Bell's palsy is a form of temporary facial paralysis resulting from damage or trauma to a facial nerve. Generally, the condition affects only one of the two facial nerves and one side of the face; however, in rare cases, it can affect both sides.
Bell's palsy is named for Sir Charles Bell, a nineteenth-century Scottish surgeon who was the first to describe the condition. Bell's palsy, which is not related to
stroke, is the most common cause of facial paralysis.
Understanding the Facial Nerves
The facial nerve (also called the seventh cranial nerve) 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. The facial nerve also carries nerve impulses to the:
- Lacrimal (tear) glands
- Saliva glands
- 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.
Who Is Affected by Bell's Palsy?
Bell's palsy afflicts approximately 40,000 Americans each year. It affects men and women equally, and can occur at any age, but it is less common before age 15 or after age 60.
Symptoms of Bell's palsy usually begin suddenly and reach their peak within 48 hours. They range in severity from mild weakness to total paralysis, and may include:
- Twitching, weakness, or paralysis on one or both sides of the face
- Drooping eyelid or corner of the mouth
- Drooling
- Dry eye or mouth
- Impairment of taste
- Excessive tearing in the eye.
The condition often causes significant facial distortion.
Most
Bell's palsy research scientists believe that a viral infection, such as
viral meningitis or the
common cold sore virus (herpes simplex), causes the condition when the facial nerve swells and becomes inflamed in reaction to the infection.
Several medical conditions associated with the disorder include:
In order to make a
Bell's palsy diagnosis, a healthcare provider will ask a number of questions, perform a physical exam, and recommend certain tests. The healthcare provider will also rule out other causes of facial paralysis. There is no specific laboratory test to confirm a diagnosis of Bell's palsy.
To help see the amount of damage and rule out other possible causes of facial paralysis, a healthcare provider may recommend the following tests:
- Electromyography
- X-rays
- MRI (magnetic resonance imaging)
- CT scan.
Treatment of Bell's Palsy
Bell's palsy affects each individual differently. Some cases are mild and do not require treatment, as the symptoms usually improve on their own within two weeks. For others, treatment may include medications and other therapeutic options. There is no cure.
Recommended treatment for Bell's palsy may include:
- Medications
- Eye protection
- Physical therapy
- Certain alternative treatments.
Surgery for Bell's palsy is generally not recommended.
Recovering From Bell's Palsy
The prognosis for individuals with Bell's palsy is generally quite good. The extent of nerve damage determines the extent of the recovery time. With or without treatment, most individuals begin to get better within two weeks after the initial onset of symptoms and recover completely within three to six months.
In rare cases, a person can have a recurrence of the condition, either on the same or the opposite side of the face.
