Ménière's disease

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Ménière's disease is a disorder of the inner ear that can affect hearing and balance. It is characterized by episodes of dizziness and tinnitus and progressive hearing loss, usually in one ear. It is caused by an increase in volume and pressure of the endolymph of the inner ear. It is named after the French physician Prosper Ménière, who first reported that vertigo was caused by inner ear disorders in an article published in 1861.^[1]

Historical Background

Ménière's disease had been recognized prior to 1972, but it was still relatively vague and broad at the time. Committees at the Academy of Ophthalmology and Otolaryngology made set critera for diagnosing Ménière's, as well as defining two sub categories of Ménière's: cochlear (without vertigo) and vestibular (without deafness).

In 1972, the academy defined critera for diagnosing Ménière's disease as:

1. Fluctuating, progressive, sensorineural deafness.
2. Episodic, characteristic definitive spells of vertigo lasting 20 minutes to 24 hours with no unconsciousness, vestibular nystagmus always present.
3. Usually tinnitus.
4. Attacks are characterized by periods of remission and exacerbation.

In 1985, this list changed to alter wording, such as changing "deafness" to "hearing loss associated with tinnitus, characteristically of low frequencies" and requiring more than one attack of vertigo to diagnose. Finally in 1995, the list was again altered to allow for degrees of the disease:

1. Certain - Definite disease with histopathological confirmation
2. Definite - Requires two or more definitive episodes of vertigo with hearing loss plus tinnitus and/or aural fullness
3. Probable - Only one definitive episode of vertigo and the other symptoms and signs
4. Possible - Definitive vertigo with no associated hearing loss^[1]

Cause

The exact cause of Ménière's disease is not known, but it is believed to be related to endolymphatic hydrops or excess fluid in the inner ear. It is thought that endolymphatic fluid bursts from its normal channels in the ear and flows into other areas causing damage. This may be related to swelling of the endolymphatic sac or other tissues in the vestibular system of the inner ear, which is responsible for the body's sense of balance. The symptoms may occur in the presence of a middle ear infection, head trauma or an upper respiratory tract infection, or by using aspirin, smoking cigarettes or drinking alcohol. They may be further exacerbated by excessive consumption of caffeine and salt in some patients. Excessive levels of potassium in the body (usually caused by the consumption of potassium rich foods) may also exacerbate the symptoms.

It has also been proposed that Ménière's symptoms are the result of damage caused by a herpes virus ^[1][1]. Herpesviridae are present in a majority of the population in a dormant state. It is suggested that the virus is reactivated when the immune system is depressed due to a stressor such as trauma, infection or surgery (under general anaesthesia). Symptoms then develop as the virus degrades the structure of the inner ear.

Symptoms

The symptoms of Ménière's are variable; not all sufferers experience the same symptoms. However, so-called "classic Ménière's" is considered to comprise the following four symptoms:

• Periodic episodes of rotary vertigo (the abnormal sensation of movement) or dizziness.
• Fluctuating, progressive, unilateral (in one ear) or bilateral (in both ears) hearing loss, often initially in the lower frequency ranges.
• Unilateral or bilateral tinnitus (the perception of noises, often ringing, roaring, or whooshing), sometimes variable.
• A sensation of fullness or pressure in one or both ears.

Ménière's often begins with one symptom, and gradually progresses. A diagnosis may be made in the absence of all four classic symptoms.^[1] However, having several symptoms at once is more conclusive than having each individual symptom had separate times.^[1]

Attacks of vertigo can be severe, incapacitating, and unpredictable. In some patients, attacks of vertigo can last for hours or days, and may be accompanied by an increase in the loudness of tinnitus and temporary, albeit significant, hearing loss in the affected ear(s). Hearing may improve after an attack, but often becomes progressively worse. Vertigo attacks are sometimes accompanied by nausea, vomiting, and sweating.

Some sufferers experience what are informally known as "drop attacks" — a sudden, severe attack of dizziness or vertigo that causes the sufferer, if not seated, to fall. Patients may also experience the feeling of being pushed or pulled (Pulsion). Some patients may find it impossible to get up for some time, until the attack passes or medication takes effect. There is also the risk of injury from falling.

In addition to hearing loss, sounds can seem tinny or distorted, and patients can experience unusual sensitivity to noises (hyperacusis). Some sufferers also experience nystagmus, or uncontrollable rhythmical and jerky eye movements, usually in the horizontal plane, reflecting the essential role of the balance system in coordinating eye movements.

Other symptoms include so-called "brain fog" (temporary loss of short term memory, forgetfulness, and confusion), exhaustion and drowsiness, headaches, vision problems, and depression. Many of these latter symptoms are common to many chronic diseases.

Diagnosis

Many disorders have symptoms similar to Ménière's. The diagnosis is usually established by clinical findings and medical history. However, a detailed oto-neurological examination, audiometry and head magnetic resonance imaging (MRI) scan should be performed to exclude a tumour of the cranial nerve VIII (vestibulocochlear nerve) or superior canal dehiscence which would cause similar symptoms. Because there is no definitive test for Ménière's, it is only diagnosed when all other causes have been ruled out.

Ménière’s disease typically starts between the ages of 20 and 50 years. Men and women are affected in equal numbers.- American Academy of Otolaryngology−Head and Neck Surgery

Ménière's typically begins between the ages of 30 and 60 and affects men slightly more than women.^[1][1]

Treatment

Initial treatment is aimed at both dealing with immediate symptoms and preventing recurrence of symptoms, and so will vary from patient to patient. Doctors may recommend vestibular training, methods for dealing with tinnitus, stress reduction, hearing aids to deal with hearing loss, and medication to alleviate nausea and symptoms of vertigo.

Several environmental and dietary changes are thought to reduce the frequency or severity of symptom outbreaks. Most patients are advised to adopt a low-sodium diet^[1], typically one to two grams (1000-2000mg) at first, but diets as low as 400mg are not uncommon. Patients are advised to avoid caffeine, alcohol and tobacco, all of which can aggravate symptoms of Ménière's. Some recommend avoiding Aspartame. Patients are often prescribed a mild diuretic (sometimes vitamin B6). Many patients will have allergy testing done to see if they are candidate for allergy desensitization as allergies have been shown to aggravate Ménière's symptoms.^[1]

Women may experience increased symptoms during pregnancy or shortly before menstruation, probably due to increased fluid retention.

Lipoflavonoid is also recommended for treatment by some doctors.^[1]

Many patients consider fluorescent lighting to be a trigger for symptoms. The plausibility of this can be explained by how important a part vision plays in the overall mechanism of human balance.

The endolymphatic shunt operation consists of opening the mastoid bone and identifying the endolymphatic sac which is located in the posterior fossa dura. To find the sac, the sigmoid sinus is denuded of its bony cover except for a small rectangle of thin bone named Bill's Island, after Dr. William House. The sigmoid sinus is then collapsed with gentle pressure and the sac exposed behind the posterior semicircular canal. The sac is then incised and a shunt tube is inserted. The picture on the right shows a Huang-Gibson tube with a one-way valve that allows fluid to seep out but not back into the sac. This procedure decreases the endolymphatic fluid pressure.^[1]

Treatments aimed at lowering the pressure within the inner ear include antihistamines, anticholinergics, steroids, and diuretics.^[1] A medical device that provides transtympanic micropressure pulses is now showing some promise and is becoming more widely used as a treatment for Ménière's.^[1]

Surgery may be recommended if medical management does not control vertigo. Injection of steroid medication behind the eardrum, or surgery to decompress the endolymphatic sac may be used for symptom relief. Permanent surgical destruction of the balance part of the affected ear can be performed for severe cases if only one ear is affected. This can be achieved through chemical labyrinthectomy, in which a drug (such as gentamicin) that "kills" the vestibular apparatus is injected into the middle ear. The nerve to the balance portion of the inner ear can be cut (vestibular neurectomy), or the inner ear itself can be surgically removed (labyrinthectomy). These treatments eliminate vertigo, but because they are destructive, they are used only as a last resort. Typically balance returns to normal after these procedures, but hearing loss may continue to progress.^[1]

The anti herpesvirus drug Aciclovir has also been used with some success to treat Ménière's Disease^[1]. The likelihood of the effectiveness of the treatment was found to decrease with increasing duration of the disease possibly because the accumulation of viral damage to the inner ear over time meant that suppression of the virus made no significant difference to the symptoms. Morphological changes to the inner ear of Ménière's sufferers have also been found which it was considered likely to have resulted from attack by a herpes simplex virus^[1]. It was considered possible that long term treatment with an acyclovir (greater than six months) would be required to produce an appreciable effect on symptoms. Herpes viruses have the ability to remain dormant in nerve cells by a process known as HHV Latency Associated Transcript. Continued administration of the drug should prevent reactivation of the virus and allow for the possibility of an improvement in symptoms. Another consideration is that different strains of a herpes virus can have different characteristics which may result in differences in the precise effects of the virus. Further confirmation that Aciclovir can have a positive effect on Ménière's symptoms has been reported^[1].

Progression

Progression of Ménière's is unpredictable: symptoms may worsen, disappear altogether, or remain the same.

Sufferers whose Ménière's began with one or two of the classic symptoms may develop others with time. Attacks of vertigo can become worse and more frequent over time, resulting in loss of employment, loss of the ability to drive, and inability to travel. Some patients become largely housebound. Hearing loss can become more profound and may become permanent. Some patients become deaf in the affected ear. Tinnitus can also worsen over time. Some patients with unilateral symptoms, as many as fifty percent by some estimates, will develop symptoms in both ears. Some of these will become totally deaf.

Yet the disease may end spontaneously and never repeat again. Some sufferers find that after eight to ten years their vertigo attacks gradually become less frequent and less severe; in some patients they disappear completely. In some patients, symptoms of tinnitus will also disappear, and hearing will stabilize (though usually with some permanent loss).

See also

• Balance disorder
• Neurectomy
• Superior canal dehiscence syndrome

References

External links

Meniere's Disease at the Open Directory Project

de:Morbus Menièrefr:Maladie de Menière hr:Ménièreova bolest it:Sindrome di Ménière he:מחלת מנייר nl:Ziekte van Ménière ja:メニエール病 no:Ménières sykdomfi:Ménièren tauti sv:Ménières sjukdom