Although there are several different disorders of the inner ear, and many are very common, they all present with hearing loss, vertigo or both. The prevalence of hearing loss in industrial populations is about 10% and of vestibular and balance disorders about 20–30%. The common peripheral vestibular disorders amenable to medical and rehabilitative treatments are Ménière’s disease, vestibular neuronitis, vestibular migraine, benign paroxysmal positional vertigo (BPPV), motion intolerance and visual induced vertigo (motion sickness), and age-related balance deterioration (presbystasis). Here I will focus on the aetiology, histopathophysiology, clinical presentation and management of Ménière’s disease which is a common otological problem characterised by episodic vertiginous spells, hearing loss, tinnitus and aural fullness (there is a rather arcane debate whether these symptoms should be grouped under Ménière’s disease or Ménière’s syndrome).

EPIDEMIOLOGY

The prevalence of Ménière’s disease is about 1% and it is more common in industrialised countries and in adult white populations.1 There is a slight female preponderance and the typical age of onset is 30–50 years. Bilateral disease is not uncommon (15–20%), but both sides are seldom affected simultaneously except in patients with autoimmune disease.1^–3 Genetic predisposition has been reported in families with Ménière’s disease.4^, 5 Factors such as diet,6 weather changes (low pressure fronts),7 emotional and physical stress,8 and urban living can precipitate attacks and make any symptoms worse.

AETIOLOGY AND HISTOPATHOLOGY

Prosper Ménière was the first to realise that vertigo and hearing loss could be attributable to a disorder of the inner ear as opposed to “brain congestion” which was the accepted cause prior to Ménière’s published case report.9 Seventy seven years later, the first histopathological description of “endolymphatic hydrops” (fig 1) was simultaneously and independently provided by Yamakawa,10 and Hallpike and Cairns.11 Since then the histological entity of “endolymphatic hydrops” has been associated with Ménière’s disease, although not all patients with the histopathology have the typical symptoms.12^, 13 The conventional view is that hydrops is caused by either increased production of endolymph by the stria vascularis, or decreased absorption by the endolymphatic sac. Recently, however, it has been suggested that hydrops is the result of dysfunction of the spiral ligament fibrocytes, which interferes with the recycling of K+ ions and results in osmotic imbalance and expansion of the endolymphatic compartment.14 Many factors such as genetic abnormalities, infections, allergies, autoimmune disorders, dietary, endocrine and vascular problems could be responsible for the development of hydrops but the exact underlying cause is unclear.

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Figure 1

Cochlear hydrops: the endolymphatic space (EL) volume increases and compresses Reissner’s membrane (RM) so reducing the vestibular perilymphatic space (PL) which ultimately leads to the aural pressure and vertiginous episodes of Ménière’s disease.

NATURAL HISTORY

The natural history of Ménière’s disease is poorly understood. Few studies1^, 2^, 15^–19 have had adequate length of follow-up (14 years19 and 21 years1) and sufficient numbers of patients (53,16 11919 and 1612) to allow reasonable conclusions about the natural history of the syndrome. These studies also underscore the difficulty in making the initial diagnosis if the presenting symptom is just hearing loss, tinnitus or vertigo, but not all of the symptoms which make up the typical presentation of “Ménière’s disease”. What we do know is:

• Hearing deteriorates over time to about 50 db loss in 60–80% of patients.

• Speech scores (understanding/clarity) drop with time to below 50% which is the minimal level at which a hearing device can be used.

• Audiometry (pure tone audiograms) show variable configurations such as low frequency rising or high frequency falling patterns.

• Vertiginous episodes vary between 6 and 11 per year (average 4),1 and decline with time.

Vestibular testing (mostly electronystagmography) shows progressive decline of the caloric response, relative to the normal ear, over five years, and various types of spontaneous and positional nystagmus during or between episodes.

The treatments used in the studies of prognosis did not appear to alter the natural history of the disease. An often quoted paper in otology circles which reviewed treatment results over 25 years15 reported that most studies described “improvement” in 20–30%, “failure” in 10–25% and “recovery ” in 60%. Recovery meant reduction of vertiginous episodes, and this was independent of any treatment in most studies. However, this report, and other studies, did not address hearing recovery (it is important to note that most studies of Ménière’s disease have focused on vertigo despite the fact that the final disability is hearing loss1^, 20).

CLINICAL PRESENTATION AND DIAGNOSIS

The typical Ménière’s patient is a middle aged adult presenting with rotational vertigo (with nausea and vomiting) lasting 30 minutes to hours, unilateral fluctuating hearing loss and tinnitus. The hearing loss frequently affects the low frequencies, especially early in the disease. Tinnitus is often described as a harsh roaring machine-like sound, especially during vertigo attacks. Patients also may have hyperacusis (hypersensitivity to sounds) and duplacusis (distortion of sound) in the affected ear. In atypical forms, the initial symptom can be tinnitus or hearing loss. The time between the initial symptom and the subsequent typical constellation of symptoms varies from months to years. Therefore, in taking the history, the physician should focus carefully on the patient’s symptoms, any otological history (for example, ear disease or surgery), the general medical history, allergies and medications in order to tailor appropriate laboratory tests and narrow the differential diagnosis (see below).

The diagnosis of Ménière’s disease is mainly clinical, based on the history and audiometry. Therefore, it is important that clinicians use standardised diagnostic criteria. Laboratory tests are obtained to support the diagnosis and to tailor and monitor treatments. Guidelines have been proposed by the American Academy of Otolaryngology - Head and Neck Surgery (AAO-HNS) for the diagnosis as possible, probable, definite and certain according to the criteria shown in the box.21 However, physicians continue to use the terms cochlear hydrops, when vertigo is absent, and vestibular hydrops for cases without hearing loss, which are considered variants of the disease. This is important, especially in the differential diagnosis. For example, patients with only cochlear symptoms may have genetic or immune mediated hearing loss while patients with only vestibular symptoms may have vestibular neuronitis, BPPV or vestibular migraine. Other atypical presentations include the otolith crisis of Tumarkin (drop attacks usually of late Ménière’s disease with sudden falls to one side with no warning at all, and not necessarily in the middle of a typical Ménière’s episode) and the Lermoyez phenomenon (improvement of hearing after vertigo episodes).

EXAMINATION

Patients presenting with dizziness or vertigo should have a general medical, neurotological and neurological examination, including using either Frenzel’s glasses or video goggles to pick up eye movement abnormalities that would otherwise be missed on routine examination.22 The important components of the neurotological examination are the ear itself, neck movements, eye movements, vestibular responses (vestibulo-ocular (VOR) and vestibulo-spinal (VSR)), cranial nerves, motor and sensory signs, and cerebellum.

• Ear examination is generally normal with no evidence of middle ear effusion or vascular lesions.

• Hearing loss and hyperacusis are often present in Ménière’s ears, especially during, or around, the time of an attack.

• Neck movements should be normal except in the acute or subacute stages of a Ménière’s episode when patients self-restrict movements to reduce dizziness or vertigo.

• Saccadic, pursuit and optokinetic eye movements are usually normal with no dysconjugate movements or gaze-evoked nystagmus.

• Spontaneous nystagmus observed after removing visual fixation by Frenzel glass or video goggles, post head shake nystagmus and positional nystagmus are all frequently present in the acute or subacute stages of an episode. Most, if not all, types of central nystagmus are enhanced with visual fixation and therefore can be readily seen with the naked eye. Frenzel’s glasses or video-electronystagmography remove visual fixation and enhance the detection of peripheral nystagmus which is commonly suppressed by visual fixation.

• The vestibulo-spinal response is examined by asking patients to stand up unassisted and walk for several steps watching for any gross gait abnormalities or side stepping (abnormalities are more evident during an acute episode and less so during subacute and inactive stages of the disease).

• Romberg’s sign is conducted with eyes open and eyes closed with the arms outstretched and observing postural sway and post stepping (Unterberger-Fukuda) rotation with eyes closed.

• The vestibulo-cerebellar examination is conducted by observing the vestibulo-ocular visual suppression response.

• The remainder of the neurological examination is usually normal in Ménière’s patients. Positive neurological findings on examination should direct the physician’s attention to the presence of central nervous system disease.

DIAGNOSTIC TESTS

In the course of evaluating patients with hearing and balance disorders, the tests that are commonly considered include audiometry, vestibular tests, blood tests and imaging (CT of the temporal bone and MRI of the brain). These need to be tailored according to the history and physical findings.

In Ménière's patients the most valuable test is audiometry to document the type and degree of hearing loss. Pure tone and speech audiometry should be obtained in all patients. Typically it shows a low frequency rising pattern in the early stage of the disease but patients can also present with peak or high frequency profiles (fig 2). If asymmetrical hearing loss is present, a contrast MR scan of the brain and internal auditory canals is needed to rule out a vestibular schwannoma or brain stem lesion such as a demyelinating plaque (fig 3).

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Figure 2

Early and late audiometric profile of Ménière’s disease. In the early stage, a low frequency rising pattern is evident in the right ear (red circles). The peak pattern (red dots) is evident later in the disease. Also note that the left ear exhibits a peak pattern (black X) in the late stage suggesting bilateral rather than just unilateral disease.

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Figure 3

(A) Audiogram of a patient presenting with right hearing loss and episodic vertigo. (B) Although the clinical history was in favour of Ménière’s disease, the MRI (T2-weighted) showed a well defined demeyelinating plaque (arrow) in the right cochlear/vestibular nuclei of the brainstem.

Other tests such as electrocochleography and electro- or video-nystagmography are not usually needed in the early phase of management. Electronystagmography should however be considered in patients undergoing intratympanic gentamicin treatment, labyrinthectomy or vestibular nerve section to rule out subclinical disease (vestibular weakness) in the contralateral inner ear.

Laboratory tests are seldom needed. However, thyroid function, syphilis serology, autoimmune and routine chemistry should be done in patients presenting with bilateral Ménière’s.

MANAGEMENT

Most Ménière’s patients can be managed as an outpatient; however, elderly dehydrated patients may need to be admitted.

The most distressing symptom of an acute attack is the vertigo which should be treated symptomatically; 5 mg diazepam (Valium) with 2 mg glycopyrolate (Robinul) is very effective. Sublingual administration of 2 mg lorazepam (Ativan) is also very effective in controlling and shortening the duration of an attack.

The long-term treatments for Ménière’s disease vary considerably worldwide, the main aim being to reduce the frequency of the vertiginous episodes and the development of increasing hearing loss:24^, 25

• Diuretics and a low-salt diet (if patients are salt sensitive based on their diaries) may decrease the natural progression of sensorineural hearing loss.2^, 25

• Systemic and intratympanic corticosteroids have the potential for controlling vertigo and improve hearing, and offer a new treatment leading to significant speech discrimination recovery, allowing for hearing aid use in ears that would otherwise have become deaf.26

• The prevalence of allergy appears to be higher in Ménière’s patients than in the general population, or the population of patients visiting an otological clinic for other symptoms; allergy therapy may improve vertigo and tinnitus.27

• Betahistine (B-Serc) is commonly used in Europe, Canada and many other countries.24 It is believed that it exerts its effect by increasing the blood circulation to the inner ear and it also acts as a pre-synaptic agonist to histamine receptors. A recent meta-analysis28 showed its efficacy in treating non- Ménière’s vertigo.

• Other treatments include pressure equalising tubes, pressure machines, laser, acupressure, acupuncture, hydrotherapy, oxygen therapy and herbal medications but there are no randomised trials.

• Inner ear gentamicin perfusion is effective in controlling vertigo and Tumarkin drop attacks.29^–31

• A recent study comparing vestibular nerve section to intratympanic gentamicin treatment concluded that both interventions are acceptable for Ménière’s disease patients; however, gentamicin caused more hearing loss, and vestibular nerve section controlled vertigo better.32

Ménière’s disease can be very disabling, physically and emotionally, to patients and their families. It is critical to address the emotional impact of the disease and aggressively treat secondary anxiety and depression. It is also important to assess the impact of the disease on the functional capacity of the patient at home and work. Certain jobs can be hazardous to Ménière’s patients such as flying, policing and firefighting, construction jobs, working with heavy machinery, and most jobs requiring critical control of balance. Physicians should have low thresholds for approving permanent or temporary disability to a Ménière’s patient, particularly bilateral cases.