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Ménière's Disease
Ménière's disease or Ménière's syndrome can be a disabling condition where hearing loss, tinnitus, vertigo and a feeling of fullness in the ear come together in various proportions and extents. Bandolier this month has examined the evidence concerning the incidence and prevalence of the disease; we have also run a search on MEDLINE for randomised controlled studies (RCTs) of treatments published since 1990 (using the terms Ménière and random*). The only results have been for betahistine treatment, and these have been expanded by RCTs of betahistine trials in the 1980s.
What is Ménière's Disease?
The constant pathological finding in Ménière's disease is a progressive distension of the endolymphatic space of the inner ear. It appears that fluid build-up in the endolymphatic space (endolymphatic hydrops), caused either by overproduction or reduced absorption, exposes hair cells responsible for sensing movement and balance to progressive damage or paralysis. The result of that paralysis is that the person has an attack of dizziness, often with nausea and vomiting.
Early on these attacks can be short, as the damage to the hair cells is temporary and they can begin to function normally when the hydrops resolves. Repetitive insults lead to irreversible changes as the hair cells die; when dead they do not regrow, and hearing loss, in particular, can become permanent. There is an excellent recent review of Ménière's disease.
What causes Ménière's Disease?
The simple answer is that there is no simple answer. A review of over 300 articles published between 1983 and 1989 [2] covers many papers which look at the aetiology of Ménière's disease. One `theme' in the reports on aetiology and pathology seems to be an increase in immunoglobulins both in the endolymphatic fluid and in serum, occurring in a high proportion of patients with Ménière's disease. While it is likely to be a multifactorial condition, some sort of underlying infection (probably viral) or auto-immune component seems likely in patients with this condition.
How is Ménière's Disease diagnosed?
The usual clinical diagnosis is the triad of symptoms of vertigo, hearing loss and tinnitus, often with a feeling of fullness of the ear. The tinnitus and hearing loss are usually unilateral, and the disease at onset is often mild, with attacks lasting for an hour or so. In some patients, however, the onset can be much more serious, with trains of episodes resulting in significant nausea, vomiting and prostration.
Electrocochleography (ECOG) exposes the ear to a train of click or tonal stimuli recorded by an electrode situated close to the cochlea which records action potentials from the firing of auditory neurones. Endolymphatic hydrops results in a widening of the wave-form with multiple peaks that is quite different from the normal result. This test is quite simple and can be carried out in most ENT centres.
How common is Ménière's Disease?
There are a number of reports concerning the incidence and prevalence of Ménière's disease. The numbers vary quite considerably from study to study, and quite clearly different diagnostic criteria have been used at different times and in different places.
In Northern Ireland, Wilmot estimated from experience over a 25-year period that the incidence was between 1 and 2 cases per 10,000 population per year (say 200 cases per million).
Stahle and colleagues estimated the incidence of Ménière's disease in a Swedish population in 1973; this was possible because Ménière's disease was recorded on the health records of all inpatients with the diagnosis in Sweden. A computer analysis was conducted in the Uppsala and Skåne parts of Sweden, with a combined population of over 2 million. In 1973, the two regions with a joint population of 2,263,285 had 257 patients diagnosed with Ménière's disease (114 cases per million) of whom 60% were women, and most (228) cases were between 15 and 69 years.
Watanabe's paper on the incidence of Ménière's disease in Japan also has some interesting historical data on incidence from the UK in the 1950s and 1960s; results from Oxford in the mid 1950s suggest an incidence of about 560 per million, though higher figures are also quoted.
In the 1970s nation-wide surveys on the incidence of Ménière's disease were carried out in Japan. Though they reveal much of interest about age and sex distributions, severity and other aspects of disease, the only national figure for incidence based on a one-day survey was 160 cases per million, though figures on a 1-week survey were much lower, at 35 per million.
In the United states, a very thorough study of the incidence and prevalence of Ménière's disease was carried out in the population of Rochester, Minnesota, using a centralised diagnostic index at the Mayo clinic. This study examined cases between 1951 and 1980. The incidence of Ménière's disease in 1980 was 153 cases per million of population. Median ages of onset and diagnosis were 50 and 53 years respectively, although half the cases were diagnosed within 6 months of onset. This is a most important paper giving useful information about this difficult disease. The prevalence of the disease was 2,182 per million.
A recent report from Siena and Latium from two hospitals serving the needs of 104,000 people, over 13 years found 111 cases, almost all being diagnosed between the ages of 10 and 70 years, with a distinct peak between 40 and 50 years. This gives an incidence of 82 cases per million. Interestingly, the incidence was some 3 times higher in hospital workers than the general population, and the authors suggested that this may reflect a higher rate of diagnosis - and that the figures for the general population may be reduced by under-diagnosis.
What is the natural history of Ménière's disease?
There does not seem to be a clear answer to this question. In some patients the unilateral disease appears to "burn-out" with deafness remaining but with the vertigo and tinnitus declining. Other patients (the minority, but perhaps up to 25%) go on to develop a severe bilateral disorder where the vertigo remains - and where ablation of the inner ear becomes necessary.
Can lifestyle changes help?
It is suggested that food allergy or excess caffeine, nicotine or alcohol may be in some way involved in the aetiology of Ménière's disease. This is far from being proven. It is suggested that avoidance of caffeine, etc., may help. Bandolier has found no evidence of that in any RCT or other study.
Are there surgical treatments?
There are a number of surgical procedures, but Bandolier was not able to find randomised controlled trials of their effectiveness. We would be happy to report on such trials in future if any readers can bring them to our attention - computer literature searches are not infallible.
Are there medical treatments?
Yes, there are a number, but the only RCTs that we could find referred to betahistine. The mechanism of action of betahistine appears to be by promoting better circulation in the microvasculature, leading to reduction in endolymphatic hydrops.