Bell's Palsy

Definition

Definition of Bell's Palsy
Bell's palsy is a form of facial paralysis resulting from a dysfunction of the cranial nerve VII (the facial nerve) that results in the inability to control facial muscles on the affected side. Several conditions can cause facial paralysis, e.g., brain tumor, stroke, and Lyme disease. However, if no specific cause can be identified, the condition is known as Bell's palsy. Named after Scottish anatomist Charles Bell, who first described it, Bell's palsy is the most common acute mononeuropathy (disease involving only one nerve) and is the most common cause of acute facial nerve paralysis.

Symptoms

Symptoms of Bell's Palsy
Symptoms of Bell's palsy include:

1. Sudden weakness or paralysis on one side of your face that causes it to droop. This is the main symptom. It may make it hard for you to close your eye on that side of your face.
2. Drooling.
3. Eye problems, such as excessive tearing or a dry eye.
4. Loss of ability to taste.
5. Pain in or behind your ear.
6. Numbness in the affected side of your face.
7. Increased sensitivity to sound.

Causes

Causes of Bell's Palsy
The cause of Bell's palsy is not clear. Most cases are thought to be caused by the herpes virus that causes cold sores.

1. In most cases of Bell's palsy, the nerve that controls muscles on one side of the face is damaged by inflammation.
2. Many health problems can cause weakness or paralysis of the face. If a specific reason cannot be found for the weakness, the condition is called Bell's palsy.

Diagnosis

Diagnosis of Bell's Palsy
Your doctor may diagnose Bell's palsy by asking you questions, such as about how your symptoms developed. He or she will also give you a physical and neurological exam to check facial nerve function.

If the cause of your symptoms is not clear, you may need other tests, such as blood tests, an MRI, or a CT scan.

Treatment

Treatment of Bell's Palsy
Most people who have Bell's palsy recover completely, without treatment, in 1 to 2 months. This is especially true for people who can still partly move their facial muscles. But a small number of people may have permanent muscle weakness or other problems on the affected side of the face.

If your doctor suspects that your Bell's palsy is caused by inflammation, you may be given corticosteroids, such as prednisone, to reduce the inflammation. If your doctor thinks that a virus is causing your Bell's palsy, he or she may prescribe antiviral drugs, such as acyclovir. But there is no clear evidence that antiviral drugs are effective for Bell's palsy.

Prognosis

Prognosis of Bell's Palsy
Even without any treatment, Bell's palsy tends to carry a good prognosis. In a 1982 study, when no treatment was available, of 1,011 patients, 85% showed first signs of recovery within 3 weeks after onset. For the other 15%, recovery occurred 3-6 months later. After a follow-up of at least 1 year or until restoration, complete recovery had occurred in more than two-thirds (71%) of all patients. Recovery was judged moderate in 12% and poor in only 4% of patients. Another study found that incomplete palsies disappear entirely, nearly always in the course of one month. The patients who regain movement within the first two weeks nearly always remit entirely. When remission does not occur until the third week or later, a significantly greater part of the patients develop sequelae. A third study found a better prognosis for young patients, aged below 10 years old, while the patients over 61 years old presented a worse prognosis.

Prevention

Prevention of Bell's Palsy
There is no known way to prevent Bell's palsy.