Pathophysiology of Meniere's Disease

Visit a playground and you might see children spinning madly on a merry-go-round. The goal is to go as fast as possible so they can get as dizzy as possible. The medical term for this whirling dizziness is vertigo. For those with Meniere's disease, vertigo is no game. This condition can be debilitating and has no cure. Fortunately, there are treatments to help manage the symptoms.

• Round and round we go

What is Meniere's Disease?

• Named after Prosper Meniere, a French physician, Meniere's disease affects the inner ear. It causes vertigo (spinning dizziness), ringing (tinnitus) in the ear, hearing loss and the sensation of fullness in the ear. It can affect both ears but usually only one. It is more common in people who are in their 40's and 50's. The National Institute on Deafness and Other Communication Disorders (NIDCD) believes that approximately 615,000 people in the United States have Meniere's disease.

Causes

• Symptoms of Meniere's disease arise from the inner ear, a series of curving passages and chambers called the labyrinth. The bony labyrinth encases a smaller version of itself, the membranous labyrinth. The membranous labyrinth contains hair-like sensors and fluid (endolymph). The sensors respond to movement of the fluid, signaling the brain regarding acceleration and rotation. There is also fluid (perilymph) between the membranous and bony labyrinth. Meniere's disease occurs if the fluids fail to maintain a precise volume, pressure and chemical balance. Scientists are not sure, however, what causes the fluid imbalance.

Diagnostic Tests

• Several tests aid in diagnosis. Audiometry measures hearing and if problems are coming from the inner ear or the nerve going to the brain. An electronystagmography grades performance of sensors in the inner ear that control eye movement. Other tests include rotary-chair testing (controlled by computer) or posturography (using computer-controlled platform that measures balance). An MRI or CT may rule out other causes such as tumor or multiple sclerosis. Auditory brainstem response audiometry, done under anesthesia, tests the nerves and hearing centers of the brain.

Functional Impact

• Meniere's disease can influence productivity and overall quality of life. The associated vertigo is unpredictable and varies in intensity, preventing some from driving or operating heavy machinery. Symptoms may force a person to lose time from work or social activities. Some chronic sufferers require a cane for stability when walking. Since they may trigger an episode, the Mayo Clinic recommends avoiding sudden movements and bright lights. Watching television or reading may worsen symptoms. Ringing in the ears at night often disturbs sleep.

Treatment

• Motion sickness medications may control symptoms. MayoClinic.com reports diuretics sometimes reduce the severity and frequency of episodes. Avoid caffeine, smoking and stress/anxiety since they also contribute. Ear injections with gentamicin or steroids are options. Specialized physical therapy may retrain the brain in how it processes balance information. One surgical treatment is cutting the vestibular nerve. Physicians consider removal of the labyrinth (labyrinthectomy) in only the most severe cases since it results in complete hearing loss in the affected ear.