Menieres Disease

Meniere's disease (endolymphatic hydrops) is an inner ear problem stemming from a labyrinthine dysfunction. It's associated with increased fluid pressure within the labyrinth. Although it usually affects adults between ages 30 and 60, it may begin at any age. It occurs in both sexes.

The disease involves only one ear at first, but about 20% of patients eventually develop problems in both ears. Even with proper treatment, this chronic disease can cause hearing loss.

Causes

The fluid-filled semicircular canals (labyrinths) of the inner ear, in conjunction with the cranial nerve VIII, control balance and sense of body position. Meniere's disease involves a swelling of part of the canal (endolymphatic sac). The endolymphic sac controls the filtration and excretion of the fluid in the semicircular canals.

The exact cause of Meniere's disease is unknown. In some cases, it may be related to middle ear infection (otitis media), syphilis, or head injury. Other risk factors include recent viral illness, respiratory infection, stress, fatigue, use of prescription or nonprescription drugs including aspirin, and a history of allergies, smoking, and alcohol use. There may be genetic risk factors as well.

Signs and Symptoms

In taking the patient's history, note the cardinal symptom or Meni.ere's disease: vertigo. The patient may complain that the symptom has a sudden onset and lasts up to several hours. If the disorder has progressed, the patient may relate that attacks occur more frequently, as often as every 2 or 3 days. The dizziness may be so severe that the patient loses his balance and falls to the affected side.

The patient may also complain about tinnitus that occurs as a low, fluctuating buzzing, hissing, or humming sound in the ear that is often louder before and during an attack; this may be the only symptom the patient notices between attacks. He may report a distortion in sound, hearing loss, and a feeling of pressure or fullness in the affected ear.

Between attacks, the patient may be free of vertigo. The patient may experience imbalance, unsteady gait, history of falls, inability to maintain an upright position or posture, inability to walk heel to toe on examination. visual changes (blurred vision, diplopia), altered taste or smell, and altered communication. In addition, findings may include hypotension, vomiting or diarrhea, changes in lifestyle, withdrawal, depression, fear, anxiety, and panic. Because these signs can mimic other disorders, diagnostic tests must be performed to confirm the diagnosis.

Diagnostic tests

Electronystagmography is used to measure the electropotential of eye movements when nystagmus is produced and provides a graphic recording of labyrinthine function.

Audiometric tests reveal sensorineural loss and loss of discrimination and recruitment. An auditory brain stem response test helps determine if a cochlear or retrocochlear lesion is causing hearing loss.

Magnetic resonance imaging is used to evaluate the structure of the brain and rules out brain lesions or tumors. Laboratory testing must be done to rule out metabolic problems (hypoglycemia or thyroid, lipid, or autoimmune disorders).

Treatment

Management of Meniere's disease aims to eliminate vertigo and prevent further hearing loss. For an acute attack, the patient may assume whatever position is comfortable. Atropine may stop the attack in 20 to 30 minutes. Dimenhydrinate, meclizine, diphenhydramine, or diazepam may relieve a mild attack. A severe attack may respond to epinephrine or diphenhydramine.

Long-term management includes the use of diuretics or vasodilators, vestibular suppressants, labyrinthine exercises, and restricted sodium intake. Prophylactic antihistamines or mild sedatives may also help. Three-fourths of patients respond to a salt­free diet and the use of diuretics. However, diuretic efficacy hasn't been proven. Avoiding tobacco, alcohol, and caffeine may be recommended. In the anxious and fearful or depressed patient, a psychological evaluation is indicated.

If disease persists after more than 2 years of treatment or produces incapacitating vertigo, the patient may require surgery. Some patients benefit from endolymphatic sac decompression (endolymphatic shunt). This procedure creates an opening in the labyrinth to drain excess fluid from the ear. A more complex procedure resects the vestibular nerve, which carries impulses from the mechanisms involved with position sense in the inner ear to the brain. If the patient has severe hearing loss in one ear, radical labyrinthectomy may be helpful.

Prevention

There is no known prevention for Meniere's disease, but prompt treatment of ear infection and other related disorders may be helpful.