Ménière's disease
Ménière's disease (MD) is a disease of the inner ear that is characterized by potentially severe and incapacitating episodes of vertigo, tinnitus, hearing loss, and a fullness in the ear. Typically, only one ear is affected initially, but over time, both ears may become involved. Episodes generally last from 20 minutes to a few hours. The time between episodes varies. The hearing loss and ringing in the ears can become constant over time. The cause of Ménière's disease is unclear, but likely involves both genetic and environmental factors. A number of theories exist for why  it occurs, including constrictions in blood vessels, viral infections, and autoimmune reactions. About 10% of cases run in families. Symptoms are believed to occur as the result of increased fluid buildup in the labyrinth of the inner ear. Diagnosis is based on the symptoms and a hearing test. Other conditions that may produce similar symptoms include vestibular migraine and transient ischemic attack. No cure is known. Attacks are often treated with medications to help with the nausea and anxiety. Measures to prevent attacks are overall poorly supported by the evidence. A low-salt diet, diuretics, and corticosteroids may be tried . Physical therapy may help with balance and counselling may help with anxiety. Injections into the ear or surgery may also be tried if other measures are not effective, but are associated with risks. The use of tympanostomy tubes, while popular, is not supported. Ménière's disease was first identified in the early 1800s by Prosper Ménière. It affects between 0.3 and 1.9 per 1,000 people. It most often starts in people 40 to 60 years old. Females are more commonly affected than males. After 5 to 15 years of symptoms, the episodes of the world spinning sometimes stop and the  person is left with loss of balance, poor hearing in the affected ear, and ringing or other sounds in the affected ear or ears. Signs and symptoms. Ménière's is characterized by recurrent episodes of vertigo, fluctuating hearing loss, and tinnitus; episodes may be preceded by a headache and a feeling of fullness in the ears. People may also experience additional symptoms related to irregular reactions of the autonomic nervous system. These symptoms are not symptoms of Meniere's disease per se, but rather are side effects resulting from failure of the organ of hearing and balance, and include nausea , vomiting, and sweating, which are typically symptoms of vertigo, and not of Ménière's. This includes a sensation of being pushed sharply to the floor from behind. Sudden falls without loss of consciousness (drop attacks) may be experienced by some people. Causes. The cause of Ménière's disease is unclear, but likely involves both genetic and environmental factors. A number of theories exist including constrictions in blood vessels, viral infections, and autoimmune reactions. Mechanism. The initial triggers of Ménière's disease are not fully understood, with a variety of potential inflammatory causes that lead to endolymphatic hydrops (EH), a distension  of the endolymphatic spaces in the inner ear. EH, in turn, is strongly associated with developing MD, but not everyone with EH develops MD: "The relationship between endolymphatic hydrops and Meniere's disease is not a simple, ideal correlation." Additionally, in fully developed MD, the balance system (vestibular system) and the hearing system (cochlea) of the inner ear are affected, but some cases occur where EH affects only one of the two systems enough to cause symptoms. The corresponding subtypes of MD are called vestibular MD, showing symptoms of vertigo, and cochlear MD, showing symptoms of hearing loss and tinnitus . The mechanism of MD is not fully explained by EH, but fully developed EH may mechanically and chemically interfere with the sensory cells for balance and hearing, which can lead to temporary dysfunction and even to death of the sensory cells, which in turn can cause the typical symptoms of MD - vertigo, hearing loss, and tinnitus. Diagnosis. The diagnostic criteria as of 2015 define definite MD and probable MD as: Definite Probable A common and important symptom of MD is hypersensitivity to sounds. This hypersensitivity is easily diagnosed by measuring the loudness discomfort levels (LDLs). Symptoms of MD overlap with  migraine-associated vertigo (MAV) in many ways, but when hearing loss develops in MAV, it is usually in both ears, and this is rare in MD, and hearing loss generally does not progress in MAV as it does in MD. People who have had a transient ischemic attack (TIA) or stroke can present with symptoms similar to MD, and in people at risk magnetic resonance imaging should be conducted to exclude TIA or stroke. Other vestibular conditions that should be excluded include vestibular paroxysmia, recurrent unilateral vestibulopathy, vestibular schwannoma, or a tumor of the endolymphatic sac. Management. No cure for  Ménière's disease is known, but medications, diet, physical therapy, and counseling, and some surgical approaches can be used to manage it. Medications. During MD episodes, medications to reduce nausea are used, as are drugs to reduce the anxiety caused by vertigo. For longer-term treatment to stop progression, the evidence base is weak for all treatments. Although a causal relation between allergy and Ménière's disease is uncertain, medication to control allergies may be helpful. To assist with vertigo and balance problems, glycopyrrolate has been found to be a useful vestibular suppressant in patients with Meniere's disease. Diuretics , such as the thiazide-like diuretic chlortalidone, are widely used to manage MD on the theory that it reduces fluid buildup (pressure) in the ear. Based on evidence from multiple but small clinical trials, diuretics appear to be useful for reducing the frequency of episodes of dizziness but do not seem to prevent hearing loss. In cases where hearing loss and continuing severe episodes of vertigo occur, a chemical labyrinthectomy, in which a medication such as gentamicin is injected into the middle ear and kills parts of the vestibular apparatus, may be prescribed. This treatment has the risk of worsening  hearing loss. Diet. People with MD are often advised to reduce their sodium intake. Reducing salt intake, however, has not been well studied.Based on the assumption that MD is similar in nature to a migraine, some advise eliminating "migraine triggers" such as caffeine, but the evidence for this is weak. There is no high-quality evidence that changing diet by restricting salt, caffeine or alcohol improves symptoms. Physical therapy. While use of physical therapy early after the onset of MD is probably not useful due to the fluctuating disease course, physical therapy to help retraining of the balance system  appears to be useful to reduce both subjective and objective deficits in balance over the longer term. Counseling. The psychological distress caused by the vertigo and hearing loss may worsen the condition in some people. Counseling may be useful to manage the distress, as may education and relaxation techniques. Surgery. If symptoms do not improve with typical treatment, surgery may be considered. Surgery to decompress the endolymphatic sac is one option. A systematic review in 2015 found that three methods of decompression have been used - simple decompression, insertion of a shunt, and removal of the sac. It found some evidence  that all three methods were useful for reducing dizziness, but that the level of evidence was low, as trials were not blinded nor were placebo controls used. Another 2015 review found that, on autopsy, shunts used in these surgeries often turn out to be displaced or misplaced, and recommended their use only in cases where the condition is uncontrolled and affecting both ears. A systematic review from 2014 found that in at least 75% of people, EL sac decompression was effective at controlling vertigo in the short term (>1 year of follow-up) and long term (>24 months ). An estimated 30% of people with MD have Eustachian tube dysfunction. While a 2005 review found tentative evidence of benefit from tympanostomy tubes for improvement in the unsteadiness associated with the disease, a 2014 review concluded that their use is not supported. Destructive surgeries are irreversible and involve removing entire functionality of most, if not all, of the affected ear; as of 2013, almost no evidence existed with which to judge whether these surgeries are effective. The inner ear itself can be surgically removed via labyrinthectomy, although hearing is always completely lost in the affected ear with this operation. The  surgeon can also cut the nerve to the balance portion of the inner ear in a vestibular neurectomy. The 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 is required. Prognosis. Ménière's disease usually starts confined to one ear; it extends to both ears in about 30% of cases. People may start out with only one symptom, but in MD all three appear with time. Hearing loss usually fluctuates in the beginning stages and becomes more permanent in later stages. MD  has a course of 5–15 years, and people generally end up with mild disequilibrium, tinnitus, and moderate hearing loss in one ear. Epidemiology. From 3 to 11% of diagnosed dizziness in neuro-otological clinics are due to MD. The annual incidence rate is estimated to be about 15 cases per 100,000 people and the prevalence rate is about 218 per 100,000, and around 15% of people with Meniere's disease are older than 65. In around 9% of cases, a relative also had MD, indicating a genetic predisposition in some cases. The odds of MD are greater for people of  white ethnicity, with severe obesity, and women. Several conditions are often comorbid with MD, including arthritis, psoriasis, gastroesophageal reflux disease, irritable bowel syndrome, and migraine. History. The condition is named after the French physician Prosper Menière, who in an 1861 article described the main symptoms and was the first to suggest a single disorder for all of the symptoms, in the combined organ of balance and hearing in the inner ear. The American Academy of Otolaryngology–Head and Neck Surgery Committee on Hearing and Equilibrium set criteria for diagnosing MD, as well as defining two subcategories - cochlear (without vertigo) and  vestibular (without deafness). In 1972, the academy defined criteria for diagnosing MD as: 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. Finally in 1995, the list was again altered to allow for degrees of the disease: In 2015, the International Classification for Vestibular Disorders Committee of the Barany Society published consensus diagnostic criteria in collaboration with the American Academy of Otolaryngology – Head and Neck Surgery, the European Academy of Otology and Neuro-otology, the Japan Society  for Equilibrium Research, and the Korean Balance Society.