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Alternative names Return to top
Facial palsyDefinition Return to top
Bell's palsy is a disorder caused by damage to cranial nerve VII, involving sudden facial drooping and decreased ability to move the face.Causes, incidence, and risk factors Return to top
Bell's palsy is an acute form of cranial mononeuropathy VII, and it is the most common form of this type of nerve damage (peripheral neuropathy). Statistics indicate that the disorder affects approximately 2 in 10,000 people. However, the actual incidence is likely to be much higher (around 1 in 500 to 1 in 1,000).
The disorder is a mononeuropathy (involvement of a single nerve) that damages the seventh cranial (facial) nerve, the nerve that controls movement of the muscles of the face. The cause is often not clear, although herpes infections may be involved.
The disorder is presumed to be associated with inflammation of the facial nerve where it travels through the bones of the skull. Other causes of cranial mononeuropathy VII, such as head injury and tumor, need to be excluded. Other conditions, such as sarcoidosis, diabetes, and Lyme disease, are associated with Bell's palsy.
Symptoms Return to top
Signs and tests Return to top
Examination shows upper and lower facial weakness, which is almost always isolated to one side of the face or occasionally to the forehead, eyelid, or mouth. Despite a patient reporting feeling sensory symptoms, the loss of sensation on examination is a rare and disturbing finding. Blood pressure is normal. If there are no other abnormalities on examination, no imaging studies are usually done.
Blood tests for sarcoidosis or Lyme disease may be considered under some circumstances. If there is no improvement in the facial paralysis after several weeks, an MRI is done to rule out other causes of the dysfunction. An EMG and nerve conduction studies may also be done to determine the severity of nerve damage.
Treatment Return to top
In many cases, no treatment is necessary. The goal of treatment is to relieve the symptoms.Expectations (prognosis) Return to top
The outcome varies. Approximately 60% to 80% of cases resolve completely within a few weeks to months. Some cases result in permanent changes. The disorder is not a threat to life.Complications Return to top
Calling your health care provider Return to top
Call for an appointment with your health care provider if facial drooping or other symptoms of Bell's palsy occur. Only a trained health care provider can discriminate Bell's palsy from other, more serious conditions, such as stroke. If you develop signs of Bell's palsy, call your health care provider immediately so that a stroke can be ruled out as quickly as possible.Prevention Return to top
Use of safety measures may reduce the incidence of head injury. Many of the other factors associated with this disorder are not readily preventable. Update Date: 7/20/2004 Updated by: Joseph V. Campellone, M.D., Division of Neurology, Cooper University Hospital, Camden, NJ. Review provided by VeriMed Healthcare Network.
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Page last updated: 28 October 2004 |