March 11, 2006
Imagine driving down the road and suddenly your eyes become blurred and start twitching. You blink and try as best you can to continue. Then your facial muscles begin to get numb, weaken and almost freeze. You feel a sudden pain. Maybe there is something really wrong. You are "scared to death." As soon as possible, you head for the nearest emergency room. The doctor examines you and assesses your symptoms. You are told that your symptoms are a classic attack of Bell’s Palsy.
Bell’s Palsy is defined by the National Institute of Neurological Disorders and Stroke –an Institute of the National Institutes of Health — as a form of temporary facial paralysis. It may result from damage or trauma to one of the two facial nerves. The facial nerve is also called the seventh cranial nerve. It is a paired structure that travels through a narrow, bony canal (called the Fallopian canal), in the skull beneath the ear, to the muscles on each side of the face. For most of its journey, the nerve is encased in this bony shell.
Each facial nerve directs the muscles on one side of the face, including those that control eye blinking and closing, and facial expressions such as smiling and frowning. In addition, the facial nerve carries nerve impulses to the lacrimal or tear glands, the saliva glands and the muscles of a small bone in the middle of the ear called the stapes. The facial nerve also transmits taste sensations from the tongue.
When Bell’s Palsy occurs, the function of the facial nerve is disrupted, causing an interruption in the messages the brain sends to the facial muscles. This interruption results in facial weakness or paralysis.
It was named for Sir Charles Bell, a 19th-century Scottish surgeon who was the first to describe the condition. The disorder, which is not related to stroke, is the most common cause of facial paralysis. Generally, Bell’s Palsy affects only one side of the paired facial nerves, and one side of the face; it is rare to have both sides involved.
Naturally, the symptoms become complex because the nerve has so many functions. Damage to the nerve or disruption in its function can lead to many problems. Symptoms may vary from person to person, and range in severity from mild weakness to total paralysis. There can be twitching, weakness or paralysis in one or both sides of the face, drooping of the eyelid and a corner of the mouth, drooling, impairment of taste, and excessive tearing in one eye. Most often, these symptoms begin suddenly, and reach their peak within 48 hours. They can lead to significant facial distortion.
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Other symptoms may include pain or discomfort around the jaw and behind the ear, ringing in one or both ears, headache, loss of taste, hypersensitivity to sound on the affected side, impaired speech, dizziness and difficulty eating or drinking.
The mechanism in which Bell’s Palsy occurs is that the facial nerve becomes swollen, inflamed or compressed. Then facial weakness or paralysis can be the result. Many scientists believe that a viral infection such as viral meningitis or even the common cold sore virus (herpes simplex) can cause the disorder. They say that when the facial nerve becomes inflamed and swollen it is a reaction to an infection. This causes pressure within the Fallopian canal leading to an infarction to the nerve cells. An infarction can cause death of the nerve cells due to insufficient blood and oxygen to the cells. In mild cases the only damage is to the myelin sheet, or fatty covering that insulates the nerve fibers in the brain.
Bell’s Palsy is almost always associated with some kind of influenza, or other flu-like illnesses. Other conditions can be headaches, chronic middle-ear infection, high blood pressure, diabetes, tumors, Lyme disease and trauma such as skull fracture or other facial injury.
Over 40,000 Americans are afflicted with the disease annually. It affects men and women equally and can occur at any age. It is less prevalent before age 15 or over age 60. It disproportionately attacks pregnant women and people who have diabetes or upper respiratory ailments such as flu or a cold. This is another reason to get an annual flu shot.
Making a diagnosis is based on the patient’s symptoms. There is no specific laboratory test to confirm diagnosis. The diagnosis is made strictly on the individual’s symptoms. There is a test called electromyography (EMG) that can confirm the presence of nerve damage and determine the severity and extent of nerve involvement. An x-ray of the scull can help rule out infection or tumor. Magnetic resonance imaging (MRI) or a computed tomography (CT) scan can eliminate whether there are other causes of pressure on the facial nerve.
There is no known cure or standard of treatment of Bell’s Palsy. The most important thing is to eliminate the source of the nerve damage. Each individual reacts differently. Some cases turn out to be mild and do not require treatment because the symptoms can subside within two weeks.
Recent studies have shown that steroids are effective in treating Bell’s Palsy. An antiviral drug such as acyclovir may be used in combination with an anti-inflammatory drug such as the steroid prednisone. Analgesics such as aspirin, acetaminophen, or ibuprofen may relieve pain. Patients should consult with their physicians to make sure that none of the above interferes with any other medications a patient is taking.
Extremely important is the treatment of the eye that may become dry because of the inability to blink that leaves the eye exposed to irritation and drying out, especially at night. Artificial tears, or gels, that lubricate the eyes and eye patches are also effective.
Physical therapy to stimulate the facial nerve may help maintain muscle tone is also effective. Likewise, facial exercises to stimulate the muscles to prevent contracture are also important. Moist heat on the face is also helpful. Rarely, cosmetic surgery may be required to restore the damaged facial muscles.
The prognosis for those with Bell’s Palsy is generally very good. The extent of the nerve damage determines the recovery. Improvement is gradual, and most individuals get better within two weeks. Sometimes, for those with more severe involvement, it may require several months before a full recovery. It is rare to have a recurrence.
For more information on neurological disorders or research funded by National Institute of Neurological Disorders and Stroke, contact the Institute’s Brain Resources Network: Brain, P.O. Box 5801, Bethesda, Md. 20824; call 1-800-352-9424; or visit http://www.rarediseases.org.