What is Meniere’s disease?

Meniere’s disease is an inner ear disorder that usually causes dizziness, vertigo, hearing loss, or tinnitus (a ringing in the ears). Meniere’s generally only affects one ear, though it can affect both. People may experience Meniere’s disease as a period of muffled or muted hearing followed by intense dizziness. For some people, these dizzy spells happen weeks or months apart; others have repeated episodes much closer together. In the most severe cases, called “drop attacks,” Meniere’s disease can cause you to lose your balance altogether and fall to the ground. Milder forms can bring on sweating and nausea similar to the effects of motion sickness. Meniere’s disease is a medical puzzle. While the source of the symptoms is understood, the underlying causes of the condition haven’t been discovered yet. You may have heard that Meniere’s is incurable, which is partly true. While there are ways to relieve the symptoms with lifestyle changes, medication, and even surgery, the condition itself has no permanent cure. Meniere’s disease is a rare condition, affecting only 0.2 percent of the US population, with about 45,000 new cases diagnosed per year. It is more likely to affect people over the age of 40^[1].

What is vertigo?

Vertigo describes a particular type of dizziness where you feel like your surroundings are moving or spinning even though they aren’t. Your sense of balance depends on your brain being able to correctly interpret signals from your eyes, sensory nerves, and the structures of your inner ear. Vertigo occurs when your brain tries to interpret signals that don’t match^[2]. This mismatch can sometimes be caused by a problem with the delicate structures of the inner ear. For example, if the inner ear, which senses forward and backward motion and gravity, incorrectly signals to your brain that you are moving while your eyes and sensory nerves signal to your brain that you are standing still, you may experience an unpleasant spinning or falling sensation. Depending on the cause of the incorrect signal, vertigo can pass in a few seconds or last for several hours and can be severe enough to make you nauseous.

What is motion sickness?

Motion sickness is a common reaction to riding in boats, planes, cars, and other vehicles. Like vertigo, it is caused by a mismatch in the signals that determine your sense of balance, and can lead to queasiness, dizziness, nausea, and vomiting. One common cause is reading in a moving car; your eyes focus on the page in front of you and don’t signal to your brain that you are moving, while your inner ears and sensory nerves detect the car’s forward motion and signal it to your brain. Motion sickness occurs as the brain struggles to interpret these contradictory signals^[3]. Motion sickness can occur even if your eyes, ears, and sensory nerves are all working perfectly; they may just be reacting to the disorienting movement of the vehicle. You can sometimes relieve motion sickness by looking out into the distance or changing your seat.

Meniere’s disease causes

It’s not clear why people develop Meniere’s disease. The symptoms arise when a fluid called endolymph builds up in the inner ear, but the root cause of that buildup is not yet known. The delicate structures of the inner ear, or labyrinth, regulate our sense of balance as well as our hearing by sending signals to the brain. These structures are usually filled with endolymph, which is secreted into the labyrinth from the endolymphatic sac and then drains away. A certain amount of endolymph is crucial to the normal function of the inner ear, but the pressure of excessive fluid interferes with these signals by stretching and deforming the space and membranes of the inner ear^[4]. This creates sensations like dizziness and vertigo, as well as hearing loss and a muffling or buzzing sensation in the ear itself. Excessive endolymph buildup is known as “endolymphatic hydrops,” but not all cases of endolymphatic hydrops have the symptoms of Meniere’s disease. Theories that have been investigated to explain endolymph buildup include:

• Drainage problems: The labyrinth may become blocked, which stops endolymph from draining normally. As more and more endolymph is secreted into the inner ear, the pressure builds, interfering with normal hearing and balance.
• Immune system response: As part of an immune response or allergic reaction, the tissues of the inner ear may secrete an abnormal amount of fluid into the space of the labyrinth.
• Viral infection: The fluid byproducts of a viral infection may likewise increase the total volume and pressure of the endolymph.
• Genetic issues: A small percentage of people may inherit genetic disorders that cause their bodies to produce too much endolymph, straining the inner ear. Genetic factors may also lead to abnormally small, weak, or misshapen structures in the inner ear, making them more vulnerable to disruption even by normal endolymph production^[5].

However, none of the factors listed above have been found to play a major role in Meniere’s disease. Researchers are continuing to search for environmental or genetic factors that may help explain the root cause of the disease. Only a small number of cases show a family connection; the vast majority of Meniere’s patients do not have a family history of the condition. This makes the search for genetic risk factors even more difficult. So far, no genes have been associated with Meniere’s disease^[6]. Meniere’s disease is diagnosed more often adults age 40 and older, though it has been diagnosed in people of all ages. The condition affects people of all backgrounds, though it appears to be slightly more common in people of European descent.

Meniere’s disease symptoms

Meniere’s disease can produce symptoms that range from mild to intense. The condition can affect hearing, the sense of balance, or both. Signs of the condition include:

• Tinnitus: Tinnitus has been described as a whooshing, buzzing, rushing, ringing, whistling sound in the ear. These sounds do not have an outside source; instead they are heard inside the ear itself. The sounds may vary in intensity, and they may come and go over time^[7].
• Hearing Loss: Meniere’s may be accompanied by partial or total loss of hearing, usually in one ear. This may be experienced as muffling or distortion of loud sounds, often affecting lower tones first. Hearing loss is usually intermittent but can become permanent if untreated^[8].
• Vertigo: A sensation of spinning or moving that comes on suddenly, seemingly without any cause. These episodes can last from 20 minutes to several hours, but not more than 24 hours. Recurring attacks of vertigo may indicate Meniere’s.
• Aural Fullness: A feeling of pressure or fullness in one ear can mean a buildup of endolymph in the inner ear.

The symptoms of Meniere’s disease can also be caused by more serious conditions, including brain tumors and multiple sclerosis. If you experience a combination of these symptoms, especially vertigo and hearing loss, it’s best to seek advice from your healthcare provider.