Bell's palsy

Causes and Risks:
Bell's palsy is an acute form of cranial mononeuropathy VII and is the most common form of this type of nerve damage ( peripheral neuropathy ). Statistics indicate that the disorder affects approximately 2 out of 10,000 people, however, the actual incidence is likely to be much higher (around 1 out of 500 to 1,000). The disorder is a mononeuropathy (involvement of a single nerve) that damages the 7th cranial (facial) nerve, the nerve that controls movement of the muscles of the face. The cause is unknown. In some cases, the disorder is presumed to be associated with inflammation of the facial nerve where it travels through the bones of the skull. It may also be caused by head injury , tumor , hypertension , or infarction.

Prevention:
Use of safety measures may reduce the incidence of head injury . Many of the other factors associated with this disorder are not readily preventable.

Symptoms:
  • pain behind or in front of the ear
    • may precede weakness of facial muscles by 1-2 days

  • impairment of taste
  • sensitivity to sound (hyperacusis) on the affected side
  • headache
  • face feels stiff
  • face feels pulled to one side
  • difficulty with eating and drinking
  • change in facial appearance

  • facial paralysis of one side of the face
    • difficulty closing one eye
    • difficulty with fine facial movements

  • drooling

Note: Symptoms begin suddenly and hit their peak usually within 48 hours. Seventy-five percent of cases are preceded by upper respiratory infection .

Signs and Tests:
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 subjective sensory symptoms, the loss of sensation on examination is a rare and disturbing finding. Blood pressure is normal. A skull x-ray may be done to rule-out infection or tumor .

Treatment:
In many cases, no treatment is necessary. The goal of treatment is to relieve the symptoms.

Corticosteroids may reduce swelling and relieve pressure on the facial nerve for some persons. Corticosteroids must be given early to be most effective; preferably within 24 hours of the onset of paralysis .

Lubricating eye drops or eye ointments may be recommended to protect the eye if it cannot be closed completely. The eye may need to be patched during sleep to protect it.

Surgical procedures to decompress the facial nerve have not been shown to routinely benefit people with Bell's palsy.

Prognosis:
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:



Call Your Healthcare Provider:
Call for an appointment with your health care provider if facial drooping or other symptoms of Bell's palsy occur.


Drooping of the eyelid is called ptosis. Ptosis may result from damage to the nerve that controls the muscles of the eyelid, problems with the muscle strength (as in myasthenia gravis), or from swelling of the lid.



Facial paralysis (palsy) may be associated with Lyme disease. (Courtesy of the Centers for Disease Control and Andrea Kiesk M.D., Marquette Clinic, Marquette, MI.)