Health

The next most common cause of vertigo is Meniere’s disease. The inner ear is encased in the densest bone in the body, called the otic capsule. Within that very dense bone there are very delicate membranes that are responsible for generating our sense of balance, as well as our hearing. These membranes contain two different fluids: one called perilymph and the other called endolymph. These fluids normally maintain a pressure balance with the fluid that surrounds our brain. This happens through the endolymphatic duct, and within the endolymphatic sac, which lies adjacent to the dura. Occasionally, these fluids get out of balance, resulting in too much fluid in the inner ear. This puts the membranes of the inner ear under stretch, and causes Meniere’s disease. We do not know why this fluid imbalance develops. There is no way to see these membranes in a living person, but we have learned what the end result is by studying cadavers. 

The symptoms of Meniere’s disease vary in severity from person to person, but there are certain things that they all have in common. When the membranes of the hearing part of the inner ear are put under stretch, it causes a sensation of fullness (like the ear is plugged) or pressure (like the ear won’t pop), hearing loss (particularly in the low frequencies), and ringing (called tinnitus). The hearing loss can fluctuate as the pressure in the inner ear fluctuates, but over time it may progress to a permanent and severe sensorineural (or nerve) hearing loss.

The tinnitus is usually described as a “whooshing” or “roaring”. Eventually the membranes of the inner ear can be stretched to the point of breaking. When the membranes break, or rupture, in the balance part of the inner ear, it causes vertigo. This vertigo typically lasts 30 minutes to an hour, but may last several hours. Over time as the pressure is released, the symptoms subside. However, once the membranes heal, the pressure begins to rebuild and the symptoms return.  It is possible that either part of the inner ear can be affected independently. For example, if only the hearing part of the inner ear is affected, there will be tinnitus, hearing loss, and pressure—but no vertigo. If the balance part of the inner ear is the only part affected, there will be vertigo without tinnitus, pressure, or hearing loss. There is no way to see into the inner ear to confirm that there is too much fluid, so this diagnosis relies entirely on symptoms. Hearing tests and VNG studies can add information and help confirm the diagnosis, but because the symptoms fluctuate, the testing may be done when things are relatively normal. When active, the hearing test looks like the diagram below. It shows hearing loss isolated to the lower frequency of the right ear. VNG, when abnormal due to Meniere’s, shows one inner being less responsive than the other ear.

Example of Audiogram with low frequency hearing loss

There is no cure for Meniere’s disease. Like other chronic non-curable diseases (i.e., diabetes) our goal is to control the symptoms. Like diabetes, there is a whole spectrum of severity in Meniere’s disease. Treatment depends on the severity of the disease. The first line of treatment is medical management and dietary changes.            

Diets that are high in salt make Meniere’s disease worse. Consultation with a dietician is the best way to ensure that you are not getting too much salt. It is generally recommend that someone with Meniere’s disease take in less than 1.5 gm of salt per day. However, a simpler approach is not adding salt to any food, and avoiding processed foods and meats that are typically very high in sodium (smoked meats, pickled foods). Chocolate, alcohol (particularly red wine and beer), and caffeine may also precipitate attacks and should be avoided.           

The medicines prescribed for Meniere’s disease are intended to address two things: the first is to control or limit the episodic vertigo, the second is to treat the acute episodes when they occur. Nearly 80 percent of people are able to significantly limit the number of vertigo attacks they have by taking a diuretic (aka, water pill). Potassium-sparing diuretics are most commonly prescribed. These are designed to reduce the amount of potassium that is lost with the excess fluid. However, all diuretics cause some potassium to be lost, and occasionally potassium supplementation is required. Most people are able to avoid this by simply eating foods that are high in potassium (bananas, tomatoes, etc). It is not known exactly how diuretics affect the fluid balance of the inner ear, but they are the first line treatment. Even with the best control, there may still be occasional “breakthrough” episodes. For acute vertigo, medications are prescribed that suppress the signal the brain receives from the inner ear. This helps stop the attack. These medicines include anti-histamines, anti-nausea medications, benzodiazepines, and steroids. Benzodiazepines like valium (diazepam) and xanax (alprazolam) are the most effective at stopping acute vertigo. They act centrally to suppress the signal received from the inner ear. Meclizine (anti-histamine) and compazine (anti-nausea) are often prescribed, but they cause sleepiness and are less effective than benzodiazepines.            

Some people seem to have an autoimmune component to the Meniere’s disease. This means that their body is reacting to itself or something in the environment, which in turn is causing inflammation. The inflammation affects the inner ear. This is a fairly small subset of people, but this group responds well to oral steroids (which reduce the inflammation). Allergy testing and immunotherapy often help patients who respond well to steroids. In that subset of people who don’t respond to medical management, the next step in treatment depends on the status of their hearing. The next level of treatment is divided into ablative treatments (treatments that “turn off” the affected vestibular system) and non-ablative treatments. These can be surgical or non-surgical.           

The Meniette device is a non-ablative treatment that does not affect hearing. It consists of placing a pressure equalization tube through the eardrum, and using the device. The device sends pressure pulses into the middle ear. These pressure waves are passed into the inner ear and in turn “pump” the excess fluid out of the inner ear. It is effective in nearly 50 percent of patients, but requires the purchase of a device and 10-minute treatments several times a day. If the treatments stop, the benefit is lost and the symptoms return.           

Endolymphatic shunt decompression is a non-ablative surgical procedure that is effective 80 percent of the time. It is an outpatient surgical procedure where the sac that lies against the dura is opened and a plastic shunt is placed into the sac to hold it open. The shunt rarely effects hearing and has been shown to be effective long term.            

It is possible to turn off (ablate) the affected ear by injecting gentamycin through the eardrum into the middle ear. Gentamycin is an antibiotic that is known to injure the inner ear (called ototoxicity). It is done in the office and may require 3-4 treatments. Nearly two-thirds of patients will suffer some hearing loss as a result of the treatment. In addition, nearly one quarter will have a recurrence of dizziness down the road. Also, because it often leaves some residual function in the balance system on the treated side, there may be some persistent dizziness. It is a good option in people with poor hearing in the affected ear or who are poor surgical candidates due to other health issues.Depending on the hearing level in the affected ear, there are a few ablative surgical procedures that can be used. These procedures are extremely effective in eliminating vertigo. The concern when using any ablative method is the potential for the disease to develop in the opposite ear. Loss of both inner ear balance systems can cause severe disability. If a person were suddenly to lose both inner ear balance systems, he would not be able to steady his eyes on the horizon as his head moved. There would be a constant feeling of the horizon bouncing or jostling every time this patient moved. This is called oscillopsia. People with Meniere’s disease who lose both balance systems often are able to compensate and have significantly less disability than you would expect. This is because the loss occurs slowly, and gives the time for the brain to adjust.

Bilateral Meniere’s disease (disease involving both inner ears) occurs in 10-30 percent of people. If the disease is clearly defined to one ear, as it most often is, the surgically ablative approaches are excellent options.  If the hearing is still good, it is possible to selectively cut the nerve to the inner ear balance system while leaving the hearing nerve intact. This is vestibular nerve section and is performed through a craniotomy. If the hearing is poor, it is possible to remove the inner balance system and cut the balance nerve at the same time. This approach, called larbyrinthectomy with vestibular nerve section, is also very effective but will leave the ear without any hearing. The advantage to either of these approaches is the near complete response and long-term reliability.           

A very small subset of people suffers from “drop attacks” due to Meniere’s disease. These attacks are also known as a “crisis of Tamarkin.” The person will collapse without losing consciousness and describes a sensation of “a hand forcing them to the ground.” These are rare, but can be dangerous. This subset of patients requires surgical ablation of the inner ear.