Chances are Good for Recovery from Bell's Palsy

Bell's palsy is a form of temporary facial paralysis resulting from damage or trauma to one of the two main nerves that control the muscles and glands of the face. Swelling, inflammation and compression affect the function of the affected nerve and disrupt the messages the brain sends to the facial muscles. The disruption results in facial weakness or paralysis.

Most scientists believe that Bell's palsy is initiated when a viral infection such as meningitis or the common cold sore virus (herpes simplex) causes inflammation in the facial nerve. Bell's palsy usually affects only one of the paired facial nerves and one side of the face, however, in rare cases, it can affect both sides.

The 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 often cause significant facial distortion. In addition to paralysis, symptoms of Bell's palsy can include twitching, weakness, drooping of the eyelid or corner of the mouth, drooling, dry eye or mouth, impairment of taste, and excessive tearing in the eye.

Other symptoms include pain or discomfort near the jaw and behind the ear, ringing in one or both ears, headache, loss of taste, hypersensitivity to sound on the affected side, impaired speech, dizziness and difficulty eating or drinking.

Rapid, Thorough Assessment is Crucial
According to John S. Rhee, MD, MPH, Associate Professor of Otolaryngology and Communication Sciences and Chief of the Division of Facial Plastic and Reconstructive Surgery, the symptoms must be carefully assessed before an accurate diagnosis of Bell's palsy can be made.

"It is a diagnosis of exclusion," says Dr. Rhee. "We try to rule out other reasons for facial nerve paralysis first. Though Bell's palsy is the most common cause of sudden-onset facial nerve paralysis, we are obligated to rule out all of the other potential causes."

For instance, he noted, it is vital for a stroke or a tumor to be ruled out, since those conditions call for a completely different treatment. Screenings such as computed tomography (CT) scans and magnetic resonance imaging (MRI) are used to help rule out other causes of the paralysis. Blood tests will be used to rule out conditions such as Lyme disease or thyroid problems.

The doctor will also thoroughly assess the patient's facial movements while performing motions such as smiling, puckering, raising the eyebrows and closing the eyes. Facial symmetry and wrinkles are closely observed because these can change suddenly due to the effects of palsy on muscle tone, Dr. Rhee said.

Once a diagnosis of Bell's palsy has been made, the doctor can use tests such as electroneuronography (which measures the electrical activity of the muscle with nerve stimulation) to determine the presence and extent of nerve damage.

In addition, "There are studies that suggest that MRI scanning will show inflammation of the facial nerve near a certain area of the brain that is suggestive of the pattern of Bell's palsy," said Dr. Rhee.

Treatment
Bell's palsy affects each individual differently. Some cases are mild with facial muscle paresis (incomplete paralysis) and do not require treatment, as the symptoms usually subside on their own within two weeks. For others, treatment might include medications and other therapeutic options.

Recent studies have shown that steroids are an effective treatment for Bell's palsy and that an antiviral drug such as acyclovir, combined with an anti-inflammatory drug such as the steroid prednisone, may be effective in improving facial function by limiting or reducing nerve damage.

Since Bell's palsy can interrupt the eyelid's natural blinking ability, another important factor in treatment is eye protection. Keeping the eye moist and protecting it from debris and injury, especially at night, is essential.

Some Bell's palsy patients experience synkinesis, a phenomenon in which the damaged nerve grows back to the wrong areas and cause misdirected muscle responses, such as tears when laughing or chewing; or eye blinking eye when talking or chewing.

"As the nerve grows back, it doesn't grow back to the right target," said Dr. Rhee. "When you smile or eat, your eye closes. Or when you close your eye your mouth twitches," describing the effects of synkinesis.

Botox, often used to relax facial muscles, can help relieve some the effects of synkinesis. "What we do is selectively weaken some of the muscles that are spastic so the synkinesis is less pronounced," Dr. Rhee said.

Progress has also been made for those who suffer from prolonged facial paralysis due to Bell's palsy. Dr. Rhee and his colleagues now have patients work with a facial retraining specialist for biofeedback and physical therapy to reduce spasticity and retrain the brain to optimize altered facial muscle movements.

Dr. Rhee explained that ideally, physical therapy should be initiated early in the recovery process to attempt to minimize the synkinetic effects of Bell's palsy.

"There are some studies to suggest that this type of intervention can help in the ultimate outcome, versus no intervention at that time. If you have the physical therapy and biofeedback therapy early on, you may have less synkinesis than those patients that do not have the therapy at that time during recovery," Dr. Rhee said.

"They think with the biofeedback and retraining, the patient is trying to direct the nerve fibers back to their appropriate target," Dr. Rhee added. "The idea of intervention potentially is to get the nerves to direct themselves to the right target."

Prognosis Varies According to Severity
The prognosis for individuals with Bell's palsy is generally very good. The extent of nerve damage determines the extent of recovery. 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.

Patients who experience partial weakness are the most likely to have a full and complete recovery. Even if patients have areas of complete paralysis but begin to regain movement within three weeks or so, "they most likely will have no residual effects from the event," Dr. Rhee said. "If they show signs of coming back between three weeks and three months, they will most likely have some residual effects from the Bell's palsy."

"When people who come in with early improvement, although they are still very worried, I tell them that chances are things are going to be just fine, they just need more time," Dr. Rhee said.

Dr. Rhee practices at the Froedtert & Medical College of Wisconsin Otolaryngology and Communication Sciences Clinic, the Zablocki VA Medical Center, the Otolaryngology Clinic at Greenway, and the Surgicenter of Greater Milwaukee.

This article includes information from the National Institute of Neurological Disorders and Stroke.

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.