| Ménière's disease | |
|---|---|
| Classification and external resources | |
Inner ear |
|
| ICD-10 | H81.0 |
| ICD-9 | 386.0 |
| OMIM | 156000 |
| DiseasesDB | 8003 |
| MedlinePlus | 000702 |
| eMedicine | emerg/308 |
| MeSH | D008575 |
Ménière's disease ( /meɪnˈjɛərz/)[1] is a disorder of the inner ear that can affect hearing and balance to a varying degree. It is characterized by episodes of vertigo and tinnitus and progressive hearing loss, usually in one ear. It is named after the French physician Prosper Ménière, who, in an article published in 1861, first reported that vertigo was caused by inner ear disorders. The condition affects people differently; it can range in intensity from being a mild annoyance to a chronic, lifelong disability.[2]
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Ménière's often begins with one symptom, and gradually progresses. However, not all symptoms must be present for a doctor to make a diagnosis of the disease.[3] Several symptoms at once is more conclusive than different symptoms at separate times.[4] Other conditions can present themselves with Ménière's-like symptoms, such as syphilis, Cogan's syndrome, autoimmune disease of the inner ear, dysautonomia, perilymph fistula, multiple sclerosis, acoustic neuroma, and both hypo- and hyperthyroidism.[5]
The symptoms of Ménière's are variable; not all sufferers experience the same symptoms. However, so-called "classic Ménière's" is considered to have the following four symptoms:[6]
Some may have parasitic symptoms, which aren't necessarily symptoms of Ménière's, but rather side effects from other symptoms. These are typically nausea, vomiting, and sweating which are typically symptoms of vertigo, and not of Ménière's. Vertigo may induce nystagmus, or uncontrollable rhythmical and jerky eye movements, usually in the horizontal plane, reflecting the essential role of non-visual balance in coordinating eye movements.[12] Sudden, severe attacks of dizziness or vertigo, known informally as "drop attacks," can cause someone who is standing to suddenly fall.[13] Drop attacks are likely to occur later in the disease, but can occur at any time.[13]
There is an increased prevalence of migraine in patients with Ménière’s disease.[14]
Ménière's disease is idiopathic, but it is believed to be linked to endolymphatic hydrops, an excess of fluid in the inner ear.[15] It is thought that endolymphatic fluid bursts from its normal channels in the ear and flows into other areas, causing damage. This is called "hydrops." The membranous labyrinth, a system of membranes in the ear, contains a fluid called endolymph. The membranes can become dilated like a balloon when pressure increases and drainage is blocked.[16] 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. In some cases, the endolymphatic duct may be obstructed by scar tissue, or may be narrow from birth. In some cases there may be too much fluid secreted by the stria vascularis. 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 salt in some patients. It has also been proposed that Ménière's symptoms in many patients are caused by the deleterious effects of a herpes virus.[17][18][19] 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 anesthesia). Symptoms then develop as the virus degrades the structure of the inner ear.
Ménière's disease affects about 190 people per 100,000.[20] Recent gender predominance studies show that Ménière's tends to affect women more often than men.[20] Age of onset typically occurs in adult years, with prevalence increasing with age.[20]
Doctors establish a diagnosis with complaints and medical history. However, a detailed otolaryngological examination, audiometry and head MRI scan should be performed to exclude a vestibular schwannoma or superior canal dehiscence which would cause similar symptoms. There is no definitive test for Ménière's, it is only diagnosed when all other causes have been ruled out. If any cause had been discovered, this would eliminate Ménière's disease, as by its very definition,[21] as an exclusively idiopathic disease, it has no known causes.
Ménière's disease had been recognized as early as 1860s, but it was still relatively vague and broad at the time. The American Academy of Otolaryngology-Head and Neck Surgery Committee on Hearing and Equilibrium (AAO HNS CHE) set criteria for diagnosing Ménière's, as well as defining two sub categories of Ménière's: cochlear (without vertigo) and vestibular (without deafness).[22]
In 1972, the academy defined criteria for diagnosing Ménière's disease as:[23]
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.[24] Finally in 1995, the list was again altered to allow for degrees of the disease:[25]
Several environmental and dietary changes are thought to reduce the frequency or severity of symptom outbreaks. It is believed that since high salt diets cause water retention, it can lead to an increase (or at least preventing the decrease) of fluid within the inner ear, although the relationship between salt and the inner ear is not fully understood. High-salt intake is thought to alter the concentrations of fluid in the inner ear and Ménière's episodes could be accelerated by high-salt binges.[26] Recommended salt intake is often around one to two grams per day.[26] Diuretics have traditionally been prescribed to facilitate a low-salt diet although there is no definite supportive evidence.[26]
Additionally, patients may be advised to avoid alcohol, caffeine, and tobacco, all of which can aggravate symptoms of Ménière's. Many patients will have allergy testing done to see if they are candidates for allergy desensitization, as allergies have been shown to aggravate Ménière's symptoms.[27]
Both prescription and over-the-counter medicine can be used to reduce nausea and vomiting during an episode. Included are antihistamines such as meclozine or dimenhydrinate, trimethobenzamide and other antiemetics, betahistine, diazepam, or ginger root.[28] Betahistine, specifically, is of note because it is the only drug listed that has been proposed to prevent symptoms due to its vasodilation effect on the inner ear.[26]
The antiherpes virus drug acyclovir has been used with some success to treat Ménière's Disease.[17] The likelihood of the effectiveness of the treatment was found to decrease with increasing duration of the disease, probably because viral suppression does not reverse damage. Morphological changes to the inner ear of Ménière's sufferers have also been found in which it was considered likely to have resulted from attack by a herpes simplex virus.[18] It was considered possible that long term treatment with 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 of 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 acyclovir can have a positive effect on Ménière's symptoms has been reported.[29]
Studies done over the use of transtympanic micropressure pulses have indicated promise with patients who had not been previously treated by gentamicin or surgery.[30][31] Other studies suggest less clear results and propose that micropressure devices are simply placebos.[26]
Sufferers tend to have high stress and anxiety due to the unpredictable nature of the disease.[32] Healthy ways to combat this stress can include aromatherapy, yoga, t'ai chi,[33] and meditation. Greenberg and Nedzelski recommend education to alleviate feelings of depression or helplessness.[26]
If symptoms do not improve with typical treatment, more permanent surgery is considered.[34] Unfortunately, because the inner ear deals with both balance and hearing, few surgeries guarantee no hearing loss.
Nondestructive surgeries include those which do not actively remove any functionality, but rather aim to improve the way the ear works.[35] Intratympanic steroid treatments involve injecting steroids (commonly dexamethasone) into the middle ear in order to reduce inflammation and alter inner ear circulation.[36] Surgery to decompress the endolymphatic sac has shown to be effective for temporary relief from symptoms. Most patients see a decrease in vertigo occurrence, while their hearing may be unaffected. This treatment, however, does not address the long-term course of vertigo in Ménière's disease.[37] Danish studies even link this surgery to a very strong placebo effect, and that very little difference occurred in a 9-year followup, but could not deny the efficacy of the treatment.[38]
Conversely, destructive surgeries are irreversible and involve removing entire functionality of most, if not all, of the affected ear.[39] The inner ear itself can be surgically removed via labyrinthectomy although hearing is always completely lost in the affected ear with this operation.[4] Alternatively, a chemical labyrinthectomy, in which a drug (such as gentamicin) that "kills" the vestibular apparatus is injected into the middle ear can accomplish the same results while retaining hearing.[40] In more serious cases surgeons can cut the nerve to the balance portion of the inner ear in a vestibular neurectomy. Hearing is often mostly preserved, however the surgery involves cutting open into the lining of the brain, and a hospital stay of a few days for monitoring would be required.[41] Vertigo (and the associated nausea and vomiting) typically accompany the recovery from destructive surgeries as the brain learns to compensate.[41]
Physiotherapists also have a role in the management of Meniere’s disease. In vestibular rehabilitation, physiotherapists use interventions aimed at stabilizing gaze, reducing dizziness and increasing postural balance within the context of activities of daily living. After a vestibular assessment is conducted, the physiotherapist tailors the treatment plan to the needs of that specific patient.[42]
The central nervous system (CNS) can be re-trained because of its plasticity, or alterability, as well as its repetitious pathways. During vestibular rehabilitation, physiotherapists take advantage of this characteristic of the CNS by provoking symptoms of dizziness or unsteadiness with head movements while allowing the visual, somatosensory and vestibular systems to interpret the information. This leads to a continuous decrease in symptoms.[42]
Although a significant amount of research has been done regarding vestibular rehabilitation in other disorders, substantially less has been done specifically on Meniere’s disease. However, vestibular physiotherapy is currently accepted as part of best practices in the management of this condition.[42]
Ménière's disease usually starts confined to one ear, but it often extends to involve both ears over time. The number of patients who end up with bilaterial Ménière's is debated, with ranges spanning from 17% to 75%.[43]
Some Ménière's disease sufferers, in severe cases, may end up losing their jobs, and will be on disability until the disease burns out.[44] However, a majority (60-80%) of sufferers will not need permanent disability and will recover with or without medical help.[43]
Hearing loss usually fluctuates in the beginning stages and becomes more permanent in later stages, although hearing aids and cochlear implants can help remedy damage.[45] Tinnitus can be unpredictable, but patients usually get used to it over time.[45]
Ménière's disease, being unpredictable, has a variable prognosis. Attacks could come more frequently and more severely, less frequently and less severely, and anywhere in between.[46] However, Ménière's is known to "burn out" when vestibular function has been destroyed to a stage where vertigo attacks cease.
Studies done on both right and left ear sufferers show that patients with their right ear affected tend to do significantly worse in cognitive performance.[47] General intelligence was not hindered, and it was concluded that declining performance was related to how long the patient had been suffering from the disease.[48]
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