Stanford Ear Institute
Meniere’s Disease (Endolymphatic Hydrops)
What is Meniere’s Disease?
Meniere’s disease (also called “Meniere’s syndrome” or “endolymphatic hydrops”) is a disorder of the inner ear which causes intermittent vertigo (dizziness), hearing loss, tinnitus (ear noises), and ear pressure. The attacks can be quite unpredictable and variable in intensity, frequency, and duration.
The underlying cause of Meniere’s disease is still unknown, although it is related to a disorder of fluid pressures in the inner ear. It affects about 1 in 2,000 people, usually occurring between the ages of 30 and 50 years. Usually only one ear is affected, although about 15% to 25% of people have some symptoms in the other ear during their lifetime.
Although Meniere’s disease can be quite troublesome and disruptive, there are things that can be done to control the symptoms. There is currently no known cure, but the majority of individuals can be helped either through changes in behavior, the use of medications, middle ear injections, or occasionally surgery.
What are the Symptoms?
Vertigo – Attacks of vertigo involve the perception of movemen, which can be a spinning, rocking, or falling sensation. This usually lasts for several hours, and is often associated with nausea, vomiting, and sometimes sweating. Attacks may occur in clusters, or may be spaced out over months or years. There may be some unsteadiness or disequilibrium after an attack which may last for days. The balance problems associated with Meniere’s disease are usually the most disruptive of its symptoms, and so requires the most treatment. In the vast majority of individuals, the attacks of vertigo subside with time, with about 80% of sufferers improving significantly over a 3 to 5 year period.
Hearing loss -- The hearing in the affected ear is usually decreased. The low frequencies are usually affected first. There may also be distortion of perceived sound. The hearing loss often fluctuates in the early stage of the disease, becoming worse just before or during the attacks of dizziness. Although the hearing gradually worsens, Meniere’s disease rarely results in deafness of the affected ear.
Tinnitus -- The perception of noises in the affected ear is common. This is typically a “rushing” sound, although ringing or buzzing also occur. The loudness may vary with time, and often becomes worse just before and during an attack of dizziness.
Ear pressure or fullness -- The affected ear may feel full or “stuffy”. The ear may feel like it “needs to be popped”, and may be confused for a disorder of the eustachian tube. The fullness often gets worse right before an attack of dizziness, and may provide some warning that a dizzy spell is approaching.
What Causes the Symptoms?
The inner ear is both an organ of hearing and balance. Both of these parts of the inner ear contain separate spaces divited by thin membranes. These compartments are filled with different types of fluid, called “perilymph” and “endolymph”.
The perilymph and endolymph surround the hair cells responsible for detecting both sound and motion, and the fluids are critical for maintaining healthy inner ear function. The two fluids are very different chemically, and must be kept separated for the ear to function correctly. One possible cause for the symptoms of Meniere’s disease is from having too much endolymph pressure in the inner ear.
Endolymph is created in a part of the cochlea called the “stria vascularis”, which is similar in many ways to parts of the kidney. This explains why a low salt diet and water pills can help with decreasing endolymph production and lessen symptoms. The endolymph is reabsorbed in a part of the inner ear called the “endolymphatic sac”. It may be that a failure of this sac to remove excess endolymph results in too much fluid in Meniere’s disease.
If there is too much endolymph, it swells and stretches the suurounding membranes. This can cause a sense of pressure in the ear, tinnitus, and hearing loss. If the pressure of the endolymph continues to increase, the inner membrane may burst, allowing mixture of the endolymph with the surrounding perilymph. This causes the ear to “short circuit” and triggers the acute attacks of vertigo seen with the disease. The symptoms improve as the hole in the inner membrane heals, and the fluid return to there normal composition.
With repeated episodes of swelling, bursting, and healing, the inner membrane becomes stretched out and floppy, much as a toy balloon which has been blown up repeatedly. As this occurs, the acute attacks of vertigo improve, however, the hearing loss usually persists.
The disorder of endolymph reabsorption may have a variety of underlying causes. It may be from bacterial or viral infections, head trauma, other metabolic or immune-related disease. In the majority of patients, a cause is never identified.
How is the Diagnosis made?
The diagnosis of Meniere’s disease is made on the basis of the symptoms it causes. There is no single test which “proves” that a patient has Meniere’s disease. There are tests that may help confirm the diagnosis and will exclude other diseases. These tests may include tests of hearing (audiogram), nerve recordings (auditory brianstem respoinse, or ABR), tests of balance (electronystagmogram or “ENG”), blood tests, and possibly radiology scans of the head and ears (MRI).
How is Meniere’s Disease Treated?
Preventing acute attacks
An important part in the management of Meniere’s disease is for the patient to recognize if there is any particular behavior or exposure which seems to precipitate an attack. There may a wide variety of causes, such as emotional stress, food sensitivities, or allergies. If there are particular triggers, identifying and avoiding them is a major step in controlling the disease.
Low salt diet
Just as the intake of salt can affect blood pressure, it can affect the pressure of the inner ear fluids. It is the sodium in salt which is to be avoided. People with Meniere’s disease will often note that eating a high-sodium meal will be predictably followed by an attack 12 to 48 hours later. A diet with less than 1.5 grams (1500 milligrams) of sodium is recommended. This is considerably less than the average American diet, and it requires some determination and planning to follow. There are excellent cookbooks and pamphlets available in most bookstores and pharmacies to help with diet planning.
Diuretics, or “water pills”, can be used with a low salt diet to further reduce the fluid pressure in the inner ear.
Emotional stress, fatigue, or other illness will precipitate an attack in many patients with Meniere’s disease. Finding ways to avoid stress and maintain general good health will often contribute greatly to controlling the attacks. The symptoms of the disease itself if often the source of a great deal of stress, which can itself make the symptoms worse. Professional counseling, or stress-reduction programs are beneficial in many cases. Support groups are available for individuals with Meniere’s disease, and publish informational newsletters which are often helpful.
Avoid certain substances
Caffeine, alcohol, and smoking are other substances that commonly make Meniere’s disease worse and should be avoided.
Treating acute attacks
Vestibular suppressants/ Sedatives
Relaxants such as Ativan, Valium, or Klonopin improve the symptoms of an acute attack by three mechanisms. (1) They suppress the balance disturbance of the inner ear by reducing the abnormal signals sent to the brain, (2) they induce sleep, and (3) they reduce the anxiety caused by an attack. They do not act to prevent the fluid pressure problem responsible for the attack, and so only provide symptomatic relief. Less powerful vestibular suppressants, such as Antivert or Dramamine also work in some cases, but are often inadequate in a severe attack.
These medicines must often be take following an anti-emetic (anti-nausea) medication so that they are absorbed. In severe attacks, these medications may be given in injectable form to bring relief. These medications may be helpful for several days following an acute attack, but rarely are needed chronically.
Medicines which reduce the sensation of nausea (such as Compazine or Phenergan) can bring considerable relief during an acute attack. Often these are more effective when used as a rectal suppository early in an attack so that the medication may be absorbed and allow additional medications so be taken without being vomited before they can work.
In the unusual cases where attacks of vertigo are not controlled with behavior modification, diet, and medicines, surgical procedures may be highly effective. All of the surgical treatments are aimed at reducing the acute vertigo, and none have been shown to improve the hearing loss or tinnitus (ear noises).
Gentamicin is normally used as an antibiotic, but it also can be used to selectively eliminate the balance potion of the inner ear while preserving the remaining hearing. This is performed through sequential injections of the gentamicin through the ear drum in the office. The number of injections needed varies, but overall, about 80% of patients will receive some benefit from this treatment.
In some patients, and injection of steroids (Dexamethasone) into the middle ear can help reduce the severity of the disease. This is not as likely as gentamicin is to cause permanent improvement in attacks of vertigo,. However, there is less risk of hearing loss, and in some cases, a steroid injection can help the hearing improve.
Endolymphatic sac operation
The endolymphatic sac is a portion of the inner ear felt to be central to the origin Meniere’s disease. It is the area where the endolymphatic fluid is reabsorbed, and where the inner ear fluid pressure is regulated. The surgical removal of bone and scar from around this sac allows some patients to better control their inner ear pressure, and so have fewer attacks. About 1/2 to 2/3 of patients who have this operation will improve.
Vestibular nerve section
If the balance nerves to the affected ear are surgically divided, the brain will no longer experience the ear’s abnormal bursts of activity during acute attacks. The balance nerves may be cut while preserving hearing in the majority of patients. The procedure is highly effective in the control of acute attacks, with about 95% of patients experiencing relief. However, it is a more involved operation requiring surgery near the brain, and patients usually need to stay in the hospital for several days to a week.
The complete surgical removal of the organ of balance is termed a “labyrinthectomy.” This is as highly effective as the vestibular nerve section, and the operation has fewer significant complications. The disadvantage of this option is that hearing is permanently lost in the operated ear. It is therefore generally reserved for individuals with no useful hearing on the affected side.
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Stanford Ear Institute