What is Bell's palsy?

Causes and Symptoms

The most likely cause of Bell’s palsy
is a weakened immune system produced by the common cold virus or herpes viruses. The condition has also been associated with chronic middle ear
infection, sarcoidosis, Lyme disease, high blood pressure, tumors, and trauma to the head. A diagnosis of Bell’s palsy is made from facial appearance and weakness, blood tests, electromyography to confirm nerve damage, and magnetic resonance imaging (MRI) or computed tomography (CT) to assess any pressure on the facial nerve.

In 99 percent of cases, Bell’s palsy produces paralysis on only one side of the face. Other symptoms may include an inability to close the eye on the affected side, frequent tearing from that eye, dryness of the affected eye, drooping of the eyelid and mouth, drooling, increased sensitivity to sound and ringing in the affected ear, impairment of taste, jaw pain, impaired speech, headache, and dizziness. Typically, the symptoms appear rather suddenly and peak within the first forty-eight hours after onset. Most patients experience dramatic improvement within two weeks, and most recover totally within three to six months after onset.

Treatment and Therapy

Various treatments can be effective if administered within seven days after onset. Antiviral drugs such as acyclovir, famciclovir, or valacyclovir cause the virus to run its course faster by binding viral enzymes so that the harmful cells cannot replicate. Prednisone, a synthetic hormone that mimics the natural steroid cortisol produced by the body, is also administered to help reduce swelling and the inflammation compressing the seventh cranial nerve.

The application of moist heat can help reduce pain and discomfort. The affected eye should be kept moist to protect it from debris and injury. Facial massage and exercise may help prevent the permanent shrinkage of facial muscles. Since vitamins B1, B6, and B12 are essential for proper nervous system functioning, a B-complex vitamin is often prescribed. Ample rest is necessary to restore the immune system.

Perspective and Prospects

First described in the nineteenth century by Scottish surgeon Sir Charles Bell, Bell’s palsy affects approximately forty thousand Americans each year. It can occur at any age but is less common before age fifteen and after age sixty. Diabetics are particularly susceptible to the condition, as are pregnant women, particularly during the last trimester.

No cure has been found for Bell’s palsy. Research focuses on achieving a better understanding of how the nervous system works, developing methods of repairing damaged nerves and restoring full use of injured areas, and finding ways to prevent nerve damage. Methylcobalamin, an essential component in the process of building nerve tissue, shows promise for treating Bell’s palsy.

Bibliography:

"Bell's Palsy." MedlinePlus, Apr. 23, 2013.

"Bell's Palsy Fact Sheet." National Institute of Neurological Disorders and Stroke, Sept. 4, 2012.

Matthews, Gary G. Cellular Physiology of Nerve and Muscle. 4th ed. Hoboken, N.J.: John Wiley & Sons, 2009.

Standring, Susan, et al., eds. Gray’s Anatomy. 40th ed. New York: Churchill Livingstone/Elsevier, 2008.

Waxman, Bruce. Electrotherapy for Treatment of Facial Nerve Paralysis (Bell’s Palsy). Rockville, Md.: Department of Health and Human Services, 1984.

Wood, Debra, and Rimas Lukas. "Bell's Palsy." Health Library, Oct. 11, 2012.