of minerals, such as potassium. Patients should supplement their diet with potassium-rich foods, such as bananas, cantaloupe, spinach, sweet potatoes and oranges.

Dietary changes - there are some dietary changes which can help reduce fluid retention. Generally, the less fluid retention a patient has the less severe and frequent his/her symptoms Meniere's disease symptoms will be. These measures are known to help:

• Many smaller meals evenly distributed throughout the day helps regulate body fluids. Rather than three large meals a day, try to go for six smaller ones.


• Eat less salt - the less salt you consume the less fluid your body will retain. Do not add any salt to your meals. Cut out most junk foods.


• Cut out MSG (monosodium glutamate) - any foods with MSG added should be struck off your shopping list.

Caffeine - caffeine has been shown to make tinnitus louder. If you avoid caffeine completely you may find symptoms improve.

Smoking - a significant number of patients report improved symptoms after they give up smoking.

Stress, anxiety - experts are not sure whether stress/anxiety cause symptoms or whether they are caused by the disease. However, some studies indicate that good stress and anxiety management may help lessen the intensity of symptoms. If your levels of anxiety, stress, and possibly depression are affecting your life, or if you would like to have better control, talk to your doctor. Professional psychotherapy, as well as some medications have been known to help many patients with Meniere's disease.

Middle ear injections - some middle ear injections (injected into the middle ear) may improve symptoms of vertigo. They include:

• Gentamicin - this is an antibiotic that reduces the balancing function of the ear so that the other ear takes over the body's balance. Gentamicin may reduce the severity and frequency of vertigo attacks. There is a risk of further hearing loss.


• Steroids - some patients report better control over vertigo attacks with such steroids as dexamethasone. Dexamethasone is less effective than gentamicin, but has a much lower risk of causing further hearing loss.

Surgery - this may be an option if the patient did not respond to other treatments, or if symptoms are very severe. Surgery options include:

• Endolymphatic sac decompression - a small portion of bone is removed from over the endolymphatic sac. Occasionally, a shunt is placed (a tube that drains excess fluid from the inner ear).


• Labyrinthectomy - a portion of the inner ear is surgically removed. This takes away both the hearing and balance function of the affected ear. This procedure is only done if the patient is either totally, or almost totally deaf in that ear.


• Vestibular nerve section - the vestibular nerve is cut. This nerve connects the balance and movement sensors in the inner ear to the brain. A vestibular nerve section is aimed at preserving hearing in the affected ear, while addressing the problems with vertigo.

Vestibular rehabilitation therapy - patients who have problems with their balance between episodes of vertigo may benefit from exercises and activities aimed at helping the body and the brain regain the ability to process balance data properly.

Hearing aid - a patient with Meniere's disease who has suffered hearing loss from the affected ear may benefit from a hearing aid. A hearing aid is an instrument to help in hearing.

What are the complications of Meniere's disease?

The biggest problem of Meniere's disease is not knowing when episodes of vertigo will occur. The patient may have to lie down and miss out on social, leisure, work, or family activities. Patient's also have a higher risk of falling down, having accidents while driving a vehicle or operating heavy machinery, as well as developing depression or suffering from high levels of anxiety.

Vehicle licensing authorities in many countries, such as the DVLA (Driver and Vehicle Licensing Agency), UK, state that if you drive a car or motorcycle and have recently been diagnosed with Meniere's disease you must cease driving. You will not be allowed to drive again until you have satisfactory control of your symptoms - this will need to be confirmed by your GP or ENT specialist.

A person who drives a large goods vehicle, or a passenger-carrying vehicle, and has been diagnosed with Meniere's disease will have his/her license either revoked or refused. Reapplication for a license is possible after a stipulated period without any symptoms.

Written by Christian Nordqvist


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