Inner Ear Condition (Meniere's Disease)

What is Meniere's Disease?

In 1861, Prosper Meniere identified the inner ear as the source of the triad of symptoms that now bears his name. Although much research has been done to elucidate the aetiology of this condition, it has resulted in little new understanding and generated much controversy. Many theories have been postulated, including viral, autoimmune and allergy. The histopathophysiology of this condition shows a swelling of the endolymphatic compartment within the inner ear and is termed endolymphatic hydrops. The pathogenesis is unknown and could be either overproduction or reduced absorption of endolymph.

Clinical Symptoms

The classic triad of Meniere's Disease is vertiginous (spinning) dizziness, tinnitus and deafness. The majority of patients suffer unilateral disease although some studies report that in up to 35% of patients the second ear becomes involved.
Vertigo--the patient experiences sudden onset of spinning lasting from 20 minutes to 24 hours. This is incapacitating and is associated with nausea and vomiting. The patient prefers to lie down with eyes closed, keeping the head still. Some patients experience a prodrome of ear fullness or tinnitus before the spell starts. Most patients are perfectly well between attacks
Hearing loss--in the early stages, the hearing loss is mainly in the low frequencies and fluctuates (returning to normal between attacks of dizziness). As the disease progresses, all thresholds become involved and the deafness can become severe to profound in the late stages.
Tinnitus--a symptom accompanying the hearing loss which varies in intensity but tends to increase as the hearing deteriorates.
Tumarkin Crisis--a very rare condition where the patient falls spontaneously to the ground without vertigo, hearing loss, tinnitus, nausea and vomiting. Some have described it as a push to the ground. Unless there is injury, the patient is able to resume the previous activity. This crisis is thought to be a sudden, undefined change in the otolithic organs. If patients suffer from this condition, they should not be allowed to drive.
The clinical course of Meniere's disease is unpredictable, with periods of activity separated by periods of quiescence. During the active times there may be frequent attacks which can suddenly settle. The vertiginous spells tend eventually to become less frequent and intense as the condition 'burns' itself out over 10 to 20 years. In the late stages, the hearing loss and tinnitus can be severe.

Investigations

An audiogram will reveal the nature of any hearing loss. In the early stages, a mild low-tone sensorineural deafness may be seen which may fluctuate with thresholds returning to normal when the patient is asymptomatic.
Electronystagmography (ENG) is sometimes performed to confirm the level of function of the diseased ear. In about 50% of patients, a caloric weakness is found confirming a hypofunctioning labyrinth in the suspected ear.

Imaging

All patients with Meniere's disease should have an MRI done to exclude on acoustic nerve tumour.

Management

Acute attacks

The acute attack is best managed by giving the patient bed rest. The only medication that is required at this time is a labyrinthine sedative drug. Many of these patients will vomit and therefore the drug is usually more effective if given intramuscularly or rectally. Stemetil (prochlorperazine) is probably the most useful drug as it has the additional benefit of being an anxiolytic agent.

Prevention of attacks

The long-term management of Meniere's disease is fraught with controversy. Many claims have been made for various regimes but none has been shown to influence the course of the condition in a long-term controlled trial. Vasodilators (betahistine 8 mg tds), oxygen-carrying molecules (Duxaril 1 tab bd), diuretics (hydrochlorthiazide 50 mg OM), sedatives (valium 2 mg tds) are some examples in the literature.
Patients should also be advised to reduce salt and caffeine intake. Stress management should be advocated if possible.

Surgical Treatment

Surgery is indicated only very rarely in Meniere's disease and also tends to be surrounded by controversy. The only indication is to control the attacks of dizziness when they have become incapacitating. All surgical procedures carry some risk to the hearing but they are subdivided into those aimed at perserving hearing and those where the hearing is deliberately sacrificed.