For an unknown reason, the vast majority of cases affect those between the ages of 19 and 60 and onset is often overnight. It disproportionately affects diabetics, those with upper respiratory ailments like the cold or flu, those who are pregnant, or people who have high blood pressure or are obese.
Bell’s Palsy; Possible Causes
Sir Charles Bell, a 19th-century Scottish surgeon, first described the strange malady that seemingly struck out of nowhere. He wrote about the seventh cranial nerve, the facial nerve, and its influence over different facial muscle groups.
Here’s a little anatomy lesson for you. The 7th cranial nerve originates in the spinal cord. It is the seventh set of nerves, starting from the top, that makes its way between the cervical vertebrae, travels through the skull, beneath the ear and then to muscles on both sides of your face.
This nerve controls facial muscles, lacrimal (tear) glands, salivary glands and a small bone in the middle ear called the stapes, which is responsible for muffling sounds, and transmits taste sensations.
The cause of Bell’s palsy is undetermined, though many scientists believe it can be traced to the same virus that causes cold sores, mononucleosis, chicken pox or shingles -- the herpes simplex virus.
In most cases of the illness, inflammation of the seventh cranial nerve is thought cause facial paralysis. In reaction to an infection, the nerve becomes inflamed, causing damage to the fatty covering (myelin) of the nerve as it is compressed by the bony canals it travels through in the skull. This causes disruption of brain signals to facial nerves affecting motor control and typically ends with paralysis on one side of the face or rarely, both sides. Symptoms may appear after a cold, ear infection or eye infection.
Symptoms of Bell’s Palsy
Because of the complexity of the facial nerve and its travels through the skull and head, damage to it can lead to many problems. The main symptom is sudden weakness or paralysis on one side of the face, causing the eyelid and corner of the mouth to droop or pull up.
Other symptoms include twitching, drooling, difficulty closing the affected eye, dry eyes or mouth, excess tearing of the eyes, loss of ability to taste, and numbness in the affected area of the face. Sufferers often wake to these Bell’s palsy symptoms because they come on suddenly and are often noticed in the morning.
Symptoms tend to reach their peak in about 48 hours but in the meantime can lead to significant facial distortion. Other common symptoms consist of ringing in one or both ears, difficulty eating or drinking, headache, pain and discomfort around the jaw and behind the ear, dizziness, impaired speech, and hypersensitivity to sounds.
Though these signs are similar to a stroke or transient ischemic attacks, slight brain disturbance similar to a mini-stroke, there is no link to Bell’s palsy. But care must be taken to rule out stroke, Lyme disease or tumors.
Diagnosis and Treatment
Diagnosis of Bell’s palsy is based on the patient’s symptoms present during a physical examination. Surprisingly, there isn’t a definitive test for a diagnosis of this disease. So the patient should be proactive and ask questions about short- and long-term prognosis. The physician typically will perform a physical a neurological exam to check facial nerve function. Other tests could be ordered if the cause of the sudden onset of Bell’s palsy remains unknown, such as blood tests to rule out bacterial infection, and MRIs or CT scans.
Treatment
In mild cases of Bell’s palsy, symptoms generally subside within approximately two weeks without treatment. Most recover within three months. Facial function was completely restored within six months in 70 percent of Bell’s palsy patients who experienced complete paralysis of one side of the face. Of those patients with partial paralysis, 94 percent of them recovered within six months.
Steroids like prednisone, which fight inflammation and swelling, have been used successfully in these cases. The use of prednisone is controversial because Bell’s palsy often resolves on its own, so some researchers say the use of the steroid is not necessary. But a 2012 report concluded that steroids are highly beneficial for increasing the likelihood of recovery of the facial nerve function in new-onset Bell’s palsy.
Guidelines for directing prednisone application prescribes its use within the first 72 hours, up to a week in some studies, for it to be maximally effective. One survey showed that the oral steroid significantly shortened the duration of episodes of Bell’s palsy.
Other non-drug treatments for patients are physical therapy, facial exercises, neuromuscular retraining and acupuncture. There is one controversial aspect of physical therapy: Some experts say not to start exercising your facial muscles right away. The thought behind this is that you may inadvertently stimulate the “wrong” muscles to jump in and help with certain facial movements. Over time, these movements may become automatic. If you are worried about your facial muscles atrophying quickly, they don’t -- so no worries there.
Synkinesis is also a concern with this illness. This phenomenon occurs when regenerated nerve endings implant themselves into the wrong facial muscles. This causes movement in other parts of the face that happen simultaneously as other normal movements are occurring. An example of this would be your brain sending a signal to smile, and as you smile, your eye also closes. But with appropriate and specific physical therapy training, muscles can be retrained to react normally.
Thankfully, Bell’s palsy is a rare disease, but it remains a bit of a medical mystery. Further research into the causes and treatment of this disease is needed, but with proper and immediate diagnosis of this illness, a patient’s prognosis is very good.